RESEARCH ON TRINUCLEAR MOLYBDENUM CLUSTER COMPOUNDS——CRYSTAL AND MOLECULAR STRUCTURE OF Mo_3(μ_3-S)(μ_2-S_2)_3[S_2P(OEt)_2]_3Cl

The title crystal is straw-yellow in colour, belonging to the triclinic system. The space group is P with the following unit cell parameters:a=11.570(2), b=13.093(1), c=14.399(2), α=102.62(1), β=102.15(1), γ=111.87 (1)°, V=1870(1), Z=2, D_(calc)=1.960g·cm~(-3).The crystal structure was solved by the heavy atom method and refined by full-matrix least-squares to a final conventional R factor of 0.055. The results show that the crystal structure consists of neutral trinuclear Mo cluster molecules, in which three independent Mo atoms form an equilateral triangle with an average side length of 2.725(3), corresponding to a Me-Me single bond. On one side of the triangle one μ_3-S atom binds the three Mo atoms together to form a monoeapped trinuclear cluster. In addition, three S_2 radicals acting as μ_2 bridges are located between each two Mo atoms. Each Mo atom is also coordinated to two terminal S atoms of an [S_2P(OEt)_2]~- radical so as to complete a distorted pentagonal bipyramid configuration.     

STRUCTURE OF (C_5H_7S_2) [Mo_3(μ_3-0) (μ-X)_3(μ-OAc)_3C1_3] (X=Cl,Br)

<正> Introduction. In order to synthesize trinuclear Mo cluster compounds with three bridge-linked acetoxyle groups, we changed the reaction condition described in reference(1) thus obtaining two new cluster compounds with the formula(C_5H_7S_2)[Mo_3(μ_3-O)(μ-X)_3(μ-OAc)_3Cl_3] (referred to beIow as compound (Ⅰ) when X=C1 and compound (Ⅱ) when X=Br). The diffraction work shows that the crystals of these two compounds are isomorphic.     

Synthesis,structure and electrochemistry of dithiocarbamato phenthiolate oxo-molybdenum(Ⅳ)complexes[MoO(SΦ)_2(S_2CNEt_2)]

The reaction of Mo(0) complex [Mo(CO)_4(S_2CNEt_2)]~- with phenthiolate [Et_4N]SΦin acetonitrilo in the presence of small amount of air affords a new oxo-molybdenum com-plex [MoO(SΦ)_2(S_2CNEt_2)]~-,which crystallizes in two forms of crystals,[Et_4N][MoO(SΦ)_2(S_2CNEt_2)](1a) and [Et_4N][MoO(SΦ)_2(S_2CNEt_2)]·(CH_3)_2CHOH (1b).The structures of1a and 1b were determined from three-dimensional X-ray data.1a crystallizes in the mo-noclinie,space group C_c with a=12.321(4),b=15.245(4),c=16.087(9);β=98.44(4)°.V=2989~3,Z=4,D_c=1.35 g/cm~3 and R=0.031 for 2434 reflections [I>3(I)].1b crystallizes inthe monoclinic,space group P2_1/n with a=9.861(1),b=20.357(3),c=17.122(5)A;β=92.27(2)°,V=3434.3~3,Z=4;D_c=1.29 g/cm~3 and R=0.051 for 2852 independeut reflections [I>3σ(I)],The structures of 1a and 1b reveal that the anion [MoO(SΦ)_2(S_2CNEt_2)]~- contains asingle oxo ligand coordinating to a molybdenum(Ⅳ) and the geometry around Me(Ⅳ) atomis a distorted square pyramid.Interestingly,the solvate molecule isopropanol of 1b is linkedto oxo group by a hydrogen-bond of 1.928A,leading to the increase of Mo=O bond distance(1.718).Mo—S distances are 2.44 and 2,39.The electrochemical behavior of 1 wasdiscussed also.     

RESEARCH ON TRINUCLEAR MOLYBDENUM CLUSTER COMPOUNDS——CRYSTAL AND MOLECULAR STRUCTURE OF (C_5H_7S_2)_3[Mo_3(μ_3-S)(μ_2-S_2)_3Cl_7]

The space group of the title crystal is Pnam. The unit cell parameters are: a=17.226(4), b=14.306(7), c=15.074(4); z=4, Dobs=2.03g·cm~(-3), D_(calc)=2.063g·cm~(-3). The crystal structure was solved by the heavy atom method and refined by the full-matrix least-squares until the final conventional discrepancy factor was reduced to 0.068. The results of the investigation show that the crystal consists of trinuclear Mo cluster anions [Mo_3(μ_3-S)(μ_2-S_2)_3Cl_7]~(3-) together with planar (C_5H_7S_2)~ monocations, surrounding the cluster anions. In the cluster anion three Mo atoms, forming a nearly equilateral triangle (2.755(1), 2.755(1), 2.743(1)), are bound by a μ_3-S bridging atom, while each pair of Mo atoms is bridged further by a μ_2-S_2 ligand. Besides, each Mo atom is coordinated to two terminal Cl atoms, so that the coordination sphere of each Mo atom approaches closely a pentagonal bipyramid. In addition, a single Gl atom, not at all involved in the coordination spheres of the three Mo atom     

RESEARCH ON TRINUCLEAR MOLYBDENUM CLUSTER COMPOUNDS——CRYSTAL AND MOLECULAR STRUCTURE OF Mo_3(μ_3—O)(μ_2—S_2)_3[S_2P(OEt)_2]_3I

The title crystals are golden yellow rhomboic plates, belonging to the monoelinic system. The space group is P_(B_1)/n with unit cell parameters a=16.570(2), b=12.370(1), c=20.007(2), β=99.97(1)°, Z=4, D_c=1.938 g.cm~(-3). The crystal structure was solved mainly by the heavy atom method and refined by the full-matrix least-squares to a final R factor of 0.047 based on 4387 unique reflections with intensities I≥2σ(I). The results show that the crystal structure consists of neutral mono-oxo-capped trinuclear molybdenum cluster molecules with an average Mo-Mo bond length of 2.626(4) and an average Mo-O bond length of 2.036(2) respectively. Each pair of Mo atoms is further bridged by an S_2~(2-) radical, in which one S atom is essentially situated on the triangular plane formed by these three Mo atoms and the other one is situated on the side of the plane opposite to the μ_3-O atom. Besides, each Mo atom is coordinated to two S atoms belonging to an [S_2P(OEt)_2]~-radical so as to complete a nearly pen     

STUDY ON STRUCTURE OF SULFUR-BRIDGED TRANSITION METAL CLUSTERS——CRYSTAL AND MOLECULAR STRUCTURE OF (C_5H_7S_2)_3 [Mo_3(μ_3-S)_2 (μ_2-Cl)_3Cl_6]

The compound (C_5H_7S_2)_3[Mo_3 (μ_3--S)_2 (μ_2--Cl)_3 Cl_6] forms dark black octahedralcrystals with the following crystallographic parameters: a=22.885(10)A, c=25.407(7)A. Thespace group is I4_1/α, Z=16, ρ_(obs.)=2.073g/cm~3, ρ_(calc.)=2.126g/cm~3. The 1621 independentreflections with I≥3σ were collected on a CAD-4 four-circle diffractometer by means of MoK_αradiation. The structure was solved by three-dimensional Patterson synthesis and refined byleast squares technique to a final discrepancy factor of R=0.056. The results of our investiga-tion reveal that the molecule consists of a trinuclear Mo cluster anion and three planar mono-cations.surrounding the cluster anion. As the core of the anion the triad of Mo atoms, possessing anequilateral triangular configuration, is linked by two μ3--S bridging atoms and three μ2--Clatoms. Besides, two terminal Cl atoms are attached to each Mo atom to form an octahedralconfiguration. The diamagnetism and the short Mo-Mo distances (2.556 A, 2.641 A, 2.653 A)clearly indicate the existence of Mo-Mo bonds. The anion as a whole has an idealized D_(3h) localsymmetry.     

STUDY ON TRINUCLEAR MOLYBDENUM CLUSTER COMPOUNDS——THE CRYSTAL AND MOLECULAR STRUCTURE OF THE TWO TRINUCLEAR MOLYBDENUM CLUSTERS(C_5H_7S_2)[Mo_3(μ_3-O )(μ-X)_3(μ-OAc)_3Cl_3](X=Cl,Br)

The crystal structure of two isomorphic cluster compounds with formula (C_5H_7S_2)-[Mo_3(μ_3-O)(μ-X)_3(μ-OAc)_3Cl_3] (X=Cl for compound (Ⅰ) and compound (Ⅱ)) has been investigated by X-ray diffraction method. The parameters of two crystals are: a=10.423(1),b=17.095(4), c=14.062(7), β=97.54(4)(°); Dc=2.20gcm~(-3), D_o=2.17g cm~(-3) for compound (Ⅰ). and a=10.511(3), b=11.213(2), c=14.053(3), β=96.12(2)(°); D_c=2.52g cm~(-3), D_o=2.53gcm~(-3) for compound (Ⅱ). The space groups are P2_1/C. Z=4. The 2621 and 2548 independent reflections with I>3σ(I) were collected on a CAD-4 four-circle diffractometer by means of MoKα radiation. The crystal structures were solved by heavy atom method and refined by full-matrix least-squares technique to a final discrepancy factors of R=0.061 and 0.051 respectively. The results of investigation show that the molecule consists of the cation (C_5H_7S_2)+ and the trinuclear Mo cluster anion, the configuration of which is similar to that of (Et_4N)_2[Mo_3(μ_3-O)(μ     

THE CRYSTAL STRUCTURE OF Mo_203[S_2P(OC_2H_5)_2]_4

<正> Introduction. In an attempt to synthesize Mo cluster compounds from the high-valenced Mo compounds in P_2S_5/EtOH-HC1 system we have obtained a brownblack rhombohedral crystal. The composition of it Mo_2O_3[S_2P(OC_2H_5)_2]_4 has been confirmed by X-ray single crystal structure determination, which reveals that the crystal structure is different from that by Knox, J. R. & Prout, C. K. (1969).     

Synthesis and structure of an open-type trinuclear molybdenum cluster compound[Mo_3(μ_3-S)(μ-S)_2-(μ-OAc)(S_2CNC_4H_8)_3(O)_2]·0.5CH_2Cl_2·2H_2O

The title compound was prepared by the reaction of Mo_3S_4(dtp)_4(H_2O)[ctp=S_2P(OEt)_2]with NaOAc·3H_2O and C_4H_8NCS_2NH_4.Crystallographic data:[Mo_3(μ_3-S)(μ-S)_2(μ-OAc)-(S_2CNC_4H_8)_3(O)_2]·0.5CH_2CI_2·2H_2O,Mr=980.18,triclinic,space group P,α=12.360(3),b=16.653(6),c=9.206(2)A,α=101.97(2),β=108.32(2),γ=86.14(3)°.V=1759.6(9)A~3,Z=2,Dc=1.85 g/cm~3,F(000)=962,μ(Mo K_α)=16.53 cm~(-1).Final R=0.044 for 4301 reflections with I≥3σ(I).This compoundmay be regarded as a mixed-valent trinuclear molybdenum cluster{Mo_2(V)Mo(Ⅳ)(μ_3-S)(μ-S)_2-(μ-OAc)(S_2CNC_4H_8)_3(O)_2}.The Mo-Mo distances are 2.783(1),2.833(1)and 3.374(2)A in the Mo_3non-equilateral triangle and there exist only two Mo-Mo bonds.The cluster was obtained by oxi-dation and ligand substitution of{Mo_3(μ_3-S)(μ-S)_3[μ-S_2P(OEt_2)][S_2P(OEt)_2]_3(H_2O)}.     

SYNTHESIS AND STRUCTURE OF A TRITHIOCARBONATO Mo(Et_4 N)_2 [(S_2)Mo_2O_2(μ-S)_2(CS_3)]

A new trithiocarbonato Mo complex(Et_4N)_2[(S_2)Mo2O_2(μ-S)_2(CS_3)]was obtained from asystem containing MoO_4~(2-),S_x~(2-),and CS_2 and characterized by IR and X-ray structural analysis.The complex crystallizes in the (?)onoclinic space group P2_1/c with a=9.539(3)(?),b=20.745(2)(?),c=15.452(2)(?),β=94.58(2)°,and Z=4.The structure was solved by direct anddifference Fourier synthesis methods.Least squares refinement using 2910 reflections withI>3σ(I)converged to R=0.054.The CS_3~(2-) iigand in the complex chelates to Mo atom andvalues of the C-S bond distances in the CS_3~(2-) ligend indicate a substantial contribution ofthree resonance forms.     

Synthesis and crystal structure of [V_2(μ-S_2)_2(S_2CNEt_2)_4]·2CH_3Cl

[V_2(μ-S_2)_2(S_2CNEt_2)_4].2CH_3Cl was synthesized by the reaction of NaS_2CNEt_2,Li_2S andVOCl_3 at room temperature.Crystal data:M=1061.3,space group Pbca,with the orthorhombicparameters:a=20.123(3),b=20.485(4),c=10.911(3),V=4497.7,Z=4,D_c=1.57g/cm~3,Mo Kσradiation(λ=0.71069()?),μ=13.2 cm~(-1),F(000)=2168.Final R=0.041 and R_w=0.047 for 2288 ob-served reflections with I>3σ(1).The coordination sphere of each V atom in title compound is a dis-torted tetragonal prism composed of two bidentate dithiocarbamate and two S_(2~((2-)) ligands.The V—Vdistance is 2.890 while the V—S distances fall in the range of 2.422—2.505.     

STUDY ON THE REACTION PERFORMANCE OF CLUSTER COMPOUND——A REACTION OF Cu(+2) CAPTURING LIGANDS FROM MOLYBDENUM CLUSTER AND THE CRYSTAL STRUCTURE OF ITS PRODUCT Cu_8Cl_2[S_2P(OEt)_2]_6

The oxidation-reduction reaction of the molybdenum cluster compound Mo_3(μ_3-S)(μ-S)_2-[μ-SOP(OEt)_2] [S_2P(OEt)_2]_3(O)_2 with CuCl_2·2H_2O has been investigated and the chemical components of its product, Cu_8Cl_2[S_2P(OEt)_2]_6, were confirmed. The crystal belongs to the triclinic system and the space group is P with the following unit cell parameters: a=11.578 (5), b=12.663 (3), c=14.317 (4); α=55.54 (2)°, β=57.35 (3)°, γ=72.23 (3)°; Z=1; D_(calc)=1.926 g·cm~(-3). Final discrepancy factor of R is 0.075 for 3573 unique reflections with I≥3σ(I). The results of investigation show that the crystal structure consists of molecular chains with Cu_8Cl_2[S_2P(OEt)_2]_6 as structural unit, in which eight Cu atoms form a cube-shaped cage. The coordination sphere of each Cu atom is a tetrahedron configuration. The distances between Cu atoms are 3.018-3.437, which indicates that there are no metal-metal bonds between Cu atoms. It is worthwhile to study further the phenomenon how Cu(+2) captures the     

THE STRUCTURE AND SYNTHESIS OF [MoFe_3S_4(Etadtc)·_5]MeCN

<正> INTRODUCTION. More and more models of active center were suggested with wide study on the MoFe-protain and FeMo-cofactor of nitrogenase. Most of them contain MFe_3S_(3+4) (M=Mo,Fe) cubane-type core, so a great interest has been focused on the Studies of MoFe_4, cubane-type compounds. The type species have been reported by holm et al. We have also made researches on the single cubane-like compounds. Here we describe the synthesis and structure of [MoFe_3S_4(Et_2dtc)_5MeCN (1).     

SYNTHESIS, STRUCTURE AND ELECTROCHEMICAL STUDIES ON SINGLE MoFe_3S_4 AND WFe_3S_4 CUBANE-TYPE CLUSTER COMPOUNDS*

Single cubane-like clusters, MFe_3S_4(R_2dtc)_5 (M=Mo, R_2=—(CH_2)_4—, Bz_2; M=W, R_2=Me_2, —(CH_2)4—; dtc=dialkyldithiocarbamate) were synthesized by assembly reaction of (NH_4)_2MS_4 (M=Mo, W), FeCl_2 with R_2dtcNa (or NH_4) in DMF. The structure, IR, EPR and cyclic voltammogram are described and discussed. MoFe_3S_4(C_4H_8dtc)_5 was also obtained from the conversion of linear cluster Fe(DMF)_6[(FeCl_2)_2MoS_4] in the presence of C_4H_8dtc NH_4. Both clusters MoFe_3S_4(C_4H_8dtc)_4·2C_2H_5CN and WFe_3S_4(C_4H_8dtc)_5·2DMF crystallize in the monoclinic space group C2/c with a=12.544(2), (Mo-cluster), 12.533(4) (W-cluster); b=20.478(4), 20.121(6); c=19.582(7), 19.659(2);β=102.82(2), 102.96(3)°; and Z=4, 4. Their structures were refined to R=0.057 and 0.064 with use of 2690 and 2179 reflections (ι>3Q(I)), respectively. Many similarities in structure for Mo and W clusters indicate that both Mo and W play a very similar role in the clusters.     

A CLUSTER COMPOUND WITH DI-ENDOXYGEN LIGANDS——THE CRYSTAL AND MOLECULAR STRUCTURE OF [Fe(MOS_4O)_2][N(C_2H_5)_4]3

[Fe(MoS_4O)_2] [N(C_2H_3)_4]_3 cluster compound with di-end-oxygen ligands has been prepared and characterized by the X-ray diffraction method. The compound crystallizes in a monoclinic space group P2_1/n with lattice parameters a=13.019(4), b=16.959(5), c=18.234(5), β=97.34(2)(°), Z=4. The final agreement factors are R=0.0740, Rw=0.0598. The terminal bond length, Mo-S_t and bridged one, MO-S_b for the compound are much longer than the counterpart without end-oxygen ligand. It possibly suggests that low valence of molybdenum and smaller electronegativity of sulphur than oxygen lead to the charge transfer as S→Mo→O.     

SYNTHESIS AND CRYSTAL STRUCTURE OF TWO TRINUCLEAR MOLYBDENUM CLUSTERS CONTAINING A LOOSE COORDINATION SITE, {Mo_3(μ_3—S)(μ—S)_3[S_2P(OEt)_2]_4-(C_3H_3ON)}·CH_3CN (Ⅰ) AND {Mo_3-(μ_3—O)(μ—S)_3[S_2P(OEt)_2]_4-(C_3H_3ON)}(Ⅱ)

The synthesis and crystal structure of two trinuclear molybdenum clusters containing a loosecoordination site, {Mo_3(μ_3-S)(μ-S)_3[S_2P(OEt)_2]_4(C_3H_3ON)}· CH_3CN (Ⅰ) and {Mo_3(μ_3- O)-(μ- S)_3[S_2P(OEt)_2]_4(C_3H_3ON)} (Ⅱ), are reported. Cluster (Ⅰ) belongs to the monoclinic spacegroup p2_1/n, a = 16.579 (3), b = 16.959 (2), c = 16.867 (2) A, β= 94.44 (1)°, V = 4728A~3,Z = 4, D_c = 1.778g·cm~(-3). The crystal structure was solved by the Patterson method with afina1 R value of 0.045. Cluster (Ⅱ) belongs to the triclinic space group Pi, a = 13.175 (4),b = 13.372(6), c = 16.656(3)A, α= 117.87(4), β= 60.09(3), γ= 109.03(3)°, ν= 2231A~3,Z = 2, D_3 = 1.798g·cm~(-3). Direct methods were used to solve the crystal structure with afinal R value of 0.066. Both clusters are monocapped trinuclear ones having an oxazoleoccupied coordination site as their main structural characteristic. The difference in cappingatoms results in the difference in their skeletons, Mo_S_4 in cluster (Ⅰ) vs. Mo_3OS_3     

MOLYBDENUM-IRON MIXED METAL CLUSTERS (Ⅰ)——THE SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF (η~5-C_5H_5)_2Mo_2Fe_2(μ_4-Te)(μ_3-Te)_2(CO)_6

The reaction of Fe_2(μ_3-Te)_2(CO)_9 with Mo_2(CO)_6(η~5-C_5H_5) affords the title compound. Its X-ray analysis shows a butterfly structure for the Mo_2Fe_2 core; the two molybdenum atoms occupy the hinge with a Mo—Mo bond distance of 2.819 and the two iron atoms are on the tops of the wings with an average Mo—Fe bond distance of 2.932(2). Each molybdenum is bonded to a Cp ring, and three CO ligands are terminally bonded to each iron atom. One tellurium atom quadruply bridges Mo_Fe_2 with Mo—Te(μ_4)=2.625(2). and Fe—Te(μ_4)=2.713(2). Two tellurium atoms triply bridge the two triangular Mo_2Fe faces with Mo—Te(μ_3)=2.678(1) and Fe—Te(μ_3)=2.513(3). The molecule has C_(2v) symmetry and a bicapped triangle bipyramidal skeleton. Crystallographic parameters are as follows: space groupImm2(orthorhombic), a=14.562(3), b=10.391(1), c=7.139(4), V=1080.2(i)~3, Z=2, ρ(cald)=1.819g·cm~(-3). The final R factor was 2.2％ for 620 independent reflections(I>2σ(I)).     

SYNTHESES AND STRUCTURAL STUDIES OF Mo-Fe-S-CLUSTER COMPOUNDS Ⅶ.SPECTROSCOPIC STUDY OF THE [MoFe_3S_4] CUBANE UNIT IN (Bt_4N)4(Mo_2Fe Sa(SR)_12] AND RELATED COMPOUNDS

<正> INTRODUCTION. In the study of nitrogenases, scientists have proposed many models for the active center of MoFe protein and for FeMoco. All of them contain a basic structural unit [FeS_2M] (M=Fe or Mo). We have reported some structural regularities in a series of linear Mo-Fe-S compounds. In order to investigate the electron distribution and the synergism of metal atoms within a Mo-Fe-S cluster with [MoFe_3S_4] cubane unit, we have synthe     

(NH_4)_2[MO_2(S_2)_6]·8/3H_2O的晶体结构

(NH_4)_2[Mo_2(S_2)_6]·~(8/3)H_2O的黑色晶体属于正交晶系,D_2~3-P22_12_1空间群,晶胞参数a=12.064(6)A,b=12.534(4)A,c=19.558(9)A,V=2957(3)A~3,Z=4,D_c=2.23 g·cm~(-3)。结构修正后,R=0.092,R_ω=0.072.晶体由[MO_2(S_2)_6]~(2-)二核原子簇离子、NH_4~ 离子和H_2O分子组成。晶体中有两套晶体学上独立的[Mo_2(S_2)_6]~(2-)离子,其一处在一般位置,另一处在二重轴上。每一不对称单位中含有1.5个[Mo_2(S_2)_6]~(2-)离子,在[Mo_2(S_2)_6]~2-离子中,每个Mo被4个S_(2-)~2侧接配位,按变形的十二面体排列,其中的两个桥式连接于两个Mo之间,其余两个接在外端。Mo-S键长2.441A(平均),S—S键长2.049A(平均)。Mo-Mo键长2.784A(平均),与单键键长相当。Mo的形式价态为五价,很可能是MO~(lV)-Mo~(VI)混合价态,从而在颜色上产生显著特点.     

SYNTHESIS AND STRUCTURE OF A NEW DINUCLEAR MOLYBDENUM(O) COMPLEX [Et_4N]_2 [Mo_2 (CO)_8 (SCH_2COOEt)_2]

<正> t Reaction of Et^NI, NaSCH2COOEt with Mo(CO)6 in MeCN affords a new dinuclear molybdenum(O) complex, [Eti,N]2 [Mo2(CO) 8(SCH2COOEt)2] (I) . The crystal and molecular structure has been determined from three-dimensional X-ray data. 1_ crystallizes in the triclinic, space group PI with a=10.362(1), b= 10.391(1), c=10.815(2) X, a=91.64(2), 6=100.07(2), Y=H4.46(1)? Z=l, R= 0.048 for 2975 reflections with I?o(I). Noribonding of Mo...Mo distance (3.939(11)A) in _! supports the previous speculation for the two-electron redox properity,of complex anion, [Mo2(CO)g(SR)2J2~.