1037632-74-8Relevant articles and documents
Synthesis, Structures, and properties of 1,2,4,5-benzenetetrathiolate linked group 10 metal complexes
Arumugam, Kuppuswamy,Shaw, Mohamed C.,Chandrasekaran,Villagran, Dino,Gray, Thomas G.,Maguey, Joel T.,Donahue, James P.
, p. 10591 - 10607 (2010/02/15)
Dimetallic compounds [(P-P)M(S2C6H2S 2)M(P-P)] (M=Ni, Pd; P-P=chelating bis(phosphine), 3a-3f) are prepared from O=CS2C6H2S2C=O or nBu2SnS2C6H2S 2SnnBu2, which are protected forms of 1,2,4,5-benzenetetrathiolate. Selective monodeprotections of O=CS 2C6H2S2C=O or nBu 2SnS2C6H2S2Sn nBu2 lead to [(P-P)Ni(S2C6H 2S2C=O)] or [(P-P)Ni(S2C6H 2S2SnnBu2)]; the former Is used to prepare trimetallic compounds [(dcpe)Ni(S2C6H 2S2)M(S2C6H2S 2)Ni(dcpe)] (M = NI (6a) or Pt (6b); dcpe = 1,2- bis(dicyclohexylphosphino)ethane). Compounds 3a-3f are redox active and display two oxidation processes, of which the first is generally reversible. Dinickel compound [(dcpe)Ni(S2C6H2S2)Ni(dcpe) ] (3d) reveals two reversible oxidation waves with ΔE1/2=0.66 V, corresponding to Kc of 1.6 x 1011 for the mixed valence species. Electrochemical behavior is unstable to repeated scanning In the presence of [Bu4N][PF6] electrolyte but indefinitely stable with Na[BArF24] (BArF24 = tetrakis(3, 5-bis(trifluoromethyl)phenyl)borate), suggesting that the radical cation generated by oxidation Is vulnerable to reaction with PF6 -. Chemical oxidation of 3d with [Cp2Fe][BArF 24] leads to formation of [3d][BArF24]. Structural identification of [3d][BArF24] reveals appreciable shortening and lengthening of C-S and C-C bond distances, respectively, within the tetrathioarene fragment compared to charge-neutral 3d, indicating this to be the redox active moiety. Attempted oxidation of [(dppb)Ni(S2C 6H2S2)Ni(dppb)] (3c) (dppb = 1,2-bis(diphenylphosphino)benzene) with AgBArF24 produces [[(dppb)Ni(S2C6H2S2)Ni(dppb)] 2(w-Ag2)][BArF24]2, [4c][BArF 24]2, in which no redox chemistry has occurred. Crystal structures of bis(disulfide)-linked compounds [(P-P)Ni(S2C 6H2(w-S2)2C6H 2S2)Ni(P-P)] are reported. Near IR spectroscopy upon cationlc [3d]+ and neutral 6a reveals multiple intense absorptions In the 950-1400 nm region. Time-dependent density functional theory (DFT) calculations on a 6a model compound indicate that these absorptions are transitions between ligand-based π-type orbitais that have significant contributions from the sulfur p orbitais.
A convergent approach to the synthesis of multimetallic dithiolene complexes
Arumugam, Kuppuswamy,Yu, Rongmin,Villagran, Dino,Gray, Thomas G.,Mague, Joel T.,Donahue, James P.
, p. 5570 - 5572 (2009/02/03)
Controlled base hydrolysis of one or both of the protected 1,2-dithiolene chelates of 1,3,5,7-tetrathia-s-indacene-2,6-dione (O=CS2C 6H2S2C=O) enables the stepwise synthesis of di- and trimetallic complexes with 1,2,4,5-benzenetetrathiolate as the connector. Treatment of O=CS2C6H2S2C=O with MeO-, followed by [NiBr2(dcpe)] [dcpe = 1,2-bis(dicyclohexylphosphino)ethane], yields [(dcpe)Ni(S2C 6H2S2C=O)] (4). The reaction of 4 with EtO -, followed by [MX2(dcpe)] (X = halide), yields [(dcpe)Ni-(S2C6H2S2)M(dcpe)] [M = Ni (5a), Pd (5b)]. Deprotection of the 1,3-dithiol-2-one group of 4, followed by introduction of 1/2 equiv of MX2 and then I2, yields the neutral trimetallic compounds [(dcpe)Ni(S2C6H 2S2)]2M [M = Ni (6a), Pt (6b)]. Tetrahedralization at nickel is observed in 5a, which density functional theory calculations attribute to second-order Jahn-Teller effects, while 6a and 6b display an end-to-end folding of ～46°. A color darkening is observed in moving from 4 to compounds 6 due to the increasing size of the conjugated metal-organic π system. Intense, broad absorptions in the near-IR are observed for 6a and 6b.
