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61.
The reaction of [Mn{SSi(OBu(t))3}2(MeOH)4] with imidazole and its two methyl substituted derivatives leads to different types of heteroleptic manganese(II) thiolate complexes. Reaction with 1-methylimidazole gives the silanethiolate devoid of methanol but with two nitrogen ligands and thus central MnN(2)S(2) core. The reaction with imidazole leads to the methanol solvated complex with only one nitrogen ligand but manganese coordination sphere enlarged to MnO(2)NS(2) due to an O,S-chelation by tri-tert-butoxysilanethiolate ligand. Molecules of this compound interact through a set of N-H...(Me)O-H...S hydrogen bonds with methanol hydroxyl group being simultaneously acceptor and donor. With 2-methylimidazole the product is an assembly of two different neutral complexes joined again by hydrogen bonds, however, this time of N-H...S type. One of these complexes has the previously mentioned MnO(2)NS(2) core. The second neutral complex exhibits four donor atoms (MnNOS(2)core) derived from four independent ligands, i.e., two silanethiolate rests, one N-heterocyclic base and one alcohol. This structure presents similarities with a zinc-based alcohol dehydrogenase active site that have never been obtained before, including with other metals (Zn, Co). It may, therefore, be considered the first neutral structural model of liver alcohol dehydrogenase (LADH). 相似文献
62.
We have investigated the effects of low molecular weight organic acid ligands on the adsorption of the insecticidal toxin
from Bacillus thuringiensis (Bt) by the colloidal (<2 μm particle-size) fraction of some soils. The desorption of the bound toxin by NaCl and phosphate
buffer has also been measured. The soils used were a red soil (Ultisol), a latosol (Oxisol), a yellow brown soil (Alfisol)
and a yellow cinnamon soil (Alfisol) from central and southern China. The adsorption isotherms were all of the L-type, and
the data fitted the Langmuir equation (R2 > 0.97). When present at low concentrations, organic acids (acetate, oxalate, citrate) had an inhibitory effect on toxin
adsorption. Uptake, however, was promoted when the organic acid concentration exceeded 10 mM. The toxin was very strongly
bound by the soils but the soil-toxin interaction weakened in the presence of organic acids. A small portion of the toxin
was adsorbed by electrostatic and ligand exchange interactions. The addition of organic acids appeared to enhance these interactions.
Responsible Editor: Thomas B. Kinraide 相似文献
63.
The variations in the coordination environment of Co(II), Cu(II) and Zn(II) complexes with the neutral, tridentate ligand bis[1-(cyclohexylimino)ethyl]pyridine (BCIP) are reported. Analogous syntheses were carried out utilizing either the M(BF4)2 · xH2O or MCl2 · xH2O metal salts (where M = Co(II), Cu(II) or Zn(II)) with one equivalent of BCIP. When the hydrated metal starting material was used, cationic, octahedral complexes of the type [M(BCIP)2]2+ were isolated as the tetrafluoroborate salt (4, 5). Conversely, when the hydrated chloride metal salt was used as the starting material, only neutral, pentacoordinate [M(BCIP)Cl2] complexes (1-3) formed. All complexes were characterized by X-ray diffraction studies. The three complexes that are five coordinate have distortions due mainly to the pyridine di-imine bite angle. The [Cu(BCIP)Cl2] (2) also exhibits deviations in the Cu(II)-Cl bond distances with values of 2.4242(9) and 2.2505(9) Å, which are not seen in the analogous Zn(II) and Co(II) structures. Similarly, the two six coordinate complexes (5, 6) are also altered by the ligand frame bite angle giving rise to distorted octahedral geometries in each complex. The [Cu(BCIP)2](BF4)2 (6) also exhibits Cu(II)-Nimine bond lengths that are on average 0.14 Å longer than those found in the analogous 5 coordinate complex, [Cu(BCIP)Cl2]. In addition to X-ray analysis, all complexes were also characterized by UV/Vis and IR spectroscopy with 1H NMR spectroscopy being used for the analysis of the Zn(II) analogue (3). 相似文献
64.
Yu-Ning Chang 《Inorganica chimica acta》2007,360(1):136-142
The coordination chemistry of a potentially tridentate, dianionic biphenolato phosphine ligand with respect to group 1 metals is described. Deprotonation of bis-(3,5-di-tert-butyl-2-hydroxyphenyl)phenylphosphine (H2[OPO]) with two equivalents of n-BuLi, NaH, or KH in dimethoxyethane (DME) solutions produces the corresponding dinuclear alkali metal complexes [OPO]M2(DME)2 (M = Li, Na, K). The X-ray structure of [OPO]Li2(DME)2 reveals that the two lithium atoms are bridged by both phenolato oxygen donors with only one lithium being coordinated to the phosphorus donor. Consistently, variable-temperature 31P{1H} and 7Li{1H} NMR spectroscopic studies elucidate the coordination of the phosphorus donor in [OPO]Li2(DME)2 to one of the lithium atoms in solution. Interestingly, an X-ray diffraction study of the potassium complex indicates a dimeric structure with S2 symmetry for this species in which the four potassium atoms are bridged by both phosphorus and oxygen donors of the biphenolato phosphine ligands. These alkali metal complexes are active initiators for catalytic ring-opening polymerization of ε-caprolactone. 相似文献
65.
Larisa A. Tomachynski Victor Ya. Chernii Alexander N. Chernega Sergey V. Volkov 《Inorganica chimica acta》2007,360(5):1493-1501
The synthesis of new zirconium and hafnium mixed ligand phthalocyanine complexes PcM(β-ketoester)2, where M-Zr (IV), Hf (IV); Pc - the dianion of phthalocyanine, and β-ketoester - the out planed ligand, is reported. The obtained complexes are characterized by 1H NMR, IR, UV-Vis spectroscopy and cyclic voltammetry. 1H NMR and elemental analysis confirm the substitution of two Cl atoms for two β-ketoester fragments to the central atom of the macrocycle. The data of 1H NMR, UV-Vis spectroscopy have allowed us to conclude that two β-ketoester ligands are in the cis geometry to the phthalocyanine plane. X-ray crystallography for bis(isopropyl 3-oxobutanoato)hafnium(IV)phthalocyanine confirms this conclusion. The central macrocycle of the phthalocyanine ligand is not exactly planar (deviations from the least-square plane exceed 0.15 Å) and has the conformation of an essentially flattened crown. The Hf(1) atom is 1.349(3) above this least-square plane. Cyclic voltammetry investigation shows that the introduction of two β-ketoester ligands to the central atom of phthalocyanine complex leads to both chemical and electrochemical stabilization of the whole Pc system. 相似文献
66.
A new coordination polymer, [Zn2(mal)(1,10-phen)Cl]n (1), (mal = malate, 1,10-phenanthroline), has been synthesized with malic acid and fumaric acid which are generated from maleic acid under hydrothermal reactions. At about the same condition, we get [Cd(fma)(2,2′-bpy)(H2O)]n (2) (fma = fumarate, 2,2′-bpy=2, 2′-bipyridine). The diverse products illustrate that the carbon-carbon doublebond of the maleic acid has two kinds of reaction trends under different conditions. Complex 1, which displays a two-dimensional (4, 8) lattice-type network, is formed from Zn and maleic through the addition reaction with water molecule. If the Zn is changed by Cd, at the same reaction condition with 1, a two-dimensional supramolecular network complex 2 is formed through the conformation transform reaction. To our knowledge, a lot of coordination polymers have been constructed from malic acid and fumaric acid directly; however, these kinds of complexes have seldom been synthesized from maleic acid under hydrothermal reaction. As is known, the rigid carbon-carbon double bond makes maleic acid lead to some unique structural features which the saturated aliphatic acid does not possess. To illustrate this clearly, a simple one dimensional complex 3, [Cd(glut)(1,10-phen)(H2O)]n (glut = glutarate), is synthesized. Furthermore, complex 1 and complex 3 exhibit intense photoluminescent property at room temperature. 相似文献
67.
A new series of chiral carboxylate-bridged complexes of Mn(II), Co(II), and Ni(II) has been synthesized by reaction of M(II) salts with (S)-2-hydroxy-2-methyl-butanedioic acid ((S)-citramalic acid) under solvothermal conditions. The Mn(II) compound 1 is obtained as a crystalline powder, whereas the Co(II) and Ni(II) compounds (2 and 3 respectively) are obtained as single crystals. All the compounds crystallize in orthorhombic chiral space group P212121. Compounds 2 and 3 are isostructural, and their structure consists in helicoïdal chains of M(II) centres linked by carboxylate bridges. The magnetic data indicate a rather weak coupling interaction between paramagnetic centres. The Mn(II) compound 1 exhibits antiferromagnetic ordering at TN = 2.64 K. The Co(II) and Ni(II) compounds show ferromagnetic interactions within the chains. For 3, the chains couple antiferromagnetically, which leads to a metamagnetic behaviour with TN = 1.69 K. 相似文献
68.
Soma Sen Samiran Mitra David L. Hughes Georgina Rosair Cdric Desplanches 《Inorganica chimica acta》2007,360(15):4085-4092
Two new dicyanamide bridged 1D polynuclear copper(II) complexes [Cu(L1){μ1,5-N(CN)2}]n (1) [L1H = C6H5C(O)NHNC(CH3)C5H4N] and [Cu(L2){μ1,5-N(CN)2}]n (2) [L2H=C6H5C(O)CHC(CH3)NCH2CH2N(CH3)2] have been synthesised and structures of both the complexes and their crystal packing arrangements have been established by X-ray crystallography. For complex 1, a tridentate hydrazone ligand (L1H) obtained by the condensation of benzhydrazide and 2-acetylpyridine is used, whereas a tridentate Schiff base (L2H) derived from benzoylacetone and 2-dimethylaminoethylamine is employed for the preparation of complex 2. Variable temperature magnetic susceptibility measurement studies indicate there are weak antiferromagnetic interactions with J values −0.10 and −1.41 cm−1 for 1 and 2, respectively. 相似文献
69.
Two structurally related flexible imidazolyl ligands, bis(N-imidazolyl)methane (L1) and 1,4-bis(N-imidazolyl)butane (L2) reacted with Mn(II) salts of aliphatic dicarboxylic acids resulted in the formation of a number of novel metal-organic coordination architectures. All complexes have been structurally characterized by X-ray diffraction analysis. The different coordination modes of dicarboxylate anions due to their chain length, rigidity and diimidazolyl functionality lead to a range of different coordination structures. The coordination polymers exhibit 1D single chain, 2D sheet and 3D network structures. The aliphatic dicarboxylates can adopt chelating μ2, bridging μ2, and chelating-bridging μ3 coordination modes, or act as uncoordinated counter anions. The central metal ions are coordinated in N2O4 and N4O2 fashions depending on the ancillary ligands. The topology of [Mn(male)(L1)(H2O)2] (1, male = maleate) gives rise to singly bridged 1D chains, whereas compound [Mn(mal)(L1)(H2O)] · H2O (2, mal = malonate) exhibits 2D sheets in which the metal centers are bridged by both imidazolyl ligands and dicarboxylates. Compounds [Mn(L1)2(H2O)2](suc) · 6H2O (3, suc = succinate) and [Mn(L1)2(H2O)2](fum) · 6H2O (4, fum = fumarate) show doubly bridged 1D chains, and the dicarboxylate groups are not coordinated but form 2D corrugated sheets with water molecules intercalated between the cationic layers. Compound [Mn(suc)(L2)(H2O)2] (5, suc = succinate) was built from very flexible succinate and 1,4-bis(N-imidazolyl)butane which yielded three-dimensional interpenetrate networks, both succinate anion and the imidazolyl ligand act as bidentate bridging. 相似文献
70.
The reactions of N,N-dimethylaminopropyl chalcogenolates with platinum(II) compounds have been carried out and complexes of the types [PtCl(ECH2CH2CH2NMe2)]2 (1) (E = S (1a) and Se (1b)), [Pt(ECH2CH2CH2NMe2)2]n (2) (E = S (2a) and Se (2b)), [(PtCl2)2{(Me2NCH2CH2CH2E)2}]n (3), [PtX(SeCH2CH2CH2NMe2)]2 (4) (X = SePh (4a) and OAc (4b)) and [PtCl(ECH2CH2CH2NMe2)(PR3)]n (5) (E = S, Se, Te) have been isolated. These complexes have been characterized by elemental analysis, IR, UV-Vis, NMR (1H, 13C, 31P, 77Se, 195Pt) spectroscopy and FAB mass spectral data. The structures of [PtCl(SeCH2CH2CH2NMe2)]2 (1b) and [PtCl(SCH2CH2CH2NMe2)(PPr3)]2 (5a) have been established by single crystal X-ray diffraction data. Both the molecules have dimeric structures. In 1b, two platinum atoms are held together by symmetrically bridging Se atoms of the chelating selenolate groups. In 5a, two thiolates form a four-membered Pt2S2 bridge with dangling NMe2 groups. 相似文献