A COMPARATIVE STUDY OF THE DONOR-ACCEPTOR PROPERTIES IN ANALOGOUS RGANOMETALLIC Al4…. X (X=CO, CS, and CSe) ASSITED BY NBO ANALYSIS

Charge transfer between a metal and its ligand is fundamental for the structure and reactivityof a metal complex as it directly dictates the distribution of electron density within thecomplex. In this work, the nature and extent of the orbital interaction between A14 and CO,CS or CSe can be judged by comparing the forms and occupancies of the NBOs in theisolated fragments with those in the complexes. The NBO result demonstrates that the mostsignificant changes in the occupancy of Al4.. X (X=CO, CS, and CSe) are related todisembarkation of the carbon lone pair [1]. The π* orbital on CO receives electrons from theπ orbital on Al, thus an increase of in occupancy of the CO π* NBO's with an associateddepletion of the Al4 total π symmetry. In this paper we reported the results of charge transferanalysis with associated thermodynamic properties for Al4…CO, Al4 …. CS, and Al4…. CSecomplexes that obtained by HF/3-21G level calculation.