Synthesis and crystal structure of an ionic cluster {[Mo_3(μ_3-O)(μ-S)_3(dtp)_3(py)_3][CdI(dtp)_2]}

A new cluster compound {[Mo3(μ3-O)(μ-S)3(dtp)3(py)3][CdI(dtp)2]} (dtp=S2P(O-was obtained from the reaction of (Mo3OS3(dtp)4(H2O)] with a CdI2-Bu4NI mixture.The molecular structure is composed of a cluster cation [Mo3OS3(dtp)3(py)3]+ and the complex anion [CdI(dtp)2]-Crystal data:Triclinic,space group P1 with cell parameters a=1.4672(7),b=1.5356(5),c=1.6806(5) nm,α=74.59(3),β=67.89(4),7=78.86(3)°,V=3.364(2) nm3,and Z=2,least-squares refinement of 8941 reflections gives a final agreement factor of R=0.052,Rw=0.065.     

Syntheses and Crystal Structures of Two Trinuclear Iron(Ⅲ) Carboxylate Complexes: [Fe3(μ3-O)(μ-O2CEt)6(H2O)3]Cl.3H2O and [Fe3(μ3-O)(μ-O2CEt)6Py3]Cl(Py=pyridine)

Two new oxo-centered trinuclear iron complexes [Fe3(μ3-O)(μ-O2CEt)6(H2O)3]Cl.3H2O 1 and [Fe3(μ3-O)(μ-O2CEt)6Py3]Cl 2 were prepared in non-aqueous solvent and their crystal structures have been determined. Crystal 1 is monoclinic, space group P21/n, a=9.909(3), b=24.467(8), c=14.542(7)(), β=107.85(4)° V=3356(4)()3, Z=4, Mr=765.52, Dc=1.52 g/cm3, μ=14.28 cm-1, F(000)=1588 and R=0.059, Rw=0.071 for 3745 unique reflections with I>3σ(I). Crystal 2 belongs to the monoclinic system with space group C2/c, a=13.750(3), b=18.439(4), c=16.696(3)(), β=93.42(3)°, V=4226(3)()3, Z=4, Mr=894.73, Dc=1.41 g/cm3, μ=11.4 cm-1, F(000)=2322 and R=0.058, Rw=0.062 for 2272 unique reflections with I>3σ(I). The two structures contain the same trimetal framework in which three iron(Ⅲ) atoms form a nearly equilateral triangle with a μ3-oxygen atom in the centre.     

Syntheses and characterization of the vanadium trimer (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(4,4′-bipyridine) and the vanadium hexamer [(V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6]2(μ2-N1,N2-di(pyridin-4-yl)oxalamide)

Reacting VO(acac)₂ with six equivalents of dibenzylphosphinic acid in the presence of 4,4′-bipyridine or μ₂-N¹,N²-di(pyridin-4-yl)oxalamide leads to trimeric (V₃(μ₃-O)O₂)(μ₂-O₂P(CH₂C₆H₅)₂)₆(4,4′-bipyridine) or the hexamer [(V₃(μ₃-O)O₂)(μ₂-O₂P(CH₂C₆H₅)₂)₆]₂(μ₂-N¹,N²-di(pyridin-4-yl)oxalamide). The complexes were characterized by spectroscopic (FTIR and ¹H NMR spectroscopies), TGA, and by single crystal X-ray diffraction measurements. The structures consist of a planar central core where three vanadium ions are arranged in the form of a quasi-isosceles triangle and contain an interstitial O which is multiply bonded to one V and weakly interacting at different bond distances to the remaining two V ions.     

A hexanuclear cobalt(III) complex containing the pseudocubane fragment [Co4(μ4-O)2(μ3-O)2] in its metal framework and a solvated dibenzyl ether molecule

Room-temperature oxidation of a mixture of the complex (Co^II)₃(μ-OOCBu _t )₆(NEt₃)₂ and dibenzyl ether (DBE) with atmospheric oxygen in dichloromethane-benzene (4: 1) gave the hexanuclear complex [(Co^III)₆(μ₄-O)₂(μ₃-O)₂(μ-OOCBu ^t )₉(OH)₂(HOOCBu ^t )](HNEt₃) · 0.5DBE · C₆H₆ (I) as the major reaction product. According to X-ray diffraction data, the metal framework of complex I contains the pseudocubane fragment [Co₄(μ₄-O)₂(μ₃-O)₂] linked with two “peripheral” cobalt(III) ions. The possibility of using complex I as an intermediate catalyst for liquid-phase oxidation of DBE as well as the conformational changes in the DBE molecule due to its adaptation to the metal complexes are discussed.     

Syntheses, X-ray structural characterizations, and thermal stabilities of two nonclassical trinuclear vanadium(IV) complexes, (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(H2O) and (V3(μ3-O)O2)(μ2-O2P(CH2C6H5)2)6(py), and polymeric complexes of stoichiometry (VO(O2PR2)2)∞, R2 = Ph2 and o-(CH2)2(C6H4)

The preparation and structural characterization of two trinuclear vanadium complexes, (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(H(2)O), 1, and (V(3)(μ(3)-O)O(2))(μ(2)-O(2)P(CH(2)C(6)H(5))(2))(6)(py), 2, are reported. In these nonclassical structures, the planar central core consists of the three vanadium atoms arranged in the form of an acute quasi-isosceles triangle with the central oxygen atom multiply bonded to the vanadium atom at the center of the vertex angle and weakly interacting with the two other vanadium atoms on the base sites, each of which contain one external multiply bonded oxygen atom. Reacting VO(acac)(2)in the presence of diphenylphosphinic acid affords (VO(O(2)PPh(2))(2))(∞), 3, while 2-hydroxyisophosphindoline-2-oxide at room temperature in CH(2)Cl(2) affords ((H(2)O)VO(O(2)Po-(CH(2))(2)C(6)H(4))(2))(∞), 4, and at 120 °C in EtOH yields (VO(O(2)P(o-(CH(2))(2)(C(6)H(4)))(∞), 5 on the basis of elemental analyses. The thermal and chemical stability of the complexes were assessed by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) measurements. The bond strengths of the vanadium atoms to the OH(2) ligand in 1 and to the NC(5)H(5) ligand in 2 were assessed at 10.7 and 42.0 kJ/mol respectively. Room temperature magnetic susceptibility measurements reveal magnetic moments for trinuclear 1 and 2 at 3.02(1) and 3.05(1) μ(B/mol), and also close to spin only values (1.73 μ(B)) values for 3, 4, and 5 at 1.77(2), 1.758(7), and 1.77(3) μ(B), respectively. Variable-temperature, solid-state magnetic susceptibility measurements were conducted on complex 2 in the temperature range of 2.0-298 K and at an applied field of 0.5 T. Magnetization measurements at 2 and 4 K confirmed a very weak magnetic interaction between the vanadyl centers.     

Synthesis and Characterization of Tetrametal Cluster [Co2(CO)6][μ-HC2CH2OCH2C2H-μ][Co2(CO)6]

The treatment of dipropargyl ether HC2CH2OCH2C2H with Co2(CO)8 resulted in the formation of a novel cluster [Co2(CO)6][μ-HC2CH2OCH2C2H-μ][Co2(CO)6]. The cluster was characterized by C/H analyses, IR and 1H NMR spectroscopy and X-ray crystal structure determination. It belongs to monoclinic system, space group P21/c with the following crystallographic parameters: a=18.149(2), b=7.0111(7), c=20.897(2)(A), β=115.318(7)°, V=2403.7(5)(A)3, Z=4, Mr=665.97, Dc=1.840 g·cm-3, F(000)=1304.00, μ(Mo-Kα)=27.76 cm-1 and R=0.030 for 2372 observed reflections.     

Synthesis and structure of three isomeric cluster complexes (μ-H)Os3μ-O2CC5H4Mn(CO)3(PPh3)2(CO)8

The reaction of (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(CO)₁₀ with PPh₃ in the presence of Me₃NO gave mono- and disubstituted heterometallic complexes (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(PPh₃)(CO)₉ and (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃ (PPh₃)₂(CO)₈. Crystal structure determination was performed for three isomeric cluster complexes (μ-H)Os₃μ-O₂CC₅H₄Mn(CO)₃(PPh₃)₂(CO)₈, which are both geometrical and conformational isomers differing in color. The geometrical isomerism is due to the attachment of the PPh₃ group at different vertices of the Os₃ triangle relative to the O₂CC₅H₄Mn(CO)₃ bridging ligand. The conform ational isomerism implies that the molecules have the same arrangement of ligands and differ only in the values of bond angles between the planar fragments of the clusters.     

Preparation of organozirconium aromatic compounds in mixed aqueous-organic solvents: X-ray structures of [Cp2ZrCl(μ2-O′,O′′C-C6H5)], [(CpZr)3(μ2-O′,O′′C-C6H3Cl2)3(μ3-OH)(μ2-OH)3](Cl2C6H3COO)2, and [(CpZr)3(μ2-O′,O′′C-C6H4Cl)3(μ3-OH)(μ2-OH)3]Cl2·CH2Cl2

A new and facile method is presented for the synthesis of zirconocene carboxylate compounds, in which zirconocene dichloride (Cp₂ZrCl₂) is dissolved in 1 M aqueous HCl solution and the requisite ligand is dissolved in an organic solvent. Five such compounds [Cp₂ZrCl(μ₂-O′,O′′C-C₆H₅)] (1), [Cp₂ZrCl(μ₂-O′,O′′C-C₆H₃Cl₂)] (2), [Cp₂Zr(μ₂-O′,O′′C-C₆H₃(OH)Cl)₂] (3), [Cp₂Zr(μ₂-O′,O′′C-C₆H₃(OH)(NO₂))₂] (4), and [Cp₂Zr(μ₂-O′,O′′C-C₆H(OH)Cl₃)₂] (5) have been obtained by this method. The effect of pH on the stability of Cp₂ZrCl₂ in 1 M HCl solution has been investigated by UV/vis spectrophotometry and ¹H NMR spectrometry. The results showed that the aqueous Cp₂ZrCl₂ solutions became less stable with increasing pH, liberating cyclopentadiene. Accordingly, at higher pH (～7), two trinuclear zirconium monocyclopentadienyl compounds, [(CpZr)₃(μ₂-O′,O′′C-C₆H₃Cl₂)₃(μ₃-OH)(μ₂-OH)₃](Cl₂C₆H₃COO)₂ (6) and [(CpZr)₃(μ₂-O′,O′′C-C₆H₄Cl)₃(μ₃-OH)(μ₂-OH)₃]Cl₂·CH₂Cl₂ (7), were obtained. All compounds 1–7 have been characterized by FT-IR, ¹H NMR spectra and elemental analysis. In all of the compounds, the aromatic acid acts as a bidentate ligand in coordinating to the zirconium; both chelating and bridging modes are observed. X-ray crystallographic studies on 1, 6, and 7 have revealed that the geometries at zirconium are distorted octahedral in 6 and 7, and distorted trigonal-bipyramidal in 1.     

Further studies of M3(μ3-O)(μ-X)3(μ-O2CCH3)3L3 (M=Mo,W) type clusters with nine core electrons

Four new compounds having nine cluster electrons and cores of the types Mo₃OCl₃, Mo₃OBr₃, and W₃OCl₃ are reported. Compound (1) prepared by reduction of [Bu₄N][Mo₃OCl₆(OAc)₃] in THF with metallic zinc, was shown by X-ray crystallography to be Mo₃OCl₄(OAc)₃ (THF)₂ (1). It forms crystals in space groupP2₁ with unit cell dimensionsa=9.472(2) Å,b=13.546(4) Å,c=9.652(2) Å, =101.70(2)°,V=1201(1) Å₃,Z=2. The [Mo₃(₃-O)(-Cl)₃]⁴⁺ core is surrounded by three -O₂CCH₃ anions, one Cl^–, and two THF and has Mo-Mo distances of 2.620(1) Å, 2.613(1) Å, and 2.530(1) Å, with the shortest bond between the two Mo atoms to which the THF molecules are coordinated. Compounds [Bu₄N]₂ [Mo₃OBr₆(O₂CCH₃)₃] · Me₂CO, (2) and [Mo₃OBr₃(O₂CCH₃)₃(PMe₃)₃]₃ · BF₄, (3) are the first two nine-electron Mo₃ species with a [Mo₃(₃-O) Br₃]⁴⁺ core. Both were obtained by zinc reduction of [Mo₃OBr₆(O₂CCH₃)₃]^– in the presence of (NBu₄) Br (2) or PMe₃ and NaBF₄ (3), and each was characterized crystallographically. Compound (2) crystallized in space group Cc with unit cell dimensionsa=25.037(5) Å,b=12.827(2) Å,c=21.484(4) Å, =122.96(1)⁰,V=5790(3) ų,Z=4. While the anion has no crystallographically required symmetry, its virtual symmetry is C_3v . The Mo-Mo distances are 2.619(2) Å, 2.610(3) Å, 2.644(2) Å, with a mean value of 2.624[14] Å. Compound (3) crystallized in space groupP2₁/c with unit cell dimensionsa=10.846(2) Å,b=25.033(5) Å,c=12.641(5) Å, =94.74(2)⁰,V=3420(2) ų,Z=4. The cation occupies a general position but has virtual C_3v symmetry, with Mo-Mo distances of 2.601(2) Å, 2.610(2) Å, 2.627(2) Å, with a mean value of 2.613[14] Å. Thus the anionic and cationic Mo₃ clusters in (2) and (3), respectively, have average Mo-Mo distances that are equal within experimental error. Compound (4), [NEt₄]₂ [W₃OCl₆(O₂CCH₃)₃] is the first 9-electron compound of this type containing tungsten. It was prepared by reduction of [Et₄N][W₃OCl₆(OAc)₃] in benzene with Na/Hg. It crystallized in space groupP2₁2₁2₁ with unit cell dimensionsa=11.076(2) Å,b=14.345(2) Å,c=21.026(3) Å,V=3574(1) ų,Z=4. The anion resides on a general position but has virtual C_3v symmetry, with W-W distances of 2.577(1) Å, 2.612(1) Å, 2.584(1) Å and a mean value of 2.591[15] Å.     

Novel heterometallic Schiff base complexes featuring unusual tetranuclear {Co(III)2Fe(III)2(μ-O)6} and octanuclear {Co(III)4Fe(III)4(μ-O)14} cores: direct synthesis, crystal structures, and magnetic properties

A one-pot reactions of cobalt powder with iron(II) chloride in dimethylformamide (DMF; 1) or dimethyl sulfoxide (DMSO; 2) solutions of polydentate salicylaldimine Schiff base ligands (H(2)L(1), 1; H(4)L(2), 2) based on 2-aminobenzyl alcohol (1) or tris(hydroxymethyl)aminomethane (2), formed in situ, yielded two novel heterometallic complexes, [Co(III)(2)Fe(III)(2)(L(1))(6)]·4DMF (1) and [Co(III)(4)Fe(III)(4)(HL(2))(8)(DMSO)(2)]·18DMSO (2). Crystallographic investigations revealed that the molecular structure of 1 is based on a tetranuclear core, {Co(III)(2)Fe(III)(2)(μ-O)(6)}, with a chainlike metal arrangement, while the structure of 2 represents the first example of a heterometallic octanuclear core, {Co(III)(4)Fe(III)(4)(μ-O)(14)}, with a quite rare manner of metal organization, formed by two pairs of {CoFe(HL(2))(2)} and {CoFe(HL(2))(2)(DMSO)} moieties, which are joined by O bridges of the Schiff base ligands. Variable-temperature (1.8-300 K) magnetic susceptibility measurements showed a decrease of the μ(B) value at low temperature, indicative of antiferromagnetic coupling (J/hc = -32 cm(-1) in 1; J/hc = -20 cm(-1) in 2) between the Fe(III) magnetic centers in both compounds. For 2, three J constants between Fe(III) centers were assumed to be identical. High-frequency electron paramagnetic resonance spectra allowed one to find spin Hamiltonian parameters in the coupled-spin triplet and quintet states of 1 and estimate them in 2. The "outer" and "inner" Fe atoms in 2 appeared separately in the M?ssbauer spectra.     

Novel polyselenidoarsenate and selenidoarsenate: solvothermal synthesis and characterization of [Co(phen)3][As2Se2(μ-Se3)(μ-Se5)] and [Co(phen)3]2[As8Se14

Novel cobalt polyselenidoarsenate [Co(phen)(3)][As(2)Se(2)(μ-Se(3))(μ-Se(5))] (1; phen = 1,10-phenanthroline) was methanolothermally synthesized by the reaction of CoCl(2), As(2)O(3), and Se templated by phen in a CH(3)OH solvent at 130 °C. The same reaction in a H(2)O solvent yielded cobalt selenidoarsenate [Co(phen)(3)](2)[As(8)Se(14)] (2). In 1, the AsSe(+) units are alternately joined by the μ-Se(3)(2-) and μ-Se(5)(2-) bridging ligands to form a novel helical polyselenidoarsenate chain [As(2)Se(2)(μ-Se(3))(μ-Se(5))(2-)](∞). In 2, eight pyramidal AsSe(3) units are connected via corner sharing into the new member of the selenidoarsenate aggregate [As(8)Se(14)](4-) with a condensation grade of 0.571, which represents the first discrete selenidoarsenate(III) with a condensation grade of above 0.50. The octahedral complex [Co(phen)(3)](2+) is formed in situ to act as a countercation in compounds 1 and 2. 1 and 2 exhibit steep absorption band gaps at 2.09 and 2.16 eV, respectively.     

The synthesis and crystal structure of novel Mo-Sn tetranuclear cubane-like cluster [Mo3(SnBr3)(μ3-O)(μ3-S)3(dtp)3(py)3]·(CH2Cl2)

The synthesis and crystal structure of the first example for hybrid Sn-Mo tetranuclear cubane-like cluster compound containing S/O mixed triple capping atom [Mo₃(SnBr₃)(μ ₃-O)(μ ₃-S)₃(dtp)₃(py)₃]·(CH₂Cl₂) (A) (dtp=S₂P(OC₂H₅)₂) are reported. The compound is prepared by the reaction of [Mo₃(μ ₃-O)(μ-S)₃(dtp)₄·(H₂O)] with SnBr ₃ ^? . The molecular structure of the cluster can be described as a [Mo₃OS₃] core with the SnBr ₃ ^? fragment linked to {Mo₃} triangle by three (μ ₃-S). Three Mo-Mo bond lengths are 2.616(2), 2.620(2), 2.628(2) Å, respectively, and the molecule has approximately C_3v symmetry. There is no bonding between Sn and Mo atoms, however, the addition of SnBr ₃ ^? may cause electron transfer from Sn²⁺ to [Mo₃OS₃] core to result in the shortening of Mo-Mo bond distances. The compound crystallizes in the monoclinic space group P2₁/n with refined lattice parameters ofa=13.012(4),b=22.877(6),c=18.585(6) Å,β=96.34(3)°,V=5498(3)ų, andZ=4. Full matrix refinement converged with final agreement factor ofR=0.054,R _w=0.064.     

Syntheses and molecular structures of organo-tellurium(IV) halides trans-[(Ph2Te)(μ-Cl)2]n,cis-[(Ph2Te)(μ-Cl)2]n, [(p-MeC6H4)2TeBr2], and [{(p-MeC6H4)2TeBr}2(μ-O)]

Abstract

Treatment of Ph₂Te with aqueous hydrogen chloride under air in refluxing THF gave trans-[(Ph₂Te)(μ-Cl)₂]_n (1), whereas interaction of Ph₂Te with ammonium chloride under similar condition afforded cis-[(Ph₂Te)(μ-Cl)₂]_n (2). Reaction of (p-MeC₆H₄)₂Te and bromine in refluxing THF resulted in formation of a discrete complex [(p-MeC₆H₄)₂TeBr₂] (3) with a step-like tetrameric structure, which further reacted with sodium hydroxide in refluxing THF to give a dinuclear tellurium oxide [{(p-Me-C₆H₄)₂TeBr}₂(μ-O)] (4) with a bridging oxygen atom. Complexes 1–4 have been spectroscopically characterized and their crystal structures have been established by X-ray crystallography.     

Synthesis and Crystal Structure of [Ni(II)(L)(py)_3]·(py)

1 INTRODUCTION Schiff bases and their metal complexes are useful reagents in organic synthesis[1], and they have exhi- bited some biological activities as anticancer and antitumor drugs[2]. The crystal structures and physi- cal and chemical properties of many Schiff bases and their transition metals complexes have been re- ported[3~5]. Further interest in the coordination che- mistry of nickel(II) arises from the role of these complexes in several catalytic reactions, such as electrocat…     

Synthesis and characterization of linked alkyne-bridging Co2C2 tetrahedral clusters and expansion reactions of (Co2(CO)6(μ-HCCCH2OOC))2R with Fe3(CO)12

Two new linked alkyne-bridging tetrahedral carbonyl clusters containing Co₂C₂ Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₃COOCH₂CCH-μ)Co₂(CO)₆, 1, and Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₈COOCH₂CCH-μ)Co₂(CO)₆, 2, have been prepared by reactions of two dipropargyl esters (HC≡CCH₂OOC)₂R (R = (CH₂)₃, (CH₂)₈) with Co₂(CO)₈. Expansion reactions of 1 and Co₂(CO)₆(μ-HCCCH₂OOCCOOCH₂CCH-μ)Co₂(CO)₆, 3, with Fe₃(CO)₁₂ give two new mixed-metal linked clusters Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₃COOCH₂CCH-μ,η⁴)Co₂Fe₂(CO)₁₂, 4, and Co₂(CO)₆(μ-HCCCH₂OOCCOOCH₂CCH-μ,η⁴)Co₂Fe₂(CO)₁₂, 5. The new clusters were characterized by elemental analysis, IR, ¹H-NMR and ESI-MS analysis.     

Syntheses and Crystal Structures of Two Trinuclear Iron(Ⅲ) Carboxylate Complexes:〔Fe_3(μ_3-O)(μ-O_2CEt)_6(H_2O)_3〕Cl·3H_2O and 〔Fe_3(μ_3-O)(μ-O_2CEt)_6Py_3〕Cl(Py=pyridine)

１ＩＮＴＲＯＤＵＣＴＩＯＮＴｒｉｎｕｃｌｅａｒｏｘｏ ｃｅｎｔｅｒｅｄｍｅｔａｌｃａｒｂｏｘｙｌａｔｅａｓｅｍｂｌｉｅｓｏｆｔｈｅｇｅｎｅｒａｌｃｏｍｐｏｓｉｔｉｏｎ〔Ｍ３（μ３ Ｏ）（μ２ Ｏ２ＣＲ）６（Ｌ）３〕ｎ＋ｈａｖｅｂｅｎｏｆｉｎｔｅｎｓｅ...     

Binuclear Osmium μ-Oxocarboxylate Complexes [Os2(μ-O)(μ-O2CR)2Cl4L2] (R = CH3, CCl3; L = PPh3, AsPh3) and Their Electrochemical Behavior in Dichloromethane

Cyclic voltammetry and galvanostatic coulometry techniques were used to determine how the redox properties of osmium binuclear -oxocarboxylates [Os₂ ^IV(-O)(-O₂CR)₂Cl₄L₂] (R = CH₃, CCl₃; L = PPh₃ and R = CH₃; L = AsPh₃) are influenced by the nature of the bridging carboxylate ligand RCOO^– and ligand L. It was shown that all compounds in solution of dichloromethane undergo two single-electron reduction processes. The data obtained were compared with the DFT calculations of the electronic structure of the model complexes [Os₂ ^IV(-O)(-O₂CR)₂Cl₄L₂] (R = CH₃, CCl₃; L = PH₃ and R = CH₃; L = AsH₃).     

An oxo-centered carboxylate-bridged trinuclear complex: synthesis,crystal structure,and magnetic properties of [Cr3(μ3-O)(HL)2(H2O)3](ClO4)3

A new complex [Cr₃(μ₃-O)(HL)₂(H₂O)₃](ClO₄)₃, L = 1,4,7-triazacyclononane-N,N′,N′′-tripropionate(tacntp), has been synthesized and structurally characterized. The complex crystallizes in the orthorhombic, space group Pccn, with unit cell parameters a = 18.245(3) Å, b = 18.955(3) Å, c = 27.806(4) Å, α = 90°, β = 90°, γ = 90°. The complex has a trimetallic structure with three metal ions at the corners of a nearly equilateral triangle and the center occupied by a triply-bridging oxygen. Variable-temperature magnetic susceptibility indicates that the total spin value of the ground state is 3/2.     

混合价双核锰配合物[(Phen)2Mn(μ-O)2Mn(Phen)2]ClO4)3CH2ClCOOH·2H2O的合成与表征

锰在某些生物的氧化还原活性部位起着重要的作用. 绿色植物光系统Ⅱ(PSⅡ)中的氧释放配合物(OEC)、含锰过氧化氢酶(Mn Catalase)、含锰超氧化物歧化酶(MnSOD)、含锰核糖核苷酸还原酶(Mn RR)等活性部位存在着双核或多核锰的配合物[1～3]. 因此, 模拟合成不同氧化态的、不同类型配体和不同核数锰的配合物, 研究其结构和光谱等性质, 对揭示生物体中锰酶的催化氧化还原过程将有重要意义. 混合价Mn(Ⅲ, Ⅳ)配合物的研究对于揭示PSⅡ中两分子H2O氧化为O2的机理具有重要意义[2,4]. 这类配合物的研究已有一些报道[5～10], 邻菲咯啉(Phen)作为配体形成的配合物[(Phen)2Mn\5(μ-O)2Mn(Phen)2](PF6)3*CH3CN的研究虽有报道[11], 但其晶体中两个锰离子配位环境几乎相同. 本文用新方法合成了双核锰配合物(该法容易得到单晶)并进行了表征.