共查询到20条相似文献,搜索用时 15 毫秒
1.
A. Giraudeau P. Lemoine M. Gross P. Braunstein 《Journal of organometallic chemistry》1980,202(4):455-468
Linear trimetallic MPPtIIL2M complexes (M = Cr(CO)3(η-C5H5), Mo(CO)3- (η-C5H5), W(CO)3(η-C5-H5), Mn(CO)5, Fe(CO)3NO, Co(CO)4; L = t-BuNC, cyclo- C0H11 NC) are reduced on platinum and gold electrodes in non-aqueous medium. All these complexes undergo irreversible one electron reductions, which result in the rupture of one Ptmetal bond and the liberation of one M? ion per mole reduced. Coupled ESR spectroscopy and coulometry show that a radical is generated during the reduction of the trimetallic complexes. The several ESR signals obtained for these paramagnetic Pt1 species exhibit no hyperfine structure.The electrochemical behaviour of MPtL2M complexes is compared with that of the following linear trimetallic complexes: MHgM and (MAuM)?. 相似文献
2.
Triflate salts of three (Pt(pip2NCN))2(mu-L)2+ (pip2NCNH = 1,3-bis(piperidylmethyl)benzene) dimers bridged by a series of nitrogen-donor ligands (L = pyrazine (pyz), 1,2-bis(4-pyridyl)ethane (bpa), trans-1,2-bis(4-pyridyl)ethylene (bpe)) are reported. These complexes have been fully characterized by 1H NMR spectroscopy and elemental analysis. The X-ray crystal structures of [(Pt(pip2NCN))2(mu-pyz)](CF3SO3)2 and [(Pt(pip2NCN))2(mu-bpe)](CF3SO3)2 x 2CH2Cl2 are reported. [(Pt(pip2NCN))2(mu-pyz)](CF3SO3)2: triclinic, P, a = 12.5240(5) A, b = 14.1570(6) A, c = 14.2928(6) A, alpha = 106.458(1) degrees , beta = 92.527(1) degrees , gamma = 106.880(1) degrees , V = 2303.46(17) A(3), Z = 2. [(Pt(pip2NCN))2(mu-bpe)](CF3SO3)2 x 2CH2Cl2: monoclinic, P21/c, a = 10.1288(6) A, b = 16.3346(9) A, c = 17.4764(10) A, beta = 90.882(2) degrees , V = 2891.1(3) A3, Z = 2. These structures and solution measurements provide evidence for the strong trans-directing properties of the pip2NCN- ligand. The electronic structures of these complexes and those of the 4,4'-bipyridine (bpy) dimer, (Pt(pip2NCN))2(mu-bpy)2+, also have been investigated by UV-visible absorption and emission spectroscopies, as well as cyclic voltammetry. The accumulated data indicate that variations in the bridging ligands provide remarkable control over the electronic structures and photophysics of these complexes. Notably, the bpa dimer exhibits a broad, low-energy emission from a metal-centered 3LF excited state, whereas the bpe and bpy dimers exhibit structured emission from a lowest pyridyl-centered 3(pi-pi*) excited state. In contrast, the pyz dimer exhibits remarkably intense yellow emission tentatively assigned to a triplet metal-to-ligand charge-transfer excited state. 相似文献
3.
Matsumoto Z Aridomi T Igashira-Kamiyama A Kawamoto T Konno T 《Inorganic chemistry》2007,46(8):2968-2970
Treatment of LambdaL-[Co(L-cys-N,S)(en)2]+ (l-H2cys = L-cysteine) with [PtCl4]2- in water, followed by the addition of acid, gave an S-bridged CoIII2PtII trinuclear complex ([1]4+), which was reversibly converted to its deprotonated complex ([2]2+) in an aqueous solution. While [1]4+ formed only a trans isomer, [2]2+ existed as a mixture of trans and cis isomers. The selective formation of a cis isomer was achieved by treatment of [1]4+ or [2]2+ with phthalic acid in water, which afforded a unique CoIII4PtII2 hexanuclear complex ([3]4+). Complex [3]4+ was reverted back to [1]4+ by treatment with aqueous HCl, accompanied by the complete cis-to-trans conversion. 相似文献
4.
Sibbons KF Al-Hashimi M Motevalli M Wolowska J Watkinson M 《Dalton transactions (Cambridge, England : 2003)》2004,(20):3163-3165
Incorporation of a tertiary amide donor within the framework of a C(2)-symmetric analogue of 1,4,7-triazacyclononane derived from L-valine results in the isolation of a very rare example of a classical Werner copper(II) complex in which tertiary amide coordination occurs; despite the monomeric nature of the complex in the solid state, frozen solution EPR studies reveal the presence of a triplet ground state consistent with a dimeric species. 相似文献
5.
Chan JC Lam WH Wong HL Zhu N Wong WT Yam VW 《Journal of the American Chemical Society》2011,133(32):12690-12705
The synthesis, characterization, electrochemistry, photophysics and photochromic behavior of a new class of cyclometalated platinum(II) complexes [Pt(C(∧)N)(O(∧)O)] (1a-5a and 1b-5b), where C(∧)N is a cyclometalating 2-(2'-thienyl)pyridyl (thpy) or 2-(2'-thienothienyl)pyridyl (tthpy) ligand containing the photochromic dithienylethene (DTE) unit and O(∧)O is a β-diketonato ligand of acetylacetonato (acac) or hexafluoroacetylacetonato (hfac), have been reported. The X-ray crystal structures of five of the complexes have also been determined. The electrochemical studies reveal that the first quasi-reversible reduction couple, and hence the nature of lowest unoccupied molecular orbital (LUMO) of the complexes, is sensitive to the nature of the ancillary O(∧)O ligands. Upon photoexcitation, complexes 1a-3a and 1b-3b exhibit drastic color changes, ascribed to the reversible photochromic behavior, which is found to be sensitive to the substituents on the pyridyl ring and the extent of π-conjugation of the C(∧)N ligand as well as the nature of the ancillary ligand. The thermal bleaching kinetics of complex 1a has been studied in toluene at various temperatures, and the activation barrier for the thermal cycloreversion of the complex has been determined. Density functional theory (DFT) calculations have been performed to provide an insight into the electrochemical, photophysical and photochromic properties. 相似文献
6.
Nefzi A Hoesl CE Pinilla C Kauffman GB Maggiora GM Pasquale E Houghten RA 《Journal of combinatorial chemistry》2006,8(5):780-783
The individual and combinatorial syntheses of individual as well as a mixture-based diversity of 195 112 platinum(II) coordination complexes of chiral tetraamines are described. The use of both solid-phase synthesis and solution phase follow-on approaches were found to best afford the title compounds. 相似文献
7.
Philippe Arrizabalage Paule Castan Jean-Pierre Laurent 《Transition Metal Chemistry》1980,5(1):324-327
Summary K2PtCl4 and K2PdCl4 react with thiohydantoin (2 moles) to give new types of bidentate chelate complexes PtL2 · 2H2O and PdL2 · 2H2O, where L is the deprotonated ligand. With palladium the rate of reaction is very fast, whereas in the platinum case reaction occurs stepwise allowing isolation and characterization, by elemental analysis, n.m.r. and by i.r. spectroscopy, of intermediate species. 相似文献
8.
9.
10.
Mulyana Y Kepert CJ Lindoy LF Parkin A Turner P 《Dalton transactions (Cambridge, England : 2003)》2005,(9):1598-1601
The metal-directed assembly of new molecular frameworks incorporating 4-(4-pyridyl)pyrazole (L), containing non-linear coordination vectors, is presented. Three metallo-arrays of types [Co(LH)2(NO3)4], [Co(LH)2(H2O)4][NO3]4.H2O and [Zn2(L-H)2Cl2].2EtOH are reported. The cobalt(II) in [Co(LH)2(NO3)4] displays distorted octahedral geometry, with the two protonated pyridyl-pyrazole ligands coordinated through their pyrazole nitrogen atoms in a trans-orientation; the remaining four coordination sites are occupied by nitrate anions. Two internal hydrogen bonds occur between each pyrazole NH and the oxygens of adjacent coordinated nitrato ligands. Short intermolecular hydrogen bonds also occur between the two pyridinium hydrogens and bound nitrate ligands on different molecules to yield a two-dimensional hydrogen-bonded array. Two of these arrays interpenetrate to form an extended two dimensional layer; such layers stack throughout the crystal structure. A second product of type [Co(LH)2(H2O)4][NO3]4.H2O exists as two crystallographically independent, but chemically similar, forms. In each form, the two protonated pyridyl-pyrazole ligands occupy trans positions about the cobalt, with the remaining four coordination sites being filled by water molecules to yield a distorted octahedral coordination geometry. Intramolecular hydrogen-bonding is observed between the two non-coordinated pyrazoyl nitrogen atoms and bound water oxygen atoms. The third complex, [Zn2(L-H)2Cl2].2EtOH, contains dimer units consisting of two zinc(II) ions bridged by two pyrazoylate groups in which the coordination geometry of each zinc approximates a tetrahedron. Each zinc is bound to two deprotonated pyridine-pyrazole ligands (L-H), one pyridyl group (from a different dimeric unit) and one chloro ligand. Each pyridyl nitrogen thus connects each of these zinc dimers to an adjacent dimer unit, forming a three-dimensional network containing small voids. The latter are occupied by ethanol molecules which form hydrogen bonds to the chloro ligands. 相似文献
11.
12.
The fluorine substituted thiourea 2,6-F2C6H3C(O)NHC(S)NEt2 was prepared in good yield from the reaction of 2,6-F2C6H3C(O)Cl with KSCN and Et2NH in acetone. Using this compound several heteroleptic, monocationic Pd(II), Pt(II) and Ru(II) complexes of the type cis-[M{κ2S,O-2,6-F2C6H3C(O)NC(S)NEt2}(L)]PF6 [M = Pt, Pd; L = (Ph3P)2, tBu2bipy, 1,10-phen] as well as [Ru(η6-p-cym){κ2S,O-2,6-F2C6H3C(O)NC(S)NEt2}(PPh3)]PF6 were prepared in high yields. The compounds were characterised by spectroscopic methods and, in one case, by single crystal X-ray diffraction. 相似文献
13.
A novel lead(II) complex with the Schiff base benzil bis(semicarbazone), [Pb(LH2)2(NO3)]NO3 · 1/2H2O, has been synthesised and structurally characterized as well as the free ligand. The coordination number of Pb(II) is seven provided by two neutral ligand molecules and one nitrato group. The most interesting characteristic of this complex is the different behaviour observed in the two bis(semicarbazone) molecules. One of them is a N2O2 chelate ligand, whereas the other one is bonded to the lead ion only through one of the semicarbazone branches. The seventh position in the lead coordination sphere is provided by one oxygen atom from a nitrato ligand. 相似文献
14.
15.
Several new 1D coordination polymers have been synthesised using the anionic ligand carbamoyldicyanomethanide, C(CN)2(CONH2)− (cdm). The polymeric complexes [Cu(cdm)2(py)2]·2MeOH (1), [Cu(cdm)2(4-Etpy)2]·2MeOH (2), [Cu(cdm)2(3,5-Me2pzH)2]·2MeOH (3) and [Cu(cdm)2(3-HOCH2py)2]·2MeOH (4) (py = pyridine; 3,5-Me2pzH = 3,5-dimethylpyrazole) contain Cu(II) atoms bridged by μ2-(N,N′) cdm ligands between equatorial and axial coordination sites. The use of monodentate co-ligands brings about polymeric products, in contrast to the use previously of chelating co-ligands which facilitate the formation of discrete products. These 1D polymeric complexes are connected by hydrogen bonding between the amide functionalities and the lattice solvent. In the structures of 3 and 4 the neutral ligands also contain hydrogen bond donor groups that supplement the amide ring motif. Two other complexes have been obtained that are polymeric chains of alkoxide-bridged Cu(II) dimers. The complexes [Cu(cdm)(MeO)(2-amp)] (5) and [Cu(cdm)(dmap)] (6) (2-amp = 2-(aminomethyl)pyridine and dmap = dimethylaminopropoxide) are remarkably similar despite the different ligands that they contain. Bridging between dimers is via μ2-(N,O) cdm ligands, consequently altering the nature of the hydrogen bonding between adjacent chains compared to the simple polymeric species 1–3. 相似文献
16.
Vimal K. Jain 《Transition Metal Chemistry》1996,21(6):494-497
Summary Binuclear PdII and PtII complexes of the type [M2Cl2(-Opy)2(PR3)2] [M = Pd or Pt; Opy = 2-OC5H4N (2-hydroxypyridinate ion); PR3 = PEt3, Pn-Bu3, PMe2Ph or PMePh2] were synthesized and characterized by elemental analysis, 1H- and 31P-n.m.r. spectroscopies. The Pd complexes exist in the sym trans form, whereas the corresponding Pt complexes were generated as different isomers. 相似文献
17.
Makiura R Nagasawa I Kimura N Ishimaru S Kitagawa H Ikeda R 《Chemical communications (Cambridge, England)》2001,(17):1642-1643
The present paper deals with a rare platinum(II) complex containing the kappa-I2 ligand, which is an unusual example of a six-co-ordinated octahedral platinum(II) complex. 相似文献
18.
The photofragmentation of (3-Me-4',6'-dfppy)Pt(dpm) (dfppy = difluorophenylpyridinato; dpm = dipivaloylmethyl or 2,2,6,6,-tetramethyl-3,5-heptanedionato- O, O) in a molecular beam is reported. Time-of-flight mass spectra (TOF-MS) and resonance-enhanced multiphoton ionization (REMPI) data are presented and discussed. The dissociation patterns are strongly wavelength-dependent. With 355 nm excitation, the heaviest mass platinum-containing fragments are Pt(+) and diatomic PtC(+). The formation of PtC(+) is the result of an intramolecular rearrangement on the ligand. During irradiation with 410-500 nm light, the fragmentation pattern changes such that the parent ion and platinum-containing fragments of the parent are formed in abundant yield. The (3-Me-4',6'-dfppy) ligand remains intact and coordinated to platinum, but coordinated (dpm) successively breaks apart. A spin-forbidden charge-transfer absorption band centered at around 460 nm plays an important role in the gas-phase photoexcitation of the parent molecule; it is observed in the REMPI spectrum of the parent ion. 相似文献
19.
Zheng BS Zhang XY Zhu HW Luo SX Lindoy LF McMurtrie JC Turner P Wei G 《Dalton transactions (Cambridge, England : 2003)》2005,(8):1349-1351
Discrete cobalt(II) and nickel(II) complexes of type ML (where L is a bis(2,4-pentanedionate) derivative incorporating a -SCH2CH2S- bridge between the gamma-carbons of respective beta-diketone units) have been synthesised and represent the first examples in which a gamma-substituted, thioether-containing beta-diketone ligand coordinates via a sulfur and oxygen donor in preference to the classical coordination mode involving both beta-diketonate oxygens. 相似文献
20.
Dinuclear Pt(2)Br(2)(dppf)(2)(mu-C(8)H(4)S(2)) exchanges with isonicotinic acid to release free bithiophene and gives a molecular square [Pt(4)(dppf)(4)(mu(2)-O(2)CC(5)H(4)N)(4)](4+)4OTf(-) which is an "all-ring" system with four Pt rings disposed at the corners of a larger macrocyclic ring. The related mononuclear complex PtBr(eta(1)(C2)-C(4)H(3)S)(dppf) reacts with AgOTf (OTf = triflate) to give [Pt(2)(dppf)(2)(mu(2),eta(1)(C),eta(1)(S)-C(4)H(3)S)(2)](2+)2OTf(-) with an unusual six-membered ring formed by the fusion of two Pt-thienyl entities at the sulfur sites. All the complexes are structurally characterized by single-crystal X-ray crystallography. 相似文献