PLATINUM THIOETHER MACROCYCLIC CHEMISTRY - SYNTHESIS AND ELECTROCHEMISTRY OF [PTL][PF6]2(L = [12]-ANES(4), [14]-ANES(4) OR [16]-ANES(4)) AND [PT2([28]ANES8)][PF6]4 - CRYSTAL-STRUCTURE OF [PT([12]ANES4)][PF6]2-CENTER-DOT-MECN

A series of mono- and bi-nuclear platinum(II) complexes [PtL][PF6]2 (L = [12]-, [14]- or [161-aneS4) and [Pt2([28]aneS8)] [PF6]4 have been s ynthesised by reaction of the crown thioethers with platinum(II) salts . Spectroscopic and structural data confirm square-planar homoleptic t hioether co-ordination at Pt(II) in each case. The complex [Pt([12]ane S4)] [PF6]2.MeCN crystallises in the orthorhombic space group Pnma wit h a = 16.7983(9), b = 9.3213(7), c = 14.1954(8) angstrom and Z = 4. Th e structure shows the cation disordered over a mirror plane, with the Pt(II) ion bound to all four thioether donors in a distorted square-pl anar stereochemistry, Pt-S(1) 2.266(4), Pt-S(4) 2.297(4) angstrom, and the metal ion lying 0.282 angstrom above the S4 co-ordination plane. The methylene carbons of the macrocycle are all directed to the opposi te side of the S4 plane from the Pt(II) ion leaving the top face of th e metal centre exposed. Electrochemical studies on [PtL]2+ show an irr eversible one-electron reduction at E(pc) = -1.41, -1.45 and -1.50 V v s. ferrocene-ferrocenium for L = [12]-, [14]- and [16]-aneS4 respectiv ely at a scan rate of 180 mV s-1. The complex [Pt2([28]aneS8)]4+ exhib its an irreversible two-electron reduction at E(pc) = -1.48 V vs. ferr ocene-ferrocenium.