Liangren Huang

Syntheses and stereochemistry of dicobalt(II) complexes [Co2(dppm)(μ-SR)2(SR)2](dppm Ph2PCH2PPh2; R C6H5, m-C6H4CH3, p-C6H4CH3 and p-C6H4-tC4H9) and [Co2(dppe)(μ-SPh)3(SPh)] (dppe Ph2PCH2CH2PPh2)

Abstract From reactions of Co(dppm)2Cl2 or Co(dppm)Cl2 with thiolate and elemental selenium or sulphur in DMF, the following complexes were prepared in good yields: [CO2(dppm)(μ-SR)2(SR)2] (R  C6H5, 1; m-C6H4CH3, 2; p-C6H4CH3, 3; and p-C6H4- tC4H9,4). Compound 1 crystallizes in two different isomeric crystals, 1A and 1S, containing three stereoisomers of molecular conformations: 1aa, 1sa and 1ss. The two different crystal structures of compound 1 were confirmed by thermal analysis and IR spectra. Compound 2 crystallizes with molecules of type ss. Compound [Co2(dppe)(μ-SPh)3(SPh)] (5) is an asymmetric molecule with one five-coordinate cobalt atom and one four-coordinate cobalt atom. From the EPR spectra and magnetic susceptibility data, it is deduced that there is antiferromagnetic coupling between the two paramagnetic cobalt(II) atoms in compounds 1–5.

A novel pentanuclear CoS raft cluster compound consisting of fused Co3(μ3-S) units: X-ray crystal structure of Co5(CO)2S3(SC5H4N)7

Abstract The reaction of Na[Co(CO)4] with Pys—(2-mercapto-pyridine) in THF at room temperature gave a dark crystalline product [Co5(CO)2(μ3-S)3(SC5H4N)7] (1). The crystal structure of 1 determined by single crystal X-ray diffraction, revealed a pentanuclear metallic core, Co5(μ3-S)3(μ-S), which can be described as a skeleton comprising three incomplete cubane-like structural units, two SCo3S3 and a SCo3S3C, in an inversion arrangement sharing two rhombic CoS3Co faces or, in other words, as a raft-type structure consisting of fused Co3(μ-S) units. The geometry around each Co atom is a distorted octahedron and the octahedra are divided into four types according to the different coordination environments. The three CoCo bond distances of 2.72–2.80 A indicate weak metal metal interactions. The formal dation states of the five cobalt atoms are one CoI and four CoIII. The formation of 1 is discussed and the cyclic voltammetry of 1 has been measured. Interestingly, 1 contains three inorganic μ3-S atoms notwithstanding the absence of inorganic S2-source in the synthetic reaction system, implying a process related to desulfurization of 2-mercaptopyridine in the preparative reaction.

Synthesis and structural characterization of a monocapped-prismane cobalt cluster [Co77(μ4-S)3(μ3-S)3(PPh3)4Br1.5Cl1.5]

Abstract The title compound has been obtained by treating CoCl(PPh3)3 with excess Li2S in chloroform. An X-ray diffraction study established that the structure of the Co7S6 core can be viewed as a monocapped-prismane or a perfect cube [Co8S6] missing a corner cobalt, which possesses a crystallographic C3 axis coincident with the Co(1)P bond.

Heteronuclear metal cluster complexes with a new coordination mode of the Fe2S2(CO)6 unit. Synthesis, structure and possible reaction pathway of the first FeCuS cluster compound, [Fe6Cu5S6(CO)18(PPh3)2]−

Abstract The first iron-copper-sulfur cluster compound [Et 4 N][Fe 6 Cu 5 (μ 4 -S) 6 (CO) 18 (PPh 3 ) 2 ] ( 1 ) is prepared by the reaction of [Et 4 N][CuCl 2 PPh 3 ] with Li 2 [Fe 2 S 2 (CO) 6 ] in mixed solvents of MeCNCH 3 OH. 1 ·MeCN crystallizes in the monoclinic, space group Pn with a = 12.426(3), b = 15.572(4), c = 20.709(4) A;β= 90.14(2)°; V = 4007.2 A 3 ; Z = 2, D c = 1.80 g cm −3 , and R 1 = 0.032, R 2 = 0.037 for 3319 independent reflections ( I >3σ( I )). The anion of 1 contains an undeca-nuclear FeCuS core with Fe 1 and Cu I , [Fe 6 Cu 5 (μ 4 -S) 6 ] − , which consists of a central trigonal bipyramid composed of five copper atoms in the center and three ‘butterfly’ type Fe 2 S 2 units chelating to the copper atoms of the central Cu 5 trigonal bipyramid along the pseudo- D 3 axis resulting in pseudo- D 3 symmetry. All the sulfur atoms in 1 are μ 4 -S, linking to two iron and two copper atoms. Around the core, twelve terminal carbonyls, six bridging CO groups and two PPh 3 ligands meet the requirement of four-coordination of the copper atoms and five-coordination of the iron atoms. FeS and CuS distances are 2.28–2.36 and 2.24–2.51 A, respectively. There are fifteen MM bonds in 1, including three FeFe of 2.5 A, six CuFe of 2.7 A and six CuCu of 2.6 A. The Fe 2 S 2 (CO) 6 units in 1 take a new coordination mode in that each unit coordinates to four metal atoms by its two sulfur atoms in a μ 4 -type fashion. A possible reaction pathway for 1 via the formation of two reactive fragments is proposed and discussed.

Molybdenum(tungsten)-iron-sulphur clusters with low valence molybdenum (tungsten) atoms: Synthesis, structure and properties of a new MFeS cluster containing an M(μ3-S)2Fe2 core with an M0 atom, [Et4N][MFe2S2(CO)8(S2CNEt2)] (M = Mo, W)

Abstract The reaction of (Et4N)[M(CO)4(S2CNEt2)] (M = Mo, W) with Li2[Fe2S2(CO)6] in THF, MeOH and MeCN at room temperature for 24 h gave dark red crystalline MFeS products, (Et4N)[MFe2(μ3-S)2(CO)8(S2CNEt2)] [M = Mo(1), W(2)]. The yields are 42 and 36% for 1 and 2, respectively. Compounds 1 and 2 were characterized by routine elemental analysis and spectroscopy. Their structures were determined from three-dimensional X-ray data. The structure of the anion of [MFe2(μ3-S)2(CO)8(S2CNEt2)]− [M = Mo(1), W(2)] reveals that 1 and 2 belong to a new class of Mo(W)FeS clusters which contain neither cubane-like MFe3S4 nor the linear M(μ2-S)2Fe unit but a new type of M(μ3-S)2Fe2 core (with the M atom in a low oxidation state), which is best viewed as a distorted tetragonal pyramid with an MFe bond distance of 2.76 A, MS of 2.40 A and a pseudo planar Fe2S2 unit (with FeS 2.25 A and Fe ⋯ Fe 3.395 A). The 57Fe Mossbauer spectra of 1 and 2 show δ = 0.008, ΔEq = 0.965 mm s−1 and δ = 0.007, ΔEq = 0.834 mm s−1 for 1 and 2, respectively, and the magnetic susceptibility measurements indicate that both 1 and 2 are diamagnetic. This implies that the iron atoms in both 1 and 2 are low spin FeII (SO) and the M atoms are M0. The influence of the introduction of the low valence M atom on the configuration of the Fe2S2(CO)6 unit in 1 and 2, the existence of M0 → Fe electron delocalization and possible synthetic reaction mechanisms are discussed.

Synthesis, structure, and properties of tetraethylammonium bis[bis(2-oxyphenyl)-disulfide-O,O',S] manganese(III)

Abstract The title compound (Et4N)[Mn(MP-MP)2] (1) was obtained by air oxidation of an acetonitrile solution of MnCl2-4H2O and Na2MP. The structure of 1 was determined by single crystal X-ray diffraction methods. Crystal data: C32H36MnNO4S4, monoclinic, P21/c, a = 9.598(3), b = 16.845(3), c = 10.702(3) A, β = 111.20(1)°, V= 1613.1 A3, Z = 2; Mr = 681.84; d x = 1.40g cm−3 F(000) = 712; μ = 6.8cm−1, crystal dimensions 0.40 × 0.20 × 0.20 mm3. The Mn atom is octahedrally and symmetrically coordinated by two MP-MP2- ligands, each providing two phenolate-oxygen and one disulfide-sulfur atoms to form a terdentate. The presence of an S-S bond is revealed by the distance of 2.093 A, which constitutes the first disulphide chelated to the Mn(III) ion. The paramagnetic nature of the high spin Mn(d4) ion is reflected in a value of μcff of 4.83 μB and broad 1H NMR absorptions at 23 ∼ 25ppm and –12∼-17ppm.

Syntheses and crystal structures of heptanuclear clusters [VS4(CuPPh3)5Br2CuX] and [VS4(CuPPh3)5Br2CuX]·CH2Cl2 (X = 0.5Br + 0.5Cl)

Abstract The preparation of the title compounds of heptanuclear heterometallic clusters by heating a mixture of (NH4)3VS4, CuCl, PPh3 and Et4NBr in a solid state reaction at low temperature has been investigated. The compounds [VS4(CuPPh3)5Br2CuX] (1) and [VS4(CuPPh3)5Br2CuX]·CH2Cl2 (2) have been characterized by single-crystal X-ray diffraction. The clusters consist of a tetrahedral VS4 core bound to an octahedral array of six copper atoms which have two different coordinations, trigonal planar and tetrahedral. Each copper atom is bound to a terminal ligand: five of these are PPh3 molecules and one a halogen atom. The geometries of the two additional bridging bromine atoms are different in the litle clusters. Forcluster 1 both bromine atoms are μ2 atoms, while for cluster 2 one is μ2-Br and the other μ3-Br.

A new molybdenum-tungsten-sulphur cluster complex family, [{(OC)4M}xM′S4]2− (M = Mo or W, M′ = Mo or W; x = 1,2). Synthesis, structure and properties of a new trinuclear mixed-valence MoS cluster, [Et4N]2[(OC)4MoS2MoS2Mo(CO)4]

Abstract The reaction of molybdenum(0) dithiocarbamato carbonyl complexes, [Et 4 N][Mo(CO) 4 (S 2 CNEt 2 ] with tetraethyl ammonium tetrathiomolybdate in MeOH affords a trinuclear mixed-valence MoS complex, [Et 4 N] 2 [(OC) 4 MoS 2 MoS 2 Mo(CO) 4 ] ( 1 ) in high yield. The structure of 1 was studied by X-ray crystallography. The structure of the anion of 1 comprises two octahedra around low-valence molybdenum atoms and a tetrahedron with the high-valence molybdenum atom in the centre sharing two edges which are the line between the bridging sulphur atoms. Thus, 1 contains a trimetallic MoS 2 MoS 2 Mo core with two Mo 2 S 2 planes sharing a molybdenum atom perpendicularly. The MoMo bond distances are 2.9979(6) and 3.0003(6) A; the MoMoMo angle is 174.46(2)° and MoS bond lengths are 2.22 and 2.53 A 95 Mo NMR measurements show that the three molybdenum atoms in 1 are in two oxidation states. The cyclic voltammetry studies on 1 and the dinuclear complex, [(OC) 4 MoS 2 MoS 2 ] 2− , reveal the existence of two different redox metal centres in 1 . The electron delocalization between the three mixed-valence molybdenum atoms is discussed by comparing them with the dinuclear molybdenum member of this cluster family.

New dinuclear molbydenum(0)-SR compound containing a “butterfly” type MoS2Mo core: synthesis, structure and cyclic voltammetry of DI-(o-methylphenthiolato)dimolybdenum(0) cotacarbonyl dianion, Mo2(o-CH3C6H4S)2(CO)8]2−

Abstract Reaction of molybdenum hexacarbonyl with o -methyl-thiophenolate in MeCN afforded a new dinuclear Mo 0 SR compound, [Et 4 N] 2 [Mo 2 ( o CH 3 C 6 H 4 S) 2 (CO) 8 ] ( 1 ). Compound 1 ·MeCN was characterized by single-crystal X-ray structure determination and its electrochemical behaviour was measured by cyclic by voltammetry. The anion of 1 contains a “butterfly” type bimetallic MoS 2 Mo core with an MoMo distance of 3.942(3) A, MoS of 2.622 A, SMoS of 77.3° and MoSMo of 97.54°, and exhibits very different electrochemical behaviour from its analogues, [Mo 2 (0-OHC 6 H 4  S ) 2 (CO) 8 ] 2− ( 4 ) with a core which consists of a non-planar MoS 2 Mo unit and a bridging carbonyl. Considering 1–4 together, the synthesis, influence of steric hindrance of ligands on MoS 2 Mo core configuration and thus on the electrochemical behaviour were discussed.

Synthesis and X-ray structure of an asymmetrical dicobalt(II) complex Co2(dppe)(µ-SPh)3SPh (dppe = Ph2PCH2CH2PPh2)

An asymmetrical dinuclear cobalt complex Co2(dppe)(µ-SPh)3SPh (dppe = Ph2PCH2CH2PPh2) has been prepared and characterized by X-ray diffraction showing the entirely different geometrical environments of the two cobalt(II) atoms.