G2(MP2) Molecular Orbital Study of [H₃AlXH₃]^- (X = C, Si, and Ge) and H₃AlYH₃ (Y = N, P, and As) Complexes

Abstract

[H3AlXH3]- (X = C, Si, and Ge) and H3AlYH3 (Y = N, P, and As) have been investigated as donor−acceptor complex types at the G2(MP2) level of theory. Both staggered and eclipsed conformations have been examined. For all complexes, the first one is found to be favored. The G2(MP2) results show that the anionic complexes are more stable than the neutral ones. They show also that this stability decreases when going from carbon to germanium for [H3AlXH3]- complexes and from nitrogen to arsenic for H3AlYH3 complexes. The interaction diagrams prove that the evolution of complexation energy depends on the coordination mode. In fact, this is a simple “HOMO−LUMO” interaction for [H3AlXH3]- anionic complexes, while for the H3AlYH3 neutral ones it is a result of two interaction types: interaction between “a1” symmetry fragments orbital (stabilizing) and interactions between “e” symmetry fragments orbital (destabilizing). A linear relationship has been established and discussed between the G2(MP2) complexation energy and the ligand G2(MP2) proton affinity, whereas no correlation has been found with the charge transfer.

G2(MP2) Investigation of Alane-[X(CH3)3]- (X = C, Si, and Ge) and Alane-Y(CH3)3 (Y = N, P, and As) Interactions

“…The same trend has been observed in the [H 3 AlXH 3 ] -(X ) C, Si, and Ge) and H 3 AlYH 3 (Y ) N, P, and As) hydrogenated complexes. 29 Concerning the bond angles ∠C-X-Al and ∠C-Y-Al, there is no notable deviation between the two compound sets. For the anionic ones, the MP2(full)/6-31G(d) optimized values are 110.5°, 115.0°, and 116.3°(Table 1) for [H 3 AlC(CH 3 ) 3 ] -, [H 3 AlSi(CH 3 ) 3 ] -, and [H 3 AlGe(CH 3 ) 3 ] -, respectively, while in the free ligand [X(CH 3 ) 3 ] -, this angle is 111.3, 120.7, and 121.6°f or [C(CH 3 ) 3 ] -, [Si(CH 3 ) 3 ] -, and [Ge(CH 3 ) 3 ] -, respectively.…”

“…32,33 The QMOA arguments have proven useful and successful for predicting the broad outlines of calculations. [29][30][31][32][33] The choice of the complexes investigated was made with the aim to include different types of strongly bound molecules (anionic one) and coordination compounds (neutral one). To the best of our knowledge, no comparative study of these complexes has been carried out.…”

Syntheses and structures of lanthanoid(ii) complexes featuring Sn–M (M = Al, Ga, In) bonds

“…However, the C Me -Al-C Me angles clearly pass from D 3h in free metallane to T d in the complex, implying covalent Sn-Al bond character, which parallels results of theoretical investigations for the model compounds [H 3 AlEH 3 ] − (E = C, Si, Ge). 14…”

G2 Molecular Orbital Investigation of H4AlXH3+ (X = N, P, and As) and H4AlYH2+ (Y = O, S, and Se) Interactions

“…[11][12][13][14][15][16][17][18][19][20][21][22][23][24] Recently, we reported a detailed ab initio molecular orbital studies of a series of donor-acceptor complexes of AlH 3 . [25][26][27][28] We showed that the stability of these complexes does not depends on the charge transfer. We have also shown that the donor-acceptor interaction was note based on a simple HOMO-LUMO mixture.…”