Nb and Ta Adducts: Connecting d(0) Metal Chlorides and Phosphorus Sulfide Cages

Phosphorus sulfide cages alpha-P4S4, alpha-P4S5, beta-P4S5, and beta-P4S6 and transition-metal chlorides TaCl5 and NbCl5 form molecular adducts in CS2/n-hexane. The crystal structures of the adducts (TaCl5)(alpha-P4S4), (TaCl5)(alpha-P4S5), (TaCl5)(beta-P4S5), (NbCl5)(beta-P4S5), and (TaCl5)(beta-P4S6) are reported and their conformation and energetic stability are discussed on the basis of ab initio electronic structure calculations. Furthermore bond lengths of coordinated and noncoordinated phosphorus sulfide cages obtained from experiment and theory are compared, emphasizing the changes within the cages that emerge upon coordination.