Studies on the Synthetic System of V/Ag/S Cluster Compounds and Structural Characterizations of V(2)AgS(4), V(2)Ag(2)S(4), and V(2)O(2)(&mgr;-S)(2) Complexes.

The reaction system (NH(4))(3)VS(4)/Ag(PPh(3))(2)Cl/R(2)dtcNa in CH(3)CN was studied to afford two V(2)Ag(1)(-)(2)S(4) cubanelike cluster compounds and a trinuclear V(3)O(3)S(2) complex. (Et(4)N)[V(2)AgS(4)(Me(2)dtc)(2)(PPh(3))].(1)/(2)CH(3)CN ([Et(4)N]1.(1)/(2)CH(3)CN) crystallizes in the monoclinic space group P2(1)/c with a = 10.525(3) Å, b = 16.340(8) Å, c = 26.834(8) Å, beta = 101.28(2) degrees, and Z = 4. Complex (Et(4)N)(2)[V(2)Ag(2)S(4)(CS(3))(2)(PPh(3))(2)] (Et(4)N2) crystallizes in the monoclinic space group C2/c with a = 21.212(5) Å, b = 20.100(4) Å, c = 15.039(2) Å, beta = 102.72(2) degrees, and Z = 4. A stepwise aggregate process including a dinuclear V(2)Y(2)(&mgr;-S)(2) (Y = S, O) intermediate was suggested to explain the formation of 1, 2, and trinuclear anion V(3)O(&mgr;-O)(2)(&mgr;-S)(2)(Et(2)dtc)(3). Structural features of these complexes show that the V(2)Y(2)(&mgr;-S)(2) moiety can be seen as an independent unit to combine with other metal ion(s). A complex containing the V(2)O(2)(&mgr;-S)(2)(Et(2)dtc)(2)(-) (3) cluster anion was separated from a reaction system of (NH(4))(3)VS(4)/PPh(3)/Et(2)dtcNa, and its solvate complex {(Et(4)N)(3)NaV(2)O(2)(&mgr;-S)(2)(Et(2)dtc)(2)}(2).(1)/(2)CH(3)OH.H(2)O crystallizes in orthorhombic space group Pnn2 with a = 31.599(1) Å, b = 17.228(5) Å, c = 14.104(7) Å, and Z = 2. Infrared frequencies at 844-970 cm(-1) were associated with a V=O stretching vibration. The V=O additional coordination to the other metal ion gives rise to the red shift of the frequency. Proton and (51)V NMR spectra exhibit a paramagnetic V(IV) center existing in the trinuclear complex (Et(4)N)[V(3)O(&mgr;-O)(2)(&mgr;-S)(2)(Et(2)dtc)(3)] ([Et(4)N]4) and d(1)-d(1) coupling of V-V of the V(2)Y(2)(&mgr;-S)(2) moiety for these complexes. Two sets of the (31)P signals for 2at 16.6-19.3 ppm with equal intensity are attributed to (31)P-(107)Ag coupling and may well hide two V atoms in a similar environment. Cyclic voltammetries show some similar electrochemical behaviors between 3 and 4 indicated by a common couple at -0.7 V/-0.65 V and an oxidation peak at +0.7 to +0.6 V which are proposed to be due to redox in the V(2)O(2)(&mgr;-S)(2) moiety.