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1.
Ashish Kumar Singh 《Journal of organometallic chemistry》2010,695(4):567-331
Reactions of the chloro-bridged arene ruthenium complexes [{(η6-arene)RuCl(μ-Cl}2] (η6-arene = benzene, p-cymene) and structurally analogous rhodium complex [{(η5-C5Me5)RhCl(μ-Cl}2] with imidazole based ligands viz., 1-(4-nitro-phenyl)-imidazole (NOPI), 1-(4-formylphenyl)-imidazole (FPI) and 1-(4-hydroxyphenyl)-imidazole (HPI) have been investigated. The resulting complexes have been characterised by elemental analyses, IR, 1H and 13C NMR, electronic absorption and emission spectral studies. Crystal structure of the representative complex [(η5-C5Me5)RhCl2(NOPI)] has been determined crystallographically. Geometrical optimisation on the complexes have been performed using exchange correlation functional B3LYP. Optimised bond lengths and angles of the complexes have been found to be in good agreement with our earlier reports and single crystal X-ray data of the complex [(η5-C5Me5)RhCl2(NOPI)]. 相似文献
2.
Binitendra Naath Mongal & Subhendu Naskar 《Journal of Coordination Chemistry》2017,70(3):451-462
In the present work, we report two methoxy-substituted phenyl-terpyridine ruthenium complexes with pyridine carboxyquinoline and NCS as ancillary ligands, [Ru(OMePhtpy)(pcqH)(NCS)](PF6) (1) and [Ru(triOMePhtpy)(pcqH)(NCS)](PF6) (2) (where OMePhtpy = (4′-(4-methoxy)phenyl-2,2′:6′,2″-terpyridine, triOMePhtpy = (4′-(3,4,5-trimethoxy)phenyl-2,2′:6′,2″-terpyridine and pcqH = pyridine-carboxyquinoline). Both complexes have been characterized by spectroscopic techniques e.g., mass, 1H-NMR and FTIR. UV–vis spectrophotometric and electrochemical studies for both complexes have been performed. The substitution pattern of the –OMe groups have been successfully utilized to tune the redox potential of the metal complexes. On the anodic side of cyclic voltammogram, 1 and 2 show an irreversible wave corresponding to RuII/III couple at 0.95 and 0.85 V, respectively. The lower RuII/III oxidation potential for 2 may be attributed to increased electron density on ruthenium due to three (+R) methoxy–groups appended to the phenyl moiety of triOMePhtpy. DFT optimization of structure and energy calculation reveals that in both complexes, HOMO is metal- and thiocyanate-based, whereas the LUMO is based on pcqH. Correlation of TDDFT results with experimental electronic spectrum indicates that bands at 502 nm (1) and 528 nm (2) are of MLLCT character from ruthenium-thiocyanate to pcqH. 相似文献
3.
The reaction between acrylonitrile and the RuH bond in HRu(CO)Cl(PPh3)3 results in the formation of a binuclear ruthenium(II) complex having chlorine bridges which are easily broken by sodio-derivatives of bidentate chelating ligands giving mononuclear hexacoordinated ruthenium(II) compounds. The RuC bond in these new complexes has been found to be stable towards nucleophilic reagents. The stereochemistry for these complexes has been suggested on the basis of IR, 1H and 31P NMR spectra. 相似文献
4.
Kim MJ Konduri R Ye H MacDonnell FM Puntoriero F Serroni S Campagna S Holder T Kinsel G Rajeshwar K 《Inorganic chemistry》2002,41(9):2471-2476
Two new ruthenium(II) polypyridyl dimers containing the large planar aromatic bridging ligands 9,11,20,22-tetraazatetrapyrido[3,2-a:2'3'-c:3' ',2'-l:2',3'-n]pentacene (tatpp) and 9,11,20,22-tetraazatetrapyrido[3,2-a:2'3'-c:3',2' '-l:2',3'-n]pentacene-10,21-quinone (tatpq) have been synthesized and characterized by (1)H and (13)C NMR, MALDI mass spectrometry, and elemental analyses. The electronic properties (UV-vis, redox, photophysical) of these dimers are analyzed in the context of orbital calculations (PM3 level) on the bridging ligands. A localized orbital model is proposed in which low-lying acceptor orbitals on the center portion of the ligands effectively quench the Ru(II)-based MLCT emission via a mechanism that can be viewed as intramolecular electron transfer to specific subunits of the bridges. 相似文献
5.
The synthesis of a series of ruthenium 1,5-disubstituted 1,2,3-triazolato complexes, 1,5-disubstituted 1,2,3-triazoles, and a triazolium salt is reported. Treatment of the ruthenium azido complex [Ru]-N3 ( 1 , [Ru] = (η5-C5H5)(dppe)Ru, dppe = Ph2PCH2CH2PPh2) with an excess of ethyl propiolate results in the formation of a mixture of the Z- and E-forms of zwitterionic N(1)-bound N(3)-ethyl acryl-4-carboxylate triazolato complexes [Ru]N3(CH=CHCO2Et)C2H(CO2) ( Z - 2 ) and ( E - 2 ). The arylation of 2 with aromatic bromides gives a series of cationic N(1)-bound N(3)-ethyl acryl-4-alkoxycarbonyl triazolato complexes {[Ru]N3(CH=CHCO2Et)C2H(CO2CH2R)}[Br] ( 3a , R = Ph ; 3b , R = C6F5; 3c , R = 4-C6H4CN, 3d , R = 2,6-C6H3F2) and the subsequent cleavage of the Ru-N bond of 3a–d gives 1,5-disubstituted 1,2,3-triazoles N3(CH=CHCO2Et)C2H(CO2CH2R) ( 4a , R = Ph; 4b , R = C6F5; 4c , R = 4-C6H4CN; 4d , R = 2,6-C6H3F2) and [Ru]-Br. A 1,2,3-triazolium salt [N3(CH=CHCO2Et)(CH2C6F5)C2H2][Br] ( 5 ) was formed by transformation of 4b in BrCH2C6F5/chloroform mixture. The structures of Z-3a and Z-5 were confirmed by single-crystal x-ray diffraction analysis and both complexes participate in non-covalent aromatic interactions in the solid-state structures which can be favorable in the binding of DNA/biomolecular targets and have shown great potential in the application of biologically active anticancer drugs. 相似文献
6.
The thermodynamics of the binding of the antitumor ammine, amine, and immine complexes of ruthenium(II) and ruthenium(III) to DNA and peptides was studied computationally using model molecules. We performed density functional calculations on several monofunctional ruthenium complexes of the formula [Ru(NH3)5B]z+, where B is an adenine, guanine, or cytosine nucleobase or an 4-methylimidazole, a dimethylthioether, or a dimethylphosphate anion and z = 2 and 3. The pentammineruthenium fragment has been intensively studied and also constitutes a good model for a wide class of antitumor ammine, amine, and imine complexes of Ru(II) and Ru(III), while the considered bases/ligands have been chosen as models for the main binding sites of DNA, nucleobases, and phosphate backbone and proteins, histidyl, and sulfur-containing residue such as methionine or cysteine. Bond dissociation enthalpies and free energies have been calculated for all the considered metal binding sites both in the gas phase and in solution and allow building a binding affinity order for the considered nucleic acid or protein binding sites. The binding of guanine to some bifunctional complexes, [Ru(NH3)(4)Cl2], [cis-RuCl(2)(bpy)2], and [cis-RuCl(2)(azpy)2], has also been considered to evaluate the effect of a second labile chloro or aquo ligand and more realistic polypyridyl and arylazopyridine ligands. 相似文献
7.
Magnesium porphyrazine having eight 5-hydroxypentylthio groups at the peripheral positions, was synthesized from 2,3-bis(5-hydroxypentylthio) maleonitrile. By the esterification reaction of octakis(5-hydroxypentylthio) porphyrazinato] Mg(II) with 3,4,5-trimethoxybenzoic acid in dicyclohexylcarbodiimide and toluene-p-sulfonic acid, esterified MgPz appending [5-thiopentyl 2-methoxy-4,6-bis(trifluoromethyl) benzoate] substituent was obtained. Further reaction of the metal-free porphyrazine with Co(II), Cu(II), Zn(II), and Fe(II) acetates have produced the metallo-porphyrazines. By reacting FePzCl with pyridine or pyrazine, the monomeric bis-axial and the oligomeric complexes were synthesized as the novel stable complexes, respectively. Their characterizations were performed by using elemental analysis, FT-IR, 1H-NMR, 13C-NMR, mass and UV-Vis spectral data. The aggregation investigations carried out in different concentrations indicate that 3,4,5-trimethoxybenzyloxy-substituted porphyrazine compounds do not have any aggregation behavior in different concentrations. Quantum chemical computations were also done to the structural and electronic properties of target compounds. 相似文献
8.
M. Andreina Moreno Sirpa Jääskeläinen Jouni Pursiainen 《Journal of organometallic chemistry》2005,690(16):3803-3814
A series of ruthenium o-phosphane complexes was synthesized and characterized. The reactivity of the prepared complexes was studied by using them as catalysts for the hydroformylation of 1-hexene. The activities depended on the binding mode of the phosphane and on the strength of the ruthenium-phosphane interaction. Strongly coordinated chelating [2-(dimethylamino)phenyl]-(diphenyl) phosphane and [2-(methylthio)phenyl]-(diphenyl) phosphane showed poor activity, while weakly chelated [2-(methoxy)phenyl]-(diphenyl) phosphane and non-chelating phosphanes such as [2-(methyl)phenyl]-(diphenyl) phosphane or [2-(ethyl)phenyl]-(diphenyl) phosphane led to higher activities. 相似文献
9.
Density functional calculations have been carried out to understand the anti-addition stereochemistry and Markovnikov regiochemistry of the hydrosilylation of terminal alkynes and the endo-dig product of intramolecular hydrosilylation of homopropargyl alcohols catalyzed by cationic cyclopentadienyl-ruthenium complexes. It has been found that hydride or silyl insertion is concerted with the oxidative addition of the H-Si bond. Hydride insertion is much more favorable than silyl insertion. Such a hydride insertion nicely reproduces the observed regioselectivity, while silyl insertion would predict the opposite result. The hydride insertion leads to the formation of a eta(2)-vinylruthenium intermediate for the reaction of acetylene or a metallacyclopropene intermediate for the reaction of propyne. In the formation of both intermediates, there is a C(alpha)-C(beta) bond rotation so that the transferring hydride becomes anti to the silyl group. This is followed by a facile reductive alpha-silyl migration transition state, which results in the overall anti-addition stereochemistry. The proposed mechanism also rationalizes the observed regio- and stereochemistry of the intramolecular reaction. 相似文献
10.
11.
Synthesis of cationic allyl complexes from trinuclear carbonyl clusters of iron,ruthenium and osmium
V.V. Krivykh T. Asunta O.V Gusev M.I. Rybinskaya 《Journal of organometallic chemistry》1980,338(1):55-58
Thermal and photochemical reactions of trinuclear carbonyls of Fe, Ru, Os with allyl alcohol in acidic meclium as well as their reactions with (CH3)3NO · 2H2O with subsequent protonation have been studied. Cationic mononuclear allyltetra-carbonyl complexes of Fe, Ru, Os and a cationic Os cluster with π-allyl ligand, have been obtained. 相似文献
12.
We carry out a theoretical investigation of the recently reported M(smif)(2) series1,2 and find a number of interesting phenomena. These include complex potential energy surfaces with near-degenerate stationary points, low-lying states, non-trivial electron configurations, as well as non-innocent ligand behavior. The M(smif)(2) exhibit a delicate balance between geometry and electronic structure, which has implications not only for their reactivity but also for controlling their properties through ligand design. We address methodological issues and show how conceptual quantities such as oxidation states and electronic configurations can be extracted through a simple analysis of the electron and spin densities-without a complicated examination of the underlying orbitals. 相似文献
13.
Darren Griffith Alberta Bergamo Sara Pin Marta Vadori Helge Müller-Bunz Gianni Sava Celine J. Marmion 《Polyhedron》2007
Herein, we describe the synthesis and characterisation of a novel class of PtII and PtIV pyridinehydroxamic acid (pyhaH) complexes of general formula cis-[PtIICl2(x-pyhaH)2] and cis-[PtIVCl4(x-pyhaH)2], respectively (where x = 3 or 4) in which the pyridinehydroxamic acid is coordinated to the platinum ion via the pyridine nitrogen only leaving the hydroxamic acid free to potentially release cytotoxic nitric oxide (NO). The crystal structure of the PtIV derivative, cis-[PtCl4(4-pyhaH)2] · 2CH3OH is reported. To establish the biological effect of the uncoordinated hydroxamic acid moiety in the PtII compounds synthesised, the corresponding pyridinecarboxylic acid (pycaH) complexes of general formula cis-[PtIICl2(x-pycaH)2] (where x = 3 or 4) and the PtII pyridine (py) complex, cis-[PtIICl2(py)2] were synthesised and served as reference standards. The NO-releasing properties of each of the PtII compounds, the pyhaH and the pycaH ligands were studied. The PtII pyridinehydroxamic acid derivatives were found to induce potent in vitro effects attributable to either NO-release from the hydroxamic acid moiety and/or stimulation of inducible nitric oxide synthase of endothelial cells. 相似文献
14.
Mohammad Solimannejad Masumeh Gharabaghi Ibon Alkorta Goar Sánchez-Sanz 《Structural chemistry》2012,23(3):847-856
Ab initio calculations at MP2 computational level using aug-cc-pVTZ basis set were used to analyze the interactions between
1:1 and 1:2 complexes of acetylene and nitrosyl hydride. The structures obtained have been analyzed with the atoms in molecules
and the density functional theory–symmetry adapted perturbation theory methodologies. Four minima were located on the potential
energy surface of the 1:1 complex. Twenty-four different structures have been obtained for the 1:2 complexes. Five types of
interactions are observed, CH···O, CH···N, NH···π hydrogen bonds and orthogonal interactions between the π clouds of triple
bond, or the lone pair of oxygen with the electron-deficient region of the nitrogen atom. Stabilization energies of the 1:1
and 1:2 clusters including basis set superposition error and ZPE are in the range 3–8 and 6–17 kJ mol−1 at MP2/aug-cc-pVTZ computational level, respectively. Blue shift of NH bond upon complex formation in the ranges between
18–30 and 20–96 cm−1 is predicted for 1:1 and 1:2 clusters, respectively. The total nonadditive energy in the 1:2 cluster, calculated as the sum
of the supermolecular nonadditive MP2 energy and the three-body dispersion energy, presents values between −1.48 and 1.20 kJ mol−1. 相似文献
15.
16.
Ab initio and density-functional theory electronic structure calculations have been performed for the 1:1 complexes of tetrahydrofuran with water, hydrogen fluoride, and ammonia. Upon hydrogen bonding with H2O and HF, the structure of tetrahydrofuran (THF) remains relatively unchanged with the exception of THF sites involved in hydrogen-bonding interaction. But the similar findings are not true, upon hydrogen bonded with NH3, where the C2 symmetry of THF changed. The hydrogen-bonding strength for the 1:1 complexes of THF with water, HF, and NH3 is found to be in the order HF>H2O>NH3, which is well characterized by the order in bond angles O2H15F14, O2H16O14, and O2H15N14 closer to linearity, respectively, and the redshifted of stretching frequencies of upsilon(FH), upsilon(OH), and upsilon(NH), respectively. This work is an attempt to provide important predictions and to aid in future experimental and theoretical studies towards the understanding of such hydrogen-bonded van der Waals systems. 相似文献
17.
Cembran A Bernardi F Garavelli M Gagliardi L Orlandi G 《Journal of the American Chemical Society》2004,126(10):3234-3243
In this paper, we identify the most efficient decay and isomerization route of the S(1), T(1), and S(0) states of azobenzene. By use of quantum chemical methods, we have searched for the transition states (TS) on the S(1) potential energy surface and for the S(0)/S(1) conical intersections (CIs) that are closer to the minimum energy path on the S(1). We found only one TS, at 60 degrees of CNNC torsion from the E isomer, which requires an activation energy of only 2 kcal/mol. The lowest energy CIs, lying also 2 kcal/mol above the S(1) minimum, were found on the torsion pathway for CNNC angles in the range 95-90 degrees. The lowest CI along the inversion path was found ca. 25 kcal/mol higher than the S(1) minimum and was characterized by a highly asymmetric molecular structure with one NNC angle of 174 degrees. These results indicate that the S(1) state decay involves mainly the torsion route and that the inversion mechanism may play a role only if the molecule is excited with an excess energy of at least 25 kcal/mol with respect to the S(1) minimum of the E isomer. We have calculated the spin-orbit couplings between S(0) and T(1) at several geometries along the CNNC torsion coordinate. These spin-orbit couplings were about 20-30 cm(-)(1) for all the geometries considered. Since the potential energy curves of S(0) and T(1) cross in the region of twisted CNNC angle, these couplings are large enough to ensure that the T(1) lifetime is very short ( approximately 10 ps) and that thermal isomerization can proceed via the nonadiabatic torsion route involving the S(0)-T(1)-S(0) crossing with preexponential factor and activation energy in agreement with the values obtained from kinetic measures. 相似文献
18.
In concert with the recent photoabsorption experiments of gas-phase Schiff-base retinal chromophores (Nielsen et al. Phys. Rev. Lett. 2006, 96, 018304), quantum chemical calculations using time-dependent density functional theory coupled with different functionals and under the Tamm-Dancoff approximation were made on the first two excited states (S1 and S2) of two retinal chromophores: 11-cis and all-trans protonated Schiff bases. The calculated vertical excitation energies (Tv) and oscillator strengths (f) are consistent with the experimental absorption bands. The experimentally observed phenomenon that the transition dipole moment (mu) of S2 is much smaller that of S1 was interpreted by 3D representation of transition densities. The different optical behaviors (linear and nonlinear optical responds) of the excited states were investigated by considering different strengths of external electric fields. 相似文献
19.
Avilov I Minoofar P Cornil J De Cola L 《Journal of the American Chemical Society》2007,129(26):8247-8258
A series of Ir(III)-based heteroleptic complexes with phenylpyridine (ppy) and 2-(5-phenyl-4H-[1,2,4]triazol-3-yl)-pyridine (ptpy) derivatives as coordinating ligands has been characterized by a number of experimental and theoretical techniques. Density functional theory (DFT) calculations were able to reproduce and rationalize the experimental redox and excited-states properties of the Ir complexes under study. The introduction of fluorine and trifluoromethyl substituents is found not only to modulate the emission energy but also often to change the ordering of the lowest excited triplet states and hence their localization. The lowest triplet states are best characterized as local excitations of one of the chromophoric ligands (ppy or ptpy). The admixture of metal-to-ligand charge-transfer (MLCT) and ligand-to-ligand charge-transfer (LLCT) character is small and strongly depends on the nature of the excited state; their role is, however, primordial in defining the radiative decay rate of the complexes. The extent of charge-transfer contributions depends on the energy gaps between the relevant molecular orbitals, which can be modified by the substitution pattern. 相似文献
20.
Velders AH van der Schilden K Hotze AC Reedijk J Kooijman H Spek AL 《Dalton transactions (Cambridge, England : 2003)》2004,(3):448-455
The didentate ligand 2-phenylazopyridine (azpy) can--in theory--give rise to five different isomeric complexes of the type [Ru(azpy)2Cl2], of which three have been known since 1980. The molecular structures of the cis-dichlorobis(2-phenylazopyridine) ruthenium(II) complexes alpha-[Ru(azpy)2Cl2] and beta-[Ru(azpy)2Cl2](in which the coordinating pyridine nitrogen atoms are in mutually trans and cis positions, respectively, whilst the azo nitrogen atoms are in mutually cis positions) were unambiguously determined in the early 1980s. The third isomer, gamma-[Ru(azpy)2Cl2], has for two decades, erroneously, been assumed to be the all-trans isomer. In a recent communication we have proven that for this gamma isomer the chloride ions are indeed in a trans geometry, but the pyridine nitrogen and azo nitrogen atoms of the two azpy ligands are in mutually cis geometries. In this paper the isolation of a fourth isomer is presented, the hitherto unknown delta-[Ru(azpy)2Cl2]. The isomeric structure of delta-[Ru(azpy)2Cl2] has been determined by 1H-NMR spectroscopy and single-crystal X-ray diffraction analysis, and is the all-trans isomer. The bis(azpy)-ruthenium(II) isomers are of interest because of the pronounced cytotoxicity they exhibit against tumour cell lines and could be very useful in the search for structure-activity relationships of antitumour-active ruthenium complexes, as among the isomers there is a significant difference in activity. It is of paramount importance to have a good understanding of the structural and spectroscopic properties of these complexes, which in this paper are compared and discussed, with a particular emphasis on 1D and 2D 1H NMR spectroscopies. 相似文献