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Tyan MR, Bokach NA, Wang MJ, Haukka M, Kuznetsov ML, Kukushkin VY: Facile cyanamide-ammonia coupling mediated by cis- and trans-[PtIIL2] centers and giving metal-bound guanidines. Dalton Trans. 2008 Oct 14;(38):5178-88. Epub 2008 Aug 11.
Diffusion of ammonia into CH (2) Cl (2) solutions of the dialkylcyanamide complexes cis- or trans-[PtCl (2)(RCN)(2)] (R = NMe (2), NEt (2), NC (5) H (10)) at 20-25 degrees C leads to metal-mediated cyanamide-ammonia coupling to furnish, depending on reaction time, one or another type of novel bisguanidine compound, i.e. the molecular cis- or trans-[PtCl (2){NH=C (NH (2)) R}(2)] (cis- and trans-) and the cationic cis- or trans-[Pt (NH (3))(2){NH=C (NH (2)) R}(2)](Cl)(2) (cis- and trans-) complexes. Compounds cis- or trans- were converted to cis- or trans-, accordingly, upon prolonged treatment with NH (3) in CH (2) Cl (2). The ammination of the relevant nitrile complexes cis- or trans-[PtCl (2)(RCN)(2)] (R = Et, CH (2) Ph, Ph) in CH (2) Cl (2) solutions affords only the cationic compounds cis- or trans-[Pt (NH (3))(2){NH=C (NH (2)) R}(2)](Cl)(2) (cis- and trans-). The formulation of was supported by satisfactory C, H and N elemental analyses, agreeable ESI (+)-MS (or FAB (+)-MS), IR, (1) H and (13) C NMR spectroscopies. The structures of trans-, trans-, cis-, trans-, cis-, and cis- were determined by single-crystal X-ray diffraction disclosing structural features and showing that the ammination gives ligated guanidines and amidines in the E- and Z-forms, respectively, where both correspond to the trans-addition of NH (3) to the nitrile species. |
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