- Synthesis and characterization of the bimetallic series [S 2WS2Fe(NCS)(X)]2- (X = Cl-, NCS -, N3-)
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The family of molecular dianions [S2WS2Fe(NCS)(X)]2-(X=Cl-,NCS-,N3-orN3-) has been synthesized and characterized by X-ray diffraction, IR, electronic and electrospray mass spectroscopies. This series of compounds was obtained using the lability of the terminal chloro ligands in [S2WS 2FeCl2]2-. A series of thioheterobimetallic anions have been synthesized: [S2WS2Fe(NCS)X]2- (X = Cl- (1); X = NCS- (2); X=N3- (3)). The molecular dianions were isolated by substitution in [S2WS2FeCl 2]2- of the labile terminal chloro ligands by NCS - and/or N3-. Anions (1) and (3) are the first iron tris-heteroleptic complexes of the well-known [S2WS2FeX2] 2- (M = Mo, W) family. The structures of the three molecular anions, isolated as tetraphenylphosphonium salts, are reported, as well as characterization by IR, electronic and electrospray mass spectroscopies.
- Dumas, Eddy,Marrot, Jér?me,Jullien, Josseline,Sécheresse, Francis
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- Trinuclear Fe-M-S complexes containing a linear Fe-M-Fe array and a bridging S2MS2 unit. Electronic structures and crystal and molecular structures of the [(C6H5)4P]2[Cl2FeS 2MS2FeCl2] (M = Mo, W) complexes
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The title complexes [Cl2FeS2MS2FeCl2]2- (M = Mo (I), W (II)) are obtained either by oxidation of the [(PhS)2FeS2MS2]2- complexes with FeCl3·6H2O or by direct syntheses from FeCl2 and the MS42- anions in acetonitrile solution. Complexes I and II undergo dissociation in donor solvents with loss of FeCl2 and formation of the dinuclear [Cl2FeS2MoS2]2- complexes. The (C6H5)4P+ salt of the [Cl2FeS2MoS2FeCl2]2- anion (I) crystallizes in the triclinic space group P1 with two molecules per unit cell. The cell dimensions for I are a = 10.197 (2) A?, b = 13.054 (2) A?, c = 20.164 (3) A?, α = 100.46 (2)°, β = 100.61 (1)°, and γ = 100.92 (1)°. The tungsten complex [(C6H5)4P]2[Cl2FeS 2WS2FeCl2] (II) is X-ray isomorphous and isostructural. The cell dimensions for II are a = 10.215 (6) A?, b = 13.071 (5) A?, c = 20.187 (7) A?, α = 100.54 (3)°, β = 100.58 (2)°, and γ = 100.97 (2)°. Intensity data for I and II were collected with a four-circle computer-controlled diffractometer with use of the θ-2θ scan technique. In all structures, all non-hydrogen atoms were refined with anisotropic temperature factors and the hydrogen atoms were included in the structure factor calculations but not refined. Refinement by full-matrix least squares of 550 parameters on 5125 data for I and 550 parameters on 9711 data for II gave final R values of 0.058 and 0.050, respectively. The structures of these trinuclear complexes consist of a tetrahedral MS42- unit bridging two FeCl2 groups. The Fe-Mo distances in I at 2.771 (2) and 2.781 (2) A? and the Fe-Fe distance at 5.552 (2) A? are all shorter than the corresponding distances in II, which are 2.795 (1), 2.808 (1), and 5.603 (1) A?, respectively. The Fe-M-Fe angles in I and II are 179.37 (6) and 179.25 (4)°, respectively. Average values of other structural parameters are as follows: for I, Fe-S = 2.296 (4) A?, Fe-Cl = 2.234 (1) A?, Mo-S = 2.206 (2) A?, Fe-Sb-Mo = 76.1 (1)°; for II, Fe-S = 2.320 (6) A?, Fe-Cl = 2.233 (10) A?, W-S = 2.209 (5) A?, Fe-Sb-W = 76.4 (2)°. The structural as well as Mo?ssbauer and magnetic properties of I and II indicate that the WS42- unit is a weaker bridging ligand than MoS42-. Chemical and electrochemical studies show that I and II undergo a one-electron reduction followed by loss of Cl- and formation of the ([Fe2Cl3S2MS2]2-) x anions.
- Coucouvanis,Simhon,Stremple,Ryan,Swenson,Baenziger,Simopoulos,Papaefthymiou,Kostikas,Petrouleas
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p. 741 - 749
(2008/10/08)
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