It is demonstrated that thiols can adsorb to gold without losing hydrogen. Dodecyl sulfide-capped gold clusters have been prepared and subjected to ligand exchange reactions in perdeuterated benzene by addition of dodecanethiol and subsequently dodecyl disulfide. It is shown by 1H NMR spectroscopy that dodecanethiol molecules are readily taken up as ligands producing characteristic broad signals corresponding to the alpha-methylene and S-H protons, with chemical shifts close to those found for thiol in solution; these signals are absent in spectra of thiolate-capped clusters. Addition of excess disulfide to such clusters capped with both dialkyl sulfides and thiols leads to the appearance of sharp signals for free dialkyl sulfide and intact thiol. Amounts of thiols up to 50% of the ligand shell are, however, taken up by the clusters under rapid and irreversible loss of hydrogen.

Despite strong twisting of the conjugated system, the tetrathiafulvalene homologue 1 reacts with the electron acceptor tetracyanoquinonodimethane to give the dication 12⊕. The anthracene moiety is embedded in the 12⊕ [(TCNQ)4]2⊖, and the dithiol rings are twisted 86° with respect to the anthracene plane: The 1:4 stoichiometry of the highly conductive salt (σ300K = 60S cm−1) is very unusual for TCNQ complexes.

The salts [C6H11N2][AuCl4] (1) and [C8H15N2][AuCl4] (2) ([C6H11N2]+ = 1-ethyl-3-methylimidazolium; [C8H15N2]+ = 1-butyl-3-methylimidazolium), prepared by a solvent-free method, display similar crystal structures. 1 crystallizes in the monoclinic P21/c space group (a = 11.1915(15) Å, b = 12.380(2) Å, c = 9.2883(13) Å; β = 98.810(16)°; Z = 4) and 2 in the triclinic P1̄ space group (a = 7.9354(14) Å, b = 8.3930(15) Å, c = 11.397(2) Å; α = 83.94(2)°, β = 87.93(2)°, γ = 78.04(2)°; Z = 2). In both cases, a unique motif is seen consisting of linear chains of alternating corner-to-face arranged [AuCl4]- ions at Au···Cl separations of 3.356(3) Å (1) and 3.452(3) Å (2). Ionic liquid behavior is observed from 58 to 220 °C for 1 and 50 to 250 °C for 2.

The synthesis, Langmuir-Blodgett (LB) deposition and charge-transfer spectra of Z-/3-(l-alkyl-4-quinolinium)-acyano-4styryldicyanomethanide (R-Q3CNQ where R = C&i 1 to CzoH41) and four substituted analogues are described. The deposition is Z-type and the properties are dependent upon the hydrophobic chain length. C6H13-Q3CNQ to C14H,,-Q3CNQ form green LB films (A,,, = 614 4 nm; HWHM = 37 k 2 nm) !nd occupy 2&34 A' per molecule at 25 mN m -" . In contrast, Cl,H3,-Q3CNQ to C2,H,,-Q3CNQ occupy 40-50 A' per molecule; their films are purple with A , , , = 565 k 4 nm and HWHM = 22 & l nm. The shift is attributed to a change in molecular tilt which causes the transition to alter from an intermolecular to an intramolecular process. Multilayer films of C, ,H3,-Q3CNQ exhibit strong second-harmonic generation (SHG) and the intensity increases quadratically with the number of LB layers.

The first imidazole-type carbene complex of platinum(II), cis-(C2H4)(1-ethyl-3-methylimidazol-2-ylidene)PtCl2, has been obtained by reacting PtCl2 and PtCl4 with ethylene in the basic [EMIM]Cl/AlCl3 (1.3:1) ionic liquid (where [EMIM]+ = 1-ethyl-3-methylimidazolium) at 200 degrees C and structurally characterized (monoclinic P21/c space group, a = 10.416(2) A, b = 7.3421(9) A, c = 15.613(2) A, beta = 101.53(2) degrees, Z = 4). This complex can be regarded as a stable analogue of the pi-alkene-Pd(II)-carbene intermediate in the Heck reaction. In addition, a series of new N,N'-dialkylimidazolium salts of platinum group metals of the type [RMIM]2[MCln], where [RMIM+] = 1-alkyl-3-methylimidazolium and M = Pt(II), Pt(IV), or Ir(IV), have been prepared and characterized. The salts [EMIM]2[PtCl6] (1) and [EMIM]2[PtCl4] (2) were prepared in the ionic liquid [EMIM]Cl/AlCl3 and the salts [BMIM]2[PtCl4] (3) and [BMIM]2[PtCl6] (4) (where [BMIM]+ = 1-n-butyl-3-methylimidazolium) and [EMIM]2-[IrCl6] (5) in aqueous or acetonitrile media. From TGA measurements, salts 1-5 decompose in air in several steps eventually to form the corresponding metal, the onset of decomposition being observed at (degree C) 260 (1), 220 (2), 200 (3), 215 (4), and 210 (5). The structures of 1, 2, and 5 were determined by single-crystal X-ray analysis. The three salts crystallize in the monoclinic P21/n space group (1, a = 7.6433(9) A, b = 16.353(2) A, c = 9.213(1) A, beta = 113.56(1) degrees, Z = 2; 2, a = 8.601(1) A, b = 8.095(2) A, c = 13.977(2) A, beta = 91.75(2) degrees, Z = 2; 5, a = 10.353(2) A, b = 9.759(2) A, c = 10.371(2) A, beta = 92.98(3) degrees, Z = 2).