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1.
Two mononuclear RuII complexes of polypyridyl ligands, cis-[Ru(bpy)2(4,4′-bpy)Cl](PF6)·H2O (1) and cis-[Ru(phen)2(CH3CN)2](PF6)2 (2) (bpy=2,2′-bipyridyl, 4,4′-bpy=4,4′-bipyridyl, and PHEN=1,10-phenanthroline), have been synthesized and characterized by elemental analyses, IR and UV–vis spectra. The crystal structures of both complexes have been determined by X-ray diffraction, indicating that each RuII center is hexa-coordinated (RuN5Cl for 1 and RuN6 for 2) and takes a distorted octahedral geometry. The favored feature of both complexes is that they are quite useful complex precursors for further constructing new functional architectures.  相似文献   

2.
The effect of five derivatives of PtII, cis dichloro-(1,2-dimethyl-3-aminopyrrolidine)platinum(II), cis dichloro-(1-methyl, 2-ethyl-3-aminopyrrolidine)platinum(II), cis dichloro-(1-ethyl, 2-methyl-3-aminopyrrolidine)platinum(II), cis dichloro-(1,2-diethyl-3-aminopyrrolidine)platinum(II), and cis dichloro-(1-propyl, 2 methyl-3 aminopyrrolidine)platinum(II) on platination of DNA was studied by CD and melting temperature determination. Reactions with the nucleotides d(ApG) and d(ApA) were also followed by 1H NMR and CD, indicating binding via N(7) and formation mainly of bifunctional, in the case of d(ApG), or monofunctional adducts, in the case of d(ApA). The crystal structure of cis dichloro-(1 ethyl, 2 methyl-3 aminopyrrolidine)platinum(II) shows the analogues cisplatin structure of these active antitumour complexes. This compound is racemic.  相似文献   

3.
Racemic [C5H5Mo(CO)2LL]PF6, (2) with LL = 2-benzoylpyridine-1-phenylethylimine, undergoes spontaneous resolution upon crystallization from acetone/CH2Cl2/ethanol. The absolute configuration of the (+)546-isomer was shown to be (R) at the Mo atom and (R) at the asymmetric carbon atom. Comparison of 2 with [C5H5Mo(CO)2LL]PF6 (1) (LL = 2-carbaldehydepyridine-1-phenylethylimine) reveals distinct changes caused by the differences resulting from the presence of the phenyl group in 2 and the change from the (RR)- to the (RS)-configuration.  相似文献   

4.
The preparations and spectroscopic characteristics are reported of a series of (trimethylgermyl)methyl- and (trimethylstannyl)methylplatinum(II) complexes with diene and P-donor ancillary ligands, cis-Pt(CH2GeMe3)2L2 (L = PPh3 or PPh2Me; L2 = dppe or cod) and cis-Pt(CH2SnMe3)2L2 (L = PPh3; L2 =cod). Thermolysis of toluene solutions of cis-Pt(CH2GeMe3)2(PPh3)2 leads to cis-Pt(Me)(CH2GeMe2CH2GeMe3)(PPh3)2 via β-alkyl migration, after (non-rate-limiting) phosphine dissociation. Estimated activation parameters (ΔH298 K = 126 ± 3 kJ mol−1, ΔS = + 17 ± 7 J mol−1 K−1 and hence Δ298 K = 121 ± 5 kJ mol−1) suggest that this system is more migration labile than its silicon analogue, primarily as a result of a lower activation enthalpy. While cis-Pt(CH2GeMe3)2(PPh2Me)2 reacts similarly but less readily, Pt(CH2GeMe3)2(dppe)2 is inert at operable temperatures. Thermolysis of Pt(CH2GeMe3)2(cod) generates 1,1,3,3,-tetramethyldi-1,3-germacyclobutane as the major organogermanium product, while from cis-Pt(CH2SnMe3)2(PPh3)2, 1,1,3,3-tetramethyldi-1,3-stannacyclobutane predominates. Mechanistic implications are discussed.  相似文献   

5.
The complexes [Ru(S,S)2(PPh3)2] [S,S = EtCOCS2, (CH2)4NCS2] react with a variety of tertiary phosphines with the substitution of triphenylphosphine and the formation of [Ru(S,S)2(PR3)2]. The reaction occurs with the formation ofthe cis isomer, except for the complex with PMe2Ph that gives rise to the trans isomer as the crystal structure shows. The effect of the different phosphines on the ruthenium complex is analysed in terms of the spectroscopic and electrochemical properties of the isolated compounds. The cyclic voltammetric studies of the cis complexes show that isomerization to the trans isomer occurs on oxidation. This isomerization is not observed in the trans-[Ru(S,S)2(PMe2Ph)2] complexes that give rise to stable trans-ruthenium(II)/ruthenium(III) couples. In a similar way the diphosphine complexes afford a quasi-reversible cis-ruthenium(II)/ruthenium(III) process.  相似文献   

6.
Raman Batheja  Ajai K. Singh 《Polyhedron》1997,16(24):4337-4345
The nucleophile [ArTe] generated in situ borohydride solution of Ar2Te2, reacts with 2-(chloromethyl) tetrahydrofuran and 2-(2-bromoethyl)-1,3-dioxolane resulting in L1 and L2, respectively. The complexes of palladium(II) and platinum(II) with L1/L2 having stoichiometries [MCl2·L2], [ML2](ClO4)2, [(DPPE)ML2](ClO)4)2, [(PPh3)2ML2](ClO4)2 and [(phen)ML2](ClO4)2 (where L = L1/L2 DPPE = Ph2PC H2CH2PPh2, PHEN = 1,10-phenanthroline and M = Pd/Pt) have been synthesized. IR, 1H, 125Te{1H} and 31P{1H} NMR and UV-vis spectral data of these species in conjunction with their molar conductance and molecular weight data have been used to authenticate the new species. In all complexes (1–20) the ligands L1 and L2 are coordinated through tellurium and in the complexes of formula [ML2](ClO4)2 (M = Pd, Pt) the ligand is bidentate with the oxygen atom used in complexation. In solution, complexes PtCl2L2 exist as a mixture of cis and trans isomers whereas only the trans isomer was observed for the palladium analogues. The [(phen)PdL2](ClO4)2(Q) quenches 1O2 readily. The plot of log [Q] vs time is linear. Mechanism compatible with the experimental observations is proposed.  相似文献   

7.
Activation volumes for aquation of cis-[Co(en)2(NO2)Cl]+, trans-[Co(en)2 (CN)Cl]+, cis-- and cis-β-[Co(trien)Cl2]+ have been determined, and are compared with values reported for a range of chloroaminecobalt(III) complexes. Variation of reported ΔV in terms of, particularly, solvation effects is discussed.  相似文献   

8.
An extension of the methods employed in the isolation of (trans) 1H/2H-decafluorocyclohexane,1 (I) from the polyfluorocyclohexane mixture obtained by the vapour phase fluorination of benzene with cobaltic fluoride at about 150°, has afforded the four remaining members of the series of decafluorocyclohexanes [the cis- and trans-1H:3H- and 1H:4H-isomers (1H:3H/-(IV), 1H/3H-(III), 1H:4H/-(VII), and 1H/4H-(VIII), respectively)] and also the cis-1H:2H-decafluorocyclohexane (II), obtained previously1,2 by the lithium aluminium hydride reduction of 1:2-dichlorodecafluorocyclohexane. The structures of the 1H:3H- and 1H:4H-decafluorides have been established by dehydrofluorination studies. The six decafluorocyclohexanes have been related to two new nonafluorocyclohexanes3 (IX and X) by further fluorination of the latter. 2H-Heptafluoroadipic acid has been obtained from 3H-nonafluorocyclohex-1-ene (V), one of the dehydrofluorination products of the 1H:3H-decafluorides.  相似文献   

9.
The synthesis, spectroscopic, and crystal structures of three heteroleptic thioether/halide platinum(II) (Pt(II)) complexes of the general formula [Pt(9S3)X2] (9S3=1,4,7-trithiacyclononane, X=Cl, Br, I) are presented. All three 9S3/dihalo complexes form very similar structures in which the Pt(II) center is surrounded by a cis arrangement of two halides and two sulfur atoms from the 9S3 ligand. The third sulfur from the 9S3 forms a long distance interaction with the Pt center resulting in an elongated square pyramidal structure with a S2X2+S1 coordination geometry. The distances between the Pt(II) center and axial sulfur shorten with larger halide ions (Cl=3.260(3) Å>Br=3.243(2) Å>I=3.207(2) Å). These distances are consistent with the halides functioning as π donor ligands, and their Pt---S axial distances fall intermediate between Pt(II) thioether complexes involving π acceptor and σ donor ligands. The 195Pt NMR chemical shift values follow a similar trend with an increased shielding of the platinum ion with larger halide ions. The 9S3 ligand is fluxional in all of these complexes, producing a single carbon resonance. Additionally, a related series of homoleptic crown thioether complexes have been studied using 195Pt NMR, and there is a strong correlation between the chemical shift and complex structure. Homoleptic crown thioethers show the anticipated upfield chemical shifts with increasing number of coordinated sulfurs. Complexes containing four coordinated sulfur donors have chemical shifts that fall in the range of −4000 to −4800 ppm while a value near −5900 ppm is indicative of five coordinated sulfurs. However, for S4 crown thioether complexes, differences in the stereochemical orientation of lone pair electrons on the sulfur donors can greatly influence the observed 195Pt NMR chemical shifts, often by several hundred ppm.  相似文献   

10.
A. Benedetii 《Polyhedron》1985,4(12):2059-2062
Some Pd(II) and Pt(II) halide complexes with 2-bromo- and 2-chloro-1,3,4-thiadiazoles have been prepared and characterized by electronic, NMR, Raman and IR spectroscopy, and by thermogravimetric analysis and conductivity measurements. All of the complexes appear to have square-planar stereochemistry with MN2x2 (X = Cl or Br) chromophores. Two of them are present in the cis configuration while for all the others unambiguous trans configurations are observed.  相似文献   

11.
Nickel(II) chromate complex with imidazole (HIm) was isolated from the [Ni2+–HIm–CrO42−] system in various experimental conditions, i.e. reagent molar ratios and nickel(II) salts. The catena(μ-CrO4-O,O′)[Ni(HIm)3H2O] (1) crystallizes in monoclinic crystal system—space group P21/n with cell parameters: a=11.784(2), b=8.899(2), c=13.934(3) (Å), β=95.19(3) (°). The unit cell contains two independent helixes, left- and right-handed, stabilized by intrahelical and interhelical hydrogen bonds (HB) and π–π interactions. The cis coordination of the CrO42− anions and the HB systems appeared to be the main determinants of the helical architecture. To the best of our knowledge the cis-chromate coordination was observed for the first time. The cis coordination causes the distortion of the nickel octahedron, which was analysed by 4 K single crystal electronic spectra with D4h symmetry approximation (gaussian resolution and crystal field parameters). This symmetry was also confirmed with the polarised electronic spectra. The magnetic properties of the complex suggest the occurrence of weak intrachain antiferromagnetic interactions between the magnetic NiII center. The computational DFT studies of complex 1 assuming three possible isomers mer[(HIm)3]–cis[(CrO42−)2], mertrans and faccis suggested that the main contribution to the stability of 1 might have interhelical and intrahelical hydrogen bonds.  相似文献   

12.
Palladium(II) halide complexes with N-ethylimidazole (N-EtIm) and N- propylimidazole (N-PropIm) with general formulae Pd(L)2X2 and Pd(L)4X2 (X = Cl, Br, I) were prepared and characterized by spectroscopic methods and conductivity measurements. These complexes are diamagnetic and have square planar stereochemistry. The Pd(L2)X2 derivatives, are non-conductors, and have trans-structures except for the cis-Pd(N-EtIm)2Br2. The biological activity of water soluble Pd(II) compounds is also reported.  相似文献   

13.
The molecular structure of the title complex [ZnBr2(C7H6N2)2] was investigated by X-ray diffraction and IR spectroscopy methods. Molecules of zinc(II) complex crystallize in the triclinic crystal system with cell constants a=7.526(2) Å, b=7.8971(8) Å, c=13.431(1) Å, Z=2 and V=791.3(2) Å3. In the molecular structure, the Zn atom is coordinated tetrahedrally by two Br anions and two benzimidazole ligands. Intramolecular steric repulsions between Br anions and benzimidazole groups have been caused to cis configuration around the central metal atom.  相似文献   

14.
The ring-opening metathesis polymerization (ROMP) of norbornene catalyzed by bis(acetonitrile) molybdenum and tungsten complexes, [M(η3-C3H5)Cl(CO)2(NCMe)2] (1-Mo: M = Mo, 1-W: M = W), which have two labile acetonitrile ligands, has been investigated. These complexes catalyzed the ROMP of norbornene as a single-component initiator. The highly cis-selective polymerization proceeded in a THF solution (95% for 1-Mo and 96% for 1-W), whereas polymerization in CH2Cl2 or toluene resulted in lower cis selectivity. The polymerization of terminal acetylenes using these complexes was also examined. The tungsten complex 1-W showed a high catalytic activity for the polymerization of terminal acetylenes, such as phenyl- and tert-butylacetylene. A highly active catalytic system for the ROMP of norbornene was achieved by the activation of the tungsten complex, 1-W, with one equivalent of phenylacetylene, giving poly(norbornene) with a high molecular weight (Mn = 391 × 104) and a high cis selectivity (cis  89%).  相似文献   

15.
Pentacarbonyl(diethylaminocarbyne)chromium tetrafluoroborate, [(CO)5− CrCNEt2]BF4 (I), reacts with PPh3 with substitution of CO and formation of trans-tetracarbonyl(diethylaminocarbyne)triphenylphosphanechromium tetra-fluoroborate, trans-[PPh3(CO)4CrCNEt2]BF4 (III). Substitution of CO by PPh3 in neutral trans-tetracarbonyl(halo)(diethylaminocarbyne)chromium complexes, trans-X(CO)4CrCNEt2 (IVa: X = Br, IVb: X = I), leads in a reversible reaction to the corresponding tricarbonyl complexes, mer-X(PPh3)(CO)3− CrNEt2 (V), PPh3 occupying the cis-position to the carbyne ligand. With PPh3 in large excess both reactions follow a first-order rate law. This as well as the activation parameters (ΔH≠ = 104–113 kJ mol−1, ΔS≠ = 64–71 J mol−1 K−1) indicate a dissociative mechanism.  相似文献   

16.
The Rh(COD) and Ir(COD) homobimetallic complexes of s-indacene-diide, 2,6-dimethyl-s-indacene-diide, as-indacene-diide, and 2,7-dimethyl-as-indacene-diide have been synthesized from the di-lithium salts of the dianions and metal dimers [M(μ-Cl)L2]2 (M = Rh, Ir; L2 = COD, NBD, (ethylene)2, (CO)2 as mixtures of syn and anti isomers. The syn/anti ratio depends on the nature of the ancillary ligands at the metal and on the s or as geometry of the bridging ligand. In the reaction of the 2,7-dimethyl-as-indacene-diide-[M(COD)]2 species with CO, the higher reactivity of the syn isomers has been justified on the basis of a greater instability of the ground state due to steric interactions between the COD groups. Bis-η1 metal-bonded intermediates have been identified in the carbonylation of iridium derivatives; on the other hand, the formation of the bis-η5 mixed complexes syn and anti-{2,7-dimethyl-as-indacene-diide-[Rh(COD)][Rh(CO)2]} and their reactivity strongly support the existence of metal---metal interaction in the rhodium derivatives.  相似文献   

17.
The reaction of 2-arylpyridinecarboxaldimine [RH4C6NC(H)Py, L (1)] with hydrated RuX3 (X = Cl, Br) in boiling C2H5OH affords dark crystals of RuX2L2. Two geometrical isomers of the compound have been isolated and characterized by analytical and spectroscopic data. The trans isomer of RuCl2L2 shows a single sharp band for ν(Ru---Cl), whereas two bands are observed for the corresponding cis isomer. The highresolution 1H NMR spectra of the isolated complexes are reported and completely assigned. All the complexes have multiple t2→π*(L) transitions in the visible region. Each of the complexes display a quasi-reversible oxidative response due to an RuIII/RuII couple in the range 0.25–0.40 V vs S.C.E. at a platinum working electrode. The formal potentials of this couple obey the Hammett relationship. The ligand-based irreversible oxidations are also briefly noted.  相似文献   

18.
A series of 3-fluorinated 4-alkoxystilbazoles (n-3F-OPhVPy) and some of the related 2-fluorinated derivatives (n-2F-OPhVPy) have been synthesized; unlike their non-fluorinated counterparts, these new stilbazoles are non-mesomorphic. A single crystal structure determination of 3-fluoro-4-undecyloxy-4'-stilbazole shows the molecule to be planar, trans with respect to the double bond and to crystallize in only one of two possible extreme rotational conformers. Reaction of these fluorinated stilbazoles with [IrCl(COD)]2 under CO affords the complexes cis-[IrCl(CO)2(n-XF-OPhVPY)] which are non-mesomorphic for X = 3, but have monotropic phases for X = 2.  相似文献   

19.
The complexes (Hal)Nb(CO)3(PR3)3 (PR3 = PEt3, Hal = I; PR3 = PMe2Ph, Hal = Cl, Br, I) and (Hal)Nb(CO)4/2(dppe)1/2 (Hal = Br, I) have been prepared by oxidative halogenation of carbonylniobate with pyridinium halides (Hal = Cl, Br) or iodine (Hal = I). In the tricarbonyls, one CO and one PR3 are labile and can be displaced by a four-electron donating alkyne to give all-trans-[(Hal)Nb(CO)2(RCCR′)(PR3)2] (PR3 = PMe2Ph; Hal = Cl, Br, I: R, R′ = H, Et, Ph; R = H, R′ = Ph. PR3 = PEt3, Hal = I: R, R′ = Pr; R = H, R′ = Bu, Ph; R = Me, R′ = Et). In the case of acetylene, INb(CO)(HCCH)2(PEt3)2 is also formed. PR3 can be displaced by P(OMe) 3. In the tetracarbonyls, two CO ligands are replaced by two isonitriles to form INb(CO)2(CNR)2dppe (R = tBu, Cy), or by one alkyne to form (Hal)Nb(CO)2(PhCCPh)dppe (Hal = Br, I). In these complexes, the remaining CO ligands occupy cis positions. The structure of BrNb(CO)2(dppe)2·THF, INb(CO)2(dppe)2·hexane and INb(CO)2(PEt3)2(MeCCEt) have been determined by a single crystal X-ray diffraction study. The alkyne complexes are best regarded as octahedral with the centre of the alkyne ligand occupying the positions trans to the halide and the CC axis aligned with the OC---Nb---CO axis. The complexes (Hal)Nb(CO)2(dppe)2 adopt a trigonal prismatic structure with the halide capping the tetragonal face spanned by the four phosphorus functions. The crystal structure of a by-product, Br2Nb(CO)(H2CPhPCH2CH2PPh2)2·1/2THF has also been determined. The geometry is pentagonal bipyramidal, with one of the bromine atoms and the CO on the axis. Some 93 Nb NMR data for the NbI complexes are presented, and preliminary observations on the reactions between the π-alkyne complexes and H2 or H are reported.  相似文献   

20.
Pt(II) and Pd(II) dichloride complexes with 5,7-ditertbutyl-1,2,4-triazolo[1,5-a]pyrimidine (dbtp) have been synthesized and characterized by infrared and 1H, 13C NMR, 13C CPMAS spectroscopy. The structures of the cis-PtCl2(dbtp)2 · EtOH (1) and cis-PdCl2(dbtp)(dmso) (2) has been determined by signal-crystal X-ray diffraction. In both complexes the X-ray crystal structures shows that heterocycle ligand (dbtp) binds the central atom monodentate via nitrogen atom N(3). In addition, compound (2) is interesting for its structural features, because it is the first report of mixed dichloride Pd(II) complexes with N-donor (triazolopyrimidine) and S-donor (dimethylsulfoxide) ligands. In this structure the Pd–Cl distances are: 2.302(1) and 2.281(1) Å, Pd–N 2.041(3) Å and Pd–S 2.245(1) Å. The 1H, 13C NMR studies show clearly that these structures are retained in solution.  相似文献   

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