129261-81-0Relevant academic research and scientific papers
Synthesis, properties, and structure of bis(cis-(methylthio)stilbenethiolato)nickel(II) and bis(cis-bis(methylthio)stilbene)nickel(II) iodide
Schrauzer,Zhang, Cheng,Schlemper
, p. 3371 - 3376 (2008/10/08)
The sulfur atoms in the bis(cis-stilbene-1,2-dithiolato)nickel(II) dianion, [Ni(S2C2Ph2)2]2- = Ni[S4C4Ph4]2-, react with alkyl halides to yield unusually stable bis(alkylthio) derivatives of composition Ni[R2S4C4Ph4], with R = alkyl. The green, diamagnetic complex with R = CH3 crystallizes in space group P21/n, with unit cell dimensions at 23°C of a = 6.127 (3) A?, b = 8.001 (3) A?, c = 27.663 (3) A?, β = 93.81 (2)°, Z = 2, and dcald = 1.407 g cm-3, and is shown to be bis((methylthio)stilbenethiolato)nickel(II), Ni[PhC(SCH3)=C(S)Ph]2. The NiS4 moiety is essentially planar with mean Ni-S bond lengths of 2.161 (2) A?. The observed ligand C-S(CH3)- and C-S bond lengths of 1.779 (5) and 1.737 (5) A? are in the range of C-S single bonds; the C-C bond distance is 1.352 (7) A?, consistent with an essentially localized electronic structure. The Ni-S-CH3 bond angles of 105.2 (2)° are smaller than expected due to crystal packing forces. In a 1:1 inclusion compound with CH2Cl2, which crystallizes in space group P1, with unit cell dimensions a = 8.424 (3) A?, b = 13.461 (3) A?, c = 14.745 (3) A?, α = 68.93 (2)°, β = 84.08 (2)°, γ = 75.10 (2)°, Z = 2, dcalc = 1.45 g cm-3, the lattice expansion causes a normalization of the Ni-S-CH3 angles to 109.2 (2)°. Variable-temperature 1H NMR measurements in solution reveal dynamic equilibria attributed to sulfur inversion and cis-trans isomerization reactions. On heating, decomposition occurs with ligand disproportionation to bis(methylthio)stilbene and nickel(II) stilbenedithiolate, [Ni(S2C2Ph2)]x. The sulfur atoms exhibit residual nucleophilic reactivity on reaction with CH3I, affording a complex of composition [(CH3)2S2C2Ph2] 2NiI2, which crystallizes in space group P21/n, with a = 8.178 (3) A?, b = 11.992 (3) A?, c = 18.229 (5) A?, β = 94.28 (2)°, Z = 2, dcalcd = 1.69 g cm-3. Its structure reveals a linear I-Ni-I moiety with two molecules of symmetrically S-bonded molecules of cis-bis(methylthio)stilbene as the ligands in the equatorial positions. The mean Ni-S bond and C-S(CH3) bond lengths are 2.379 (9) and 1.803 (4) A?, and the mean Ni-I bond lengths are 2.7989 (2) A?, respectively.
