AN AB-INITIO STUDY ON THE CONFORMATION AND GOLD(I)-GOLD(I) INTERACTION OF THE ISOMERIC H2C[P(PH)(2)AUX](2) AND HC[P(PH)(2)AUX](3)(X=I, CL)

Ab initio calculations were carried out on the complexes K2C[P(Ph)(2)A uX]2(X=I,Cl) and HC[P(Ph)(2)AuX](3)(X=I,Cl) according to their crystal structures. The potential energy curves of the conformations with res pect to the rotations of C-P bonds were generated at MP2 approximate l evels, which reveals Au(I)-Au(I) interactions. The calculations show t hat the Au( I)-Au( I) interactions exist in all the four complexes wit h the weak attraction about 10.0 similar to 16.5 kJ/mol that is close to the estimation of Schmidbaur and the calculation of Pyykko et al. f or other model complexes.