Yuheng Deng

Trinuclear vanadium dialkyldithiocarbamate complexes. Synthesis, structure and spectroscopic characterization of [Et4N][V3(μ3-S)(η2-μ-S2)3(Et2dtc)3] · 2CH3CN

Abstract A series of [V 3 S 7 (R 2 dtc) 3 ] − complexes (R=Et ( 1 ), HOCH 2 CH 2 ( 2 )) have been studied by X-ray diffraction, IR, NMR and cyclic voltammetry. The V 3 S 7 complexes show almost the same core structure features as those of corresponding [Mo 3 S 7 (R 2 dtc) 3 ] + complexes. Three V atoms possess very similar structure parameters implying their equivalence and electronic delocalization in the V 3 S 7 core. The 1 H NMR signals of the ligating R 2 dtc ligands for the V 3 S 7 complexes occur in pairs. The signals of α-CH 2 for complex 1 were found at 7.64 and 7.66 ppm and at 7.01 and 8.00 ppm for complex 2 , which significantly shifted downfield when compared to those of the respective R 2 dtcNa. This can be explained by the contact effect of the paramagnetic center through the S 2 CNCH 2 group. The cyclic voltammogram displays two reversible couples at −1.14 and 0.00 V responsible for 1−/2− and 0/1− redox processes, respectively, of the V 3 S 7 complexes.

Synthesis, structure and characterization of heterometal VFe3S4 cubane-like cluster compound (Et4N)[VFe3S4(Et2dtc)4]

A cubane-type cluster (Et 4 N)[VFe 3 S 4 (Et 2 dtc) 4 ] has been synthesized from a self-assembly reaction system VS 4 3− /FeCl 2 /Et 2 dtc − /PhS − in acetonitrile (Et 2 dtc − = diethyldithiocarbamate). The compound has been structurally characterized by X-ray crystallography. Mossbauer and structural parameters have been used to deduce the oxidation states of the metal atoms in [VFe 3 S 4 ] 3+ core indicating that there are three Fe atoms with mean oxidation state of ca +2.8. Proton NMR spectrum indicates the paramagneticity of the cluster. The chemical shift of 51 V NMR was observed at −210 ppm. Variable-temperature magnetic susceptibility measurement reveals an antiferomagnetic interaction in the VFe 3 coupling system.

Structure and characterization of a mononuclear FeII dialkyldithiocarbamate complex Fe(OC4H8dtc)2(DMF)

Abstract A ferrous dialkyldithiocarbamate complex Fe(OC 4 H 8 dtc) 2 (DMF), which contains a Fe atom with distorted square pyramidal geometry and forms a network structure by intermolecular C–H⋯S and C–H⋯O interactions has been obtained and structurally characterized. Proton NMR and IR spectra have been studied. Structural parameters and Mossbauer effect indicate the oxidation state of +2 for the Fe site. A very large quadrupole splitting of 4.10 mm s −1 was observed and associated with an asymmetric 3d 6 (t 4 2g e 2 g ) electronic configuration.

Synthesis and structural characterization of a linear copper(I) tetrathiomolybdate complex containing the Me2dtc− ligand, (Et4N)2[MoS4(CuMe2dtc)2]

Abstract A trinuclear linear MoS 4 Cu 2 complex has been obtained from a reaction system including (NH 4 ) 2 MoS 4 , CuCl and ligands. The complex (Et 4 N) 2 [MoS 4 (CuMe 2 dtc) 2 ]·2CH 3 CN crystallizes in the triclinic, space group P -1 with crystal data: a =8.834(3), b =10.621(3), c =25.119(8) A, α =89.91(3), β =100.28(3), γ =114.55(3)°, V =2102(1) A 3 , Z =2, R =0.036 and R w =0.052 for 6091 reflections with I >3 σ ( I ). The anion [MoS 4 (CuMe 2 dtc) 2 ] 2− involves an essentially tetrahedral MoS 4 moiety and two Cu(I) atoms having distorted tetrahedral geometry. Proton and 95 Mo NMR, IR and electronic spectroscopic data have been used to interpret the structural features. A cyclic voltammogram of the complex has also been studied and compared with that of an MoS 4 Cu 3 complex (Et 4 N) 2 [MoS 4 (CuEt 2 dtc) 3 ].

Study on (Et4N)[VFe3S4(R2dtc)4] complexes with cubane-type cores: Syntheses, structure, spectral and magnetic properties and chemical behaviors in solution

Abstract A series of cubane-type cluster compounds (Et4N)[VFe3S4(R2dtc)4] (R2=OC4H8 (1), C5H10 (2), C4H8 and Et2) and (Ph4P)[VFe3S4(Bz2dtc)4] have been synthesized from a self-assembly reaction system VS43−/FeCl2/R2dtc−/PhS− in DMF and characterized. A formation mechanism of the VFe3S4 cubane was suggested to contain a possible process in which linear intermediate [VS4(FeL2)2]3− was converted to incomplete cubane-type intermediate. The dynamic study on the 1H NMR for 1 and (Et4N)[VFe3S4(Et2dtc)4] exhibits a possible metal exchange in DMSO solution, accompanying the formation of Fe4S4(R2dtc)4. Cyclic voltammograms show similar electrochemical behaviors between 1 and 2 indicated by an quasi-reversible redox couple at +0.35 to +0.66 V and two reduced peaks at −0.35 to −0.42 V and −0.75 to −0.86 V, respectively. The chemical shifts of 0.51 to 0.57 mm s−1 in Mossbauer effect of the VFe3S4 cubanes exhibit the equivalence of the three Fe atoms showing that the VFe3 skeleton can be treated as a valence-delocalized system. The metal formal oxidation states were deduced as intermediate between V(II)+3Fe(III) and V(III)+Fe(II)+2Fe(III). A magnetic exchange model based on the former valence system of V(II)/3Fe(III) was used for the fitting of variable-temperature magnetic susceptibilities, revealing an antiferromagnetic interaction in the VFe3 coupling system.

Synthesis and structure of a novel MoFe4S4 cubane-like cluster (Me3PhCH2N)2 [MoFe4S4 (SC6H11)7]

A novel (Me3PhCH2N)2[MoFe4S4(SC6H11)7] cubane-like cluster was obtained from a reaction system including (NH4)2MoS4, FeCl2 and NaSC6H11 in methanol, and characterized by X-ray crystallography. The title compound crystallizes in triclinic space group\(P\bar 1\) witha = 1.523 1(3), b =1.610 5(3),c = 1.838 3(4) nm, α = 77.18 (3)°, β = 75.17(3)°, γ = 64.60(3)°, and Z = 2. Also included in this paper are the discussions on the variation of the reaction products obtained from the participation of cyclohexylthiolate and on the changes of the structural features of the products.