Molecular and electronic structures of some chiral complexes of dimolybdenum (II)

Abstract

The complexes β-Mo2X4(PP)2; X = Cl, Br; PP = S,S-dppb, dppe, dedp have been synthesized starting from Mo2(O2CCF3)4 by using Me3SiX; X = Cl, Br, as reagents. A synthetic route has been found which yields mixed ligand complexes of the type β-Mo2X2X'2(PP)(PP'); X,X' = Cl, Br; PP,PP' = S,S-dppb, dppe. All products have been characterized by their spectroscopic properties and some by elemental analysis. The molecular structures of the four complexes β-Mo2X4(PP)2; X = Cl, Br; PP = S,S-dppb, dppe, have been determined by X-ray crystallographic methods. Their structural parameters have been compared with those of similar molecules reported previously. The Mo-P bond distances and Mo-Mo-L bond angles have been found to be correlated with the torsion angle P-Mo-Mo-P. The electronic structures of several conformers of the model compound Mo2Cl4(PH3)4 have been calculated by the SCF-Xα-SW method. The results of these calculations have been used to explain the observed correlation between structural parameters. The electronic absorption bands in the range of 300 nm to 850 nm have been assigned to various transitions on the basis of the theoretical calculations and some empirical corrections...