REACTION OF BIS(β-ALANINATO)COPPER(II) WITH FORMALDEHYDE: X-RAY CRYSTAL STRUCTURE OF AQUABIS(N,N-DIMETHYL-β-ALANINATO)COPPER(II) HEXAHYDRATE

Abstract

The reaction of bis(β-alaninato)copper(II) with formaldehyde results in the formation of blue crystals of aquabis(N,N-dimethyl-β-alaninato)copper(II) hexahydrate, [Cu(C₅H₁₀NO₂)₂(OH₂)].6H₂O which crystallize in the monoclinic space group C2/c with unit cell dimensions a = 20.799(2), b = 8.112(1), c = 23.639(1)Å, β = 96.50(1)° and Z = 8. The structure has been refined to final R = 0.047 and R_w = 0.053 for 1690 reflections with I ≥ 2.55σ(I).     

SELENOETHER COMPLEXES OF COPPER(II) ‐ SYNTHESIS,SPECTROSCOPY AND STRUCTURES

Abstract

The red-brown copper(II) diselenoether complexes, [Cu (L-L)₂][BF₄]₂ (L-L = MeSeCH₂CH₂SeMe, MeSeCH₂CH₂CH₂SeMe or PhSeCH₂CH₂SePh) have been prepared from copper(II) fluoroborate and the ligands in anhydrous dichloromethane. Some new dithioether analogues are also described. The reaction of MeSeCH₂CH₂SeMe and copper(II) fluoroborate in ethanol led to an unstable dark green substance which appeared to contain both copper(I) and copper(II) and was formulated [Cu(MeSeCH₂CH₂SeMe)₂] [BF₄]_x. The complexes were characterised by analysis, UV-visible and e.p.r. spectroscopy, and magnetic measurements, and cyclic voltammetry has been used to probe the Cu (II)/Cu(I) redox couples. The complexes are too unstable in solution to obtain crystals for an X-ray study, but structural data has been obtained for both the Cu(II) and Cu(I) complexes by copper K-edge EXAFS studies. Ditelluroethers reduce copper(II) salts to copper(I) complexes.     

SPECTROSCOPIC and REDOX BEHAVIOUR OF SOME COPPER(II) ‐ THIOETHER COMPLEXES

Abstract

The features of electronic spectra and redox chemistry of a number of Cu(II)-thioether complexes have been examined. The origin of the intense absorption in the region around 14,000–16,000 cm^?1 is attributed to (π)S → d(Cu²⁺) CTB, that obscures the less intense d-d (Cu²⁺) band. The relationship between spectral characteristics and redox potentials of CuL^2+/+ couples values is discussed.     

ELECTRONIC STRUCTURES AND BONDING PROPERTIES OF MIXED LIGAND COPPER(II) COMPLEXES OF 2-(2-PYRIDYLETHYL)PICOLYLAMINE AND DIPICOLYLAMINE. MOLECULAR STRUCTURES OF (2,2′-BIPYRIDINE)[2-(2-PYRIDYLETHYL)PICOLYLAMINE]COPPER(II) PERCHLORATE AND (DIPICOLYLAMINE)(1,10-PHENANTHROLINE)COPPER(II) PERCHLORATE

Abstract

Mixed ligand copper(II) complexes of 2-(2-pyridylethyl)picolylamine (pepica) of [Cu(pepica)(pi-colinato)](ClO₄)(H₂O) and the [Cu(pepica)(L)](ClO₄)₂ type, where L stands for 2,2′-bipyridine (bipy), 1,10-phenanthroline, neocuproine, and ethylenediamine, and dipicolylamine(dipica) of the [Cu(dipica)(L)](ClO₄)₂(H₂O) _n type, where L for 2,2′-bipyridine (n = 0), 1,10-phenanthroline (phen, n = 0), and neocuproine (n = 1), have been synthesized and characterized by elemental analyses, and IR, electronic and EPR spectroscopic measurements. The molecular structures of [Cu(pepica)(bipy)](ClO₄)₂ (1) and [Cu(dipica)(phen)](ClO₄)₂ (2) have been determined using three dimensional X-ray diffraction data. Complex 1 consists of discrete distorted square pyramidal [Cu(pepica)(bipy)] cations, with a meridional pepica ligand and one of the pyridine rings of the bipy ligand forming a basal plane. The other pyridine nucleus of the bipy is bound at the apex having an elongated bond distance of 2.255 Å and tilted off the normal z axis by ～15°. Complex 2 comprises discrete distorted trigonal bipyramidal [Cu(dipica)(phen)] cations, with the two pyridine nuclei of the dipica ligand and one of the pyridine rings of the phen forming an equatorial trigonal plane and the remaining pyridine ring of the phen and the amine nitrogen of the dipica on the axial sites. The trigonal bipyramidal cation, distorted toward a square pyramidal structure, has an enlarged equatorial N(py)–Cu–N(py) angle of 132.4° and an elongated equatorial Cu–N(phen) bond of 2.156 Å. All of the complexes exhibit axial type EPR spectra. Gaussian resolved d-d spectra for these complexes, except the dipica-bipy and dipicaphen ones, yield an orbital sequence of d_x ²- _y ² ≥ d_z ² > d_xy > d_yz ～d_xz . The bonding properties of the tridentate and the bidentate ligands are elucidated.     

COMPLEXES OF 4,5-DIAZAFLUORENE AND 9,9′-BIS(4,5-DIAZAFLUORENYL) WITH NICKEL(II), COPPER(II) AND ZINC(II)

Abstract

Complexes having the compositions [LMCl₂], [L₂MCl₂], [L₂Cu][PF₆], [L′MCl₂] and [L′(MCl₂)₂] of 4,5-diazafluorene, L, and 9,9′-bis(4,5-diazafluorenyl), L′, have been prepared from MCl₂ (M = Ni, Cu, Zn) and characterised. Steric strain or the bite angle of the pro-ligand has no recognisable effect on its coordination chemistry with smaller 3d-metals.     

ESR SPECTRA STUDY OF COPPER(Ⅱ) COORDINATION COMPLEXES OF PYRIDI

The ESR spectra of powdered samples of Cu(Ⅱ) complexes with pyridine and its sixhomologues and pyrrol, aniline, as well as their solutions are measured at 77K in this paper.The electronic levels of these complexes are calculated from the ESR spectral parameters.It is found that the non-pyridine ligands of complexes which can be substituted by pyridinemolecules of solvent in solution of pyridine/chloroform form Py_4Cu~(2 ). A molecular configura-tion is proposed. for Py_4Cu~(2 ) in solution. It is shown that the treatment with D_(2h) symmetryinstead of D_(4h) symmetry leads to a more satisfactory explanation of the ESR spectra.     

CRYSTAL STRUCTURES OF COPPER (Ⅱ) AND COBALT (Ⅲ) COM- PLEXES OF o-HYDROXYBENZYLGLYCINATE (HBG)

<正> The structures of two complexes C(CuOC6H4CH2NHCH2COO)2 (H2 O)]·H2P(1) and [Co(NH3)6[Co(OC6H4CH2NHCH2COO)2]2[C1]·10H2O (2) were determined by X-ray analyses. Compound (1) crystallizes in the orthorhombic space group P212121 with a=11. 357(1),b= 24. 304(2),c=7.317(4) A,Z= 4;While compound (2) in the monoclinic space group A2/a(C2/c) with a=23. 486(9) ,b=26. 605(6) ,c= 10. 542(1) A,γ= 128. 42(4)°,Z= 4. In compound (1),two Cu(Ⅱ) ions are bonded together by the phenolic oxygen atoms of two tridentate chelating ligands and each of them is separately coordinated by the carboxyl oxygen,amino nitrogen of each chelate ligand and by the fifth oxygen atom as well (from aqua or the carbonyl group in adjacent molecule). Thus the coordination of each Cu(Ⅱ) is a square pyramid with distances of 1. 93- 1. 97A to the four corner atoms and 2. 30 and 2. 32 A to the apex atoms. The whole molecule has an approximately planar configuratioir with the two pyramid apexes pointing towards one side. Compound (2) consists of     

PREPARATIONS OF COPPER (Ⅰ) COMPLEXES WITH NOVEL PYRAZOLYLBORATES

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STRUCTURES OF COPPER(I) AND ZINC(II) COMPLEXES WITH N,N′-BIS(2-PYRIDINYL)THIOUREA (BPT)

Abstract

Copper(I) and zinc(II) complexes with N,N′-bis(2-pyridinyl)thiourea (BPT), [Cu(BPT)₂]ClO₄ (1) and [Zn(BPT)₂](ClO₄)₂ (2) were synthesized by reaction of M(ClO₄)₂ (M = Cu, Zn) with BPT in methanol solution. The crystal structures of complexes (1) and (2) were characterized by X-ray diffraction: (1) is triclinic, space group P, with a = 10.162(2), b=14.483(6), c = 9.496(2) Å, α = 105.80(2)°, β = 106.94(2)°, γ = 82.71(3)°, V = 1284.4(7) ų, Z = 2, and final R = 0.047, R _w = 0.061; (2) is monoclinic, space group C2/c, with a = 15.15(1), b = 6.299(3), c = 30.16(1)Å, β = 93.49(7)°, V = 2872(2)ų, Z=4, and final R = 0.049, R_w = 0.070. Both of the complexes exhibit novel structures. Two N atoms and two S atoms from two BPT groups coordinate to one M atom. The M atom shows distorted tetrahedral geometry. IR spectra and ther-moanalyses of BPT and its complexes (1) and (2) are briefly discussed.     

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 metalliccopper with triphenylphosphine in a mixed solvent(acetone,dichloromethaneand trichloromethane),and affords the binuclear copper complex(Cu(C_6H_5COO)_2(OPPh_3))_2.Crystals are monoclinic,space group A_2/a,withcell 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 onetriphenylphosphine oxide group to form binuclear complexes.     

ELECTROLYTIC REMOVAL OF COPPER FROM GUANYL-O-ALKYL-ISOUREA COPPER COMPLEX

A facile method for removing copper from guanyl-0-alkylisoureacopper complex was found by using electrolysis.The complex was electrolyzedat a copper cathode in dilute hydrochloric or nitric acid to give guanyl-O-alkylisourea salt in high yield and current efficiency.     

CRYSTAL AND MOLECULAR STRUCTURE OF THE ADDUCT OF BIS (1,1,1 TRIFLUORO 3-2-2'''' THENOYLACETONATO) COPPER (II) WITH PYRIDINE

<正> Mr=666.12, triclinic, Pl, a=8.868(1), b=9.719(2), c=10.861(1) A,α=58.23(1)°, β =64.06(1)° r =71.63(1)°; V =711.2 A3; 2=1, Dc=1.555 g.cm-3,for 3724 reflections with I≥ 3σ(I). In the title compound, the copper atomhas a distorted octahedral coordination with four Cu-O long bonds and twoCu-N short bonds. ,     

SYNTHESIS AND STRUCTURE OF PERCHLORATOBIS-(2,2''''-BIPYRIDYL) COPPER (Ⅱ) PERCHLORATE

<正> C20H16Cl2CuN4O8,JMr = 574. 82,triclinic,space group PI,a =7. 397 (1),b=11. 172(3),c=15. 185(5)A,α=66. 28(2),β=76. 91(1),γ= 80. 74(2)°,V = 1115. 6A3,Z = 2,D=1. 71g·cm-3,μ=12. 76cm-1,F(000) = 582,R=0. 045,Rw = 0. 048. The Cu atom is coordinated by four N atoms from the two 2,2'-bipyridyls and two O atoms from two ClO4- groups,forming a distorted octahedron. A chain structure is developed through the coordinated ClO4-.     

NICKEL(II) AND ZINC(II) COMPLEXES OF β-ALANINEHYDROXAMIC ACID

Abstract

Potentiometric and spectrophotometric studies of Ni(II) coordination to β-alaninehydroxamix acid (β-Alaha) have shown 4N coordination of β-Alaha for 1:2 species and their planar geometry. The geometry of the species formed in the nickel(II)-β-Alaha below ca. pH 7 is octahedral. The differences between the stabilities of zinc(II)-β-Alaha and zinc(II)-α-alaninehydroxamic acid complexes can be explained by the terdentate coordination of the β-alaninehydroxamic acid.     

CALORIMETRIC STUDY OF THERMOCHROMIC COMPLEXES. 2. HEAT CAPACITY AND PHASE TRANSITION OF BIS(N,N‐DIETHYLETHYLENEDIAMINE)COPPER(II) PERCHLORATE

Abstract

The thermochromic phase transition of bis(N,N-diethylethylenediamine) copper(II) perchlorate has been studied by adiabatic calorimetry in the 12–359 K temperature range. A large heat capacity anomaly was observed at 317.64 K with a long heat-capacity tail extending down to ～200 K. The enthalpy and entropy of the phase transition were found to be δ_trs H = 17.43 kJ mol^?1 and δ_trs S = 55.21 J K^?1 mol^?1, respectively. Together with a calorimetric study of a homologous thermochromic complex, bis(N,N-diethylethylenediamine)copper(II) tetrafluoroborate (J. Phys. Chem. Solids, 55, 99 (1994)), the nature of the present thermochromic phase transition is well described by a puckering motion of the copper-ligand chelate rings and a change in the ligand-field strength estimated on the basis of the angular overlap model. The correlation between structures, electronic spectra and thermal properties is discussed.     

SYNTHESIS AND MAGNETISM OF BINUCLEAR COPPER(Ⅱ) COMPLEXES CONTAINING SALUCYLAMIDATOCUPRATE(Ⅱ)

New binuclear copper(Ⅱ) complexes, [Cu(samen)Cu(NO_2-phen)]·H_2O and [Cu(sampn)-Cu(NO_2-phen)]·2H_2O have been synthesized, where samen~(4-), sampn~(4-) and NO_2-phen denote N, N′-ethylenedisalicylamidate anion, N, N′-1, 2-propanedisalicylamidate anion and 5-nitro-1, 10-phenanthroline respectively. 3ased on IR, elemental analyses and electronic spectra, the complexes are proposed to have a phenoxy-bridged structure and to consist of the Cu(Ⅱ)ion in distorted planar environment. The complexes have been characterized with varlable-temperature magnetic susceptibility (4—300 K) and the observed data were fit to those from a modified Bleaney-Bowers equation by least-squares method, giving the exchange integral J=-63.0 cm~(-1) (samen) and J=-46.5cm~(-1) (sampn). This indicates the existence of antiferromagnetic spin exchange interaction among the metal ions.     

STUDY ON THE KINETICS OF POLYMERIZATION OF MMA BY COPPER (Ⅱ) CHELATING RESINS

The polymerization of MMA initiated by copper (Ⅱ) chelating resins/CCl4 system was studied. From the kinetic data, the kinetic equation of polymerization can be expressed asRp = Ke-56400/RT[MMA]1.57[CCl4]m[RESIN-Cu]0.18where m:3-4. 5,when [CCl4] 0. 1-6. 93M. The free radical polymerization mechanism is proposed. The primary radicals are formed by the process of complexation-chlorine transformation among the copper(Ⅱ)chelating resin,CCl4 and methacrylate.     

A NEW METHOD OF PREPARATION OF IRON(II) PORPHYRIN COMPLEXES — ISOLATION AND CHARACTERIZATION OF BIS(N-BUTYLAMINE) IRON(II) PORPHYRIN

Abstract

Fe(II)T(p-X)PP(NH₂Bu ⁿ )₂ (X = H, Cl, CH₃, OCH₃, TPP = dianion of meso-tetraphenylporphyrin) complexes have been prepared by the reduction of Fe(III) porphrins with n-butylamine in antiformin/dichloromethane in air, and by sodium borohydride reduction. The complexes were characterized by electronic and IR spectra and elemental analysis.     

THE CHEMICAL CONSTITUENTS OF COLEUS ESQUIROLII(II)

Three new diterpenoids,named esquirolin B(1),C(2),D(3)respectively,and two known cemocundseariocal(4)and taraxerol were isolated from Coleus esquirolii(Levl).The structure elucidation was achieved byspectroscopic means     

SYNTHESIS OF FUSED PHOSPHORUS HETEROCYCLIC COMPOUNDS(II)

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