Structures and Spectral Properties of (O-sec.-Butyldithiocarbonatio-S,S') Bis(triphenylphosphine) Copper(I) and Silver(I) Complexes

New complexes (PPh 3 ) 2 M(S 2 COR) [R = sec.-butyl, M = copper (1), silver (2)] were synthesized by the reaction of excessive triphenylphosphine and copper(II) or silver(I) xanthate, and characterized using IR, EA,'H NMR and TG. Their crystal structures have been determined by X-ray diffraction. The light yellow crystal of the complex (1) is triclinic of space group P1, with parameters a = 10.300(2) A, b = 13.120(3) A, c = 14.570(3) A, a = 89.53(3),β = 72.81(3),γ = 78.61(3)°, and Z= 2. The yellow crystal of the complex (2) is triclinic of space group P1, with parameters a = 10.330(2) A, b = 13.410(3) A, c = 14.420(3) A, a = 88.61(3), β = 73.60(3), y = 78.93(3)°, and Z = 2. In the two complexes, the central Cu or Ag atom is in a distorted tetrahedral environment and chelated by two phosphorus atoms from the triphenylphosphine groups and two sulfur atoms from the O-alkyldithiocarbonate. IR and 'H NMR results supported the structures. The thermal analytical data indicate that the complex (1) began to decompose at 122.3° and decomposition was complete at 370.9°, leaving Cu 2 S, while the complex (2) began to decompose at 133.3° and decomposed completely at 290.3° to Ag 2 S.