共查询到20条相似文献,搜索用时 0 毫秒
1.
Sharma LA Singh OI Singh AK Singh RK Kadam RM Bhide MK Dhobale AR Sastry MD 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2004,60(7):1593-1600
Electron paramagnetic resonance (EPR) investigations were conducted on [Cu(II) (1-phenylamidino-O-n-butylurea) en (H2O)]2(2+) (1) and [Cu(II) sulphato-mono (1-phenylamidino-O-methylurea)]2 (2) respectively, in the temperature range 300-77K. Fine structure characteristics of S = 1 system, was observed in both complexes with zero field splitting of 0.0525 and 0.0225 cm(-1), respectively, suggesting the formation of dimeric complexes. The presence of the half-field signal (DeltaMs= +/-2), in the complex 1, further confirmed the formation of dimer. The temperature dependence of EPR signal intensity has given evidence for the ferromagnetic (FM) coupling between the two Cu2+ ions. The isotropic exchange interaction constants J, were evaluated from this and were found out to be approximately 57 and approximately 27 cm(-1), respectively, for the complexes 1 and 2. The photoacoustic spectra of these complexes had shown a band around 26,400 cm(-1) characteristic of metal-metal bonding giving an independent support for the existence of dimeric Cu2+ species. The high magnetic moment values at room temperature for complex 1 (2.68 microB) and complex 2 (2.00 microB), obtained from the magnetic susceptibility measurements, support the formation of ferromagnetically coupled Cu2+ dimers. 相似文献
2.
Seven new Cu(II) complexes based on a binuclear planar unit [Cu(mu-L(1))](2), [[Cu(mu-L(1))(NO(3))(H(2)O)](2) (1), [Cu(mu-L(1))(HL(1))(ClO(4))](2) (2), [Cu(4)(mu-L(1))(6)(NO(3))(2)] (3), [Cu(4)(mu-L(1))(6)(L(1))(2)] (4), [Cu(4)(mu-L(1))(6)(mu-L(2))](n) (5), [Cu(4)(mu-L(1))(6)(mu-L(3))](n) (6), [[Cu(4)(mu-L(1))(4)(mu-L(4))(2)](H(2)O)(3)](n) (7) (HL(1) = 3-(2-pyridyl)pyrazole, L(2) = 1,8-naphthalenedicarboxylate, L(3) = terephthalate, L(4) = 2,6-pyridinedicarboxylate)}, have been synthesized and characterized by elemental analysis, IR, and X-ray diffraction. In 1 and 2, the Cu(II) centers are linked by deprotonated pyrazolyl groups to form dinuclear structures. 3 and 4 have similar gridlike tetranuclear structures in which two additional deprotonated L(1) ligands bridge two [Cu(mu-L(1))](2) units perpendicularly. 5 and 6 consist of similar one-dimensional (1-D) chains in which gridlike tetranuclear copper(II) units similar to that of 3 are further linked by L(2) or L(3) ligands, respectively. And, in 7, L(4) ligands link [Cu(mu-L(1))](2) binuclear units to form a tetranuclear gridlike structure in chelating/bridging mode and simultaneously bridge the tetranuclear units to form a 1-D chain. The magnetic properties of all complexes were studied by variable-temperature magnetic susceptibility and magnetization measurements. The obtained parameters of J range from -33.1 to -211 cm(-1), indicating very strong antiferromagnetic coupling between Cu(II) ions. The main factor that affects the |J| parameter is the geometry of the Cu(N(2))(2)Cu entity. From the magnetic point of view, 1 and 2 feature "pure" dinuclear, 3 and 5 tetranuclear, and 4, 6, and 7 pseudodinuclear moieties. 相似文献
3.
4.
Campos-Carrasco A Broeckx LE Weemers JJ Pidko EA Lutz M Masdeu-Bultó AM Vogt D Müller C 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(8):2510-2517
The coordination chemistry of the bidentate P,N hybrid ligand 2-(2'-pyridyl)-4,6-diphenylphosphinine (1) towards Pd(II) and Pt(II) has been investigated. The molecular structures of the complexes [PdCl(2)(1)] and [PtCl(2)(1)] were determined by X-ray diffraction, representing the first crystallographically characterized λ(3)-phosphinine-Pd(II) and -Pt(II) complexes. Both complexes reacted with methanol at the P=C double bond at an elevated temperature, leading to the corresponding products [MCl(2)(1H·OCH(3))]. The molecular structure of [PdCl(2)(1H·OCH(3))] was determined crystallographically and revealed that the reaction with methanol proceeds selectively by syn addition and exclusively to one of the P=C double bonds. Strikingly, the reaction of [PdCl(2)(1H·OCH(3))] with the chelating diphosphine DPEphos at room temperature in CH(2)Cl(2) led quantitatively to [PdCl(2)(DPEphos)] and phosphinine 1 by elimination of CH(3)OH and rearomatization of the phosphorus heterocycle. 相似文献
5.
Tzeng BC Chen BS Chen CK Chang YP Tzeng WC Lin TY Lee GH Chou PT Fu YJ Chang AH 《Inorganic chemistry》2011,50(12):5379-5388
A series of Re(I) complexes, [Re(CO)(3)Cl(HPB)] (1), [Re(CO)(3)(PB)H(2)O] (2), [Re(CO)(3)(NO(3))(PB-AuPPh(3))] (3), and [Re(CO)(3)(NO(3))(PB)Au(dppm-H)Au](2) (4) [HPB = 2-(2'-pyridyl)benzimidazole; dppm = 2,2'-bis(diphenylphosphinomethane)], have been synthesized and characterized by X-ray diffraction. Complex 1, which exhibits interesting pH-dependent spectroscopic and luminescent properties, was prepared by reacting Re(CO)(5)Cl with an equimolar amount of 2-(2'-pyridyl)benzimidazole. The imidazole unit in complex 1 can be deprotonated to form the imidazolate unit to give complex 2. Addition of 1 equiv of AuPPh(3)(NO(3)) to complex 2 led to the formation of a heteronuclear complex 3. Addition of a half an equivalent of dppm(Au(NO(3)))(2) to complex 2 yielded 4. In both 3 and 4, the imidazolate unit acts as a multinuclear bridging ligand. Complex 4 is a rare and remarkable example of a Re(2)Au(4) aggregate in combination with μ(3)-bridging 2-(2'-pyridyl)benzimidazolate. Finally, complex 2 has been used to examine the Hg(2+)-recognition event among group 12 metal ions. Its reversibility and selectivity toward Hg(2+) are also examined. 相似文献
6.
7.
Arroyo M Miguel D Villafañe F Alegria EC Pombeiro AJ 《Dalton transactions (Cambridge, England : 2003)》2012,41(23):7017-7025
Molybdenum and tungsten complexes containing the pypzH (3-(2-pyridyl)pyrazole) ligand as a chelating bidentate are prepared: [Mo(CO)(4)(pypzH)], cis-[MoBr(η(3)-allyl)(CO)(2)(pypzH)], cis-[MoCl(η(3)-methallyl)(CO)(2)(pypzH)], [MI(2)(CO)(3)(pypzH)] (M = Mo, W) from [Mo(CO)(4)(NBD)] or the adequate bis(acetonitrile) complexes. The deprotonation of the molybdenum allyl or methallyl complexes affords the bimetallic complexes [cis-{Mo(η(3)-allyl)(CO)(2)(μ(2)-pypz)}](2) or [cis-{Mo(η(3)-methallyl)(CO)(2)(μ(2)-pypz)}](2) (μ(2)-pypz = μ(2)-3-(2-pyridyl-κ(1)N)pyrazolate-2κ(1)N). The allyl complex was subjected to an electrochemical study, which shows a marked connection between both metallic centres through the bridging pyridylpyrazolates. 相似文献
8.
K.-F. Tebbe 《无机化学与普通化学杂志》1982,489(1):93-110
Studies on Polyhalides. III. Crystal Structures of [Cu(NH3)4I2 · I2] and [Cu(NH3)4I3]I3 Tetramminecopper(II)tetraiodide [Cu(NH3)4I2 · I2] (I) crystallizes monoclinically in the space group C2/m with a = 1 185.9 pm, b = 892.8 pm, c = 656.8 pm, β = 111.10° and Z = 2 formula units. Tetramminecopper(II)hexaiodide [Cu(NH3)4I3]I3 (II) crystallizes orthorhombically in the space group Pnnm with a = 874.9 pm, b = 1 089.8 pm, c = 885.3 pm, and Z = 2 formula units. A special feature of these structures are coordinated polyiodide ions I42? (I) or I3? (II). In both compounds four coplanar nitrogen atoms and two axial iodine atoms form a quasi-octahedral coordination around copper with the usual (4+2)-tetragonal distortion. The copper ions are connected by linear, centrosymmetric polyiodide ions I42? (I) or I3? (II). Therefore infinite planar zigzag chains of units [Cu(NH3)4I4] (I) or [Cu(NH3)4I3]+(II) are resulting. The counterion I3? (II) is intercalated between these chains. 相似文献
9.
《Journal of Coordination Chemistry》2012,65(6):455-461
Reaction of the ligand 3-(pyridin-2-yl)pyrazole (L) with Cu(ClO4)2 and CuX2 (X=Cl, Br, I) gives complexes with stoichiometry [Cu(L)2X]ClO4 (X = Cl, Br, I). The new complexes were characterized by elemental analyses and infrared and electronic spectroscopy. The crystal structure of the [Cu(L)2Br]ClO4 was determined by X-ray crystallography. The cation complex (i.e. [Cu(L)2Br]P) contains copper(II) with a distorted trigonal bipyramid geometry with a Br― ligand occupying an equatorial site. The penta-coordinated metal atom is bonded to two pyridinic nitrogens, two pyrazolic nitrogens, and one bromide anion. The pyrazolic H atoms are hydrogen bonded to Br atoms, resulting in infinite hydrogen-bonded chains running in the b direction. There are π‐π stacking interactions (charge-transfer arrays) between the parallel aromatic rings belonging to adjacent chains that may help to form hydrogen bonding in the coordination geometry around Cu (II). 相似文献
10.
Two new 1:2 polymeric complexes of copper(II) azide with ethyl isonicotinate (1) and methyl isonicotinate (2) have been synthesized and characterized by spectroscopic and crystallographic methods. The polymeric structure of complex (1) features six coordinated copper centers, a pair of trans-coordinated ligand molecules, and asymmetric 2-1,1 and 2-1,3-azido bridges resulting in a 1D chain structure. In complex (2), each copper atom which is located at an inversion center, is coordinated to a pair of trans ligand molecules, to the nitrogen atom of two -1,1-azido ligand and to an oxygen atom of a bridging (-O,O) nitrogen group. The i.r., electronic and e.s.r. spectra of the complexes are reported. 相似文献
11.
Pullukat T. Joseph Chorappan Pavithran Krishnan G. K. Warrier Chathakudam P. Prabhakaran 《Transition Metal Chemistry》1978,3(1):286-288
Summary Iron(II) complexes of 1-benzyl-2-phenylbenzimidazole (BPBI) and 2-coumarinylbenzimidazole (CBI) have been prepared and characterised. The chloride, bromide, iodide and thiocyanate complexes have the general formula FeL2X2 (where L = BPBI or CBI) while the perchlorate complex of CBI has the composition [Fe(CBI)3](CIO4)2. The perchlorate complex behaves as a 1 : 2 electrolyte in nitrobenzene and methanol; Fe(BPBI)2I2 shows considerable dissociation in nitrobenzene while the other complexes behave as nonelectrolytes. The i.r. spectra of the complexes suggest that N(3) of BPBI and N(3) together with the CO group of CBI are the coordination sites. The magnetic and spectral evidence suggests a regular octahedral geometry for the perchlorate complex and pseudotetrahedral configuration for the iodide and thiocyanate complexes. The other complexes appear to be distorted octahedral with halide bridging.Author to whom all correspondence should be addressed. 相似文献
12.
Ismail Warad Omar H Abd-Elkader Ahmed Boshaala Nabil Al-Zaqri Belkheir Hammouti Taibi Ben Hadda 《Research on Chemical Intermediates》2013,39(2):721-732
The preparation of new [MeC(CH2PPh2)3CuCl] 1 and its derivatives was carried out directly by mixing of CuCl and MeC(CH2PPh2)3 ligand in dry THF, the neutral precursor 1 served to prepare [MeC(CH2PPh2)3Cu(NCCH3)]BF4 2 and [MeC(CH2PPh2)3Cu(PCH2Ph)3]BF4 3. These complexes are characterized on the basis of elemental analysis, IR, EDS, 1H, 13C and 31P{1H}NMR, FAB-MS, TG/DTA and single-crystal X-ray diffraction studies. Complex 1 crystallizes in the Orthorhombic unit cells with the space group Pna2(1). The structural behavior of MeC(CH2PPh2)3 ligand in the formed complexes during the coordination reaction was monitored by 31P{1H}NMR in CDCl3 at room temperature for the first time. 相似文献
13.
Mixed ligand complexes of the type Ru(pq)(2)(PP)(2+) (pq = 2,2'-pyridylquinoline and PP = one bidentate or two monodentate phosphine ligands) have been prepared from the appropriate phosphine and Ru(pq)(2)Cl(2). The room temperature absorption spectra and low temperature (77 K) emission spectra, emission lifetimes, and quantum yields have been measured for the series of complexes and compared with those of Ru(pq)(3)(2+) and analogous Ru(bpy)(2)(PP)(2+) complexes (bpy = 2,2'-bipyridine) where possible. Emission spectra have been fit using a single mode Franck-Condon analysis. The visible absorption bands and emission bands are assigned to MLCT transitions that are blue shifted relative to Ru(pq)(3)(2+), while the emission lifetimes and quantum yields are increased. The trends in the nonradiative rate constants, k(nr), are described in terms of the energy gap, E(0), and the Huang-Rhys factor, S(M), which were obtained from the spectral fittings, and are correlated with the phosphine ligand structures. 相似文献
14.
15.
Reaction of the known germylene Ge[N(SiMe3)2]2 and a new heterocyclic variant Ge[(NMes)2(CH)2] with [L(Me2)Cu]2 (L(Me2) = the beta-diketiminate derived from 2-(2,6-dimethylphenyl)amino-4-(2,6-dimethylphenyl)imino-2-pentene) yielded novel Cu(I)-Ge(II) complexes L(Me2)Cu-Ge[(NMes)2(CH)2] (1a) and L(Me2)Cu-Ge[N(SiMe3)2]2 (1b), which were characterized by spectroscopy and X-ray crystallography. The lability of the Cu(I)-Ge(II) bond in 1a and b was probed by studies of their reactivity with benzil, PPh3, and a N-heterocyclic carbene (NHC). Notably, both complexes are cleaved rapidly by PPh3 and the NHC to yield stable Cu(I) adducts (characterized by X-ray diffraction) and the free germylene. In addition, the complexes are highly reactive with O2 and exhibit chemistry which depends on the bound germylene. Thus, oxygenation of 1a results in scission and formation of thermally unstable L(Me2)CuO2, which subsequently decays to [(L(Me2)Cu)2(mu-O)2], while 1b yields L(Me2)Cu(mu-O)2Ge[N(SiMe3)2]2, a novel heterobimetallic intermediate having a [Cu(III)(mu-O)2Ge(IV)]3+ core. The isolation of the latter species by direct oxygenation of a Cu(I)-Ge(II) precursor represents a new route to heterobimetallic oxidants comprising copper. 相似文献
16.
Köhn RD Pan Z Haufe M Kociok-Köhn G 《Dalton transactions (Cambridge, England : 2003)》2005,(16):2793-2797
As the first 1st-row transition metal complexes having six tertiary amine donor groups, bis(triazacyclohexane) sandwich complexes [L2M](BF4)2 (L = benzyl- or p-fluorobenzyl-triazacyclohexane, M = Cu or Zn) have been obtained by the protonolysis of Et2Zn in the presence of L or by reaction of [Cu(MeCN)4](BF4) with L in CH2Cl2 and subsequent air oxidation via an unprecedented Cu(I)(2) sandwich complex containing a short Cu-Cu contact. 相似文献
17.
18.
19.