A structural and Mössbauer study of complexes with Fe(2)(micro-O(H))(2) cores: stepwise oxidation from Fe(II)(micro-OH)(2)Fe(II) through Fe(II)(micro-OH)(2)Fe(III) to Fe(III)(micro-O)(micro-OH)Fe(III)

Dinuclear non-heme iron clusters containing oxo, hydroxo, or carboxylato bridges are found in a number of enzymes involved in O(2) metabolism such as methane monooxygenase, ribonucleotide reductase, and fatty acid desaturases. Efforts to model structural and/or functional features of the protein-bound clusters have prompted the preparation and study of complexes that contain Fe(micro-O(H))(2)Fe cores. Here we report the structures and spectroscopic properties of a family of diiron complexes with the same tetradentate N4 ligand in one ligand topology, namely [(alpha-BPMCN)(2)Fe(II)(2)(micro-OH)(2)](CF(3)SO(3))(2) (1), [(alpha-BPMCN)(2)Fe(II)Fe(III)(micro-OH)(2)](CF(3)SO(3))(3) (2), and [(alpha-BPMCN)(2)Fe(III)(2)(micro-O)(micro-OH)](CF(3)SO(3))(3) (3) (BPMCN = N,N'-dimethyl-N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane). Stepwise one-electron oxidations of 1 to 2 and then to 3 demonstrate the versatility of the Fe(micro-O(H))(2)Fe diamond core to support a number of oxidation states with little structural rearrangement. Insight into the electronic structure of 1, 2', and 3 has been obtained from a detailed M?ssbauer investigation (2' differs from 2 in having a different complement of counterions). Mixed-valence complex 2' is ferromagnetically coupled, with J = -15 +/- 5 cm(-)(1) (H = JS(1).S(2)). For the S = (9)/(2) ground multiplet we have determined the zero-field splitting parameter, D(9/2) = -1.5 +/- 0.1 cm(-)(1), and the hyperfine parameters of the ferric and ferrous sites. For T < 12 K, the S = (9)/(2) multiplet has uncommon relaxation behavior. Thus, M(S) = -(9)/(2) <--> M(S) = +(9)/(2) ground state transition is slow while deltaM(S) = +/-1 transitions between equally signed M(S) levels are fast on the time scale of M?ssbauer spectroscopy. Below 100 K, complex 2' is trapped in the Fe(1)(III)Fe(2)(II) ground state; above this temperature, it exhibits thermally assisted electron hopping into the state Fe(1)(II)Fe(2)(III). The temperature dependence of the isomer shifts was corrected for second-order Doppler shift, obtained from the study of diferrous 1. The resultant true shifts were analyzed in a two-state hopping model. The diferric complex 3 is antiferromagnetically coupled with J = 90 +/- 15 cm(-)(1), estimated from a variable-temperature M?ssbauer analysis.     

Two heptacopper(II) disk complexes with a [Cu(7)(μ(3)-OH)(4)(μ-OR)(2)](8+) core

The reaction of CuX(2) (X(-) ≠ F(-)) salts with 1 equiv of 3-pyridyl-5-tert-butylpyrazole (HL) in basic methanol yields blue solids, from which disk complexes of the type [Cu(7)(μ(3)-OH)(4)(μ-OR)(2)(μ-L)(6)](2+) and/or the cubane [Cu(4)(μ(3)-OH)(4)(HL)(4)](4+) can be isolated by recrystallization under the appropriate conditions. Two of the disk complexes have been prepared in crystalline form: [Cu(7)(μ(3)-OH)(4)(μ-OCH(2)CF(3))(2)(μ-L)(6)][BF(4)](2) (2) and [Cu(7)(μ(3)-OH)(4)(μ-OCH(3))(2)(μ-L)(6)]Cl(2)·xCH(2)Cl(2) (3·xCH(2)Cl(2)). The molecular structures of both compounds as solvated crystals can be described as [Cu?Cu(6)(μ-OH)(4)(μ-OR)(2)(μ-L)(6)](2+) (R = CH(2)CF(3) or CH(3)) adducts. The [Cu(6)(μ-OH)(4)(μ-OR)(2)(μ-L)(6)] ring is constructed of six square-pyramidal Cu ions, linked by 1,2-pyrazolido bridges from the L(-) ligands and by basal, apical-bridging hydroxy or alkoxy groups, while the central Cu ion is bound to the four metallamacrocyclic hydroxy donors in a near-regular square-planar geometry. The L(-) ligands project above and below the metal ion core, forming two bowl-shaped cavities that are fully (R = CH(2)CF(3)) or partially (R = CH(3)) occupied by the alkoxy R substituents. Variable-temperature magnetic susceptibility measurements on 2 demonstrated antiferromagnetic interactions between the Cu ions, yielding a spin-frustrated S = (1)/(2) magnetic ground state that is fully populated below around 15 K. Electrospray ionization mass spectrometry, UV/vis/near-IR, and electron paramagnetic resonance measurements imply that the heptacopper(II) disk motif is robust in organic solvents.     

A trinuclear bis(dioximate)(chloro)(nitrosyl)ruthenium(II) complex containing two (2,2′-bipyridine)copper(II) groups

A trinuclear bis(cyclohexanedioximate)(chloro)(nitrosyl)ruthenium(II) complex containing two (2,2-bipyridine)-copper(II) groups has been synthesized and its electronic and electrochemical properties investigated. According to ZINDO/S calculations, the electronic structure of the ruthenium(dioximate)(nitrosyl) moiety is strongly delocalized. The electrochemical behavior has been interpreted with the aid of spectroelectrochemical measurements. In the trinuclear complex, it has been shown that the copper(II) ions can promote the oxidation of the NO species generated electrochemically, and also mediate the redox reactions of the complex, under a dioxygen atmosphere.     

高氯酸诺氟沙星铜(Ⅱ)(英)

0CommentExtensiveinvestigationshavebeendoneaboutthesupramolecularchemistryofmetalionswithNor-floxacin(H-Norf,1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylicacid)sincemanyorganiccompoundsusedinmedicinedonothaveapurelyorganicmodeofaction;someareacti-vatedorbiotransformedbymetalions,othershavedi-rectorindirecteffectonthemetalionmetabolism[1~5].ThereactionofCu(ClO4)2·6H2OwithH-Norfunderhydrothermalconditionsgivesamonomericcomplex[Cu(H-Norf)2](ClO4)2(1)inwhichCu髤i…     

Theory of hydride-proton transfer (HPT) carbonyl reduction by [Os(III)(tpy)(Cl)(NH═CHCH(3))(NSAr)

Quantum mechanical analysis reveals that carbonyl reduction of aldehydes and ketones by the imine-based reductant cis-[Os(III)(tpy)(Cl)(NH═CHCH(3))(NSAr)] (2), which is accessible by reduction of the analogous nitrile, occurs by hydride-proton transfer (HPT) involving both the imine and sulfilimido ligands. In carbonyl reduction, water or alcohol is necessary to significantly lower the barrier for proton shuttling between ligands. The -N(H)SAr group activates the carbonyl group through hydrogen bonding while the -NC(H)CH(3) ligand delivers the hydride.     

Formation and isomerization of cis,cis-Ir(H)2(--Ph)(CO)(PPh3)2 and cis,cis-Ir(H)(--Ph)2(CO)(PPh3)2 in oxidative addition of hydrogen and phenylacetylene to trans-Ir(CO)(--Ph)(PPh3)2

Oxidative addition of H–R (H--Ph and H₂) to trans-Ir(--Ph)(CO)(PPh₃)₂ (2) gives the initial products, cis, cis-Ir(H)(--Ph)₂(CO)(PPh₃)₂ (3a) and cis, cis-Ir(H)₂(--Ph)(CO)(PPh₃)₂ (3b), respectively. Both cis-bis(PPh₃) complexes, 3a and 3b undergo isomerization to give the trans-bis(PPh₃) complexes, trans, trans-Ir(H)(--Ph)₂(CO)(PPh₃)₂ (4a) and cis, trans-Ir(H)₂(--Ph)(CO)(PPh₃)₂ (4b). The isomerization, 3b→4b is first order with respect to 3b with k₁=6.37×10⁻⁴ s⁻¹ at 25°C under N₂ in CDCl₃. The reaction rate (k₁) seems independent of the concentration of H₂. A large negative entropy of activation (ΔS^≠=−24.9±5.7 cal deg⁻¹ mol⁻¹) and a relatively small enthalpy of activation (ΔH^≠=14.5±3.3 kcal mol⁻¹) were obtained in the temperature range 15∼35°C for the isomerization, 3b→4b under 1 atm of H₂.     

Synthesis and Crystal Structure of [Ni(Ⅱ)(L)(py)3]·(py)

The title complex, C37H34N6NiO5, has been prepared and characterized by X-ray diffraction analysis. It crystallizes in the monoclinic system, space group P21/c with a = 1.15244(8), b = 1.69679(12), c = 1.78341(13) nm, β = 102.2320(10)°, V = 3.4082(4) nm3, Z = 4, Mr = 701.41, F(000) = 1464, Dc = 1.367 g/cm3 and μ(MoKα) = 0.622 mm-1. The structure was refined to R = 0.0459 and wR = 0.1199 for 5718 observed reflections. The intramolecular hydrogen bonds in the crystal structure play important roles in the title complex's thermostability.     

Low-spin bis(2-methylimidazole)(octaethylporphyrinato)iron(III) chloride (perp-[Fe(OEP)(2-MeHIm)(2)]Cl): a consequence of hydrogen bonding?

The synthesis and characterization of low-spin bis(2-methylimidazole)(octaethylporphyrinato)iron(III) chloride (perp[Fe(OEP)(2-MeHIm)2]Cl) is reported. The structure shows that the cation is a low-spin species with two imidazole ligands having a relative perpendicular orientation. The porphyrin core is very ruffled, which leads to shortened equatorial bonds of 1.974(4) A and slightly elongated axial Fe-N bond lengths of 2.005(10) A that are about 0.02 A shorter and 0.03 A longer, respectively, in comparison to bis-imidazole ligated iron(III) species with parallel oriented axial ligands. A one-dimensional hydrogen-bond chain is formed between chloride anions and uncoordinated imidazole nitrogen atoms. Compared with paral-[Fe(OEP)(2-MeHIm)2]ClO4, hydrogen bonding may play an important role in the differences in the two structures. M?ssbauer spectra show broadened quadrupole doublets with quadrupole splittings of 1.81 mm/s at RT and 1.94 mm/s at 20 K. The isomer shift ranges from 0.26 to 0.36 mm/s. These confirm that the title complex is a low-spin iron(III) species with the ground state (dxy)2(dxz,dyz)3. Crystal data: monoclinic, space group P2(1)/c, a = 14.066(3) A, b, 20.883(4) A, c = 19.245(4) A, beta = 109.67 degrees , and Z = 4.     

Synthesis,crystal structure,and magnetic properties of a new end-to-end thiocyanato-bridged dicobalt(II) complex CoII(dien)(H2O)(NCS)(μ1,3-NCS)CoII(dien)(NCS)2 (dien = diethylenetriamine)

Synthesis, characterization, crystal structure, and magnetic properties of the first single µ_1,3-thiocyanato-bridged dicobalt(II) compound, [Co^II(dien)(H₂O)(NCS)(µ_1,3-NCS)Co^II(dien)(NCS)₂] (1; dien = diethylenetriamine), are described. In 1, cobalt(II) is six coordinate with distorted-octahedral geometry. The Co(1) ··· Co(2) distance is 5.99 Å. The magnetic properties of 1 have been investigated by variable-temperature magnetic susceptibility measurements. The metal centers are coupled by weak ferromagnetic interaction (J = 1.14 cm^?1). The structure and magnetic properties are compared with related thiocyanate-bridged compounds.     

Unsymmetrically substituted disilyne Dsi(2)(i)PrSi-Si≡Si-SiNpDsi(2) (Np = CH(2)(t)Bu): synthesis and characterization

The unsymmetrically substituted disilyne, Dsi(2)(i)PrSi-Si≡Si-SiNpDsi(2) (Np = CH(2)(t)Bu) 2, was synthesized and characterized by X-ray crystallography to show a trans-bent structure with a silicon-silicon triple bond length of 2.0569(12) ?. The (29)Si chemical shifts of the triply bonded silicon atoms of 2 are quite different, being observed at 62.6 ppm for the Dsi(2)(i)PrSi side and 106.3 ppm for the Dsi(2)NpSi side, indicating different hybridizations on the triply bonded silicon atoms at each site.     

Alkylimido osmium(VI) and ruthenium(VI) porphyrins. Crystal and molecular structures of Os(TTP)(O)(NBu~t)·EtOH and Os(4-Cl-TPP)(NBu~t)_2

Oxo(tert-butylimido) or bis(tert-butylimido)osmium(VI) porphyrins Os(Por)(O)(NBut) and Os(Por)(NBut)2, [Por=meso-tetrakis(p-tolyl)porphyrinato (TTP) and meso-tetrakis(4-chlorophe-nyl)porphyrinato (4-Cl-TPP)] were synthesized by air oxidation of bis(tert-butylamme)osmium(II) porphyrins [Os(Por)(H2NBut)2 (Por=TPP, 4-Cl-TPP], depending on whether tert-butylamine is present. The bis(tert-butylamine)ruthenium(II) porphyrins [Ru(Por)(H2NBut)2, Por=TTP, 4-Cl-TPP] can undergo bromine oxidation to give oxo(tert-butylimido)ruthenium(VI) complexes in quantitative yields. All these new complexes were characterized by 1H NMR, UV-Visible and IR spectroscopy. The X-ray crystal structures of Os(TTP)(O)(NBut).EtOH and Os(4-Cl-TPP)(NBut)2 have been determined. Crystal data: for Os(TTP)(O)(NBut).EtOH: monoclinic, space group P21/c, a=1.3546(6) nm, b=2.3180(3) nm, c=1.6817(3) nm, B=90.84(2), V=527.97(1) nm3, Z=4. The Os=O and Os=NBut distances in Os(TTP)(O)(NBut).EtOH are 0.1772(7) nm and 0.1759(9) nm, respectively. The av     

生物综合工业(微生物工业)(上)

微生物散佈各处,天天和我們的生活打交代。它們種类繁多,包括細菌放線菌和黴菌等,即細菌一類,我們已經能鑑别一千数百种。其中病原菌不過佔全數四分之一,而大多數的微生物不但無害而是可以利用的。在农     

Synthesis and Crystal Structure of Bis(μ-bis(diphenyl-phosphino)methane)(μ-benzenethiolate)(acetonitrile)Dicopper(I) Perchlorate Diethylether Solvate

The reaction between [Cu2(μ-dppm)2(MeCN)4](ClO4)2(dppm=bis(diphenylphos-phino)methane) and [Zn(PhS)2(bpy)] (bpy=2,2'-bipyridine,PhS=benzenethiolate) gave the complex [Cu2(μ-dppm)2(μ-PhS)(MeCN)]ClO4·0.5(Et2O)(C58H52ClNO4P4SCu2·0.5Et2O) which was determined by X-ray single-crystal diffraction.The crystal is of orthorhombic,space group P212121 with a=13.6157(3),b=20.8022(6),c=21.3299(6)A,V=6041.4(3) A3,Mr=1182.54,Dc=1.300 g/cm3,F(000)=2444,μ=0.934 mm-1 and Z=4.The final R=0.0773 and wR=0.1843 for 7744 observed reflections (I>2σ(I)).The dicopper atoms are doubly bridged by dppm as well as one S donor from benzenethiolate.One copper atom is in a distorted trigonal bipyramidal environ- ment,whereas the other adopts a distorted tetrahedral geometry.     

A novel mixed-coordination cobalt(Ⅲ)complex:synthesis and structure of Co(Ⅲ)(mpp)(Hmpp)(n-Bu_3P)_2

Complex Co(Ⅲ)(mpp)(Hmpp) (n-Bu_3P)_2(1,H_mpp=2-mereapto-3-pyridinol) wasobtained from the reaction of COCl_2 with H_2mpp,n-Bu_3P and Na metal in EtOH.The Co atomin a distorted octahedral geometry is coordinated with donor atoms N,O,P and S.The twoH_2mpp ligands form two different ehelato ringa with the Co(Ⅲ) ion:one 5-membered and thoother ono 4-membered,while the two n-Bu_3P ligands are in the axial positions with the angleP(1)-Co-P(2) of 176.1°.     

Li_(1.3)Ti_(1.7)Al_(0.3)(PO_4)_3,Na_(1.3)Ti_(1.7)Al_(0.3)(PO_4)_3的离子交换研究

研究了在不同温度下的NaNO3和AgNO3水溶液中Li1.3Ti1.7Al0.3(PO4)3和Na1.3Ti1.7Al0.3(PO4)3离子交换行为.实验表明Li1.3Ti1.7Al0.3(PO4)3和Na1.3Ti1.7Al0.3(PO4)3均显示出了高选择性与Na+和Ag+进行离子交换的特征,且对Ag+的选择性高于Na+.升高温度可显著提高Ag/Li和Ag/Na的交换反应速度.     

多孔配位聚合物[Cu_(1.14)(mal)_(1.14)(4,4′-bipy)_(0.57)(H_2O)_(1.14)]_∞的合成及其晶体结构

以4,4′-联吡啶(4,4′-bipy),丙二酸(H2mal)和氧化铜为原料,在DMSO-H2O中合成了多孔配位聚合物{[Cu1.14(mal)1.14(4,4′-bipy)0.57(H2O)1.14]∞, 1},其结构经IR和X-射线单晶衍射表征.1属四方晶系,P421c空间群,晶胞参数为: a=16.357 7(7)(A), b=16.357 7(7)(A), c=7.575 5(7)(A), V=2 027.0(2)(A)3, Z=7, Dc=1.715 g·cm-3, S=1.148, Mr=299.08, F(000)=1 056, μ=2.155, △ρ=0.743 e·-3～-0.155 e·-3.最终偏离因子R1=0.020 5, wR2=0.057 4. 1中每个铜(Ⅱ)原子与4,4′-bipy的一个氮原子,两个丙二酸根的3个氧原子和一个水分子的氧原子配位,形成畸变的CuNO4四方锥结构单元.CuNO4四方锥通过4,4′-bipy和丙二酸根桥联形成二维的四方网状结构,层与层之间通过分子间氢键交错平行堆积形成三维多孔配位聚合物.     

Crystal Structure of 〔Aqua(oxalato)(1,10-phenanthroline)(H_2O)〕copper(Ⅱ) Monohydrate

1INTRODUCTIONThemixeda,a'-diimineandoxygendonorligandsofcopper(n)complexesareknowntobepossiblemodelsforenzyme~metalion-substrateandundernumerousin-vestigationst".Themixedoxalato2,2'-bipyridylcomplexesofcopper(I)havebeenwellcharacterizedL2j.Herebywereportthecrystalstructureofits1,lO-phenanthro-lineanalogue.2EXPERIMENTALThetitlecomplexwaspreparedbymixingCuCl,.2H,O,1,lO-phenanthrolineandH,C,o'inmethanol-water(1:lv/v)intheratio1:1:l.Afewdropsoftri-ethylaminewereaddedandtheresultingmi…     

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…     

手性二硫代磷酸镍(Ⅱ)(英)

Homochiral bis[(O,O′-di-2-isopropyl-5-methylcyclohexyl) dithiophosphato] nickel(Ⅱ) (1), prepared by the reaction of O,O′-di-2-isopropyl-5-methylcyclohexyl) dithiophosphato potassium with Ni(OAc)₂ displays a almost planar tetragonal geometry around Ni center composed of four S atoms from two different ligands. CCDC: 252341.     

Crystal structure of (η5-pentamethylcyclo-pentadienyl)(methyldiphenylphosphite-P)dichlororhodium(III)

The molecule (η⁵-pentamethylcyclopentadienyl)(methyldiphenylphosphinite-P)dichlororhodium(III), [(η⁵-C₅Me₅)RhCl₂(PPh₂OMe)], crystallizes in the monoclinic crystal system in space group P2₁/c with unit cell parameters a = 16.056(3) Å, b = 9.4331(18) Å, c = 15.745(3) Å, β = 108.330(4)°, V = 2263.8(7) ų and Z = 4. There is three-legged piano stool geometry about Rh. The Rh-P distance of 2.278(2) Å is shorter than those of [(η⁵-C₅Me₅)RhCl₂(PPh₂OR)] where R is an aryl group, and longer than those found in [(η⁵-C₅Me₅)RhCl₂{PPh(OR)₂}]. The structure reveals significant distortion of the pentamethylcyclopentadienyl towards ′η³,η²-enyl-ene′ coordination.