对苯二甲醛苏氨酸Schiff碱过渡金属配合物的合成及表征

对苯二甲醛和苏氨酸在乙醇溶剂中加热回流制得对苯二甲醛苏氨酸Schiff碱,并采用一锅法进一步与铜(Ⅱ)、钴(Ⅱ)、镍(Ⅱ)、锌(Ⅱ)的醋酸盐反应得到4种相应的过渡金属Schiff碱配合物;采用元素分析、电导测定、紫外光谱、红外光谱等手段对Schiff碱金属配合物的结构进行分析和表征。     

Tripodal amido complexes: molecular "claws" in main group and transition metal chemistry

The chemistry of transition metal amides has received new impetus in recent years due to the systematic exploitation of the amido function [NR(2)](-) in ligand design. A class of 3-fold symmetrical tripodal amido ligands has proved to be a valuable tool in the stabilization of early transition metal and main group metal complexes and complex fragments. Moreover, promising strategies for their use as chemical reagents and homogeneous catalysts have been developed. An overwiew of the current state of this field is given and the potential for further development will be highlighted.     

1-羟基-2-萘醛缩对溴苯胺Schiff碱过渡金属配合物的合成及表征

1-羟基-2-萘醛和对溴苯胺在乙醇溶剂中加热回流制得1-羟基-2-萘醛缩对溴苯胺Schiff碱,该Schiff碱分别与铜(Ⅱ),钴(Ⅱ),镍(Ⅱ),锌(Ⅱ)的醋酸盐反应生成相应的4种过渡金属Schiff碱配合物;采用元素分析、电导测定、紫外光谱、红外光谱等手段对上述配体及其配合物进行分析和表征。     

新型含羧基卟啉及其金属配合物的合成

合成了5－（间羰基苯甲酸）－氨基苯基－10，15，20－三苯基卟啉（m-CPTPP)及其锌（Ⅱ）、铁（Ⅲ）、铜（Ⅱ）配合物，并通过质谱、元素分析、IR、UV－Vis、^1HNMR、荧光光谱等对其进行了考察。     

Transition metal substituted derivatives of cubic MCM-48 mesoporous molecular sieves

Mesoporous Ti-, Cr- and V-substituted derivatives of the cubic silica molecular sieve MCM-48 have been hydrothermally synthesized at 373 K by an electrostatic assembly pathway using cetyltrimethylammonium cation as the templating agent. The transition metal substituted products all exhibit improved crystallinity and a narrower pore size distribution relative to the pristine molecular sieve. Transition metal substitution caused an enlargement of the cubic unit cell as well as an increase in the degree of crosslinking in the mesopore walls. The coordination of V-sites in the meso-structure is exclusively tetrahedral, as judged by NMR spectroscopy. These sites as well as those of Ti and Cr sites are active and selective for the peroxide oxidation of styrene and methyl methacrylate to benzaldehyde and methyl pyruvate, respectively.     

2-羟基-1-萘醛甘氨酸Schiff碱过渡金属配合物的合成及表征

以2-羟基-1-萘醛和甘氨酸为原料,乙醇为溶剂,加热回流制备2-羟基-1-萘醛甘氨酸Schiff碱配体,然后将该配体分别与Cu(II),Co(II),Ni(II)的醋酸盐反应生成相应的配合物。采用元素分析、紫外光谱、红外光谱、电导测定等手段对上述配体及其配合物进行表征。     

Complexes with biologically active ligands. Part 11. Synthesis and carbonic anhydrase inhibitory activity of metal complexes of 4,5-disubstituted-3-mercapto-1,2,4-triazole derivatives

Complexes containing five 4,5-disubstituted-3-mercapto-1,2,4-triazoles and Zn(II), Hg(II) and Cu(I) were synthesized and characterized by standard procedures (elemental analysis; IR, electronic and NMR spectroscopy, conductimetry and TG analysis). Both the thione as well as the thiolate forms of the ligands were evidenced to interact with the metal ions in the prepared complexes. The original mercaptans and their metal complexes behave as inhibitors of three carbonic anhydrase (CA) isozymes, CA I, II and IV, but did not lower intraocular pressure in rabbits in animal models of glaucoma.     

Transition metal complexes of polymeric amino ligands derived from triethyleneglycol dimethacrylate crosslinked polyacrylamides

Amino functions were incorporated into triethyleneglycol dimethacrylate (TEGDMA)-crosslinked (2–20 mol %) polyacrylamides by transamidation with ethylenediamine. The complexation of these polymeric ligands with the amino function in different structural environments was investigated toward Cr(III), Mn(II), Fe(III), Cu(II), Cd(II), and Pb(II) ions. The metal ion intake decreased with the extent of the crosslinking and followed the order Cu(II)>Cr(II)>Mn(II)>Fe(III)>Pb(II)>Cd(II). The pH dependence of complexation and distribution coefficient; time course and kinetics of complexation; swelling properties of the uncomplexed and complexed resins in water; recyclability; infrared (IR) spectra; electron paramagnetic resonance; ultraviolet visibility; magnetic susceptibility; and thermogravimetric and scanning electron microscopy studies were carried out. The kinetics of complexation was found to be first order. The swelling of the complexed resins is lower than that of the uncomplexed resins. Complexation resulted in the lowering of the IR absorption of the amino ligands. The IR data of the TEGDMA-crosslinked polyacrylamide amine and the corresponding Cr(III) complex reveals that the metal is coordinated with the ligand through the amino nitrogen. The SO⁼₄ is also coordinated. The number of coordinated nitrogen atoms varies as the hydrophilicity and flexibility of the polymer change with the crosslinking. Thus spectral and magnetic studies suggest a distorted octahedral geometry for Cu(II) complexes, octahedral geometry of the d³ system for Cr(III), and d⁵ high-spin octahedral geometry for Fe(III) and Mn(II) complexes. The thermal stabilities of the complexed resins increase with increase in the metal content. Surface morphology of the polymeric ligand changes on complexation. © 1996 John Wiley & Sons, Inc.     

Shaping RNA structures with metal ions and metal ion complexes

The research in our laboratory focuses on the role of metal ions and their complexes in structure formation and folding of nucleic acids. Large catalytic RNAs, like group II introns and some riboswitches, as well as shorter RNAs and DNAs containing modified nucleotides for the assembly of nanodevices are examined. Abundant metal ions like Mg2+ or natural metabolites like coenzyme B12 are in the center of interest, but also other metal ions, complexes thereof and B12 derivatives are applied with the aim to understand the largely unknown and manifold non-covalent interactions with nucleic acids. We apply a multitude of techniques, including potentiometric pH titrations, NMR spectroscopy, X-ray crystallography, gel electrophoresis and single molecule FRET experiments. Here we briefly summarize each of our research topics emphasizing the interaction of coenzyme B12 and its derivatives with the btuB riboswitch of E. coli. This highly conserved sequence, found in the 5'-untranslated region (5'-UTR) of the btuB mRNA, is involved in the regulation of the btuB protein expression. After a summary on the historical discovery of such riboswitches and their mechanism of action, we shortly focus on our own contributions to understand the structural equilibrium, high affinity and selectivity of the interaction between this specific RNA sequence and the largest and most complex cellular metabolite, coenzyme B12.     

Ethylene polymerization catalyzed by group 4 metal complexes of tridentate heteroscorpionate ligands

Considerable attention has been recently devoted to group 4 metal complexes of N,O polydentate ligands exhibiting electronic properties comparable to those of the cyclopentadienyl ligand: among these the heteroscorpionates are attractive candidates. Herein we review the results reached in olefin polymerization catalysis promoted by group 4 metals complexes of heteroscorpionate ligands, with particular reference to the work carried out in our research group. The ethylene polymerization catalyzed by titanium and zirconium complexes of the (3,5-^tBu₂-2-phenoxo)bis(3,5-Me₂-pyrazol-1-yl)methane ligand has been investigated in great detail. A solution structure of the active species was proposed on the basis of variable temperature ¹H NMR spectroscopic evidences. Kinetic mechanisms accounting for the formation of linear and branched polyethylenes obtained by the zirconium complexes have been proposed in the light of the ionic interactions of the active species and steric hindrance at metal centre determined by the heteroscorpionate ligands.     

Removal of metal catalysts from aldehyde oils

Aldehydes made from soybean or linseed oils, or their methyl esters, darkened and polymerized following preparation by ozonolysis and catalytic or chemical reduction in stainless-steel pilot-plant equipment. Treatment with a cation exchange resin in the hydrogen form substantially reduced the amount of color formed and the polymerization. When conducted prior to removal of volatiles by stripping the resin treatment of soybean aldehyde oil decreased final color from Gardner 17 to 10 with a concomitant decrease in molecular weight and viscosity due to decreased polymerization. Resin pretreatment of methyl azelaaldehydate (MAZ) increased distillation yields. Since addition of several metal salts to MAZ reduced distillation yield to varying degrees, metalcatalyzed polymerization must occur. Presented at the AOCS Meeting, Minneapolis, 1963. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Polymerization of rac-lactide catalyzed by group 4 metal complexes containing chiral N atoms

The hydroxyl- and phenoxy-bridged dinuclear zirconium and hafnium complexes, 1 and 2, containing a chiral N atom in the N₂O₂ ligand (H₂L = 2-(((2-pyridylmethyl)(2-hydroxyphenyl)amino)methyl)-4,6-di(tert-butyl)phenol) were used as catalysts for the ring-opening polymerization of rac-lactide. Experiments prove that 1 and 2 are living and controlled catalytic systems with activity up to 3.25 g_pol mmol_ini ⁻¹ h⁻¹. The isotactic-rich polylactides in a narrow polydispersity (M _w/M _n = 1.01–1.13) were produced with enantiomeric complexes 1 and 2 (P _m = 0.65–0.73). The kinetic studies show a first-order dependency in both monomer and initiator. The initiation mechanism is discussed on the basis of the MALDI-TOF MS and ¹H NMR spectra of the rac-LA oligomer prepared by 1.     

Transition metal complexes with Girard reagent-based ligands, Part I: Synthesis and crystal structure of the first cobalt(III) complexes with Schiff base derivative of Girard reagent

A new ligand, pyridoxilidene Girard-T hydrazone, [H₃L]Cl₂ · 2H₂O, and its octahedral cobalt(III) complexes [Co(HL)(NO₂)₃] · H₂O (1) and [Co(HL)₂](PF₆)₃ (2) were synthesized. The X-ray analysis of (1) showed that the complex has a mer-octahedral configuration formed by coordination of the tridentate ONO neutral Schiff-base molecule and three monodentate N-bonded NO₂ groups. Hydrogen bonds and intermolecular interactions for this complex are discussed. Complex (2) also has a mer-octahedral configuration. The ligand and complexes were characterized by elemental analysis, conductometric and magnetochemical measurements, IR and UV–Visible, ¹H and ¹³C NMR spectra.     

水杨醛缩对羟基苯甲酰肼及其配合物的荧光研究

将Schiff碱与金属盐在一定的条件下反应,生成了具有稳定的结构和生物活性的配合物.该类配合物被广泛应用于药学、催化和分析化学等领域.本实验设计合成了水杨醛缩对羟基苯甲酰肼Schiff碱配体(H2L)及其10种金属配合物.采用红外光谱、元素分析、热重-差热分析对Schiff碱配体及其配合物进行了表征.并对目标化合物的荧光活性进行了初步测定.     

Compaction of metal salt-urea complexes with triple superphosphate

It has been the experience of the fertilizer industry that urea should not be cogranulated or blended with superphosphate because urea reacts with monocalcium phosphate monohydrate (MCP·H₂O) in superphosphate to form an adduct. This reaction releases the water of hydration and causes the product to become wet and sticky or severely caked during storage. The objectives of this study were [1] to test the feasibility of preventing or retarding the reaction by complexing the urea with various salt hydrates and [2] to measure ammonia volatilization from metal salt-urea complexes on the soil surface.Three metal salt-urea complexes — Al(urea)₆(NO₃)₃, Fe(urea)₆(NO₃)₃, and Mn(urea)₄Cl₂ — were prepared and cogranulated by compaction with pure MCP·H₂O or triple superphosphate (TSP) at a mole ratio of MCP:urea as 1:2. These materials were then compared with the same material without metal salts in terms of changes in free water content during a storage period of 6 weeks. Without metal salts a rapid and significant increase in free water content of the cogranulated MCP·H₂O + urea or TSP + urea was observed. The increases in free water content were found to range from 1.5% to 1.8%, corresponding to approximately 63% and 78% of the added MCP·H₂O that reacted with urea in the cogranulated products. On the other hand, little change or only a slight increase (less than 0.5%) in free water content was observed with the cogranulated metal salt-urea complexes.Ammonia volatilization losses from urea on the soil surface were measured in a period up to 14 d with two soils: Windthorst (pH 7.6) and Savannah (pH 7.0). The fertilizer materials used were granular. In Windthorst soil, the amounts of NH₃-N lost were 25% for prilled urea, 11% for Mn(urea)₄Cl₂, and essentially none for Mn(urea)₄Cl₂ compacted with TSP at a mole ratio of MCP:urea as 1:1 or 1:2. In Savannah soil, the amounts of NH₃-N lost were 39% for prilled urea, 24% for Mn(urea)₄Cl₂, 15% for Fe(urea)₆(NO₃)₃, and less than 6% for each of the two metal salt-urea complexes compacted with TSP. The acidity that resulted from metal complexing of urea reduced NH₃ volatilization from hydrolyzed urea in soils, and additional acidity produced from hydrolysis of MCP·H₂O further reduced NH₃ losses when materials were applied as multicomponent granules (metal salt + urea + TSP).     

含有双膦酸酯基的1,3,4-噻二唑衍生物的合成

以氢亚磷酸酯为原料合成了次亚甲基双膦酸四乙基酯,又通过加成和消除反应合成了亚乙烯基双膦酸四乙基酯,再与2-胺基-5-巯基-1,3,4-噻二唑Michael反应,根据反应物物质的量不同,合成了不同的目标化合物,并探讨了其与—NH2和—HS的反应选择性,其结构均经ESI-MS、IR、1HNMR和13CNMR测试手段所确认,其生物活性在进一步的研究中。     

Apoptosis induced by metal complexes and interaction with dexamethasone

Apoptosis induced by rhodium II amidate, rhodium II propionate, cisplatin and interactions with dexamethaxone were studied on some human leukemia cell lines Raji, Jurkat and U937. Apoptosis was studied by flow cytometry, agarose gel electrophoresis and morphological analysis. Rhodium II propionate induced apoptosis in all the three cell lines, Rhodium II amidate, in the lymphoid cell lines Jurkat and Raji, and cisplatin, only in the Jurkat, a T lymphoid cell line. It has also been observed that the addition of dexamethasone enhances the apoptosis index only in U937, a monocytic line with a glucocorticoid receptor bearing.     

Transition metal diboride-silicon carbide-boron carbide ceramics with super-high hardness and strength

Three phase boride and carbide ceramics were found to have remarkably high hardness values. Six different compositions were produced by hot pressing ternary mixtures of Group IVB transition metal diborides, SiC, and B₄C. Vickers’ hardness at 9.8 N was ~31 GPa for a ceramic containing 70 vol% TiB₂, 15 vol% SiC, and 15 vol% B₄C, increasing to ~33 GPa for a ceramic containing equal volume fractions of the three constituents. Hardness values for the ceramics containing ZrB₂ and HfB₂ were ~30% and 20% lower than the corresponding TiB₂ containing ceramics, respectively. Hardness values also increased as indentation load decreased due to the indentation size effect. At an indentation load of 0.49 N, the hardness of the previously reported ceramic containing equal volume fractions of TiB₂, SiC and B₄C was ~54 GPa, the highest of the ceramics in the present study and higher than the hardness values reported for so-called “superhard” ceramics at comparable indentation loads. The previously reported ceramic containing 70 vol% TiB₂, 15 vol% SiC, and 15 vol% B₄C also displayed the highest flexural strength of ~1.3 GPa and fracture toughness of 5.7 MPa·m^1/2, decreasing to ~0.9 GPa and 4.5 MPa·m^1/2 for a ceramic containing equal volume fractions of the constituents.