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AD-A153 443 THE CONVERSION OF SMALLER BORANE FRAGMENTS TO LARGER 1/1 

STRUCTURES SVSTEHATI. . <U) UTAH UNIV SALT LAKE CITV DEPT 
OF CHEMISTRV R H PARRV ET AL. 31 DEC 94 
UNCLASSIFIED ARO-18151. 14-CH DAAG29-81-K-8181 F/G 7/2 NL 





































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BEFORE COMPLETING FORM 

I. REPORT NUMBER 2. GOVT ACCESSION NO. 

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3. RECIPIENT'S CATALOG NUMBER 

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A. TITLE («nd Submit) 

The Conversion of Smaller Borane Fragments to 

Larger Structures - Systematics of Boron 

Hydride Reactions 

S. TYPE OF REPORT « PERIOO COVERED 

Final Report 

19 June 01 - 31 Dec. 84 

6 PERFORMING ORG. REPORT NUMBER 

7. AuTHOAO) 

Robert W. Parry and Goji Kodama 

8. CONTRACT OR GRANT NUMBER!*) 

Contract DAAG-29-81-K-0101 

S. PERFORMING organization name and address 

Department of Chemistry, University of Utah 

Salt Lake City, UT 84112 

10. PROGRAM ELEMENT. PROJECT, TASK 
AREA A WORK UNIT NUMBERS 

11. CONTROLLING OFFICE NAME AND ADDRESS 

U. S. Army Research Office 

Post Office Box 12211 

Reseprrh Tripnplp Part Nr "777170 

t2. REPORT DATE 

31 Dec. 84 

IS NUMBER OF PAGES 

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»«. supplementary notes 


The view, opinions, and/or findings contained in this report are 
those of the author(s) and should not be construed as an official 
Department of the Army position, policy, or decision, unless so 

Hpri gnat-erl hv other rinrnmpnf a f j nn . 


IS 


KEY WORDS fConllnw* on rmemrma mtdm If nacassmry and idantlty by block nunbirj 

Boranes; Borane framework expansion; Diborane(4); Diborane(C); Triborane(7); 
Tetraborane(S); Tetraborane(lO); Pentaborane(9); Pentaborane(ll); Hexaborane(lO); 
Boranes, Lewis base adducts of; Tri boron Cation; Tetraboron cation; p-(dichloroboran- 
yl)pentaborane(S); 2-(dich1oroboranyl)pentaborane(9); Bis(trimethyl phosphine)- 
'diborane(4); Bis(trimethylphosphine)-diborane(4), metal complexes of; Triborane(7)- 


over 


26. ABSTRACT f«o rovorwo ot* H MmMT Wwllf, Oy block ntmibor) 

The synthesis and reaction chemistry of B4HS adducts of strong bases including 
trimethylphosphine, the boron framework expansion through the use of B2>!4'2PMe3, 
the synthesis of polyboron cations including B 3 H6-2PNe 3 and B4H7"2PHe3 + , and the 
coordination chemistry of B2N4*2PMe 3 are summarized. Described also are the 
synthesis of isomers of dichloroborylpentaborane(9), the reaction chemistry of 
b 3^7 PHj, anomalies in the reaction of 641:70 with bases, the deuteration of 
triborane adducts and the deprotonation of B5H9 with'solid KOH. 


DO , 


FORM 
JAM 71 


1473 


EDITION OF * NOV «ft It OBSOLETE 


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SECURITY CLASSIFICATION OF THIS PAGE ("BRw, Dmtm Bnlorod) 





SSCUFlTY CLASSIFICATION or Twit RAOCfWhi Q«l« tnlmr^) 

19 Continued: 

d 7 ; Phosphine-triborane; phosphine-tetraborane; Hexahydrobis(trimethylphosphine)- 
triboron(l+); Heptahydrobis(trimethylphosphine)tetraboron(l+); Tetraborane(IO), 
reactions with Lewis Bases. 



UNCLASSIFIED 


security classification of this FAoen»>>*n ©•«• *«»•»»<; 











THE CONVERSION OF SMALLER BORANE FRAGMENTS 

TO LARGER STRUCTURES - SYSTEMATICS OF 

BORON HYDRIDE REACTIONS 

FINAL REPORT 

ROBERT W. PARRY 
AND 

GOJI KODAMA 

December 31, 1984 

U.S. ARMY RESEARCH OFFICE 

f DAAG 29-76-G-0120 | 
iDAAG 29-79-C-0129 J 
DAAG 29-81-K-0101 

THE UNIVERSITY OF UTAH 
SALT LAKE CITY, UTAH 

Approved for Public Release; 
Distribution Unlimited. 



















Table of Contents 


Background and Objectives. 

Summary of the Results 

A. The Synthesis, Characterization, and Reactions Chemistry 

of Base Addition Compounds of B 4 H 3 . 

B. Boron Framework Expansion through the Use 

of & 2 H 4 * 2 PMe 3 . 

C. Synthesis of Polyboron Cations. 

D. The Coordination Cnemlstry of B 2 H 4 * 2 PMe 3 . 

E. Miscellaneous Contributions. 

References. 

Publications and Technical Reports. 

Participating Scientific Personnel. 































Background and Objectives 


Stock's early syntheses of boron hydrides Involved the reaction*of a 
rather poorly defined magnesium boride with aqueous phosphoric acid . 1 
Miserable yields of a hydride mixture containing large percentages of higher 
hydrides Mere obtained. All subsequent procedures, based largely on the Mork 
of Schleslnger, Brown, Burg, and their coworkers 2 * 8 as well as some conmerclal 
programs , 4 gave BgHg as the sole Initial product. Higher boranes 
(particularly those needed for the synthesis of carboranes) are currently made 
from dlborane by thermolysis. Through proper selection of reaction conditions 
and equipment B 4 Hiq, B 5 H 9 , B 5 H 11 , or B^qHi 4 can be prepared In fair to good 
yields , 5 but the processes are very difficult and expensive commercial 
operations. Three other rather generalized processes for converting B 2 h 6 to 
higher hydrides have been of Interest In recent years. The first of these , 6 
builds on earlier work of Hough, Marshall, Hunt, Hefferan, Adams, and 
Makhlouf 7 of Callery Chemical Company. The processes Involved the pyrolysis 
of [R 4 IOBH 4 to yield This Is follwed by the opening of the 

B 10 H 10 ~ 2 c *9* with HC1 1n HQ»*1d (C 2 H 5 ) 2 S to give B 1 qH 12 , 2S(C 2 H 5 ) 2 . From the 
latter diethyl sulfide adduct, carboranes can be obtained. Yields are 
marginal. 

A second process Involves the reaction of NaBH 4 with BgHg. Following the 
early work of Hough and Edwards 8 on the reactions of BgHg with sodium amalgam 
to give NaBH 4 and NaBgHg, Gaines showed clearly that BgHg reacts directly with 
NaBH 4 to give NaBgHy and NaB 3 H 8 . 9 Muettertles carried the process further 10 
and obtained NaB^H^ from NaBH 4 and B 2 Hg under different conditions. This 
general process has been developed beautifully In a fundamental sense by Shore 
and Ms students who have been able to build up large borane anions In a 















stepwise fashion by adding a borane group (Lewis acid) to a B-B bond In 
selected boron hydride anions . 11 Reactions such as those shown here were 
carried out: 

®4^9~ + ^2 8 2 Hg * B 5 B 12~ 

B 5 H 8 " + ^B 2 H 6 ♦ B 6 H n " 

Addition of a proton to the anion generated a neutral borane containing one 
boron more than the starting material. In some cases H 2 mas lost. A related 
process was developed In recent years by Dunks and Ordonez 1 * at Union Carbide. 

Shore and his coworkers further developed a new, systematic syntheses of 
b 2 h 6» b 4 h 10> b 5 h h» and B 10 H 14 which Involves the use of polyboron anions . 13 
A hydride Is abstracted from the anion (BH 4 ", B 3 Hg", B 4 H 9 ", or BgHjg") by use 
of a Lewis acid BX 3 , and the resulting neutral borane species combines with 
BH 3 which Is available from another source. The yields are excellent, and 
this process Is the most convenient laboratory method presently available for 
the preparation of higher boranes. 

The last process of Interest might be considered a more generalized form 
of the foregoing reactions Involving borane anions and dlborane. If one 
replaces a hydride of BH 4 ~ with a general Lewis base, the molecule LBH 3 is 
formed, where L Is a ligand or base such as R 3 P, R 3 N, or R 2 S. This species, 
like BH 4 ”, will also pick up BH 3 to give larger borane units. For example, 
the following reactions can be compared: 

la) BH 4 ♦ V 2 B 2 Hg — B 2 H 7 

lb) lbh 3 ♦ Vz b 2 h 6 —► lb 2 h 6 

2a) B 2 H 7 ~ ♦ V 2 B 2 Hg -► B 3 H 8 ‘ + H 2 

2b) LB 2 H 6 ♦ V 2 B 2 H 6 -► B 3 H 7 L + H 2 

This process has some literature precedent. Some years ago Muettertles 10 
reported that the reaction of (CH 3 ) 2 S with B 2 Hg at 70*C gives B 9 H| 3 ’S(CH 3 ) 2 . 






Several other conversions of similar type have also been reported. 

In 1962 Burg** reported that hexamethylenetetramine and several other 
Lewis bases act catalytlcally in the conversion of B 5 Hu to BgHjQ, BgH 15 , and 
b 10 h 14' In considering this process It Is reasonable to postulate that B^H^ 
reacts Initially with a Lewis base to give an adduct of general form LB x H y 
which can then react with additional B 5 H 22 (or another base borane adduct In 
the system) to give boron framework expansion. The reaction between and 

Lewis bases was thus of considerable Importance In delineating the path for 
the expansion of the boron framework. Earlier reports on the reaction of 
B 5 H 11 with bases such as NR 3 had described a confusing process from which no 
base-borane products could be characterized.Thus our initial work focussed 
on the reactions of B 5 H 11 with Lewis bases. Subsequent work involved a study 
of the reactions of the products obtained from the base reaction with BH 3 
units or other boron sources. The goal of the study was an expansion of the 
boron framework. 











II. Summary of the Results 


Points from earlier work In this laboratory which are pertlnent'to the 
problem of boron framework expansion are emphasized. Details of past work are 
available In publications which are listed elsewhere In this report. A total 
of 21 papers describing scientific developments resulting from ARO sponsorship 
have been published. 

A. The Synthesis, Characterization, and Reaction Chemistry of Base 

Addition Compounds of B 4 Hg. 

Because of the reported ability of bases such as hexamethylenetetramine 
and trl methyl amine to catalyze the conversion of B5HH to higher boranes the 
reaction of BgHn with Lewis bases was studied In some detail. The arguments 
Of symmetrical double bridge cleavage suggested that the BgHjj molecule should 
be broken Into BHj-NMeg and B 4 Hg"NMe3 by trlmethylamlne. Still all attempts 
reported In the literature to recover B^g’NRg from the B5HH-NR3 reaction 
system had been unsuccessful. On the other hand. Burg and Splelman 16 had 
Isolated H3BCO and HgB 4 C 0 from the reaction between B5H11 and CO. The two 
foregoing facts suggested that weak bases such as CO could form Isolatable 
6483 complexes, but strong bases such as trlmethylamlne would degrade the B 4 H 8 
fragment to give species such as BH 3 NMeg and (H-8) n units. Given the 
foregoing hypothesis the Isolation and characterization In this laboratory of 
B 4 Hg'NMe 3 17 and B 4 Hg*N 4 (CH2)g 18 as fairly stable , white crystalline solids 
were of singular Importance. Contrary to all earlier beliefs. It was shown 
that adducts of the form B 4 Hg base are very stable toward Lewis bases, but are 
very sensitive toward Bronsted acids. This acid sensitivity Is so high that 
the Bronsted acidity of BgHji Itself appears enough to degrade the base- 











borane, B4H 8 *NMe3 compound. Thus to avoid the presence of free B5H11 and 
B4Hg*NR3 In the same vessel B5H11 must be added slowly to the solution 
containing the free base. From this system stable B 4 Hg*NR3 can be isolated. 
If, however, NR3 Is added to a solution containing free B5K11, the B4Hg‘NR3 is 
degraded Immediately by excess B 5 h u . This small point of technique Is 
crucial to the preparation of most stable B4Hg base compounds. 

Stronger Lewis bases such as PMe 3 are even more effective In 
stabilization of borane acids than are the somewhat weaker bases like NMe 3 . 

The reaction of BgHn and PMe 3 gives a new hypho-class dibase adduct of 
B4H3. 19 The equation Is: 

( 1 ) B 5 H n + 3 PMe 3 -► B 4 Hg* 2 PMe 3 + BH 3 ‘PMe 3 

Because the strong base diadduct. B 4 Hg- 2 PMe 3 , Is so stable, the monoadduct, 
B4Hg*PMe3> can only be prepared by Indirect means. The removal of a base such 
as PMe 3 from the djadduct 20 and the removal of an H” from the formally 
analogous compound ^Hg’PMeg'H - ] 20 * 21 provide workable routes to B4H 8 *PMe 3 . 
Yields In all cases are over 90 S. 

( 2 ) B4Hg*2PMe3 + V2B£Hg CH C T"^ *^ e 3 + BH 3 *PMe 3 

, 25®C 

( 3 ) B4Hg'PMe3*H + V2 B2Hg CH Cl * * "^®3 + ®^4 

111 2 2 

^Hg’PRg] 

In addition, the monoadduct B4Hg a PMe 3 can be built up by combination of 











nailer borane units.* Equations for two such processes are: 


( 4 ) B 3 H 7 ‘THF + B 2 H 4 * 2 PMe 3 gj C T» B 4 H 8 ‘PMe 3 + BH 3 ‘PHe 3 ♦ THF (ref. 20 ) 
where THF * tetrahydrofuran, 

( 5 ) [B 3 H 6 - 2 PMe 3 3 + [B 3 Hg]" + NMe 3 * 


B 4 H 8 *PMe 3 + BH 3 ’PMe 3 + BH 3 ‘NMe 3 (ref. 20 . 22 ) 


The existence of both B 4 H 8 * 2 PR 3 and B 4 H 8 ‘PR 3 suggested that the formation of 
mono and dibase adducts of B 4 H 8 should be a general phenomenon. One can 
postulate that stronger bases form tne dibase adducts preferentially while 
weaker bases form the monoadducts more easily. This generalIzaton has been 
verified. The monoadduct B 4 H 8 *NMe 3 will add one mole of NMe 3 at - 40 *C to give 
B 4 H 8 - 2 NMe 3 . 17 The second mole of NMe 3 Is lost at higher temperatures. Other 
bases such as NMe 2 H, NMeH 2> and PMe 3 will also add to B 4 H 8 NMe 3 to give mixed 
adducts. 2 ^ As expected. It Is easier to add NMe 3 to B 4 H 8 *PMe 3 than It Is to 
add PMe 3 to B 4 H 8 *NMe 3 . It Is suggested that at low temperatures the two 
different bases appear to exhibit site preference. Base L will add to a 
different position on B 4 H 8 than will base l*. Thus at lower temperatures the 
reactivity of B 4 H 8 *L toward L’ can be different than that of B^g.’L.' toward 



•Preparation of new compounds such as CB4H9*PR 3 3 ~» B 2 h 4 * 2 PR 3 and [B 3 H 8 * 2 PR 3 ] + [B 3 h 8 ]~ are 
described elsewhere in this report. 


6 








L, even though the empirical formulas of the two final diadducts are the same. 
At higher temperatures the compounds become fluxlonal such that positional 
Isomers become Identical. When a base Is lost from the fluxlonal moTecule, 
the weaker base goes first. For example, E^Hg'CO will add PMe 3 at - 40 *C to 
give i^Hg'CO'PMeg. 24 At higher temperatures this compound decomposes to give 
B4Hg*PMe3 plus CO. Direct NMR evidence supporting the existence of low 
temperature Isomers, t^Hg'L'L', 20 was obtained by studying the diadducts 
B4Hg'PMe3*NMe3. The existence of Isomers at low temperature and the 
fluxlonallty at higher temperatures are clearly seen In B4Hg*PMe3*NMe 3 . 20 
Spectra for the compound suggest that for 64%, the bases PMe3 and NMe 3 will 
bond preferenetlally to the sites shown. 



The boron framework of B4Hg-P(NMe2)3'PMe 3 Is not fluxlonal even at room 
temperature, but hydrogen atoms do migrate. 20 

The relatively weak base PH3 will add directly to BgHji at - 95 # C . 2 5 This 
compound reacts with additional PH3 above - 95 *C to give the expected 
monoadduct: 

(6) B 5 H U + PH 3 ~ 95 °^» BgHn'PHj 


( 7 ) 


B 5 H U -PH3 + PH3 


above 


b 4 h 8 -ph 3 + bh 3 -ph 3 


If excess PH3 is not present, the low temperature BgH^ addition compound. 


b 5 h 11’ ph 3» decomposes In accordance with the equations: 

-4q 0 r 

2B 5 Hii*PH 3 B 4 H 8 ‘PH 3 + BH 3 -PH 3 + B 5 H n 

( 8 ) 

B 5 h 11' PH 3 B 4 H 10 + "PH 2 BH 2 h , and V 2 B 2 H 6 + B 4 H 8 *PH 3 

Writing B 4 H 9 " as B 4 H 8 *H” suggests that direct addition of PMe 3 to B 4 H 9 ~ 
should give the new hypho-class anion [B 4 H 8 *H"*PMe 3 3. The reaction has been 
verified. 21 P(NMe 2 ) 3 will also add to B 4 H 9 ~. The phosphine adducts decompose 
above 0*C. An NH 3 adduct exists below -40*C. 2 ® All are fluxlonal. The 
pertinent equations are: 

(9) KH + B 4 H 10 -► KB 4 Hg + Ho 

THF 

(10) KB 4 H 9 + PMe 3 -► KB 4 H g ’PMe 3 . 

THF 

The existence of the compound KB 4 h 9 *NH 3 at -40 # C now explains why the 
preparation of the dlammonlate of tetraborane, [H 2 B(NH 3 ) 2 3 + [B 3 H 8 3“ Is so sensitive to 
experimental conditions of synthesis. When the synthesis of B 4 H 1 q*2NH 3 
was first achieved, over 25 years ago, the following experimental points were 
Identified as crucial: 27 

(1) The reacting ratio NH 3 /b 4 H 10 should NOT exceed 2. 

(2) The reaction must be run In a solvent, preferably Et 2 0. 

(3) The reaction mixture must be digested for one to two weeks at -78*C. 

If these conditions are not carefully observed, a competing set of processes 
can occur. The pertinent equations are: 

(11) B 4 H 10 + NH 3 -► NH 4 + B 4 H 9 " 


6 






then 

(12) B 4 H 9 " ♦ NH 3 -► B 4 H 9 *NH 3 ' k _ 40 o c 

Decomposition 

While reaction 11 Is reversible, reaction 12 Is not and decomposition products 
are produced. It Is Interesting that NH 4 *[B 4 H 9 ‘NH 3 3~ represents another form 
of the "dlammonlate of tetraborane." 

B. Boron Framework Expansion Through the Use of B»Ha‘2PMe?. 

Using an analogy suggested many years ago In this laboratory by Parry and 
Edwards . 28 one notes that a 3-center bridge bond B H B can serve to bind 
two atoms together just as a 2-center Lewis base ♦ Lewis acid linkage generates an 
Interatomic bond. In terms of this analogy the molecule B 2 H 4 * 2 PMe 3 (A) 
can be considered to show a formal relationship to diamine molecules (B): 


H 

1RR 


r 


4f 

H 

'rr 

(A) 

(B) 


It has been known that some of the diamines, e.g. o-phenylenedlamlne , 29 react with 
dlborane through a non-symmetrical cleavage of the double bridge to give Ionic 
products. 



9 








In « completely comparable manner B 2 H4-2PMe 3 will chelate to a coordination center, 
and thus It will react with dlborane through a non-symmetrical cleavage of the 
double bridge bond to give an Ionic product: 



At room temperature the V2 mole of B 2 Hg Is released; B3H 7 -PR3 and B^-PI^-are 

produced. 3 ° 



25 e C 


B 3 H ; -PMe 3 ♦ BH 3 -PHe 3 ♦ 


The net effect of this set of reactions Is that an [HBPMe 3 ] unit from B 2 H4*2PMe 3 is 
added to B 2 Hg to give 83H 7 *PMe3. In short, the boron framework has been increased 
by one boron atom. This expansion reaction Is quite general for simpler boron 
hydrides or for borane fragments which are linked to a relatively weak base. In 
most cases the nature of the Intermediate Is not as clear as It Is for B 2 h 6 , but the 
net addition of an [HBPMe3] unit from the B 2 H4*2PMe3 ligand Is quite clear. 

The following equations are Illustrative: 


Molecule 


Source 


Receiving 

+ 

ot 


Boron 


[BHPMe 3 ] 

♦ New Adduct + BH3’PMe3 


a) B 3 H 7 'THF + B 2 H4*2PMe 3 ♦ B4H 8 'PMe 3 * + BH 3 -PMe 3 + THF (ref. 20 ) 


* B 4 H 8 *PMe 3 Is B 3 H 7 ♦ [HBPR3] 










b) B 4 H 8 -PH 3 + B 2 H 4 ’2PMe 3 ♦ B 5 H 9 ‘PMe 3 * ♦ BH 3 *PMe 3 + PH 3 (ref. 25) 

* B 5 H 9 *PMe 3 Is B 4 H 8 + [HBPMe 3 ]. 

c) B 5 H 9 -PMe 3 + B 2 H 4 -2PMe 3 ♦ B 6 H 10 *2PMe 3 * + BH 3 *PMe 3 (ref. 31) 

* BgH 10 -2PMe 3 is B 5 H 9 *PMe 3 + [HBPMe 3 3 


d) B 5 H 9 + B 2 H 4 *2PMe 3 -► , ‘B 6 H 10 -PMe 3 “ ♦ BH 3 *PMe 3 


(ref. 31) 


The B 6 H 1 Q*PMe 3 appears to be the high temperature form of B 8 HiQ*PMe 3 described 
earlier.32 It decomposes above 25*C. 

e) B 5 H n + B 2 H 4 -2PMe 3 ~ 8Q X "BgH^-PMey + BH 3 -PMe 3 (ref. 33) 


—►BgHg + BH 3 * 
—►BcHo'PMe^ + 


*—►BjH 9 *PMe 3 +V2B 2 H 6 

Although B 5 H 9 PMe 3 will add HBPMe 3 , smaller borane adducts of strong 
bases will not undergo the addition of [HBPMe 3 ]. For example: 

f) BH 3 *PMe 3 + B 2 H 4 *2PMe 3 ♦ Mo Reaction 22 


g) B 3 H 7 -NMe 3 + B 2 H 4 *2PMe 3 

h) B 3 H 7 -PMe 3 + B 2 H 4 -2PMe 3 
1) B 4 H 8 -NMe 3 + B 2 H 4 *2PMe 3 
j) B 4 H 8 -PMe 3 + B 2 H 4 *2PMe 3 


No Reaction* 
No Reaction* 


No Reaction* 


No Reaction- 3 


So far the only case where a borane fragment linked to a strong base adds an 
HBPMe 3 1 $ seen In equation c, where the larger boron fragment B 5 H 9 *PMe 3 adds 
[HBPMe 3 ], but still retains Its attached PMe 3 . Note that, whenever addition 
of [HBPMe 3 ] occurs, the stable species BH 3 *PMe 3 is also a product. The 
formation of this very stable substance Is one of the driving forces of the 
[HBPMe 3 ] addition reaction. 










C. Synthesis of Polyboron Cations. 

While polyboron anions are very well known, polyboron cations are not 
well defined. A number of such polyboron cations have now been prepared In 
this laboratory and are well characterized. The combination of polyboron 
cations and polyboron anions to give larger borane derivatives seemed to be a 
worthwhile avenue for exploration. 

1. 2PMeO+ [B?H 7 3~ . 

The synthesis of the [B 3 H 8 * 2PMe 3 ] + cation from B2H4*2PMe 3 by non- 
symmetrlcal cleavage of B2H5 has been described In part IIB. A similar non- 
symmetrical cleavage of B 4 h 10 w111 9 tve £ B 3 H 6* 2PMe 33 + £B 3 H 8 ]“. 30 

Another general route to boron cations was suggested by Benjamin 34 et al . 
In 1972. They prepared derivatives of [H 2 Bt 2 ] + of the general form C^BLL']* 
by use of [0 3 C] + [BF 4 ]”, the trltyl cation. This cation will abstract a 
hydride Ion from BH 3 *L to give [H 2 B'l] + [BF 4 ]" and 0 3 CH. If this process Is 
done In the presence of a base, L’, cations such as [t^BLL 1 ]* are obtained. 
This general process can be extended to synthesize polyboron cations. 

2. The [BdHv 2 PMeQ+ Cation . 

Treatment of the newly synthesized B 4 H 8 ‘ 2 PMe 3 with [ 03 C]* [BF 4 ]* resulted In 
the following reaction : 35 

B 4 Hg' 2 PMe 3 ♦ [C03] + CBF 4 ] ♦ CB 4 H 7 ’ 2 PMe 3 ] + CBF 4 ] ♦ 0 3 CH. 


The boron containing product Is a stable solid at room temperature If air Is 
excluded. It has been characterized by Its ^B, 31 P, and NMR spectra and 








by a boron analysis. On the basis of Its NMR spectra the following structure 
Is suggested: 


The cation Is Isoelectronlc and Isostructural with B 4 Hg~ and B 4 Hq L. 

Presumably the hydrogen atoms of B 4 Hg* 2 PMe 3 are iMde quite hydrldlc through 
attachement of the two PMej groups to the borane fragment. Under these 
conditions the hydride anion can be removed by the trltyl group. Even other 
less powerful hydride abstracting species will remove a hydride from 
B 4 H 8 * 2 PMe 3 . For example the following equation also goes as written: 

B4Hg'2PMe3 + J^Hy'THF ♦ [B4H7*2PMe3] + CB3H3] ♦ THF 

3. Other Polyboron Cations . 

Two other cations have been tentatively identified as products of the 
trltyl-hydride extraction procedure. These are formed by the processes: 

BgHg^PMeg + [ 03 C] + [BF4] * [BgHg’ 2 PMe 3 ] + [BF 4 3 ♦ 03CH. 

2 BH 3 *PMe 3 + [03C3 + CBF 43 ♦ [Me3P*BH2-H”BH2’FMe33 + [BF 4 3 + BgCH. 

While characterization data are quite strong, more complete characterization 
Is still In progress. 

D. The Coordination Chemistry of B^^PMe^ . 

In section IIB the compound B 2 H 4 * 2 PMe 3 was compared to a diamine molecule 



13 













and It was proposed that a three center bridge bond can be used to 

bind a ligand to a positive center just as a Lewis electron pair can be 
used. If this premise is adopted, reaction between neutral B2H4*2PMe3 and 
metal salts such as ZnC1 2 would be anticipated. 




"Si 

I I 

H— B-B—H 


PVej 


PMe s 


The compound has been completely characterized. An X-ray study has been 
completed. Reports from this laboratory on the ZnCl2*B 2 H4*2PMe3 complex are 
now In the literature. 36 

The coordination of borane fragments to metals through B^ M bonds Is 
fairly well established for anions . Thus complexes of B 3 H 8 ~ are well 
recognized 37 * 38 and the complex substance Mn 3 (C 0 )iQB 2 H 7 39 may be considered as 
a complex of B 2 Hg~ 2 In which the normally unstable anion is stabilized by 
coordination. On the other hand, the ability of a neutral borane adduct to 
coordinate with a metal had not been demonstrated previously. Other neutral 
borane adducts such as BH 3 *PMe 3 and B 3 H 7 *PMe 3 did not react with ZnCl 2 . 

apparently both the "H.H chelating bite distance" and the electron density 

on the hydrogen atoms are Important factors In the formation of these chelate 
coordination compounds. Preferential complex formation may well provide 


Improved routes for the separation of the components In a complex reaction 










A number of smaller, yet significant, contributions have been made during 
the course of our Investigations under ARO sponsorship. These are enumerated 
briefly here. 

1 . D1cnlorobory1pentaborane(9), BC1 2 * 85113 . 

Three Isomers of BC1 2*85113 are possible depending upon the positions of 
the BC1 2 group attached to the pyramidal structure of the pentaborane 
framework. These are 1-, 2-, and »-1somers as Illustrated In the figure. 



l-ltomer Z-Isomer w-Isomer 


The l- 1 somer was prepared In Gaines' laboratory at the University of 
Wisconsin 40 and the y-lsomer was prepared In our laboratory , 41 and both were 
reported in the same year. The missing 2-lsomer Is now prepared, and has been 
characterized . 42 The steps for the 2-1somer preparation are 









R »0 BCK or BF 3 

y-BCl 2 -B s H 8 -=-+> 2 -(R 2 0 -BC 1 2 )-B 5 H 8 - _ R g -- = -» 2 -BCl 2 *B 5 H 8 

The 1X B and *H NMR spectra and the mss spectral data confirmed the Identity 

of 2 -BCl 2 *BgH 8 . Like the y-lsomer, the compound Is very sensitive to. air. 

Bromine cleaves the external B-B bond to give 2 -BrB 8 H 8 , and ethylene Inserts 

to form 2 -(BC 1 2 CH 2 CH 2 ) 'BgHjj. 

The study of reaction chemistry of both y- and 2-BC1 2 *B5H 8 Is being 
pursued. The reaction with dlborane Is noteworthy. While the resulting 
mixtures from the treatment of 2 - 1 somer with B 2 Hg consisted of the components 
which appeared to contain the B5 framework In their structures, those from 
the y-Isomer contained substantial amounts of BiqH^. 

2 . Reaction Chemistry of 83117^3. 

The reaction chemistry of B 3 H7*PH3 has been compared and contrasted with 
the previously defined reaction chemistry of BH3*PH 3 with NH3. In general 
differences In behavior can be understood In terms of the greater acid 
strength of B3H7 as compared to BH 3 . Details are being published. 43 * 44 


3 . Anomalies In the Reactions of B4H1Q With Bases. 

When B4H10 reacts with one mole of PMe 3 In THF one would expect the 
stronger base, PMe 3 , to combine with the stronger acid, B3H7, and the weaker 
base, THF, to combine with the weaker acid, BH 3 . The process expected Is: 




PMe, 


THF 


•THF ♦ 


B 3 H 7 .PHe 3 


When the process was carled out below > 80 *C, the products observed were quite 
the opposite from those expected. The following equation describes our 


16 







observations 


.45 


MlO + PMe 3 + THF * BH 3 *PMe 3 + B 3 H 7 *THF. 

It 1$ now clear that the Initial set of products, B 3 H 7 -PMe 3 and B 3 H 7 *THF are a 
result of reaction mechanism; the observations provide support for mechanistic 
proposals on cleavage of the bridges of B 4 h 10 which were made from this 
laboratory 27 years ago. 27 


%rlv 


vu s " 

I 

H 

t*»4 H l 0 


♦ PM*, 


♦ PM*, 


■:riy* 


M-e 

i 

N 


4^ 


s 4 h 10 -pm* 3 ] 


H H 

M« 3 P-B-^U 

H ' ♦ THF - ! " - * >.BH,-PM*. ♦ B.H--THF 

►U ■ 3 J 37 

t 

The resulting Initial solution containing BH 3 *PMe 3 and B 3 H 7 *THF undergoes a 
slow equilibration at room temperature: 

BH 3 *PMe 3 + B 3 H 7 *THF — ► BH 3 *THF ♦ B 3 H 7 *PMe 3 

The equilibrium constant for this base exchange process was measured and found 
to be 4 a 1 at 25*C. 

Some related reactions of B 4 H 10 have also been studied. 45 


4. The Deuteratlon of Trlborane Adducts . 

The tr1borane(7) adducts of THF and of NMe 3 react with DC1 at -80*C In 
CH 2 CI 2 to give B 3 0 7 *THF and B 3 D 7 *NMe 3 . 45 The compound B 3 D 7 *THF can be 
converted to NaB 3 D 8 47 which can then be converted to ND 4 B 3 Dg. The latter 
compound has potential Interest as a 0 2 source. 





5. The Deprotonation of B^Hq with Solid KOH . 

It has been found that B 5 H 9 can be deprotonated with powdered, commercial 
grade KOH In THF at temperatures below -40*C. Yields of KBgHg are nearly 
quantitative . 48 

B 5 H 9 + 2K0H k + B 5 H 8 ‘ + K0H-H 2 0 









References 


1. Stock, A. “Hydrides of Boron and Silicon", Cornel University Press, Ithaca, New 
York, 1933. 

2. Flnholt, A.E.; Bond, A.C.; Schlesinger, H.I., J. Am. Chem. Soc., 1947, 69, 

1199. 

3. Schlesinger, H.I.; Brown, H.C.; Flnholt, A.E., J. Am. Chem. Soc., 1953, 75, 

1 ■' ■ ■■ — ■ ■ - 

205. Schlesinger, H.I.; Brown, H.C.; Gilbreath, J.R.; Katz, J.J., J. Am. Chem. 

Soc ., J953, _7§» 195. Schlesinger, H.I.; Brown, H.C., J. Am. Chem. Soc ., 

J953, 75. 219. 

4. Rush, J.D.; Carpenter, R.A.; Schechter, W.H.; U.S. Pat. 3,014,059, 1961. 

5. (a) Bragg, J.K.; McCarty, L.V.; Norton, F.J., J. Am. Chem. Soc ., 1951, 73, 2134. 

(b) Clark, R.P.; Pease, R., J. Am. Chem. Soc., 1951, 73, 2132. 

■ ■ - — i " — ■ — — MikAiv — 

(c) Klein, M.J.; Harrison, B.C.; Solomon, I.J., J. Am. Chem. Soc ., 1958, 80, 4149. 

6. Hill, W.E.; Johnson, F.A., Paper presented at the JANAF Meeting, January 
1978. Hill, W.E.; Hosmane, N.S.; Johnson, F.A., Paper presented at the 
4th International Meeting on Boron Chemistry, Salt Lake City/Snowbird, 

Utah, July, 1979. 

7. Marshall, M.D.; Hunt, R.M.; Adams, R.M.; Makhlouf, J.M., J. Am. Chem. 

Soc ., 1967, 89, 3361. Makhlouf, J.M.; Hough, W.V.; Hefferan, G.T., 

Inorg. Chem , J967, 1196. 

8. Hough, W.V.; Edwards, L.J.; McElroy, A.D., J. Am. Chem. Soc ., 1956, 

689. Hough, W.V.; Edwards, L.J.; McElroy, A.D.; J. Am. Chem. Soc ., 

1958, 80, 1828. 

9. Gaines, D. Inorg. Chem ., 1963, 253. 

10. Miller, H.C.; Miller, N.E.; Muettertles, E.L.; Inorg. Chem ., J964, 2* 

1465. 

11. Remmel, R.J.; Johnson, H.D.II; Jaworlwsky, I.S.; Shore, S.G., J. Am. Chem. 












Soc., 1975, 97, 5395. 


12. Dunks, G.B.; Ordonez, K.P., J. Am. Chem, Soc ., J978, 100 , 2555. 

Outer, G.A.; Schaeffer, G.H., 0. Am. Chem. Soc ., 1956, 78, 3546. 

— — — - mm MMMIk ■— 

Hawthorne, M.F.; Miller, J.J.; J. Am. Chem. Soc., 1958, 80, 754. 

■ ■ ■ — 

13. Toft, J.A.; Leach, J.B.; Hlmpsl, F.L.; Shore, S.G., Inorg. Chem.. 1982, 21. 

1 * ■ ■ ■ 

1952. 

14. Burg, A.B.; Kratzer, R., Inorg. Chem ., J962, 2» ? 25 * 

15. See, for example, Adams, R.M. In “Boron, Metallo-Boron Compounds and Boranes," 

Adams, R. M., Ed.; Interscience, 1964, 632. 

16. Burg, A. B.; Splelman, J. R.; J. Am. Chem. Soc ., 1959, J9^, 3479. 

17. Oodds, A.D.; Kodama, G., Inorg. Chem ., J979, 1465. 

18. Kondo, H.; Kodama, G., Inorg. Chem ., 1979, 1460. 

19. Kodama, G.; Kameda, M.; Inorg. Chem ., 1979, 3302. 

20. Kameda, M.; Shlmol, M.; Kodama, G., Inorg. Chem ., J984, 23, In press. 

21. Shlmol, M.; Kodama, G., Inorg. Chem ., ,1983, 22, 1542. 

22. Kameda, M.; Kodama, G., Inorg. Chem ., 1984, 23, In press. 

23. Dodds, A. R.; Ph.D. Dissertation, University of Utah, 1980. 

24. Kodama, G; Parry, R.N., 4th International Meeting on Boron Chemistry, Salt Lake 
City/Snowbird, Utah, July 1979. Paper No. 45. 

25. Jock, C.P.; Kodama, G., 7th Rocky Mountain Regional ACS Meeting, Albuquerque, 
NM, June 1984. Paper No. 67. Manuscript In preparation for publication. 

26. Snow, S.A., Kodama, G.; Parry, R.W.; 183rd ACS National Meeting. Las Vegas, 
March 1982. IN0R 139. 

27. Kodama, G.; Parry, R.W., J. Am. Chem. Soc ., 1957, 1007 . Kodama, G.; Parry, 

R.W., Proc. Int. Congr. Pure Appl. Chem ., J958, 2£, 483. Kodama, G.; Parry, 
R.W., J. Am. Chem. Soc ., 1960, 82, 6250. 

28. Parry, R.H.; Edwards, L.B., J. Am, Chem, Soc ., J959, jlh 3554. 


20 









30. Kameda, M.; Kodama, 6.; J, Am. Chem. Soc ., 1980, 102 , 3647. 

31. Kameda, M.; Kodama, G., Unpublished observation. 

32. Kameda, M.; Kodama, G., Inorg. Chem ., J981, 20, 1072. 

33. Kameda, M.; Kodama, G. t Inorg. Chem ., 1982, _21_, 1267. 

34. Benjamin, L.E.; Carvalho, D.A.; Staflej, S.F.; Takacs, E.A., Inorg. Chem ., 
1970, 9, 1844. 

35. Kameda, M.; Kodama, G., submitted tor publication. 

36. Snow, S.A., Shlmol, M.; Ostler, C.D.; Thompson, B.K.; Kodama, G.; Parry, R.W., 

Inorg. Chem., 1984, 23, 511. 

■ ■ — - ■' —— 

37. Gaines, D.F.; HIldebranddt, S.J. In "Metal Interactions with Boron Cluster"; 

Grimes, R.N., Ed.; Plenum Press: New York, 1982; Chapter 3. 

38. Wegner, P.A. In "Boron Hydride Chemistry"; Muettertles, E.L., Ed.; Academic 

Press: New York, 1973; Chapter 12. 

39. Kaesz, H.D.; Fellmann, W.; Wilkes, G.R.; Dahl, L.F., J. Am. Chem. Soc., 1965, 

■ ■ ■ ~ — ■ — ■ ■ ■■ 

87, 2753. 

40. Gaines, D.F.; Heppert, J.A.; Coons, D.W.; Jorgenson, M.W.; Inorg. Chem ., 1982 
21 3662. 

41. Nelson, M.A.; Kameda, M.; Snow, S.A.; Kodama, G., Inorg. Chem., 1982, 21, 

2898. 

42. Snow, S.A.; Kodama, G., 7th Rocky Mountain Regional ACS Meeting, Albuquerque, 
NM, June 1984. Paper No. 69. Manuscript In preparation for publication. 

43. Bishop, V.L.; Kodama, G., Inorg. Chem ., 1981, ^0, 2724. 

44. DePoy, R.E.; Bishop, V.L.; Kodama, G., 7th Rocky Mountain Regional ACS Meeting 
Albuquerque, NM, June 1984. Paper No. 68. 

45. Shlmol, M.; Kodama, G., Inorg. Chem., 1983, 22, 3300. 

46. Dodds, A.R; Kodama, G., Inorg. Chem., 1977, 16, 3353. 























III. Publications and Presentations Resulting From ARO Supported Research 
A. Publications 

1. "Reactions of Tetraborane(lO) with Mono- and Dimethylamlne." A. R. Dodds 
and G. Kodama, Inorg. Chem ., 1977, M>> 2900. 

2. "Deuteratlon of Tr1borane{7) Adducts with Anhydrous Deuterium Chloride." 

A. R. Dodds and G. Kodama, Inorg Chem ., 1977, 3353. 

3. "Reactions of Hexamethylenetetramine with Boranes." H. Kondo and G. 

Kodama, Inorg. Chem ., 1979, 1460. 

4. "Isolation and Characterization of Tr1methylam1ne-Teteraborane(8)." A. R. 
Dodds and G. Kodama, Inorg. Chem ., 1979, Mi.. 1465. 

5. "Deuterated Sodium Octahydrotrlborate(l-)." M. A. Nelson and G. Kodama, 

Inorg. Chem ., 1979, 18, 3302. 

6. "Bls(trlmethylphospnlne) Adduct of Tetraborane(8)." M. Kameda and G. 

Kodama, Inorg. Chem ., 1979, 18, 3302. 

7. "Unsymmetrlcal Cleavage of Boranes by Bls(trlmethylphosphlne)- 

D1borane(4). Formation of a Triboron Cation." M. Kameda and G. Kodama, 

J. Am. Chem. Soc., 1980, 102, 3647. 

. ■■■ ■ ■ — — ******* ■ 

8. "A Cleavage Reaction of Pentaborane(9). Formation of a New Hypho 

Trlborane Adduct." M. Kameda and G. Kodama, Inorg. Chem., 1980, 19. 2288. 

******* 1 “ 

9. "Formation of the 1:1 Phosphine Adducts of Hexaborane(lO)." M. Kameda and 

G. Kodama, Inorg Chem ., 1981, 20, 1702. 

10. "Trlborane Adducts of Phosphine and Methylphosphlnes." V. L. Bishop and 
G. Kodama, Inorg. Chem ., 1981, 20, 2724. 

11. "Deprotonation of Pentaborane(9) with solid Potassium Hydroxide." M. A. 
Nelson and G. Kodama, Inorg. Chem ., 1981, 20 3579. 

"Reaction of Pentaborane(ll) with B1s(tr1methy1phosph1ne)-D1borane(4)." 


12 . 




13. 


"Preparation and Characterization of (v-D1chlorot>oryl)Pentabor*ne(9) 


M. A. Nelson, M, Kameda, S. A. Snow, and 6. Kodama, Inorg. Chem ., 
1982, 21, 2898. 

AfkfkA ■ — 

14. "Reaction of Hexaborane(lO) with Excess Trlmethyphosphine." M. 
Kameda and G. Kodama, Polyhedron . 1983, 2, 413. 

15. “Preparation and Characterization of Potassium Nonanhydro- 
(trlmethlyphosphlne)tetraborate(l-)." M. Shlmol aned G. Kodama, 
Inorg. Chem ., 1983, 22, 1542. 

16. "Reaction of Tetraborane(lO) with Trimethyl phosphine In Tetrahy- 
drofuran." M. Shlmol and G. Kodama, Inorg. Chem., 1983, 22, 3300. 

17. "Metal Complexes of a Neutral Borane Adducts B2H4*2P(CH3)3." S. A. 

Snow, M. Shlmoi, C. 0. Ostler, 8. K. Thompson, G. Kodama, and R. W. 
Parry, Inorg. Chem ., 1984, 23^ 511. 

18. "Tetraborane(8} Adducts of Strongly Basic Phosphines", M. Kameda, M. 

Shlmol, and G. Kodama, Inorg. Chem ., 1984, 23, 3705. 

19. "Reactions of Hexahydrob1s(tr1methylphosph1ne)tr1boron(l+) 
Octahydrotrlborate(l-) with Lewis Bases. Novel Formation of 
Tetraborane(8) Adducts." M. Kameda and G. Kodama, Inorg. Chem. , 

1984, 23, 3710. 

20. "Novel Coordination of a Neutral Borane Adduct to Nickel(0). 
Formation of NKCO^EBgH^PtC^^]", S. A. Snow and G. Kodama, 
Inorg. Chem. , 1985, 24, In press. 

21. "Synthesis of Heptahydrob1s{tr1methylphosphine)tetraboron(l+) 
Cation", M. Kameda and G. Kodama, Inorg. Chem. , 1985, 24, In press. 


■ '.V, 




24 




B. Dissertations 

1. "Tr1oetny1amlne-Tetraborane(8), Methylamine Adducts of Tr1t>orane(7) 
and Related Chemistry." A. R. Dodd, Ph.D. Dissertation, University 
of Utah, 1980. 

C. Presentations 

1. "Isolation and Characterization of Tr1methylam1ne-Tetraborane(8)." 

G. Kodama and A.R. Dodds, 3rd International Meeting on Boron 
Chemistry, Ettal/Munlch, FRG, July 1976. 

2. "Reactions of Pentaborane(ll) with Methylamlnes." R. W. Parry and G. 
Kodama, 3rd International Meeting on Boron Chemistry, Ettal/Munlch, 

FRG, July 1976. 

3. "Reactions of Tr1methylam1ne-Triborane(7) and >Tetraborane(8) with 
Anhydrous Hydrogen Chloride." A. R. Dodds and G. Kodama, 172nd 
National Meeting, Amer. Chem. Soc., San Francisco, California, 

September 1976. INOR 90. 

4. "Metnylamlne Adducts of Tr1methylam1ne-Tetraborane(8)." A. R. Dodds 
and G. Kodama, 173rd National Meeting, Amer. Chem. Soc., New Orleans, 
Louisiana, March 1977. INOR 48. 

5. "Preparation and Properties of Bls(trlmethylphosphlne)- 
Tetraborane(8}." G. Kodama and M. Kameda, 33rd Northwest Regional Meeting 
Amer. Chem. Soc., Seattle, Washington, June 1978. Paper No. 145. 

6. "Phosphine and Methylphosphlne Adducts of Tr1borane(7)." V. L. Bishop and 
G. Kodama, 4th International Meeting on Boron Chemistry, 

Salt Lake City/Snowbird, Utah, July 1979. Paper No. 39. 

7. "Hypho-Tetraborane Compounds Containing Carbon Monoxide and Phosphine." G 

Kodama and R. W. Parry, 4th International Meeting on Boron Chemistry, Salt 
Lake City/Snowbird, Utah, July 1979. Paper No. 45. 


25 







8 . 


“Cleavage of Pentaborane{9) by Trlmethylphosphine." M. Kameda and G. 
Kodama, 35th Northwest-5th Biennial Rocky Mountain Joint Regional Meeting, 
Amer. Chem. Soc., Salt Lake City, Utah, June 1980. INOR 14'. 

"Reactions of Trlmethylphosphlnes Adducts of D1borane(4) with Boranes." M. 
Kameda and G. Kodama, 2nd Chemical Congress of the North American 
Continent, Las Vegas, Nevada, August, 1980. INOR 75. 

"Reaction of Hexaborane(lO) with Excess Trlmethylpnosphlne. Formation of 
"Klado" Borane Compound." G. Kodama and M. Kameda, 182nd ACS National 
Meeting, New York, NY, August 1981. INOR 15. 

"Another Form of Ammonlate of Tetraborane(lO)." S. A. Snow, G. Kodama, and 
R. W. Parry. 183rd ACS National Meeting, Las Vegas, March 1982. INOR 139. 
"Formation and Characterization of Nonahydro(trlmethylphosphlne)- 
tetraborate(l-) Ion." M. Shlmol and G. Kodama. 183rd ACS National 
Meeting. Las Vegas, Nevada, March 1982. INOR 138. 

"Reactions of Hexahydrobls(tr1methylphosph1ne)tr1boron(l+) 
Octahydrotrlborate(l-) with Trimethyl phosphine and Some Other Lewis 
Bases." M. Kameda and G. Kodama, 183rd ACS National Meeting, Las Vegas, 
Nevada, March 1982. INOR 81. 

"Recent Findings on the Reactions of Lower Borane Compounds." G. Kodama 
and R. W. Parry, ARO Working Conference on Boranes. Raleigh, North 
Carolina, May 10-12, 1982. 

"Preparation and Characterization of Chlorotr1borane(7) Adducts of 
Trimethyl phosphine and Phosphine.” M. A. Nelson and G. Kodama, 184th ACS 
National Meeting, Kansas City, Missouri, September, 1982. INOR 59. 

"Metal Complexes of B1s(tr1methylphosph1ne)-D1borane{4)," S. A. Snow, M. 
Shlmol, C. D. Ostler, G. Kodama, and R. W. Parry. Fifth International 
meeting on Boron Chemistry (IMEB0R0N V), Swansea, Wales, UK., July 1983. 
Paper No. C48. 


* »*,•*, .’ f •*_ .*_ •'«'•*,*•***•“ •’ "«* */ t '.* *.* *,• *,» ‘„*■ 1 *_* *■ * ( « * 


26 






“Phosphine (PH 3 ) Adducts of Tetraborane{8) end pentaboranedl}. 11 C. P. 

Jock and G. Kodama, 7th Rocky Mountain Regional ACS Meeting, Albuquerque, 
NM, June 1984. Paper No. 67. 

“Relative Acid Strength of Tr1borane(7) and Borane(3) as Observed In 
Reactions of Phosphine Adducts." R. E. DePoy, V. L. Bishop, and G. Kodama, 
7th Rocky Mountain Regional ACS Meeting, Albuquerque, NM, June 1984. Paper 
No. 68. 

“A New Isomer of 01chloroborylpentaborane(9).“ S. A. Snow and G. Kodama, 
7th Rocky Mountain Regional ACS Meeting, Albuquerque, NM, June 1984. Paper 


















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DTIC