Formation and structural relationship of electroactive Pt-II-Hg-II polymetallic sulfide aggregates

A series of {Pt2HgS2}, {Pt2Hg2S2} and {Pt4HgS4} complexes, viz. [(Ph3P)(4)P t-2(mu(3)-S)(2)HgCl2] 2, [(Ph3P)(4)Pt-2(mu(3)-S)(2)Hg(PPh3)]X-2 [X=Cl (3a) or PF6 (3b)], [HgPt4(PPh3)(8)(mu(3)-S)(4)]X-2 [X=PF6, (4a) or ClO4 (4b)], [ Pt-2(Ph3P)(4)(mu(3)-S)(2)Hg-2(mu-Cl)(2)Cl-2] 5, [(Ph3P)(4)Pt-2(mu(3)-S)(2)H g-2(mu-Cl)(2)(PPh3)(2)][PF6](2) 6 and [(Ph3P)(4)Pt-2(mu(3)-S)(2)Hg-2(NO3)(2 )]X-2 [X=NO3 (7a) or PF6 (7b)] have been synthesized from [Pt-2(mu-S)(2)(PP h3)(4)] 1 with the appropriate mercury(II) compounds through 1:1, 1:2 and 2 :1 Lewis acid-base additions. Formation of the major product is governed la rgely by the stoichiometric quantity of the substrates. Reaction intermedia tes can be isolated and characterized. Their conversions into the final pro ducts have been verified. Single-crystal X-ray crystallography on 2, 3b, 4b , 5 and 6 revealed a range of Pt-II/Hg-II metal sulfide cores with differen t nuclearities. V.T. P-31-{H-1} NMR study of 3b showed a rapid migration of the [Hg(PPh3)] moiety between two sulfide sites in a {Pt2HgS2} core. Cycli c voltammetry was carried out on 2, 3b, 5 and 6. Complex 3b undergoes an ap proximately reversible one electron transfer oxidation with E-p,E-a=1.10 V and E-p,E-c=1.01 V.