A cobalt-59, indium-115, gallium-69, gallium-71, bromine-79, bromine-81, and chlorine-35 nuclear quadrupole resonance study of structure and bonding in four-coordinate gallium and indium compounds containing metal-metal bonds

Abstract

Pure nuclear quadrupole resonance spectra are reported for a series of four-coordinate gallium and indium compounds having a s ligands cO(c0)4, Br, C1, THF, acac, and (CsHs)3PO. The 59C0, l151n, 69Ga, 71Ga, 79Br, 81Br, and 35Cl N Q R parameters when taken together and separately lead to qualitative structural inferences and a coherent picture of the ground-state electron distribution in these molecules. The 59C0 and 'lsIn coupling constants and the llsIn asymmetry parameters suggest that ligand angle changes in the In(II1) coordination sphere account for some of the trends. 59C0 asymmetry parameters suggest cobalt-indium (gallium) a bonding is not a major factor in these compounds. The presence of bridging and terminal halogens can be determined using '9Br, 81Br, and 35Cl NQR frequencies. The halogen frequency shifts are consistent with orbital population changes on indium a s evidenced by the 1151n coupling constants. The number of examples is limited but partial quadrupole splitting values for ligands derived from Sn(1V) Mossbauer spectra appear to predict the trends in In(II1) coupling constants. The EFG trends and carbonyl ir frequency shifts in Co(C0)4-In(Ga) bonds compared to (C0)4Co-Sn(Ge) bonds are entirely consistent but show vco to be much less sensitive than the electric field gradient to substitutions.

Protonation of rhodium-olefin complexes

“…Novel Triaryloxo-and Triaroyloxostannyl Transition Metal Complexes D. Robert Coulson* and Linda P. Seiwell Received February 24,1976 AIC601434…”