Molecular structures of M(Bu(t))3 (M = Al, Ga, In) using gas-phase electron diffraction and ab initio calculations: experimental and computational evidence for charge-transfer processes leading to photodissociation.
The gas-phase structures of AI(Bu')3 and Ga(Bu')3 have been investigated by electron diffraction and are shown to consist of monomeric units with very slightly pyramidal geometries. Salient structural parameters (r(hl)) include r(A1-C) = 2.008(2) A and r(Ga-C) = 2.032(2) A. For both compounds the ligand orientations and geometries are controlled by interligand interactions. The structures of M(Bu(t))3 (M = Al, Ga, In) have been calculated ab initio and those for the aluminium and gallium derivatives are in good agreement with the electron-diffraction structures. Comparison of the ab initio calculated structure of In(Bu')3 with those of Al(Bu(t))3 and Ga(Bu(t))3 suggests that the significantly different photochemistry exhibited by the former does not result from structural factors. In fact the compounds undergo a charge-transfer process in the UV region, with the wavelength required calculated to be slightly longer for the indium compound than for the other two.
Keys
Andrea
A
Department of Chemistry, Rice University, Houston, Texas 77005, USA. arb@rice.edu
Brain
Paul T
PT
Morrison
Carole A
CA
Callender
Rhonda L
RL
Smart
Bruce A
BA
Wann
Derek A
DA
Robertson
Heather E
HE
Rankin
David W H
DW
Barron
Andrew R
AR
D000535:Aluminum / Q000737:chemistry*; D002073:Butanes / Q000737:chemistry; D003198:Computer Simulation; D018360:Crystallography, X-Ray; D004583:Electrons; D005708:Gallium / Q000737:chemistry*; D005740:Gases / Q000737:chemistry; D007204:Indium / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D009942:Organometallic Compounds / Q000737:chemistry*; D044367:Phase Transition; D010777:Photochemistry; D011789:Quantum Theory
D002073:Butanes; D005740:Gases; D009942:Organometallic Compounds; D007204:Indium; D005708:Gallium; D000535:Aluminum