Five platinum(II) 1,4,7-trithiacyclononane (ttcn) complexes with bidentate-substituted 2,2'-bipyridine ligands have been prepared and structurally characterized: [Pt(bpy)(ttcn)](PF6)2 (bpy = 2,2'-bipyridine), triclinic, P1, a = 10.2529(3) A, b = 10.7791(3) A, c = 10.7867(3) A, alpha = 83.886(1) degrees, beta = 87.565(1) degrees, gamma = 84.901(1), V = 1179.99(6) A3, Z = 2; [Pt(4,4'-dmbpy)(ttcn)](PF6)2 x CH3CN x H2O (4,4'-dmbpy = 4,4'-dimethyl-2,2'-bipyridine), triclinic, P1, a = 10.1895(3) A, b = 11.8566(4) A, c = 13.1004(4) A, alpha = 77.345(1) degrees, beta = 79.967(1) degrees, gamma = 72.341(1) degrees, V = 1461.56(8) A3, Z = 2; [Pt(5,5'-dmbpy)(ttcn)](PF6)2 (5,5'-dmbpy = 5,5'-dimethyl-2,2'-bipyridine), triclinic, P1, a = 10.6397(4) A, b = 10.8449(4) A, c = 11.2621(4) A, alpha = 90.035(1) degrees, beta = 98.061(1) degrees, gamma = 91.283(1) degrees, V = 1286.32(8) A3, Z = 2; [Pt(dbbpy)(ttcn)](PF6)2 x CH3NO2 (dbbpy = 4,4'-di-tert-butyl-2,2'-bipyridine), triclinic, P1, a = 11.5422(7) A, b = 11.6100(7) A, c = 13.6052(9) A, alpha = 85.902(1) degrees, beta = 89.675(1) degrees, gamma = 74.942(1) degrees, V = 1755.90(19) A3, Z = 2; and [Pt(dtfmbpy)(ttcn)](PF6)2 x CH3CN (dtfmbpy = 5,5'-di-trifluoromethyl-2,2'-bipyridine): monoclinic, P2(1)/c, a = 13.1187(9) A, b = 20.9031(15) A, c = 11.3815(8) A, beta = 105.789(2) degrees, V = 3003.3(4) A3, Z = 4. For each salt, the platinum(II) center of the cation is bonded to two nitrogen atoms of the chelating diimine and two sulfur atoms of the thioether macrocycle. The third sulfur atom of ttcn forms a long apical interaction with the metal center (2.84-2.97 A), resulting in a flattened square pyramid structure. An examination of these and 17 other structures of platinum(II) ttcn complexes reveals a correlation between the apical Pt...S distance and the donor properties of the ancillary ligands, suggesting a means for using variations in ligand electronic properties to tune molecular structure. The room-temperature absorption spectra in acetonitrile solution show a broad and comparatively low-energy MLCT band maximizing near approximately 390 nm for the bpy and dialkyl-substituted bipyridyl derivatives. The maximum is dramatically red-shifted to 460 nm in the spectrum of the dtfmbpy complex as a result of the electron-withdrawing properties of the -CF(3) groups. The 3:1 EtOH/MeOH 77 K glassy solution emission spectra exhibit low-energy emission bands (lambdamax, 570-645 nm), tentatively assigned as originating from a lowest, predominantly spin-forbidden MLCT excited state that is stabilized by apical Pt...S interactions.

A series of bis(thiocyanato)gold(I) complexes with Au-Au interactions show luminescence in the range from 500 to 670 nm. The series of salts correlates emission energy with the reciprocal of the Au-Au distance. As the Au-Au distance increases, the emission energy decreases. The ligand system provides no framework for the Au-Au interaction. The emission energy seems totally determined by the Au-Au distance.

The diamagnetic square planar d(8) complexes [meso-arylcorrolato]copper(III) become paramagnetic upon warming, indicative of the equilibrium between the [corrolato]copper(III) and the [corrolato](+)* copper(II) forms of the complex. [meso-Triphenylcorrolato]copper(III) was structurally characterized and found to be saddled.

A strategy for designing cooperative outer-sphere two-electron platinum reagents is demonstrated. The novel platinum(II) complex, [Pt(tpy)(pip2NCN)][BF4] (1(BF4-)) (tpy = 2,2':6',2' '-terpyridine, pip2NCN- = 2,6-(CH2N(CH2)5)2-C6H3-), in which the metal is bonded to two pincer type ligands, has been prepared. Treatment of 1 with protic acid results in protonation of the pendant piperdyl groups, allowing for the isolation of [Pt(tpy)(pip2NCNH2)][PF6]3 (2(PF6-)3). 1H NMR spectra of 1 and 2 establish that in each complex the terpyridyl ligand is tridentate, whereas the piperdyl ligand is monodentate, bonded to platinum through the phenyl ring. The structure of the protonated complex was confirmed by an X-ray crystallographic study of crystals of 2(Cl-)3.4H2O. The cyclic voltammagram of 1 exhibits two reversible one-electron reduction waves at E degrees ' = -0.98 V and E degrees ' = -1.50 V (E degrees ' = (Epc + Epa)/2), with a DeltaEp of 65 and 61 mV, respectively. In contrast to other Pt(II) complexes, including 2, this complex also undergoes a nearly reversible two-electron oxidation process at E degrees ' = 0.40 V (DeltaEp = 43 mV, 0.01 V/s). The accumulated data are consistent with the unusual ligand architecture of 1 being capable of stabilizing and allowing for facile interconversion between the Pt(II) and Pt(IV) oxidation states.