共查询到20条相似文献,搜索用时 31 毫秒
1.
Girasolo MA Canfora L Sabatino P Schillaci D Foresti E Rubino S Ruisi G Stocco G 《Journal of inorganic biochemistry》2012,106(1):156-163
New organotin(IV) complexes of 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) and 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine (dptp) with 1:1 and/or 1:2 stoichiometry were synthesized and investigated by X-ray diffraction, FT-IR and 119Sn Mössbauer in the solid state and by 1H and 13C NMR spectroscopy, in solution. Moreover, the crystal and molecular structures of Et2SnCl2(dbtp)2 and Ph2SnCl2(EtOH)2(dptp)2 are reported. The complexes contain hexacoordinated tin atoms: in Et2SnCl2(dbtp)2 two 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine molecules coordinate classically the tin atom through N(3) atom and the coordination around the tin atom shows a skew trapezoidal structure with axial ethyl groups. In Ph2SnCl2(EtOH)2(dptp)2 two ethanol molecules coordinate tin through the oxygen atom and the 5,7-diphenyl-1,2,4-triazolo[1,5-a]pyrimidine molecules are not directly bound to the metal center but strictly H-bonded, through N(3), to the OH group of the ethanol moieties; Ph2SnCl2(EtOH)2(dptp)2 has an all-trans structure and the C-Sn-C fragment is linear. On the basis of Mössbauer data, the 1:2 diorganotin(IV) complexes are advanced to have the same structure of Et2SnCl2(dbtp)2, while Me2SnCl2(dptp)2 to have a regular all-trans octahedral structure. A distorted cis-R2 trigonal bipyramidal structure is assigned to 1:1 diorganotin(IV) complexes. The in vitro antibacterial activities of the synthesized complexes have been tested against a group of reference pathogen micro-organisms and some of them resulted active with MIC values of 5 μg/mL, most of all against staphylococcal strains, which shows their inhibitory effect. 相似文献
2.
A heterodinuclear (Ru(II), Co(III)) metal polypyridyl complex [(phen)2Ru(bpibH2)Co(phen)2]5+ {phen = 1,10-phenanthroline, bpibH2 = 1,4-bis([1,10]phebanthroline-[5,6-d]imidazol-2-yl)-benzene} has been designed and synthesized. The comparative study on the interactions of the Ru(II)-Co(III) complex with calf thymus DNA (CT-DNA) and yeast tRNA has been investigated by UV-visible spectroscopy, fluorescence spectroscopy, viscosity, as well as equilibrium dialysis and circular dichroism (CD). The antitumor activities of the complex have been evaluated by MTT {3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide} method and Giemsa staining experiment. These results indicate that the structures of nucleic acids have significant effects on the binding behaviors of metal complexes. Furthermore, the complex demonstrates different antitumor activity against selected tumor cell lines in vitro, and can make the cell apoptosis. 相似文献
3.
The combination of anhydrous SnCl4 with 18-crown-6 in aqueous conditions results in formation of the non-hydrolysed product [cis-SnCl4(H2O)2] · 18-crown-6 · 2H2O. The X-ray crystal structure shows extensive intermolecular hydrogen bonding involving the cis-octahedral SnCl4(H2O)2 units, the uncoordinated water molecules and the crown ether. Similarly, [2,2,2]cryptand reacts with an aqueous solution formed by adding anhydrous GaCl3 to slightly acidic water, affording [[2,2,2]cryptand + 2H+][GaCl4]2. 相似文献
4.
Zia-ur-Rehman Mirela M. Barsan Niaz Muhammad Auke Meetsma 《Inorganica chimica acta》2008,361(11):3322-3326
Two chlorodiorganotin(IV) complexes of 4-(2-methoxyphenyl)piperazine-1-carbodithioate (MPPDA) have been synthesized by 1:1 mole-ratio reactions of the parent acid (MPPDAH) with Me2SnCl2 or Et2SnCl2 in dry methanol. The products have been characterized by Raman and multinuclear NMR (1H, 13C and 119Sn) spectroscopy, elemental analysis, and mass spectrometry. Single-crystal X-ray diffraction studies indicate that both complexes have distorted trigonal bipyramidal geometries around the central Sn atom. 相似文献
5.
The interactions of cis- and trans-diammineplatinum compounds with 5′-GMP and 5′-dGMP in dilute aqueous solution at neutral pH were investigated by 1H nmr. In addition to the 1:2 Pt nucleotide complexes cis- and trans-Pt(NH3)2(GMP)2, it was possible to study the formation of the 1:1 Pt-nucleotide complexes with either one coordinated water or chloride ion. At 5°C GMP reacts with a stoichiometric amount of cis-diaquodiammine-platinum to yield cis-Pt(NH3)2(GMP) (H2O) as a sole reaction product. From the present results it is concluded that such a complex may play an important role as the initial reaction product between antitumor compounds like cis-Pt(NH3)2Cl2 and guanine in DNA in living organisms. The coupling constant 3J(H(1′)-H(2′)) of the H(1′) sugar proton in cis-Pt(NH3)2(GMP)2 is temperature dependent, indicating a conformational change in the sugar moiety. 相似文献
6.
Complexes of the types cis- and trans-Pt(amine)2I2 were studied by spectroscopic methods, especially by multinuclear NMR spectroscopy. In 195Pt NMR, the cis diiodo compounds with primary amines were observed between −3342 and −3357 ppm in acetone, while the trans compounds were found between −3336 and −3372 ppm. For the secondary amines, the chemical shifts were observed at lower fields. In 1H NMR, the trans complexes were observed at higher fields than the cis compounds, while in 13C NMR, the reverse was observed. The 2J(195Pt-1H) and 3J(195Pt-1H) coupling constants are larger for the cis compounds (ave. 67 and 45 Hz, respectively) than for the trans isomers (ave. 59 and 38 Hz). In 13C NMR, the values of 2J(195Pt-13C) and 3J(195Pt-13C) were also found to be larger for the cis complexes (ave. 17 and 39 Hz versus 11 and 28 Hz). There seems to be a slight dependence of the pKa values of the protonated amines or the proton affinity in the gas phase with the δ(Pt) chemical shifts. The crystal structures of eight diiodo complexes were determined. These compounds are cis-Pt(CH3NH2)2I2, cis-Pt(n-C4H9NH2)2I2, cis-Pt(Et2NH)2I2, trans-Pt(n-C3H7NH2)2I2, trans-Pt(iso-C3H7NH2)2I2, trans-Pt(n-C4H9NH2)2I2, trans-Pt(t-C4H9NH2)2I2 and trans-Pt(Me2NH)2I2. The Pt-N bond distances located in trans position to the iodo ligands were compared to those located in trans position to the amines. The Pt-N bond in cis-Pt(Et2NH)2I2 are much longer than the others, probably caused by the steric hindrance of the two very bulky ligands located in cis positions. 相似文献
7.
The polymeric structure of the complex, [SnCl4(H2O)2]18-crown-6·2H2O, prepared by the addition of a solution of SnCl4 to 18-crown-6, has been determined by X-ray analysis. The structure has been solved by three-dimensional Patterson-Fourier synthesis to a conventional R-factor of 0.13, by using 1394 reflections with I>3σ(I). The crystals are monoclinic, with a = 15.753(3), b = 15.072(3), c = 12.209(4), β = 97.77°(1.0), z = 4, and space group P21/a. The tin atom is octahedrally coordinated to four chlorine atoms and two water molecules in cis positions. A very complex network of hydrogen bonding links together the tin coordination octahedron, the two water hydration molecules, and the two crystallographically-different half crown-ethers. 相似文献
8.
The reaction of [RuCl3(2mqn)NO]− (H2mqn=2-methyl-8-quinolinol) with 2-chloro-8-quinolinol (H2cqn) afforded cis-1 [RuCl(2cqn)(2mqn)NO] (the oxygen of 2cqn is trans to the NO) (complex 1), cis-1 [RuCl(2cqn)(2mqn)NO] (the oxygen of 2mqn is trans to the NO) (complex 2) and a 1:1 mixture of cis-2 [RuCl(2cqn)(2mqn)NO] (the oxygen of 2mqn is trans to the NO) and cis-2 [RuCl(2cqn)(2mqn)NO] (the oxygen of 2cqn is trans to the NO) (complex 3). The reaction was compared with that of [RuCl3(2mqn)NO]− with 8-quinolinol (Hqn) or 5-chloro-8-quinolinol (H5cqn). Photoirradiation reaction of complex 1 at room temperature in deaerated CH2Cl2 in the presence of NO gave trans-[RuCl(2cqn)(2mqn)NO] (the Cl is trans to the NO) and complex 2 with recovery of complex 1. The reaction was contrasted with that of cis-1 [RuCl(qn)(2mqn)NO] or cis-1 [RuCl(5cqn)(2mqn)NO]. The crystal structure of complex 1 was determined by X-ray diffraction. The reactions were examined under consideration of atomic charge of the phenolato oxygen in 8-quinolinol and its derivatives calculated at the restricted Hartree-Fock/6-311G** level. 相似文献
9.
Mariappan Mariappan Masahiko Suenaga Pallepogu Raghavaiah 《Inorganica chimica acta》2011,376(1):340-349
In our search for new DNA intercalating ligands, a novel bifunctional intercalator 11-(9-acridinyl)dipyrido[3,2-a:2′,3′-c]phenazine, acdppz (has two potentially effective intercalators via dipyridophenazine(dppz) and acridine which are linked together via C-C bond) and its corresponding Ru(II) polypyridyl complex [Ru(phen)2(acdppz)]2+ (where phen = 1,10-phenanthroline) have been synthesized and characterized. The electrochemical behaviors of the ligand and its complex have been thoroughly examined. The structure of acdppz and [Ru(phen)2(acdppz)]2+ were determined by X-ray crystallography. From the crystal structure of the complex, we found that the dppz moiety is not coplanar with the acridine ring, having a dihedral angle of 64.79 in the acdppz. The selected bond lengths and angles for the crystal structure of [Ru(phen)2(acdppz)]2+ were compared to the geometry-optimized molecular structure of [Ru(phen)2(acdppz)]2+ derived by Gaussian. The interaction of [Ru(phen)2(acdppz)]2+ with calf-thymus (CT) DNA was investigated by absorption and viscometry titration, thermal denaturation studies. The above measurements indicated that the complex binds less strongly with the CT DNA due to the intercalation by the ruthenium bound acdppz with an intrinsic binding constant of 2.6 × 105 M−1. Molecular-modeling studies also support an intercalative mode of binding of the complex to the model duplex d(CGCAATTGCG)2 possibly from the major groove with a slight preference for GC rich region. Additionally, the title complex promotes the cleavage of plasmid pBR322 DNA upon irradiation under aerobic conditions. 相似文献
10.
The predominant complex formed by the reaction of cis-(NH3)2PtCl2 and guanylyl(3′-5′)cytidine has been isolated. The molar ratio of the binding of cis-(NH3)2PtCl2 to guanylyl(3′-5′)-cytidine is 1:2. The values of proton dissociation constant due to guanine and cytosine bases provide useful information for determining the binding site of the isolated complex. In addition, nmr and ir spectral data were used to determine the binding site. cis-(NH3)2PtCl2 coordinates to guanylyl(3′-5′)cytidine through N(7) position of the guanine base, but cytosine base does not participate in the binding to cis-(NH3)2Pt2+. Interbase crosslink has not been detected. The binding specificity of cis-(NH3)2PtCl2 to guanine base is discussed. 相似文献
11.
The binding modes of the [Ru(II)(1,10-phenanthroline)(L1L2) dipyrido[3,2-a:2′,3′-c]phenazine]2+ {[Ru(phen)(py) Cl dppz]+ (L1 = Cl, L2 = pyridine) and ([Ru(phen)(py)2dppz]2+ (L1 = L2 = pyridine)} to native DNA is compared to that of the [Ru(II)(1,10-phenanthroline)2dipyrido[3,2-a:2′,3′-c]phenazine]2+ complex ([Ru(phen)2dppz]2+) by various spectroscopic and hydrodynamic methods including electric absorption, linear dichroism (LD), fluorescence spectroscopy, and viscometric titration. All measured properties, including red-shift and hypochromism in the dppz absorption band, nearly perpendicular molecular plane of the dppz ligand with respect to the local DNA helix axis, prohibition of the ethidium binding, the light switch effect and binding stoichiometry, increase in the viscosity upon binding to DNA, increase in the melting temperature are in agreement with classical intercalation of dppz ligand of the [Ru(phen)2dppz]2+ complex, in which both phenanthroline ligand anchored to the DNA phosphate groups by electrostatic interaction. [Ru(phen)(py)2 dppz]2+ and [Ru(phen)(py) Cl dppz]+ complexes had one of the phenanthroline ligand replaced by either two pyridine ligands or one pyridine plus a chlorine ion. They exhibited similar protection from water molecules, interaction with DNA bases, and occupying site that is common with ethidium. The dppz ligand of these two Ru(II) complex were greatly tilted relative to the DNA helix axis, suggesting that the dppz ligand resides inside the DNA and is not perpendicular relative to the DNA helix axis. These observation suggest that anchoring the [Ru(phen)2dppz]2+complex by both phenanthroline is essential for the dppz ligand to be classically intercalated between DNA base-pairs. 相似文献
12.
《Inorganica chimica acta》1986,117(2):103-109
The hybrid, bidentate, diarylphosphino-alkoxide ligand PPh2CH2C(CF3)2O−, L1, gives the Pd2+ bis- complex Pd(L1)2, from which the chloride-bridged dinuclear complex [(L1)Pd(μ-Cl)2Pd(L1)] is made by reaction with PdCl2(PhCN)2. Cleavage of the dinuclear complex with monodentate ligands L2 then gives Pd(L1)Cl(L2) (L2 =PPh3, PPh2Me, PPhMe2, PMe3, SMe2, or pyridine); NMR data show that PR3 is cis to the phosphine site in L1 in these complexes, but SMe2 or pyridine are probably trans.A complete crystal and molecular structural determination has been made for cis-Pd(L1)Cl(PPh2Me). Crystals are monoclinic, space group P21/c, a = 10.821(1), b = 14.600(1), c = 18.674(2) Å, β = 101.25(1)°, V = 2893 Å3, Z = 4. Least-squares refinement on F of 361 variables using 3977 observations converged at a conventional agreement factor R = 0.025. The complex is square-planar, with the two phosphines cis; the 5-membered chelate ring is in a dissymmetric envelope conformation. The PdP bonds differ in length, with that to the unidentate phosphine, 2.259(1) Å, being significantly longer than that to the phosphine on the chelating ligand, 2.231(1) Å. 相似文献
13.
The present study reports a detailed investigation with the interaction of [Cr(phen)2(dppz)]3+ with serum albumins, the key protein for the transport of drugs in the blood plasma, which allows us to understand further the role of [Cr(phen)2(dppz)]3+ as sensitizer in Photodynamic Therapy (PDT).Chromium(III) complex [Cr(phen)2(dppz)]3+, (dppz = dipyridophenazine and phen = 1,10-phenanthroline), where dppz is a planar bidentate ligand with an extended π system, has been found to bind strongly with bovine and human serum albumins (BSA and HSA) with an intrinsic binding constants, Kb, of (1.7 ± 0.3) × 105 M− 1 and (2.2 ± 0.3) × 105 M− 1 at 295 K, respectively. The interactions of serum albumins with [Cr(phen)2(dppz)]3+ were assessed employing fluorescence spectroscopy, circular dichroism and UV-vis absorption spectroscopy. The serum albumins-[Cr(phen)2(dppz)]3+ interactions caused conformational changes with the loss of helical stability of the protein and local perturbation in the domain IIA binding pocket. The relative fluorescence intensity of the albumin (BSA or HSA) bound to the Cr(III) complex decreased, suggesting that perturbation around the Trp 214 residue took place. The analysis of the thermodynamic parameters ΔG, ΔH, ΔS indicated that the hydrophobic interactions played a major role in both BSA-Cr(III) and HSA-Cr(III) association processes. The binding distances and transfer efficiencies for BSA-Cr(III) and HSA-Cr(III) binding reactions were calculated according to the Föster theory of non-radiation energy transfer. All these experimental results suggests that [Cr(phen)2(dppz)]3+ binds to serum albumins, by which these proteins could act as carriers of this complex for further applications in PDT. 相似文献
14.
Ruthenium complexes with one dipyrido[3,2-a:2′-3′-c]phenazine (dppz) ligand, e.g. [Ru(phen)2(dppz)]2+ (phen = phenanthroline), shows strong binding to double helical DNA and are well-known DNA “light-switch” molecules. We have here investigated four new [Ru(phen)2(dppz)]2+ derivatives with different bulky quaternary ammonium substituents on the dppz ligand to find relationships between molecular structure and intercalation kinetics, which is considered to be of importance for antitumor applicability. Linear dichroism spectroscopy shows that the enantiomers of the new complexes exhibit very similar binding geometries (intercalation of dppz moiety between adjacent DNA base pairs) as the enantiomers of the parent [Ru(phen)2(dppz)]2+ complex. Absorption spectra and luminescence properties provide further evidence for a final intercalative binding mode which has to be reached by threading of a bulky moiety between the strands of the DNA. Δ-enantiomers of all the new complexes show much slower association and dissociation kinetics than that of a reference complex without a cationic substituent. Kinetics were not very different whether the bulky quaternary group was derived from hexamethylene tetramine or 1,4-diazabicyclo-(2,2,2)octane (DABCO) or whether it had one or two positive charges. However, a complex in which the hexamethylene tetramine substituent is attached via a phenyl group showed a lowered association rate, in addition to an improved quantum yield of luminescence. A second positive charge on the DABCO substituent resulted in a much slower dissociation rate, suggesting that the distance from the Ru-centre and the amount of charge are both important for threading intercalation kinetics. 相似文献
15.
Steffen Pospiech 《Inorganica chimica acta》2011,374(1):566-571
The ditopic tris(2-mercaptoimidazol-1-yl)borate ligand K2[(mtEt)3B-B(mtEt)3] cannot be prepared from B2(NMe2)4/4 HmtEt/2 KmtEt, because the stable intramolecular diadduct (mtEt)B(μ-mtEt)2B(mtEt) is generated instead (HmtEt = 2-mercapto-1-ethylimidazole). Introduction of a meta- or para-phenylene spacer between the two boron atoms precludes the 2-mercaptoimidazol-1-yl groups from adopting a bridging position so that the potassium salts K2[(mtEt)3B-(m-C6H4)-B(mtEt)3] and K2[(mtEt)3B-(p-C6H4)-B(mtEt)3] become readily accessible. These ligands react with [(p-cym)RuCl2]2 to give the dinuclear RuII complexes [(p-cym)Ru(mtEt)3B-(m-C6H4)-B(mtEt)3Ru(p-cym)]Cl2 and [(p-cym)Ru(mtEt)3B-(p-C6H4)-B(mtEt)3Ru(p-cym)]Cl2 (p-cym = p-cymene). After the exchange of the Cl− counterions for [PF6]−, both complexes have been crystallized and structurally characterized by X-ray diffraction. 相似文献
16.
Judith Toneatto Guadalupe Lorenzatti Gerardo A. Argüello 《Journal of inorganic biochemistry》2010,104(7):697-2767
Due to the key role of DNA in cell life and pathological processes, the design of specific chemical nucleases, DNA probes and alkylating agents is an important research area for the development of new therapeutic agents and tools in Biochemistry. Hence, the interaction of small molecules with DNA has attracted in particular a great deal of attention.The aim of this study was to investigate the ability of [Cr(phen)2(dppz)]3+ to associate with DNA and to characterize it as photocleavage reagent for Photodynamic Therapy (PDT).Chromium(III) complex [Cr(phen)2(dppz)]3+, (dppz = dipyridophenazine, phen = 1,10-phenanthroline), where dppz is a planar bidentate ligand with an extended π system, has been found to bind strongly to double strand oligonucleotides (ds-oligo) and plasmid DNA with intrinsic DNA binding constants, Kb, of (3.9 ± 0.3) × 105 M−1 and (1.1 ± 0.1) × 105 M−1, respectively. The binding properties to DNA were investigated by UV-visible (UV-Vis) absorption spectroscopy and electrophoretic studies. UV-Vis absorption data provide clearly that the chromium(III) complex interacts with DNA intercalatively. Competitive binding experiments show that the enhancement in the emission intensity of ethidium bromide (EthBr) in the presence of DNA was quenched by [Cr(phen)2(dppz)]3+, indicating that the Cr(III) complex displaces EthBr from its binding site in plasmid DNA. Moreover, [Cr(phen)2(dppz)]3+, non-covalently bound to DNA, promotes the photocleavage of plasmid DNA under 457 nm irradiation. We also found that the irradiated Cr(III)-plasmid DNA association is able to impair the transforming capacity of bacteria. These results provide evidence confirming the responsible and essential role of the excited state of [Cr(phen)2(dppz)]3+ for damaging the DNA structure. The combination of DNA, [Cr(phen)2(dppz)]3+ and light, is necessary to induce damage. In addition, assays of the photosensitization of transformed bacterial suspensions suggest that Escherichia coli may be photoinactivated by irradiation in the presence of [Cr(phen)2(dppz)]3+. In sum, our results allow us to postulate the [Cr(phen)2(dppz)]3+ complex as a very attractive candidate for DNA photocleavage with potential applications in Photodynamic Therapy (PDT). 相似文献
17.
Elisângela de Paula Silveira-Lacerda Cesar Augusto Sam Tiago Vilanova-Costa Amélia Hamaguchi Luiz Alfredo Pavanin Luiz Ricardo Goulart Maria Inês Homsi-Brandenburgo Wagner Batista dos Santos Andreimar Martins Soares Auro Nomizo 《Biological trace element research》2010,135(1-3):98-111
The aim of present study was to verify the in vitro antitumor activity of a ruthenium complex, cis-(dichloro)tetraammineruthenium(III) chloride (cis-[RuCl2(NH3)4]Cl) toward different tumor cell lines. The antitumor studies showed that ruthenium(III) complex presents a relevant cytotoxic activity against murine B cell lymphoma (A-20), murine ascitic sarcoma 180 (S-180), human breast adenocarcinoma (SK-BR-3), and human T cell leukemia (Jurkat) cell lines and a very low cytotoxicity toward human peripheral blood mononuclear cells. The ruthenium(III) complex decreased the fraction of tumor cells in G0/G1 and/or G2-M phases, indicating that this compound may act on resting/early entering G0/G1 cells and/or precycling G2-M cells. The cytotoxic activity of a high concentration (2 mg mL?1) of cis-[RuCl2(NH3)4]Cl toward Jurkat cells correlated with an increased number of annexin V-positive cells and also the presence of DNA fragmentation, suggesting that this compound induces apoptosis in tumor cells. The development of new antineoplastic medications demands adequate knowledge in order to avoid inefficient or toxic treatments. Thus, a mechanistic understanding of how metal complexes achieve their activities is crucial to their clinical success and to the rational design of new compounds with improved potency. 相似文献
18.
Nicola Margiotta Francesco Capitelli Anna G.G. Moliterni Giovanni Natile 《Inorganica chimica acta》2004,357(1):149-158
Reactions of Zeise’s salt (K[Pt(η2-C2H4)Cl3]) with oxidized phenanthroline ligands (1,10-phenanthroline-5,6-dione, phedon, and 2,9-dimethyl-1,10-phenanthroline-5,6-dione, Me2phedon) are reported. Comparison with analogous reactions involving unoxidized phen (1,10-phenanthroline) and Me2phen (2,9-dimethyl-1,10-phenanthroline) ligands indicates that these latter ligands are less capable to stabilize the five-coordinate species [PtCl2(η2-C2H4)(phenanthroline)] in which the phenanthroline and the olefin share the trigonal plane and two chlorines are in the axial positions. The X-ray structure of the four-coordinate species [PtCl2(Me2phedon)] indicates that the major difference between oxidized and unoxidized phenanthrolines is the loss of aromaticity of the central ring of phenanthroline. As a consequence, the oxidized phenanthroline becomes more flexible and can undergo a bow-like distortion so to reduce steric interaction between ortho substituents of phenanthroline and cis chlorine ligands. The increase in stability of the four-coordinate species with Me2phedon is concomitant with an increase in stability of the five-coordinate precursor complex with ethylene. In the latter case the stabilization is not of sterical origin but stems from reduced electron-donor properties of oxidized phenanthrolines. The balance of the two effects is such that the equilibrium between five- and four-coordinate species is more shifted in favour of the former species in the case of Me2phedon than in the case of Me2phen. 相似文献
19.
Med Abderrahmane K. Sanhoury Med Taieb Ben Dhia Med Rachid Khaddar 《Inorganica chimica acta》2009,362(10):3763-3768
The synthesis, characterisation and solution behaviour of a series of octahedral complexes SnCl4·2L (L = R2NP(O)(OCH2CF3)2; R = Me (1); Et (2) or L = P(O)(OCH2Rf)3; Rf = CF3 (3); C2F5 (4)) are described. Complexes 1-4 were prepared from SnCl4 and 2 equiv. of the ligand, L, in anhydrous CH2Cl2 solution. The adducts have been characterised by multinuclear (1H, 31P and 119Sn) NMR, IR spectroscopy and elemental analysis. In dichloromethane solution, the NMR data showed the presence of a mixture of cis and trans isomers for 1 and 2 and only the cis isomer for 3 and 4. The difference could be interpreted in terms of the electronic effects of the substituents on the phosphorus atom of the ligand. In addition, the solution structure of the complexes studied by variable temperature 31P-{1H} and 1H NMR in the presence of excess ligand indicated that the ligand exchange on the cis isomer dominates the chemistry. The metal-ligand exchange barriers were estimated to be 13.38 and 11.39 kcal/mol for 1 and 3, respectively. The results are discussed and compared with those previously reported for the related hexamethylphosphoramide adduct, SnCl4·2HMPA. 相似文献
20.
《Inorganica chimica acta》1986,112(2):107-112
The synthesis and crystal and molecular structure of the first zinc(II) mixed ligand chelate containing a dithiolene ligand (maleonitriledithiolate) and N,N- diethyldithiocarbamate are reported. The compound Ph4As[Zn(mnt)(Et2dtc)] crystallizes monoclinic, space group P21/c with four molecules in the unit cell; a=17.834(3), b=12.056(2), c=16.171(4) Å, β=93.73(2)°.The coordination geometry of the ZnS4 unit is nearly tetrahedral, with a dihedral angle of 87.6° between the chelate rings. The structure is compared with those of both the patent compounds (Ph4- As)2[Zn(mnt)2] and Zn2(Et2dtc)4. Ph4As[Zn(mnt)(Et2dtc)] could be used as the host lattice in single- crystal ESR investigations of the planar Cu mixed ligand complex. The rhombic spin-Hamiltonian parameters g and ACu are indicative of a low symmetry of the incorporated [Cu(mnt)(Et2dtc)]− complex anions. In order to substantiate the experimental findings about the actual structure of the copper molecules, the principal values of g and ACu were recalculated by means of Extended Hückel MO calculations. However, the calculations performed for the dihedral angles between the ligand planes varying between 0° and 90° suggest that the rotation of the ligands is not larger than 10° 相似文献