Synthesis and Crystal Structure of Dicopper(II) Compound Containing Oxalate and Reduced Imino Nitroxide Radicals

A new dicopper(II) compound with oxalate and reduced imino nitroxide radicals [Cu2(m-C2O4)(Him2-py)2(H2O)2](NO3)2 (Him2-py=1-hydroxy-2-(2-pyridyl)-4,4,5,5-tetramethyli- midazoline) has been synthesized and its crystal structure was determined by X-ray diffraction method. The complex crystallizes in monoclinic, space group P21/n with a = 9.913(4), b = 19.057(8), c = 10.169(4) ? b = 114.292(7), V = 1751(1) 3, C26H38Cu2N8O14, Mr = 813.72, Dc = 1.543 g/cm3, m(MoKa) = 1.290 mm-1, F(000) = 840, Z = 2, the final R = 0.0398 and wR = 0.0986 for 1878 observed reflections (I>2s(I)). The imino nitroxide 2-(2-pyridyl)-4,4,5,5-tetramethyl- imidazoline-1-oxyl (im2-py) is reduced in the reaction to yield Him2-py which consists of oxalato-bridged centrosymmetric [Cu2(m-C2O4)(Him2-py)2(H2O)2]2+ ions and noncoordinated NO3- anions. Each copper(II) ion is in a distorted tetragonal pyramid environment: two nitrogen atoms from Him2-py and two oxygen atoms from the oxalate group are in the basal plane, and one water molecule at the axial position.

Synthesis, Structure and Properties of Nqvel Dicopper( Ⅱ ) Complex [Cu(oxpn)Cu(tmen)_2]·(ClO_4)_2

The copper( Ⅱ ) complex, [Cu(oxpn)Cu(tmen)2](ClO4)2 was synthesized, where oxpn is N, N' -bis ( 3-aminopropyl) oxamido and tmen is N, N, N' N' -tetram-ethylethylenediamine. The crystal is triclinic, space group P 1, a=1-2349(2), b = 1.3093(2), c=1. 3855(2) nm, α=61-88(1), β=69.49(1), γ=57.91(1)°? V = 1. 6589 nm3, Z = 2. Both copper( Ⅱ ) ions are in a square pyramidal coordination environment , and linked by oxamido bridge. The distance between them is 0. 526 nm. Variable temperature (4. 2-300 K) magnetic susceptibility data for this complex show that there exists a relatively large antiferromagnetic exchange interaction between the two copper( Ⅱ ) ions with a J value of-740. 40 cm-1.

STUDY ON BINUCLEAR COPPER(I)COMPLEXES III.SYNTHESIS,CHARACTERIZATION AND ELECTROCHEMISTRY OF DICHLORO-TRIS(4-VINYLPYRIDINE)-DICOPPER(I)COMPLEX

Recent years,many novel complexes have been prepared by using hetero-bidentate ligands.However,complexes with such ligands as 4-vinylpyridine which has two different coordinating sites have not been reported,and only a few complexes of Cu(I)have been published^(1-3).The title complex Cu_2(C_5H_4N·CH=CH_2)_3Cl was prepared and characterized by elemental analyses,ICP,IR,and electronic spectra.Its conductivity,oxidation potential and reduction potential were measured.

Synthesis and Crystal Structure of a Dicopper(Ⅰ) Complex with Bis(diphenylphosphino)methane and Diethyldithiocarbamate

The title complex [Cu2(-dppm)2(-Et2dtc)](ClO4)EtOH0.25H2O (dppm = bis- (diphenylphosphino)methane, Et2dtc = diethyldithiocarbamate) has been synthesized and characterized by single-crystal X-ray diffraction analysis. The crystal structure is of monoclinic, space group C2/c with a = 42.587(1), b = 14.1653(4), c = 20.5649(5) ? = 105.945(1)? V =11928.6 3, C57H60.5ClCu2NO5.25P4S2, Mr = 1194.09, Z = 8, Dc = 1.330 g/cm3, (MoK) = 0.98 mm-1 and F(000) = 4948. A total of 15243 reflections were collected, of which 7322 were unique. The structure was refined to R = 0.0739 and wR = 0.1846 for 5135 observed reflections with I > 2(I). The crystal structure consists of the complex cation [Cu2(-dppm)2(-Et2dtc)]+, anion ClO4- and solvate H2O and EtOH, where the dinuclear Cu(Ⅰ) atoms are bridged doubly by two dppm ligands and singly by Et2dtc to give three five-membered rings. The Cu(Ⅰ) atom is in an approxi- mately trigonal-planar environment with the P2S chromophore. The short Cu贩稢u separation (2.7111 ? suggests the presence of metal-metal contact.

A NOVEL SYNTHETIC METHOD AND STRUCTURE OF TETRAKIS(BENZOATE)BIS(TRIPHENYLPHOSPHINE OXIDE)DICOPPER(II).OXIDATIVE ADDITION OF DIBENZOYL ON METALLIC COPPER

Dibenzoyl peroxide undergoes oxidative addition on metallic copper with triphenylphosphine in a mixed solvent(acetone,dichloromethane and trichloromethane),and affords the binuclear copper complex (Cu(C_6H_5COO)_2(OPPh_3))_2.Crystals are monoclinic,space group A_2/a,with cell parameters,a=24.337(3),b=10.566(1),c=21.579(2),β= 93.18(1)°, V=5540(1)~3,Z=4,R=0.042,and Rw=0.044 for 5872 observed reflections. Each copper ion is coordinated by four bridging benzoato ligands and one triphenylphosphine oxide group to form binuclear complexes.

SYNTHESIS AND MAGNETIC PROPERTY OF CARBOXYL BRIDGING DICOPPER(Ⅱ) COMPLEXES

Two new dicopper(Ⅱ) complexes with two carboxyl bridgings in one molecule[Cu(dm-phen)(HCOO)]_2(NO_3)_2 3H_2O(1). [Cu(ds-phen)(CH_3COO)]_2 (NO_3)_2 3H_2O(2). one dicopper(Ⅱ) complex with one carboxyl bridging and one hydroxo bridging in one molecule [Cu_2(OH)(C_2H_5COO)(ds-phen)_2]. (NO_3)_2 H_2O(3) and one cononuclear Cu(Ⅱ) complex [Cu(de-phen)(CF_3COO)](NO_3).H_2O(4)(dm-phen= 2,9-dimethyl-1,10-phenanthrolin)were prepared and characterized. The effective magnetic moment, u elf, was measured and their magnetic properties were discussed. The coordination modes of carboxyl moieties in all the title complexes were proposed.

The complexes of multiimidazole with copper(Ⅰ) display tyrosinase activity

The six multiimidazole copper（Ⅰ） complexes are utilized to mimic tyrosinase. The main product is 3,5-di-t-butylcatechol from o-hydroxylation of the substrate 2,4-di-t-butylphenol. The highest yield of catechol is up to 82.2% and selectivity 94.8% by [Cu（Ⅰ）2（3b）（MeCN）2]（CIO4）2 and O2 under mild conditions, which are found to be more efficient than that already reported.

Synthesis and Properties of Dinuclear Cu( Ⅱ ) Complexes Derived from Oxamidobis(propionato)cuprate( Ⅱ )

Three dinuclear complexes were synthesized and designated as Cu(obp)CuL where obp =oxamidobis(propionato), L=2,2' -bipyridyl(bpy) (1), 1 , 10-phenathroline(phen)(2) and 5-nitro-1, 10-phenathroline(NO2-phen)(3). The complexes were characterized by elemental analyses, in fared and electronic spectra, magnetic susceptibilities and ESR spectra, indicating antiferromagnetic spin exchange interactions between metal ions.

Synthesis and Crystal Structures of Two Di-Cu(Ⅱ) Complexes Based on an Asymmetric Dinucleating Ligand

Two new dicopper（II） complexes [Cu2L（OAc）2]（ClO4）·H2O （1） and [Cu2L（BPP）2]-（ClO4） （2） using an asymmetric dinucleating ligand HL and auxiliary ligands such as acetate （OAc） and bisphenyl phosphate （BPP） have been synthesized and characterized by elemental analysis, IR and single-crystal X-ray diffraction. Complex 1 crystallizes as blue single crystals that belong to the triclinic crystal system and Pī space group, while complex 2 crystallizes in a monoclinic P21/c space group. Single-crystal X-ray diffraction analysis reveals that the two copper ions in complexes 1 and 2 reside within the adjacent ligand compartments and are bridged by the endogenous phenoxo-O from ligand L and the introduction of two desired exogenous carboxylates or phosphates in the bidentate μ-1,3-bridged mode. The coordination geometries of Cu（1） and Cu（2） are both distorted square pyramids.

Synthesis,characterization,structures and magnetic property of chiral oxalate-bridged dicopper(Ⅱ) complexes

The oxalato-bridged dicopper(II) complexes [Cu2(μ-ox)(LRR)2(H2O)2(ClO4)2] (1),[Cu2(μ-ox)(LRR)2(CH3COCH3)2(ClO4)2](1a),[Cu2(μ-ox)(LSS)2(H2O)2(ClO4)2] (2) and [Cu2(μ-ox)(LRR)(LSS)2(CH3COCH3)2(ClO4)2] (3) [LRR = (8R,10R)-(-)-[4,5]-pineno2,2′-bipyridine,LSS = (8S,10S)-(+)-[4,5]-pineno-2,2′-bipyridine;ox2= oxalate] were first prepared.A possible mechanism for the formation of the chial dicopper(II) complexes was proposed.Based on elemental analysis,conductance measurement,UV-Vis spectra,CD spectra and X-ray single-crystal diffraction,the oxalato-bridged structures of 1 and 2 were deduced to adopt two Cu(II) ions and the bridged oxalate lying in the nearly same plane.The crystal structures of 1a and 3 reveal that the coordination geometry around each Cu(II) ion is an elongated and distorted octahedron and two axial solvent molecules and two perchlorate ions are anti to each other respectively in both binuclear molecules.The solution CD spectra of 1 and 2 in the visible d-d range show very weak Cotton effects with peaks at 588 and 779 nm,which are approximately of mirror image,suggesting the optical activities may be derived from the vicinal effects of the chiragenic centers at the pinene group of LRR and LSS,respectively.Complex 1 has been characterized by variable-temperature magnetic susceptibility and the data was least-square fitted to the Blenaey-Bowers equation.The exchange integral J was found to be -338.41(4) cm-1,indicating a strong antiferromagnetic interaction between two copper(II) ions.