The M(Se4)2 2−ions, M = Ni, Pd, Zn, Cd, and Hg, have been synthesized by reaction of the metal xanthate with a polyselenide solution in CH3CN-DMF. The corresponding Mn(Se4)2 2−ion was synthesized by reaction of MnCl2with a polyselenide solution in DMF. The Pt(Se4)2 2−ion was synthesized in situ by reaction of Pt(Se4)3 2−with excess BH4 −. The crystal structures of [PEtPh3]2[Ni(Se4)2] and of [PPh4]2[Zn(Se4)2] have been determined. The Ni center in the centrosymmetric Ni(Se4)2 2−ion is essentially square planar with Ni—Se distances of 2.298 (1) and 2.315 (1) Å. The two independent Zn(Se4)2 2−ions have approximately tetrahedral Zn centers, but they show significant metrical differences. Zn-Se distances range from 2.450 (5) to 2.493 (6) Å. The MSe4rings have the distorted envelope conformation. The ions (except Mn(Se4)2 2−) show two77Se NMR resonances. These occur for the following M (´(metal-bound Se), ppm; δ(ring Se), ppm): Ni (820; 748); Pd (893; 758); Pt (727; 642); Zn ( 127; 598); Cd (62; 608); Hg (76; 594). Trends in these resonance positions are rationalized in terms of the d-electron configurations of the metal. Reaction of the corresponding M(Se4)2 2−ion with dimethyl acetylenedicarboxylate affords the ions M(Se2C2− (COOCH3)2)2 2−(M = Zn, Ni).
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry