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Synthesis and redox properties of complexes of rhenium(l) with cyanoguanidine and some derivatives. Crystal structure of trans-[ReNCNC(NH2)2 (CNMe)(Ph2PCH2CH2PPh2)2] [BF4]

1994; Elsevier BV; Volume: 469; Issue: 2 Linguagem: Inglês

10.1016/0022-328x(94)88071-9

1872-8561

M. Fernanda, M. Fernanda N. N. Carvalho, Armando J. L. Pombeiro, Adrian Hills, David L. Hughes, Raymond L. Richards,

Inorganic Chemistry and Materials

Reaction of cyanoguanidine, NCNC(NH2)2, with trans-[ReCl(CNMe)(dppe)2] (dppe = Ph2PCH2CH2PPh2) in CH2Cl2 in the presence or absence of Tl[BF4], forms trans-[Re(NCNC(NH2)2)(CNMe)(dppe)2]A [A  BF4 (Ia) or Cl (Ib)]. The crystal structure of Ia has been determined by an X-ray diffraction analysis. Ib can also be obtained by using cyanamide, NCNH2, instead of cyanoguanidine, in refluxing solvent. Treatment of Ia with KOtBU affords trans-[ReNCNC(NH)NH2(CNMe)(dppe) 2] (II), trans-[Re(NCNCN)(CNMe)(dppe)2] (III) or trans-[Re(NCNHCN)(CNMe) (dppe)2[BF4] (IV). The redox properties of these complexes have been studied by cyclic voltammetry and controlled potential electrolysis at Pt electrodes in aprotic media, and the PL ligand parameter has been estimated for the cyanoguanidine and derived ligands. Moreover, cathodic reduction of I or IV partially generates II or III, respectively.