Reactions of Cycloplatinated Guanidine Complexes with Hg(OC(O)CF3)2: Formation of a One-Dimensional Coordination Polymer Containing a Pt2Hg(μ2-S(O)Me2-S,O) Repeating Unit versus a Discrete Pt2Hg2 Complex

Separate reactions of cycloplatinated 2-tolyl- and 2-anisylguanidine complexes, [Pt{kappa(2)(C,N)}(OC(O)CF3)(S(O)Me-2)] (1 and 2), with Hg(OC(O)CF3)(2) in 1:0.5 and 1:1 molar ratios afforded the one-dimensional coordination polymer (1D CP) {[(sic)Pt-III{kappa(2)(C,N)}(OC(O)CF3)(2)](2)Hg-0}(mu(2)-S(O)Me-2-S,O)center dot C7H8 (3 center dot C7H8) as bright red crystals and the discrete tetrametallic complex [(sic)Pt-II{kappa(2)(C,N)}(mu(2)-OC(O)CF3)(2)Hg-I-](2) (4) as yellow crystals in good yields. The two different products obtained in the aforementioned reactions are ascribed to the subtle differences in the N substituent of the guanidinate(1-) ligands in 1 and 2. The plausible mechanisms of formation of 3 and 4 are outlined. Complexes 3 and 4 were characterized by elemental analyses and IR and multinuclear NMR (H-1, C-13{H-1}, F-19, and Pt-195) spectroscopy. Complex 4 was also characterized by Hg-199 NMR spectroscopy. The molecular structures of 3 center dot C7H8 and 4 were determined by single-crystal X-ray diffraction studies. 1D CP 3 center dot C7H8 contains a Pt(III)-Hg(0)-Pt(III)(mu(2)-S(O)Me-2-S,O) repeating unit with a pair of unsupported Pt-Hg covalent bonds, while 4 contains a Pt(II)-Hg(I)-Hg(I)-Pt(II) chain with a pair of trifluoroacetate ligand supported Pt -> Hg coordinate bonds. 1D CP 3 center dot C7H8 falls apart into a mixture of three species, namely 6-8 and 9-11 in C6D6 and CDCl3, respectively, as revealed by multinuclear NMR spectroscopy. In CDCl3, 4 partially isomerizes to [(sic)Pt-II(OC(O)CF3)(mu(2)-OC(O)CF3){kappa(3)mu(2)(C,N,O)}Hg-I-](2) (12), wherein each Pt -> Hg coordinate bond is supported by one mu(2)-bridging trifluoroacetate ligand and one chelating bridging guanidinate(1-) ligand, as inferred from variable-temperature H-1 and F-19 NMR spectroscopy. Complex 12 is the major species and 4 is the minor species in CDCl3, while opposite situation prevails in C6D6. The observance of a mixture of two solution species for 4 is ascribed to a rapid carboxylate shift process induced by the oxygen atom of the =N(C6H4(OMe)-2) unit of the guanidinate(1-) ligand through neighboring-group participation. UV-visible absorption and emission spectra of 4 were measured in CHCl3, and from the outcome of the investigation, the possible existence of [Cl-2(H)C-Cl center dot center dot center dot(sic)(PtOC)-O-II((O)CF3){kappa(3)mu(2)(C,N,O)}Hg-I-](2) (12 '') was suggested, which is likely to have a pair of Pt-Hg covalent bonds made possible by CHCl3 coordination on the sixth site of the Pt(II) atom.

Automated summary

By reacting with Hg(OC(O)CF3)(2), separate reactions of cycloplatinated 2-tolyl- and 2-anisylguanidine complexes yielded a one-dimensional coordination polymer and a discrete tetrametallic complex with different structures and properties. The formation mechanisms and structural characteristics of these products were explained in detail, with important characterization information provided by multinuclear NMR spectroscopy and single-crystal X-ray diffraction studies.