836600-19-2Relevant academic research and scientific papers
Rhenium(III) and technetium(III) complexes with 2-mercapto-1,3-azole ligands and X-ray crystal structures
Marchesi, Elena,Marchi, Andrea,Marvelli, Lorenza,Peruzzini, Maurizio,Brugnati, Michele,Bertolasi, Valerio
, p. 352 - 362 (2008/10/09)
Reactions of labile precursors [MCl3(PPh3) 2(CH3CN)] (M = Re, Tc) with imidazole-2-thiol ligands give new trigonal bipyramidal complexes, while with benzothiazole-2-thiol and benzoxazole-2-thiol octahedral chelate compounds are obtained. Crystal structures of these metal(III) complexes are also discussed. Reactions of labile [MCl3(PPh3)2(NCMe)] (M = Tc, Re) precursors with 1H-benzoimidazole-2-thiol (H2L1), 5-methyl-1H-benzoimidazole-2-thiol (H2L2) and 1H-imidazole-2-thiol (H2L3), in the presence of PPh 3 and [AsPh4]Cl gave a new series of trigonal bipyramidal M(III) complexes [AsPh4]{[M(PPh3)Cl(H2L 1-3)3]Cl3} (M = Re, 1-3; M = Tc, 4-6). The molecular structures of 1 and 3 were determined by X-ray diffraction. When the reactions were carried out with benzothiazole-2-thiol (HL4) and benzoxazole-2-thiol (HL5), neutral paramagnetic monosubstituted M(III) complexes [M(PPh3)2Cl2(L4,5)] (M = Re, 8, 9; M = Tc, 10, 11) were obtained. In these compounds, the central metal ions adopt an octahedral coordination geometry as authenticated by single crystal X-ray diffraction analysis of 8 and 11. Rhenium and technetium complexes 1, 4 and rhenium chelate compounds 8, 9 have been also synthesized by reduction of [MO4]- with PPh3 and HCl in the presence of the appropriate ligand. All the complexes were characterized by elemental analyses, FTIR and NMR spectroscopy.
Reactivity of [M=O]3+ (M = Tc, Re) core towards 2-mercapto-1,3-azole ligands. Formation of a new organometallic complex of Re(IV) and X-ray crystal structures
Brugnati, Michele,Marchesi, Elena,Marchi, Andrea,Marvelli, Lorenza,Bertolasi, Valerio,Ferretti, Valeria
, p. 363 - 375 (2008/10/09)
Reactions of [MOCl4]- anion (M = Re, Tc) with imidazole-2-thiol ligands H2Ln give bi- and tetra-substituted complexes [MOCl2(H2L)2 (H2O)]+ and [MO(H2L)4]3+. An organometallic species is formed from reaction of [ReOCl 3(PPh3)2] and benzoxazole-2-thiol ligand HL5 by a desulfurization process. Imidazole-2-thiol derivatives H2L1-3 (H2L1 = 1H-benzoimidazole-2- thiol, H2L2 = 5-methyl-1H-benzoimidazole-2-thiol, and H2L3 = 1H-imidazole-2-thiol) act as neutral monodentate ligands in a number of technetium and rhenium complexes. Disubstituted M(V) (M = Tc, Re) complexes of the type [AsPh4]{[MOCl2(H 2Ln)2(H2O)]Cl2} are formed when [MOCl4]- react with H2L 1-3 in 1:2 stoichiometric ratio. Single crystal X-ray structure determinations were carried out on [AsPh4]{[TcOCl2(H 2L1)2(H2O)]Cl2}. The coordination sphere is pseudo-octahedral in which the sulfur atoms of two ligands sit in the equatorial plane and a water molecule is in trans to the TcO multiple bond. All the complexes react with an excess of the corresponding ligand to form tetrasubstituted cationic species {[MO(H2L n)4]Cl3}. These complexes can be also isolated by reaction of [MOCl4]- with an excess of ligand. No complex is obtained with benzothiazole-2-thiol (HL4) and benzoxazole-2-thiol (HL5). Ligand exchange reactions of [ReOCl 3(PPh3)2] with HL4,5 have also been investigated. Treating the oxo-precursor with HL4 no product is isolated, while with HL5 the chelate oxo-compound [ReOCl 2(L5)(PPh3)] is formed as two isomers. An interesting organometallic complex of Re(IV) [ReCl3(L 5*)(PPh3)2] is obtained when a slight excess of HL5 reacts with [ReOCl3(PPh3) 2] in refluxing benzene solution and in air. Geometry about the Re atom is approximately octahedral in which the equatorial plane contains three Cl atoms and the carbon atom of the benzoxazole ligand anion, the apical positions are occupied by two PPh3. The reaction with O-ethyl S-hydrogen p-tolyl carbonothioimidate HL6 which contains the same heteroatoms of HL5 does not form an organometallic species, but forms the chelate oxo-Re(V) complex [ReOCl2(L6)(PPh3)]. The solid-state structure has been authenticated by X-ray crystallography.
