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Related Complexes (relate + complex)
Selected AbstractsSynthesis and Characterization of [OsCl2(=C=CHR)(PPh3)2] and Related ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 14 2004Ting Bin Wen Abstract Treatment of [OsCl2(PPh3)3] with HC,CR (R = Ph, p -tolyl, CMe3) in the presence of HCl gives the corresponding trichloro(carbyne) complexes [OsCl3(,CCH2R)(PPh3)2] in good yields. The vinylidene complexes [OsCl2(=C=CHR)(PPh3)2] (R = Ph, p -tolyl, CMe3) are, in turn, prepared from the reactions of the carbyne complexes [OsCl3(,CCH2R)(PPh3)2] with NEt3. These new vinylidene complexes are hygroscopic and react with H2O to give (aqua)(vinylidene) complexes [OsCl2(H2O)(=C=CHR)(PPh3)2]. The structures of several of these new complexes have been determined by X-ray diffraction studies. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Chelate [2-(Iminoethyl)pyridine N -oxide]metal Complexes , Synthesis and Structural Comparison with Their Chemically Related 2-(Iminoethyl)pyridine-Derived SystemsEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 2 2006Katrin Nienkemper Abstract The N,O-chelate ligands 2-(iminoethyl)pyridine N -oxide (2a) and 2-(iminoethyl)-6-isopropylpyridine N -oxide (2b) were prepared by conventional synthetic routes, the latter involving a variant of the Reissert,Henze reaction. Treatment of 2a with FeCl2 resulted in a deoxygenation reaction of the ligand and formation of the salt [bis{2-(iminoethyl)pyridine}FeCl]+[FeCl4], (18a). In contrast, the reaction of 2a with PdCl2 or CoCl2 cleanly furnished the six-membered chelate [,N,O -2(iminoethyl)pyridine N -oxide]MCl2 complexes (19a, M = Pd) or (20a, M = Co), respectively, which were both characterised by X-ray diffraction. Treatment of 2b with [NiBr2(dme)], followed by crystallisation from THF, gave the complex [(,N,O - 2b)NiBr2(THF)] (21b), which features a distorted trigonal-bipyramidal coordination geometry of the central metal atom. The reaction of 2a with [NiBr2(dme)] gave the structurally related complex [(,N,O - 2a)NiBr2(,O - 2a)] (21a). The N,O-chelate Pd complex 19a was shown to be an active catalyst for the Suzuki coupling reaction. The ligand systems 2a,b and their related 2-(iminoethyl)pyridines 3a,b and a variety of metal complexes of ligands 3 were also prepared and characterised for comparison by X-ray diffraction. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Copper Complexes with Neutral N4 Tripodal Ligands: Influence of the Number of Nitrogen Donors on Their Structures, Properties, and Reactivity,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2009Kiyoshi Fujisawa Abstract Copper coordination complexes of the neutral tetradentate nitrogen-containing ligands tris(3,5-dimethylpyrazol-1-ylmethyl)amine (L0N4) and tris(3,5-diisopropylpyrazol-1-ylmethyl)amine (L1N4), namely the copper(II) chlorido complexes [CuII(L0N4)Cl2] (1) and [CuII(L1N4)Cl2] (2), the copper(II) nitrato complexes [CuII(L0N4)(NO3)](NO3) (3) and [CuII(L1N4)(NO3)](NO3) (4), and the copper(II) sulfato complexes [CuII(L0N4)(SO4)] (5) and [CuII(L1N4)(SO4)] (6), and the copper(I) complexes [CuI(L0N4)](PF6) (7) and [CuI(L0N4)(PPh3)](ClO4) (8), have been systematically synthesized in order to investigate the influence of the number of nitrogen donors on their structures, properties, and reactivity. All copper(II) complexes were fully characterized by X-ray crystallography and by IR/far-IR, UV/Vis absorption, and ESR spectroscopy. Although the structure of 7 was not determined by X-ray crystallography, this complex and the structurally characterized copper(I) triphenylphosphane complex 8 were fully characterized by IR/far-IR and NMR spectroscopy. A comparison of the copper(II) complexes with two tris(pyrazol-1-ylmethyl)amine ligands with different bulkiness of the pyrazolyl rings has allowed us to evaluate the second coordination sphere effects of the ligands. Moreover, the structures and physicochemical properties of these complexes are compared with those of related complexes containing the neutral tridentate tris(pyrazolyl)methane ligand and the neutral bidentate bis(pyrazolyl)methane ligand. Finally, the relative stability of the copper(I) complexes is discussed. The influence of the number of nitrogen donors in copper complexes is observed from these systematic results.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] A Comparative Study of the Optical and Electroluminescent Properties of EuIII Complexes with TTA and 2-(2,-Pyridyl)azoles: The Crystal Structure of [Eu(TTA)3(PBO)]EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 18 2006Li-Hua Gao Abstract Two EuIII mixed-ligand complexes, namely [Eu(TTA)3(PBO)]and [Eu(TTA)3(PBT)] [TTA = 1,1,1-trifluoro-3-(2-thenoyl)acetonato, PBO = 2-(2,-pyridyl)-1,3-benzoxazole, and PBT = 2-(2,-pyridyl)-1,3-benzothiazole], have been synthesized. [Eu(TTA)3(PBO)] has been structurally characterized by single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic space group C2/c. The lattice parameters are a = 41.346(4), b = 10.0538(8), c = 20.3793(16) Å, , = 110.922(2)°, Z = 8. The EuIII ion is eight-coordinate, with three bidentate TTA, anions and one bidentate N,O-chelated PBO molecule. A comparative study by UV and emission spectroscopy was carried out and electroluminescent properties of the related complexes [Eu(TTA)3(PBO)] and [Eu(TTA)3(PBT)] are reported as well. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Dispersive Effects in Chemomechanical Reactions with Polyallylamine-Derived HydrogelsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 8 2008Kazuaki Kato Abstract Volume changes of polyallylamine-derived hydrogels crosslinked with glutaraldehyde are determined with a large variety of effector compounds. Monocarboxylic effectors lead to smaller contractions, in contrast to dicarboxylate structures, which allow more effective non-covalent crosslinking between the positively charged nitrogen centers of the polymer backbone. Electroneutral compounds lead to negligible changes, whereas effectors with either a large p -moiety like in naphthoic acid or phenyl derivatives with polarizable substituents induce large contractions. This finding is in line with significant contributions of van der Waals interactions between the effectors within the hydrogel. Chemomechanical differences between regioisomeric effectors such as p - and o -nitrobenzoic acid are in agreement with independent results of dispersive interactions in related complexes. The volume decrease corresponds almost entirely to the gravimetrically determined water content of the gels. The acidity profile shows a strong contraction above pH 10, which is consistent with the known pK value of such polyamines. NMR spectra of the gels indicate strong binding of the effectors by line broadening, which is significant only for the chemomechanically active compounds. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008) [source] Vibrational spectra of clioquinol and its Cu(II) complexJOURNAL OF RAMAN SPECTROSCOPY, Issue 4 2007Claudia C. Wagner Abstract The infrared and Raman spectra of 5-chloro-7-iodo-8-hydroxyquinoline (clioquinol, CQ) and that of its Cu(II) complex of stoichiometry [Cu(CQ)2] were recorded and briefly discussed. Some comparisons were made with related complexes. The interest of the investigated systems in relation to Alzheimer's disease is briefly commented. Copyright © 2006 John Wiley & Sons, Ltd. [source] Transformation of organic molecules on the low-valent {M(Ph2PCH2CH2PPh2)2} moiety derived from trans -[M(N2)2(Ph2PCH2CH2PPh2)2] or related complexes (M = MO, W)THE CHEMICAL RECORD, Issue 5 2001Hidetake Seino Abstract A zero-valent {M(Ph2PCH2CH2PPh2)2} moiety (M = Mo, W) generated in situ by dissociation of the N2 ligands in trans -[M(N2)2(Ph2PCH2CH2PPh2)2] can activate ,-accepting organic molecules including isocyanides and nitriles, which undergo the electrophilic attack caused by a strong ,-donation from a zero-valent metal center. Cleavage of a variety of C,X bonds (X = H, C, N, O, P, halogen) also occurs at their electron-rich sites through oxidative addition to form reactive intermediates, which subsequently degradate to yield smaller molecules either bound to or dissociated from the metal center. The mechanism is substantiated unambiguously by isolation of numerous intermediate stages. © 2001 John Wiley & Sons, Inc. and The Japan Chemical Journal Forum Chem Rec 1:349,361, 2001 [source] (Acetato-,O)[tris(3,5-dimethylpyrazol-1-yl-,N2)hydroborato]zinc(II)ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2009Azizolla Beheshti The title complex, [Zn(C15H22BN6)(C2H3O2)] or (TpMe,Me)Zn(OAc), contains a tripodal tris(pyrazolyl)hydroborate ligand, a monodentate acetate ligand and a ZnII centre in a distorted tetrahedral coordination environment capped on one triangular face by a secondary Zn...O interaction with the second O atom of the acetate ligand. The four-coordination of ZnII and the essentially monodentate character of the acetate ligand are due to the high steric demands of the ligand set, which prevent chelate formation and five-coordination and lead to relatively long Zn,O and Zn,N bonds compared with related complexes of ZnII and other metals. [source] Bis(,4 -butane-1,4-dithiolato)bis[hexacarbonyldiiron(II)(Fe,Fe)]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2007Yue Zhang The novel title double-butterfly Fe/S cluster complex, [Fe4(C4H8S2)2(CO)12], which is structurally similar to the active site of the Fe-only hydrogenases, contains two inversion-related Fe2S2(CO)6 subcluster cores connected by two equivalent butyl chains to afford a 16-membered macrocycle. The formation of the 16-membered macrocycle has an influence on the C,S,Fe angles, while the Fe,Fe and Fe,S bond lengths remain similar to those in related complexes. [source] Some platinum(II) complexes derived from aromatic alkynesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 10 2002Michael I. Bruce Abstract Several trans -platinum(II) complexes, of the type R,{Pt(PBu3)2}R,{Pt(PR3)2}R,, where R, and R, are groups derived from a series of aromatic alkynes and diynes, have been prepared and characterized. Extensive spectroscopic data for these and other known related complexes are presented. A more precise structural study of trans -Pt(C,CC6H4C,CPh)2(PBu3)2 (cf. Z. Kristallogr. 1998; 213: 483) is reported. Copyright © 2002 John Wiley & Sons, Ltd. [source] Interaction of an echinomycin,DNA complex with manganese ionsACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 7 2009Roland Pfoh The crystal structure of an echinomycin,d(ACGTACGT) duplex interacting with manganese(II) was solved by Mn-SAD using in-house data and refined to 1.1,Å resolution against synchrotron data. This complex crystallizes in a different space group compared with related complexes and shows a different mode of base pairing next to the bis-intercalation site, suggesting that the energy difference between Hoogsteen and Watson,Crick pairing is rather small. The binding of manganese to N7 of guanine is only possible because of DNA unwinding induced by the echinomycin, which might help to explain the mode of action of the drug. [source] Utilization of Self-Sorting Processes To Generate Dynamic Combinatorial Libraries with New Network TopologiesCHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2006Isabelle Saur Dr. Abstract The synthesis of water-soluble, organometallic macrocycles is described. They were obtained by self-assembly in reactions of the half-sandwich complexes [{Ru(C6H5Me)Cl2}2], [{Ru(p -cymene)Cl2}2], [{Rh(Cp)Cl2}2], and [{Ir(Cp*)Cl2}2] with the ligand 5-dimethylaminomethyl-3-hydroxy-2-methyl-4-(1H)-pyridone in buffered aqueous solution at pH 8. The structure of the Ru,(p -cymene) complex was determined by single-crystal X-ray crystallography. Upon mixing, these complexes undergo scrambling reactions to give dynamic combinatorial libraries. In combination with structurally related complexes based on amino-methylated 3-hydroxy-2-(1H)-pyridone ligands, an exchange of metal fragments but no mixing of ligands was observed. This self-sorting behavior was used to construct dynamic combinatorial libraries of macrocycles, in which two four-component sub-libraries are connected by two common building blocks. This type of network topology influences the adaptive behavior of the library as demonstrated in selection experiments with lithium ions as the target. [source] Guest-dependent conformation of 18-crown-6 tetracarboxylic acid: Relation to chiral separation of racemic amino acidsCHIRALITY, Issue 7 2008Hiroomi Nagata Abstract (+)-18-Crown-6 tetracarboxylic acid (18C6H4) has been used as a chiral selector for various amines and amino acids. To further clarify the structural scaffold of 18C6H4 for chiral separation, single crystal X-ray analysis of its glycine+ (1), H3O+ (2), H5O (3), NH (4), and 2CH3NH (5) complexes was performed and the guest-dependent conformation of 18C6H4 was investigated. The crown ether ring of 18C6H4 in 3, 4, and 5 took a symmetrical C2 or C2 -like conformation, whereas that in 1 and 2 took an asymmetric C1 conformation, which is commonly observed in complexes with various optically active amino acids. The overall survey of the present and related complexes suggests that the molecular conformation of 18C6H4 is freely changeable within an allowable range, depending on the molecular shape and interaction mode with the cationic guest. On the basis of the present results, we propose the allowable conformational variation of 18C6H4 and a possible transition pathway from its primary conformation to the conformation suitable for chiral separation of racemic amines and amino acids. Chirality, 2008. © 2008 Wiley-Liss, Inc. [source] | ||||||||||||||||||||||