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Whiteoak CJ, Nobbs JD, Kiryushchenkov E, Pagano S, White AJP, Britovsek GJP. Tri(pyridylmethyl)phosphine: the elusive congener of TPA shows surprisingly different coordination behavior. Inorg Chem 2013; 52:7000-9. [PMID: 23701515 DOI: 10.1021/ic4005196] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Tri(pyridylmethyl)phosphine (TPPh), the remarkably elusive congener of tri(pyridylmethyl)amine (TPA), has been prepared, as well as the relative tri(N-methyl-pyridylamino)phosphine (TPAMP). The coordination properties of these new ligands have been evaluated for chromium(III), iron(II), and ruthenium(II) complexes and compared with the related TPA complexes. In all cases, a different coordination behavior has been observed whereby TPPh and TPAMP always act as tridentate ligands. A chromium(III) complex [Cr(TPPh)Cl3] has been prepared, which has shown low ethylene oligomerization activity. Octahedral low spin iron(II) complexes [Fe(TPPh)2](2+) and [Fe(TPAMP)2](2+) were obtained with two ligands bound to the metal center. Ruthenium(II) chloro complexes of TPA and TPPh undergo ligand exchange reactions in acetonitrile, and the ruthenium(II) complex [Ru(MeCN)2(TPA)](2+) can be oxidized by m-CPBA in acetonitrile to give a transient ruthenium(IV) oxo complex [Ru(O)(MeCN)(TPA)](2+). Attempts to generate high valent ruthenium(IV) oxo TPPh or TPAMP complexes could not be achieved, probably due to insufficient stabilization by these strong field ligands.
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Affiliation(s)
- Christopher J Whiteoak
- Department of Chemistry, Imperial College London, Exhibition Road, London SW7 2AY, United Kingdom
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Synchronizing Steric and Electronic Effects in {RuII(NNNN,P)} Complexes: The Catalytic Dehydrative Alkylation of Anilines by Using Alcohols as a Case Study. Chemistry 2013; 19:2741-8. [DOI: 10.1002/chem.201203285] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Indexed: 11/07/2022]
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Company A, Lloret J, Gómez L, Costas M. Alkane C–H Oxygenation Catalyzed by Transition Metal Complexes. CATALYSIS BY METAL COMPLEXES 2012. [DOI: 10.1007/978-90-481-3698-8_5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kojima T, Hayashi KI, Iizuka SY, Tani F, Naruta Y, Kawano M, Ohashi Y, Hirai Y, Ohkubo K, Matsuda Y, Fukuzumi S. Synthesis and Characterization of Mononuclear Ruthenium(III) Pyridylamine Complexes and Mechanistic Insights into Their Catalytic Alkane Functionalization withm-Chloroperbenzoic Acid. Chemistry 2007; 13:8212-22. [PMID: 17625799 DOI: 10.1002/chem.200700190] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A series of mononuclear RuIII complexes [RuCl2(L)]+, where L is tris(2-pyridylmethyl)amine (TPA) or one of four TPA derivatives as tetradentate ligand, were prepared and characterized by spectroscopic methods, X-ray crystallography, and electrochemical measurements. The geometry of a RuIII complex having a non-threefold-symmetric TPA ligand bearing one dimethylnicotinamide moiety was determined to show that the nicotine moiety resides trans to a pyridine group, but not to the chlorido ligand. The substituents of the TPA ligands were shown to regulate the redox potential of the ruthenium center, as indicated by a linear Hammett plot in the range of 200 mV for RuIII/RuIV couples with a relatively large rho value (+0.150). These complexes act as effective catalysts for alkane functionalization in acetonitrile with m-chloroperbenzoic acid (mCPBA) as terminal oxidant at room temperature. They exhibited fairly good reactivity for oxidation of cyclohexane (C--H bond energy 94 kcal mol(-1)), and the reactivity can be altered significantly by the electronic effects of substituents on TPA ligands in terms of initial rates and turnover numbers. Catalytic oxygenation of cyclohexane by a RuIII complex with 16O-mCPBA in the presence of H2 18O gave 18O-labeled cyclohexanol with 100% inclusion of the 18O atom from the water molecule. Resonance Raman spectra under catalytic conditions without the substrate indicate formation of a RuIV==O intermediate with lower bonding energy. Kinetic isotope effects (KIEs) in the oxidation of cyclohexane suggest that hydrogen abstraction is the rate-determining step and the KIE values depend on the substituents of the TPA ligands. Thus, the reaction mechanism of catalytic cyclohexane oxygenation depends on the electronic effects of the ligands.
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Affiliation(s)
- Takahiko Kojima
- Department of Chemistry, Faculty of Sciences, Kyushu University, Hakozaki, Higashi-Ku, Fukuoka 812-8581, Japan.
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Okumura T, Morishima Y, Shiozaki H, Yagyu T, Funahashi Y, Ozawa T, Jitsukawa K, Masuda H. Characteristics of Mononuclear Ruthenium–Oxo Complexes Adjusted by Axial Ligand for the Catalysis of Oxygen-Transfer Reactions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2007. [DOI: 10.1246/bcsj.80.507] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Lonnon DG, Craig DC, Colbran SB. Rhodium, palladium and platinum complexes of tris(pyridylalkyl)amine and tris(benzimidazolylmethyl)amine N4-tripodal ligands. Dalton Trans 2006:3785-97. [PMID: 16883405 DOI: 10.1039/b602556k] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To investigate the influence of a potentially N4-tripodal amine ligand on the structure and internal exchange processes of its complexes with late transition metals, five rhodium, six palladium and two platinum complexes have been prepared from seven alkyl-bridged N-heterocyclic amine tripodal ligands: tris(2-pyridylmethyl)amine, (2-(2-pyridylethyl))bis(2-pyridylmethyl)amine, bis(2-(2-pyridylethyl))-2-pyridylmethylamine, bis(2-(2-pyridylethyl))amine, ((6-(hydroxymethyl)-2-pyridyl)methyl)bis(2-pyridylmethyl)amine, tris(2-benzimidazolylmethyl)amine (tbima) and tris(3-ethyl-2-benzimidazolylmethyl)amine. Single-crystal X-ray diffraction studies were completed for ten complexes: the d6-rhodium(III) complexes are octahedral with kappa 4 N-bound ligands, whereas the d8-palladium(II) and d8-platinum(II) complexes are square planar, kappa 3 N-bound by the tripodal ligand with a dangling N-donor leg, except for the unusual [Pd2(tbima)2Cl2]Cl2 dimer in which each palladium(II) ion is square planar and bound by two benzimidazole legs from one tbima ligand, one leg from the other tbima ligand and a chloride ancillary ligand. Cation bilayers are a common structural motif in the crystal structures. Variable-temperature 1H NMR studies reveal exchange occurs between the coordinated and dangling N-donor legs in the palladium and platinum complexes. Exchange free energy (Delta G++ c) values have been calculated and some general rules governing the favoured complex structures and exchange pathways elucidated. The palladium(II) and platinum(II) complexes of a ligand with an pyridylethyl leg are unstable with respect to elimination of vinylpyridine.
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Affiliation(s)
- David G Lonnon
- School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia
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Tajika Y, Tsuge K, Sasaki Y. Mononuclear oxovanadium complexes of tris(2-pyridylmethyl)amine. Dalton Trans 2005:1438-47. [PMID: 15824782 DOI: 10.1039/b414532a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mononuclear oxovanadium(IV) and dioxovanadium(V) complexes of tris(2-pyridylmethyl)amine (tpa) have been prepared for the first time. Crystal structure determinations of three oxovanadium(IV) complexes, [VO(SO4)(tpa)], [VOCl(tpa)]PF6, or [VOBr(tpa)]PF6, and a dioxovanadium(v) complex [V(O)2(tpa)]PF6 disclosed that the tertiary nitrogen of the tpa ligand always occupies the trans-to-oxo site. The structures of an oxo-peroxo complex [VO(O2)(tpa)]Cl that was prepared previously and of a mu-oxo vanadium(III) complex [{VCl(tpa)}2(mu-O)](PF6)2 have also been determined. The tertiary nitrogen is located at a trans site to the peroxo and chloride ligands, respectively. The total sums of the four V-N bond lengths from the tpa ligand are remarkably similar among the six complexes, indicating that the vanadium oxidation states become less influential in tpa bonding due primarily to the coordination of electron-donating oxo ligand(s). Absorption spectra of [VOCl(tpa)]+ in acetonitrile showed a significant change upon addition of p-toluenesulfonic acid and HClO4, but not on addition of benzoic acid. Protonation at the oxo ligand by the former two acids is suggested. Cyclic voltammetric studies in acetonitrile verified the proton-coupled redox behavior of the V(III)/V(IV) process involving the oxo ligand for the first time. From the dependence of the added p-toluenesulfonic acid to the CV, redox potentials for the following species have been estimated: [V(IV)OCl(tpa)]+/[V(III)OCl(tpa)](E1/2=-1.59 V vs. Fc+/Fc), [V(IV)(OH)Cl(tpa)]2+/[V(III)(OH)Cl(tpa)]+(Epc=-1.34 V), [V(IV)(OH2)Cl(tpa)]3+/[V(III)(OH2)Cl(tpa)]2+(Epa=-0.49 V), and [V(IV)Cl2(tpa)]2+/[V(III)Cl2(tpa)]+(E1/2=-0.89 V). The reduction of [V(V)(O)2(tpa)]+ in 0.05 M [(n-Bu)4N]PF6 acetonitrile showed a major irreversible reduction wave V(V)/(IV) at -1.48 V. The metal reduction potentials of the oxovanadium(IV) and dioxovanadium(V) species are very close, reinforcing the significant influence of the oxo ligand(s).
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Affiliation(s)
- Yasunobu Tajika
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo, 060-0810, Japan
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Wu B, Janiak C. The Structure ofcis-[Chloro(dimethylsulfoxide)bis(1, 10-phenanthroline)ruthenium(II)]-tetraphenylborate, [RuCl(DMSO)(1, 10-phen)2][BPh4]. Z Anorg Allg Chem 2005. [DOI: 10.1002/zaac.200400387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Jitsukawa K, Oka Y, Yamaguchi S, Masuda H. Preparation, Structure Characterization, and Oxidation Activity of Ruthenium Complexes with Tripodal Ligands Bearing Noncovalent Interaction Sites. Inorg Chem 2004; 43:8119-29. [PMID: 15578852 DOI: 10.1021/ic0494399] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Ruthenium(II/III) complexes with tripodal tris(pyridylmethyl)amine ligands bearing one, two, or three pivalamide groups (MPPA, BPPA, TPPA: amide-series ligands) or neopentylamine ones (MNPA, BNPA, TNPA: amine-series ligands) at the 6-position of the pyridine ring have been synthesized and structurally characterized. The X-ray structure analyses of the single crystals of these complexes reveal that they complete an octahedral geometry with the tripodal ligand and some monodentate ligands. The amide-series ligands prefer to form a Ru(II) complex, while the amine-series ones give a Ru(III) complex. In the presence of PhIO oxidant, the catalytic activities for epoxidation of olefins, hydroxylation of alkane, and dehydrogenation of alcohol have been investigated using the six ruthenium complexes [Ru(II)(tppa)Cl(2)] (1), [Ru(III)(tnpa)Cl(2)]PF(6) (2), [Ru(II)(bppa)Cl]PF(6) (3), [Ru(III)(bnpa)Cl(2)]PF(6) (4), [Ru(II)(mppa)Cl]PF(6) (5), and [Ru(III)(mnpa)Cl(2)]PF(6) (6). Among them, the amide-series complexes, 1, 3, and 5, showed a higher epoxidation activity in comparison with the amine-series ones, 2, 4, and 6. On the other hand, the latter showed a higher reactivity for hydroxylation, allylic oxidation, and C=C bond cleavage reactions compared with the former. Such a complementary reactivity is interpreted by the character of the ruthenium-oxo species involving electronically equivalent formulas, Ru(V)=O and Ru(IV)-O.
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Affiliation(s)
- Koichiro Jitsukawa
- Department of Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Showa-ku, Nagoya 466-8555, Japan.
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Oxidation of alkanes with m-chloroperbenzoic acid catalyzed by iron(III) chloride and a polydentate amine. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcata.2004.05.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Alessio E. Synthesis and Reactivity of Ru-, Os-, Rh-, and Ir-Halide−Sulfoxide Complexes. Chem Rev 2004; 104:4203-42. [PMID: 15352790 DOI: 10.1021/cr0307291] [Citation(s) in RCA: 186] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Enzo Alessio
- Dipartimento di Scienze Chimiche, Università di Trieste, 34127, Italy.
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Gonzalez Cuervo L, Kozlov YN, Süss-Fink G, Shul’pin GB. Oxidation of saturated hydrocarbons with peroxyacetic acid catalyzed by vanadium complexes. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.molcata.2004.04.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Structural, spectroscopic and redox studies of a new ruthenium(III) complex with an imidazole-rich tripodal ligand. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2003.09.037] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Gott AL, McGowan PC, Podesta TJ, Tate CW. Formation and structural studies of iron(III) and ruthenium(II) complexes of 1,4,7-triazacyclononane and N-monofunctionalised 1,4,7-triazacyclononane. Inorganica Chim Acta 2004. [DOI: 10.1016/j.ica.2003.07.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Akermark B, Bjernemose J, Börje A, Chmielewski PJ, Paulsen H, Simonsen O, Stein PC, Toftlund H, Wolny JA. Strain-induced substitutional lability in a Ru(ii) complex of a hypodentate polypyridine ligand. Dalton Trans 2004:1215-20. [PMID: 15252663 DOI: 10.1039/b316093a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The ruthenium(II) complex of heptadentate N,N,N',N'-tetrakis(2-pyridylmethyl)-2,6-bis(aminomethyl)pyridine (tpap) was isolated as the hexafluorophosphate complex Ru(tpap)(PF6)2. The crystal structure has been determined for the triflate salt Ru(tpap)(CF3SO3)2.2H2O, which crystallizes in the monoclinic space group P2(1)/n. The structure was refined to a final R value of 0.0549 for 5894 observed reflections. The heptadentate ligand coordinates with six nitrogens, i.e. with two tertiary nitrogens and four pyridine nitrogens, one of the pyridines remaining un-coordinated. The resulting structure is significantly distorted from octahedral geometry with an equatorial Nsp3-Ru-Npyridine angle of 120 degrees. The consequence of the above steric strain is a labilization of the system and fluxional behaviour involving exchange between equatorially coordinated and non-coordinated pyridines has been observed by 1H NMR for Ru(tpap)(PF6)2 in d6-acetone solution. The activation parameters of DeltaG(not equal to 298) = 53 kJ mol(-1), DeltaH(not equal) = 56 +/- 1 kJ mol(-1) and DeltaS(not equal) = -10 +/- 3 J mol(-1) K(-1) were determined on the basis of NMR experiments. In addition electronic structure calculations applying density functional theory (DFT) have been performed in order to identify a transition state and to estimate the activation barrier. On the basis of NMR and DFT results the mechanism of isoexchange involving a hepta-coordinated intermediate has been proposed.
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Affiliation(s)
- Björn Akermark
- Stockholms Universitet, Organisk Kemi, Arrheniuslaboratoriet, 106 91 Stockholm, Sweden
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Bjernemose J, Hazell A, McKenzie CJ, Mahon MF, Nielsen LP, Raithby PR, Simonsen O, Toftlund H, Wolny JA. Synthesis and characterization of ruthenium(II) complexes with polypicolylamine ligands. Polyhedron 2003. [DOI: 10.1016/s0277-5387(03)00025-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Nam W, Ryu JY, Kim I, Kim C. Stereoselective alkane hydroxylations by metal salts and m-chloroperbenzoic acid. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01060-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Epoxidation activities of mononuclear ruthenium–oxo complexes with a square planar 6,6′-bis(benzoylamino)-2,2′-bipyridine and axial ligands. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)00041-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Reverse reactivity in hydroxylation of adamantane and epoxidation of cyclohexene catalyzed by the mononuclear ruthenium-oxo complexes with 6-substituted tripodal polypyridine ligands. Tetrahedron Lett 2001. [DOI: 10.1016/s0040-4039(01)00379-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Catalytic hydrocarbon oxygenation by ruthenium–pyridylamine complexes with alkyl hydroperoxides: a mechanistic insight. Inorganica Chim Acta 2000. [DOI: 10.1016/s0020-1693(99)00571-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Syntheses and characterization of a series of carbonylruthenium(I) and (II) complexes containing pyridyl ligands. J Organomet Chem 1999. [DOI: 10.1016/s0022-328x(99)00222-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Xu L, Sasaki Y. [Ru(CO)(CH3CO2)(tpa)]ClO4·C6H5CH3 (tpa=tris(2-pyridylmethyl)amine), the first ruthenium carbonyl complex of tpa. INORG CHEM COMMUN 1999. [DOI: 10.1016/s1387-7003(99)00026-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yamaguchi M, Iida T, Yamagishi T. Syntheses of mixed-ligand ruthenium(II) complexes with a terpyridine or a tris (pyrazolyl) methane and a bidentate ligand: their application for catalytic hydroxylation of alkanes. INORG CHEM COMMUN 1998. [DOI: 10.1016/s1387-7003(98)00080-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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