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1.
2.
Substitution of thf ligands in [Cr(thf)3Cl3] and [Cr(thf)2(OH2)Cl3] was investigated. 2,2′-Bipyridine (bipy) was reacted with [Cr(thf)3Cl3] to form [Cr(bipy)(thf)Cl3] (1), which was subsequently reacted with water to give [Cr(bipy)(OH2)Cl3] (2). Reaction of 1 with acetonitrile (CH3CN), pyridine (py) and pyridine derivatives to form [Cr(bipy)(L)Cl3] (L = CH3CN 3, py 4 and 4-pyR with R = NH25, But6 and Ph 7). In addition, the substitution of bipy in [Cr(thf)3Cl3] was followed by 1H NMR spectroscopy at room temperature, which showed completion of the reaction in ca. 100 min. Complex 2 was characterised by single crystal X-ray diffraction. The theoretical powder diffraction pattern of 2 was compared to the experimentally obtained powder X-ray diffraction pattern, and shows excellent agreement. The dimer [Cr2(bipy)2Cl4(μ-Cl)2] was cleaved asymmetrically to give the anionic complex [Cr(bipy)Cl4] (8) and [Cr(bipy)2Cl2]+ (9). Complexes 8 and 9 were characterised by single crystal X-ray diffraction.  相似文献   

3.
Conductometric investigation on the bis(triphenyl phosphine) ruthenium(II) complex, cis-[RuCl2(L)(PPh3)2] (A) (where PPh3: triphenyl phosphine and L: 2-(2′-pyridyl)quinoxaline, C13N3H9), in dimethylsulfoxide (DMSO) was performed at temperatures ranging from 25 to 50 °C. In addition, cyclic voltammograms of A were recorded on platinum working electrode in dichloromethane (DCM) and dimethylsulfoxide (DMSO) using n-tetrabutylammonium hexafluorophosphate (NBu4PF6) as supporting electrolyte at 25 °C. The molar conductivities (Λ) demonstrate that A behaves as uni-univalent electrolyte in DMSO over the whole temperature range. This behavior can be explained in terms of the replacement upon dissolution of chlorine and PPh3 ligands by DMSO molecules, and consequently, the formation of the ion-pair [RuCl(L)(PPh3)(DMSO)2]Cl [B+Cl] which is dissociated in some extent. The Λ values were analyzed by means of the Lee-Wheaton conductivity equation in order to estimate the limiting molar conductivities (Λo) and the ion-pair association constants (KA) of [B+Cl]. The limiting ion conductivities for the B+ ion were evaluated using n-tetrabutylammonium chloride (NBu4Cl) as “reference electrolyte”. The thermodynamic functions related with the ion association, such as Gibbs free energy , enthalpy , and entropy , were evaluated as well. The mobility of B+ was found to increase linearly with rising temperature and the consequent decrease of the viscosity (η) of DMSO. The KA and values indicate that the association of [B+Cl] increases to some extent with the rise of the temperature followed by the decrease of the dielectric constant (ε) of DMSO. The voltammetric experiments indicated that the couple Ru3+/2+ is reversible and diffusion controlled in DCM and completely irreversible in DMSO.  相似文献   

4.
The preparation, crystal structures and magnetic properties of three copper(II) compounds of formulae [Cu2(dmphen)2(dca)4] (1), [Cu(dmphen)(dca)(NO3)]n (2) and [Cu(4,4-dmbpy)(H2O)(dca)2] (3) (dmphen=2,9-dimethyl-1,10-phenanthroline, dca=dicyanamide and 4,4-dmbpy=4,4-dimethyl-2,2-bipyridine) are reported. The structure of 1 consists of discrete copper(II) dinuclear units with double end-to-end dca bridges whereas that of 2 is made up of neutral uniform copper(II) chains with a single symmetrical end-to-end dca bridge. Each copper atom in 1 and 2 is in a distorted square pyramidal environment: two (1) or one (2) nitrile-nitrogen atoms from bridging dca groups, one of the nitrogen atoms of the dmphen molecule (1 and 2) and either one nitrile-nitrogen from a terminal dca ligand (1) or a nitrate-oxygen atom (2) build the equatorial plane whereas the second nitrogen atom of the heterocyclic dmphen fills the axial position (1 and 2). The copper-copper separations through double (1) and single (2) end-to-end dca bridges are 7.1337(7) (1) and 7.6617(7) (2). Compound 3 is a mononuclear copper(II) complex whose structure contains two neutral and crystallographically independent [Cu(4,4-dmbpy)(H2O)(dca)2] molecules which are packed in two different layer arrangements running parallel to the bc-plane and alternating along the a-axis. The copper atoms in both molecules have slightly distorted square pyramidal surroundings with the two nitrogen atoms of the 4,4-dmbpy ligand and two dca nitrile-nitrogen atoms in the basal plane and a water oxygen in the apical position. A semi co-ordinated dca nitrile-nitrogen from a neighbour unit [2.952(6) Å for Cu(2)-N] is in trans position to the apical water molecule in one of the two molecules, this feature representing part of the difference in supramolecular connections in the alternating layers referred to above. Magnetic susceptibility measurements for 1-3 in the temperature range 1.9-290 K reveal the occurrence of weak antiferromagnetic interactions through double [J=−3.3 cm−1 (1), ] and single [J=−0.57 cm−1 (2), ] dca bridges and across intermolecular contacts [θ=−0.07 K (3)].  相似文献   

5.
Versatile synthetic routes have been applied to prepare the new asymmetric phosphine-phosphite ligands 8 and 12. The chiral ligands have been designed so that the corresponding ligating groups have similar electronic properties and steric bulk, but 8 forms 6-, while 12 forms 7-membered chelate rings in their coordination compounds. The chelate size variation results in a markedly different coordination behavior towards Pt(II). In their reactions with Pt(PhCN)2Cl2 at 1:1 stoichiometry 12 forms the expected Pt(12)Cl2 complex, while 8 gives the cation quantitatively. In the kinetically controlled reaction is the major product even at a 8:Pt(PhCN)2Cl2 = 1:2 ratio. Most interestingly, at 1:1 ligand to precursor ratio, cation rearranges to Pt(8)Cl2 within one day, indicating that the neutral complex is thermodynamically more favorable.  相似文献   

6.
Pt(II) complexes of the types K[Pt(R2SO)X3], NR4[Pt(R2SO)X3] and Pt(R2SO)2Cl2 (where X = Cl or Br) were characterized by multinuclear magnetic resonance spectroscopy (195Pt, 1H and 13C). In 195Pt NMR, the chloro ionic compounds have shown signals between −2979 and −3106 ppm, while the cis disubstituted complexes were observed at higher fields, between −3450 and −3546 ppm. The signal of the compound trans-Pt(DPrSO)2Cl2 was found at higher field (−3666 ppm) than its cis analogue (−3517 ppm), since π-back-donation is considerably less effective in the trans geometry. In 1H NMR, a single signal was observed for the sulfoxide in [Pt(DMSO)Cl3], but for the other more sterically hindered ligands, two series of resonances were observed for the protons in α and β positions. The coupling constant 3J(195Pt-1H) are between 15 and 33 Hz. The 13C NMR results were interpreted in relation to the concept of inversed polarization of the π sulfoxide bond. The 2J(195Pt-13C) values vary between 35 and 66 Hz, while a few 3J(195Pt-13C) couplings were observed (13-26 Hz). The crystal structures of five monosubstituted ionic compounds N(n-Bu)4[Pt(TMSO)Cl3], N(Me)4[Pt(DPrSO)Cl3], K[Pt(EMSO)Cl3], K[Pt(TMSO)Br3] · H2O and N(Et)4[Pt(DPrSO)Br3] and one disubstituted complex cis-Pt(DBuSO)2Cl2 were determined. The trans influence of the different ligands is discussed.  相似文献   

7.
《Inorganica chimica acta》2005,358(3):520-526
The strong affinity of coordinated biimidazole for chloride ion via N-H?Cl hydrogen bonding has been used as a strategy to build up two different modular assemblies between chloride and biimidazole-metal modules. The crystal structure of these two new metal-containing architectures, {[Cu(H2biim)2]Cl2 (1) and [Zn(Cl)(H2biim)2]Cl (2)}, is reported. The EPR spectrum of 1 is also discussed.  相似文献   

8.
An unexpected, new and convenient synthetic procedure for the synthesis of Pt(II)Cl2-1,5-hexadiene is reported which is done under mild conditions, including a very short reaction time of 10 min. The complex was isolated and crystallized, leading to the first reported crystal structure of the diene complex.  相似文献   

9.
The kinetics of the complex-formation reactions between monofunctional palladium(II) complexes [Pd(NNN)Cl]+, where NNN is 2,2:6,2″-terpyridine (terpy), diethylenetriamine (dien) or bis(2-pyridylmethyl)amine (bpma), with pyridine, 4-methylpyridine, 4-acetylpyridine, 4-cyanopyridine and 4-aminopyridine, have been studied in methanol at 25 °C using stopped-flow spectrophotometry. The highest reactivity was observed for the [Pd(terpy)Cl]+ complex, whereas 4-aminopyridine is the strongest nucleophile. The results, compared with those previously published on the [Pt(NNN)Cl]+ complexes, are discussed in terms of reactivity and discrimination ability of the reaction centre. The crystal structure of [Pd(terpy)(py)](ClO4)2 has been determined by X-ray diffraction. Crystals are triclinic, space group , and consist of distorted square planar [Pd(terpy)(py)]2+ cations and perchlorate anions. The Pd-N bond length to the central atom of terpy ligand is well below 2.0 Å and significantly shorter than any of the other M-N distances. The pyridine plane forms a dihedral angle of 61.9(2)° with the coordination N4 donors.  相似文献   

10.
The dimethylaminopyridine (DMAP) promoted reaction between [Os(bpy)2(CO)(OTf)]OTf (where ) and methylene chloride is reported. C-Cl bond breaking of a solvent molecule leads to the formation of the [Os(bpy)2(CO)(Cl)]OTf complex. The reactivity and redox properties of [Os(bpy)2(CO)(OTf)]OTf were investigated by means of room- and low-temperature electrochemical experiments. In CH2Cl2, at low temperature, the complex undergoes two 1e electrochemical and chemical reversible reductions (ErEr mechanism), but at room temperature a more complex electrochemical mechanism is observed, leading to the electro-synthesis of [Os(bpy)2(CO)(Cl)]OTf via electrochemical reversible and chemical irreversible reduction processes (ErCi mechanism). The DMAP nucleophilicity was used to produce the new [Os(bpy)2(CO)(Br)]OTf and [Os(bpy)2(CO)(I)]OTf complexes which have been fully characterized.  相似文献   

11.
The character and dynamics of low-lying electronic excited states of the complexes fac-[Re(Cl)(CO)3(papy)2] and fac-[Re(papy)(CO)3(bpy)]+ (papy = trans-4-phenylazopyridine) were investigated using stationary (UV-Vis absorption, resonance Raman) and ultrafast time-resolved (visible, IR absorption) spectroscopic methods. Excitation of [Re(Cl)(CO)3(papy)2] at 400 nm is directed to 1ππ(papy) and Re → papy 1MLCT excited states. Ultrafast (?1.4 ps) intersystem crossing (ISC) to 3(papy) follows. Excitation of [Re(papy)(CO)3(bpy)]+ is directed to 1ππ(papy), 1MLCT(papy) and 1MLCT(bpy). The states 3(papy) and 3MLCT(bpy) are then populated simultaneously in less then 0.8 ps. The 3MLCT(bpy) state decays to 3(papy) with a 3 ps time constant. 3(papy) is the lowest excited state for both complexes. It undergoes vibrational cooling and partial rotation around the -NN- bond, to form an intermediate with a nonplanar papy ligand in less than 40 ps. This species then undergoes ISC to the ground state potential energy surface, on which the trans and cis isomers are formed by reverse and forward intraligand papy rotation, respectively. This process occurs with a time constant of 120 and 100 ps for [Re(Cl)(CO)3(papy)2] and [Re(papy)(CO)3(bpy)]+, respectively. It is concluded that coordination of papy to the Re center accelerates the ISC, switching the photochemistry from singlet to triplet excited states. Comparison with analogous 4-styrylpyridine complexes (M. Busby, P. Matousek, M. Towrie, A. Vl?ek Jr., J. Phys. Chem. A 109 (2005) 3000) reveals similarities of the decay mechanism of excited states of Re complexes with ligands containing -NN- and -CC- bonds. Both involve sub-picosecond ISC to triplets, partial rotation around the double bond and slower ISC to the trans or cis ground state. This process is about 200 times faster for the -NN- bonded papy ligand. The intramolecular energy transfer from the 3MLCT-excited Re(CO)3(bpy) chromophore to the intraligand state of the axial ligand occurs for both L = stpy and papy with a comparable rate of a few ps.  相似文献   

12.
Complexes of the type [Pt(amine)4]I2 were synthesized and characterized mainly by multinuclear (195Pt, 1H and 13C) magnetic resonance spectroscopy. The compounds were prepared with different primary amines, but not with bulky amines, due to steric hindrance. In 195Pt NMR, the signals were observed between −2715 and −2769 ppm in D2O. The coupling constant 3J(195Pt-1H) for the MeNH2 complex is 42 Hz. In 13C NMR, the average values of the coupling constants 2J(195Pt-13C) and 3J(195Pt-13C) are 18 and 30 Hz, respectively. The crystal structure of [Pt(EtNH2)4]I2 was determined by X-ray diffraction methods. The Pt atom is located on an inversion center. The structure is stabilized by H-bonding between the amines and the iodide ions. The compound with n-BuNH2 was found by crystallographic methods to be [Pt(n-BuNH2)4]2I3(n-BuNHCOO). The crystal contains two independent [Pt(CH3NH2)4]2+ cations, three iodide ions and a carbamate ion formed from the reaction of butylamine with CO2 from the air. When the compound [Pt(CH3NH2)4]I2 was dissolved in acetone, crystals identified as trans-[Pt(CH3NH2)2(H3CNC(CH3)2)2]I2 were isolated and characterized by crystallographic methods. Two trans bonded MeNH2 ligands had reacted with acetone to produce the two N-bonded Schiff base Pt(II) compound.  相似文献   

13.
Reaction between the binuclear hydroxo complex cis-[(PPh3)2Pt(μ-OH)]2X2 (X = NO3, 1a; , 1b) and the model DNA base 9-methyladenine (9-MeAd) leads to the formation of the mononuclear species cis-[(PPh3)2Pt{9-MeAd(-H),N6N7}]X (X = NO3, 2a; PF6, 2b), in which the nucleobase chelates the Pt(II) ion with the N6 and N7 atoms. The coordination mode of the nucleobase has been determinated through a multinuclear (1H, 31P, 13C, 15N and 195Pt) NMR analysis and the nuclearity of the complex has been obtained by E.S.I. mass spectrometry. 2 represents the first example of an isolated platinum complex in which the NH2-deprotonated adenine exhibits this binding mode.  相似文献   

14.
The compounds Pt(quinap)(CN)2, and [Cu(quinap)I]2 with quinap = 1-(2-diphenylphosphino-1-naphthyl)isoquinoline were synthesized. Quinap is a bidentate ligand which contains a isoquinoline and an arylphosphine group with CT acceptor properties. Accordingly, the Pt(II) and Cu(I) quinap complexes are characterized by a phosphorescence originating from the lowest-energy MLCT triplets with some IL admixture.  相似文献   

15.
Na3TMT · 9H2O (H3TMT=2,4,6-trimercaptotriazine) reacts with M(PPP)Cl2, PPP=PhP(CH2CH2PPh2)2, M=Ni, Pd, Pt, to give the compounds [M(PPP)(HTMT)]. The nickel and palladium complexes have been characterized by single-crystal X-ray diffraction analysis. PPP is tridentate in both complexes. The nickel complex has an irregular trigonal bipyramidal configuration in which the triazine is bidentate, coordinating through one sulfur and one nitrogen donor atom. The palladium complex has an approximately square planar geometry in which the triazine forms a strong Pd-S bond in the plane and also a very weak Pd-N interaction above the plane. The 31P NMR spectrum of the platinum complex is similar to that of the palladium complex, which is consistent with the Pt complex also having an approximately square-planar structure. Variable temperature NMR spectra show that two conformational isomers of the nickel complex are present in solution at low temperatures, though exchange is fast at room temperature. DFT calculations have confirmed the possible existence of two five-coordinate isomers of comparable stability.  相似文献   

16.
The preparations are reported of cis[Pt(caffeine)2Cl2]·0.4H2O, Pd(caffeine)2Cl2, the methanol adduct of the previously known compound K[Pt(caffeine)Cl3], and Pt(caffeine)(cytidine)Cl2. Crystals of [Pt(caffeine)2Cl2]·0.4H2O are tetragonal P42/n with a = 13.156(2) 0?, c = 12.734(2) 0?, Z = 4. The structure was refined on 945 reflections to R = 0.025. The molecule is cis with a crystallographic two-fold axis bisecting the ClPtCl and NPtN angles. The Pt is square planar with PtN and PtCl bonds of 2.029(5) Å and 2.271(2) Å respectively. There is a 5.4° dihedral angle between the imidazole and pyrimidine rings, and the imidazole ring is rotated away from the coordination plane by 86.4°. Symmetry related caffeine units pack parallel to each other with an inter-ring separation of 3.45 Å.  相似文献   

17.
Violet prismatic crystals of {[Cu(tn)2]3[Pt(CN)4]2}[Pt(CN)4] (tn = 1,3-diaminopropane) were crystallized from the water-methanol solution containing CuCl2·2H2O, tn and K2[Pt(CN)4]·3H2O. Prepared complex was characterized using elemental analysis, infrared and UV-Vis spectroscopy, magnetic measurement and thermal analysis. X-ray analysis revealed an ionic character of the complex containing mononuclear square planar [Pt(CN)4]2− complex anions and penta-nuclear [Cu(tn)2-Pt(CN)4-Cu(tn)2-Pt(CN)4-Cu(tn)2]2+ complex cations. The inner Cu(II) atom of the complex cation is hexa-coordinated, whereas two crystallographically equivalent peripheral Cu(II) atoms are penta-coordinated in the shape of a deformed square pyramid. Four v(CN) absorption bands observed in the IR spectrum are in agreement with the higher number of crystallographically different cyano groups and a broad highly asymmetric band observed in the reflectance UV-Vis spectrum is consistent with the presence of both hexa- and penta-coordinated Cu(II) atoms in the structure. The temperature dependence of the inverse susceptibility suggests the presence of a weak antiferromagnetic exchange coupling between Cu(II) ions. The complex is stable up to 210 °C when its two-stage thermal decomposition starts.  相似文献   

18.
Reaction of the potassium salt of the N-thiophosphorylthiourea H2NC(S)NHP(S)(OiPr)2 (HL) with Co(II), Ni(II), Zn(II) and Cd(II) cations in aqueous EtOH leads to the chelate complexes [ML2] all showing a 1,5-S,S′-coordination formed by the CS and PS sulfur atoms of two deprotonated ligands L. The structures of the resulting compounds were studied by IR, UV-Vis, 1H, 31P{1H} NMR spectroscopy and microanalysis. The metal center is found in a tetrahedral environment in [CoL2], [ZnL2] and [CdL2]. According to NMR and UV-Vis spectroscopy the metal cation of [NiL2] exhibits square planar coordination geometry in CH2Cl2, CHCl3 and C6H6, while tetrahedral geometry is observed in acetone, DMSO and DMF. Regardless of the solvent used for the crystallization of [NiL2], the molecular structure in the solid is always square planar as was confirmed by XRD of single crystals and magnetic measurements of the polycrystalline material. The magnetic and photoluminescent properties of all complexes are also reported.  相似文献   

19.
The oxidation from to in HCl aq. was studied in situ by combining electrochemistry with XAFS spectroscopy. During the oxidation of , isosbestic points were observed in Pt LIII and LII XANES spectra as a function of time, indicating that the Pt(II/IV) redox equilibrium is the only reaction in the system. The Pt LIII and LII X-ray absorption edge energies of the initial PtIICl42− are 11562.9 and 13271.8 eV, respectively, while those of the electrolyzed species are 11564.6 and 13273.7 eV which are identical with those of a reference sample. The coordination of the electrolyzed species was characterized by structural parameters derived from the EXAFS curve fit, and identified to .  相似文献   

20.
The kinetics of the reduction of by Co(dmgBF2)2(H2O)2 in 0.041 M HNO3/NaNO3 was found to be first-order in both the oxidizing and reducing agents and the second-order rate constant is given by kobs = k1 + k2K[Cl], with k1=1.59 × 106 M−1 s−1and k2K = 1.83 × 108 M−2 s−1, at 25 °C. The term that is first-order in [Cl] is attributed to the formation of an ion-pair between and Cl. For k1, the activation parameters ΔH* and ΔS* are 2.22 ± 0.02 kcal mol−1 and −22.7 ± 0.8 cal mol−1 K−1, respectively. The self-exchange rate constant of k22 ≈ 8.7 × 10−3 M−1 s−1 for was estimated using Marcus theory and the known self-exchange rate constant for .  相似文献   

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