Equilibrium structures, harmonic vibrational frequencies, and binding energies of the mixed diboranes AlBH6, BGaH6, and AlGaH6 were obtained from abinitio quantum mechanical methods using various basis sets and levels of theory to estimate the effects of electron correlation. Good agreement is found with the experimental IR spectroscopic data on BGaH6. The calculated order of the binding energies with respect to the monomers is AlBH6>B2H6>Al2H6>BGaH6>AlGaH6>Ga2H6. The nature of the bonding in these systems is examined using Bader’s theory of atoms in molecules.

1.
A. J.
Downs
,
M. J.
Goode
, and
C. R.
Pulham
,
J. Am. Chem. Soc.
1989
,
111
,
1936
.
2.
C. R.
Pulham
,
T. M.
Brain
,
A. J.
Downs
,
D. W. H.
Rankin
, and
H. E.
Robertson
,
J. Chem. Soc. Chem. Commun.
1990
,
177
.
3.
K. Wade and A. J. Banister, The Chemistry of Aluminium, Indium and Thallium (Pergamon, New York, 1975);
F. A. Cotton and G. Wilkinson, Advanced Inorganic Chemistry (Wiley, New York, 1980).
4.
(a)
P. L.
Baxter
,
A. J.
Downs
,
M. J.
Goode
,
D. W. H.
Rankin
, and
H. E.
Robertson
,
J. Chem. Soc. Chem. Commun.
1986
,
805
.
(b)
P. L.
Baxter
,
A. J.
Downs
,
D. W. H.
Rankin
, and
H. E.
Robertson
,
J. Chem. Soc. Chem. Commun.
1984
,
1755
.
5.
M. J.
Goode
,
A. J.
Downs
,
C. R.
Pulham
,
D. W. H.
Rankin
, and
H. E.
Robertson
,
J. Chem. Soc. Chem. Commun.
1988
,
768
.
6.
(a)
K.
Lammertsma
and
J.
Leszczyński
,
J. Phys. Chem.
94
,
2807
(
1990
);
(b)
C.
Liang
,
R. D.
Davy
, and
H. F.
Schaefer
,
Chem. Phys. Lett.
159
,
393
(
1989
);
(c) B. J. Duke, J. Mol. Struct. (Theochem) (to be published).
7.
(a)
K.
Lammertsma
and
J.
Leszczyński
,
J. Chem. Soc. Chem. Commun.
1989
,
1005
. Instead of the reported 458 cm−1 the 33 cm−1 frequency is IR active;
(b) B.J. Duke, T. P. Hamilton, and H. F. Schaefer (unpublished).
8.
(a)
V.
Barone
,
C.
Minichino
,
F.
Lelj
, and
N.
Russo
,
J. Comput. Chem.
9
,
518
(
1988
);
(b)
V.
Barone
,
G.
Dolcetti
,
F.
Lelj
, and
N.
Russo
,
Inorg. Chem.
20
,
1687
(
1981
).
9.
V.
Barone
and
C.
Minichino
,
Theor. Chim. Acta
76
,
53
(
1989
).
10.
G. J. Mains (personal communication to H.F.S.).
11.
K.
Lammertsma
,
O. F.
Güner
,
R. M.
Drewes
,
A. E.
Reed
, and
P. v. R.
Schleyer
,
Inorg. Chem.
28
,
313
(
1989
).
12.
K.
Lammertsma
and
J.
Leszczyński
,
J. Phys. Chem.
94
, (
1990
).
13.
(a) J. Leszczyński and K. Lammertsma, (unpublished).
(b) K. Lammertsma, O. F. Güner, A. F. Thibodeaux, A. E. Reed, and P. v. R. Schleyer (unpublished).
14.
GAUSSIAN88: M. J. Frisch, M. Head-Gordon, H. B. Schlegel, K. Raghavachiari, J. S. Binkley, C. Gonzalez, D. J. DeFrees, D. J. Fox, R. A. Whiteside, R. Seeger, C. F. Melius, J. Baker, R. Martin, L. R. Kahn, J. J. P. Stewart, E. M. Fluder, S. Topiol, and J. A. Pople (Gaussian, Pittsburg, PA, 1988).
15.
GAMESS: (a) M. Dupuis, D. Spangler, and J. J. Wendolski, NRCC Software Catalog, University of California: Berkeley, CA, 1980, Program QG01;
(b)
M. W.
Schmidt
,
J. A.
Boatz
,
K. K.
Baldridge
,
S.
Kosecki
,
M. S.
Gordon
,
S. T.
Elbert
, and
B.
Lam
,
QCPE Bull.
7
,
115
(
1987
).
16.
For an introduction to the methods employed see W. J. Hehre, L. Radom, P. v. R. Schleyer, and J. A. Pople, Ab Initio Molecular Orbital Theory (Wiley, New York, 1986).
See also: P. Pulay, in Modern Theoretical Chemistry, edited by H. F. Schaefer (Plenum, New York, 1977), p. 153;
and
P.
Saxe
,
Y.
Yamaguchi
, and
H. F.
Schaefer
,
J. Chem. Phys.
77
,
5647
(
1982
).
17.
K. D.
Dobbs
and
W. J.
Hehre
,
J. Comput. Chem.
7
,
359
(
1986
).
18.
P. C.
Hariharan
and
J. A.
Pople
,
Theor. Chim. Acta
28
,
213
(
1973
).
19.
T. H. Dunning, Jr. and P.J. Hay, in Modern Theoretical Chemistry, edited by H. F. Schaefer (Plenum, New York, 1977), p. 1.
20.
S. Huzinaga, J. Andzelm, M. Klobukowski, E. Radzio-Andzelm, Y. Sakai, and H. Tatewski, Gaussian Basis Sets for Molecular Calculations (Elsevier, New York, 1984).
21.
S.
Huzinaga
,
J. Chem. Phys.
42
,
1293
(
1965
);
T. H.
Dunning
,
J. Chem. Phys.
53
,
2833
(
1970
).,
J. Chem. Phys.
22.
T. H.
Dunning
,
J. Chem. Phys.
66
,
1382
(
1977
); contraction due to R. S. Grev and H. F. Schaeffer.
23.
C.
Mo/ller
and
M. S.
Plesset
,
Phys. Rev.
46
,
618
(
1934
).
24.
J. A.
Pople
,
R.
Krishnan
,
H. B.
Schlegel
, and
J. S.
Binkley
,
Int. J. Quantum Chem. Symp.
13
,
325
(
1979
).
25.
B. R.
Brooks
,
W. D.
Laidig
,
P.
Saxe
,
J. D.
Goddard
,
Y.
Yamaguchi
, and
H. F.
Schaefer
,
J. Chem. Phys.
72
,
4652
(
1980
);
P.
Saxe
,
D. J.
Fox
,
H. F.
Schaefer
, and
N. C.
Handy
,
J. Chem. Phys.
77
,
5584
(
1982
).,
J. Chem. Phys.
26.
R.
Krishnan
and
J. A.
Pople
,
Int. J. Quantum Chem.
14
,
91
(
1978
);
R.
Krishnan
,
M. J.
Frisch
, and
J. A.
Pople
,
J. Chem. Phys.
72
,
4244
(
1980
).
27.
G. E.
Scuseria
,
C. L.
Janssen
, and
H. F.
Schaefer
,
J. Chem. Phys.
89
,
7382
(
1988
).
28.
(a)
D. J.
DeFrees
, and
A. D.
McLean
,
J. Chem. Phys.
82
,
333
(
1985
);
(b) scaling factor of 0.9 is common for HF optimized structures:
J. A.
Pople
,
H. B.
Schlegel
,
R.
Krishnan
,
D. J.
DeFrees
,
J. S.
Binkley
,
M. J.
Frisch
, and
R. A.
Whiteside
,
Int. J. Quantum Chem. Quantum Chem. Symp.
15
,
269
(
1981
).
29.
(a)
R. F. W.
Bader
,
Acc. Chem. Res.
18
,
9
(
1985
);
(b)
R. F. W.
Bader
, and
T. T.
Nguyen-Dang
,
Adv. Quantum Chem.
14
,
63
(
1981
);
(c)
R. F. W.
Bader
,
T. T.
Nguyen-Dang
, and
Y.
Tal
,
Rep. Prog. Phys.
44
,
893
(
1981
).
30.
Private communication to B.J.D. from A. J. Downs.
31.
R. F. W.
Bader
and
H.
Essen
,
J. Chem. Phys.
80
,
1943
(
1984
).
32.
M.
Page
,
G. F.
Adams
,
J. S.
Binkley
, and
C. F.
Melius
,
J. Phys. Chem.
91
,
2675
(
1987
).
33.
R.
Krishnan
,
J. S.
Binkley
,
R.
Seeger
, and
J. A.
Pople
,
J. Chem. Phys.
72
,
650
(
1980
).
34.
L. T.
Redmon
,
G. D.
Purvis
, and
R. J.
Bartlett
,
J. Am. Chem. Soc.
101
,
2856
(
1979
).
35.
(a) The dependence on basis set effects may be illustrated in the case of Ga, where the use of 5d vs 6d polarization functions results in an energy difference for GaH3 of 19.2 kJmo1−1 at MP4(SDTQ)/6-31G**//MP2(Full)/6-31G** using the partially uncontracted Huzinaga [433111/43111/4*, ηd = 0.207] basis (Ref. 16). This “triple-ζ” basis set gives also significantly higher absolute energies than the slightly larger DZP basis which uses the 14sllp5d/7s5p2d+polarizationd = 0.207) contraction on the gallium atom,
(b) B. J. Duke, C. Liang, and H. F. Schaefer (unpublished).
36.
The MP2(Full)/6-31G** optimized D3d structures of BH3 and A1H3 [see Ref. 6(a)] have B-H and Al-H bond lengths of 1.184 and 1.577 Å, respectively. The MP2 (Full)/Huz optimized Ga-H bond length of 1.554 Å for GaH3 (D3d) compares well with the 1.557 Å bond length obtained in a recent CASSCF/SOCI calculation, see
K.
Balasubramanian
,
Chem. Phys. Lett.
164
,
231
(
1989
).
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