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Methane Ligands (methane + ligand)
Selected AbstractsTris(pyrazolyl)methane Ligands: Syntheses and Structures of Monometallic and Metallodendritic ComplexesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 16 2004Alberto Sánchez-Méndez Abstract The substituted ligands Me3SiC(pz)3 (1) and Me3SiOCH2C(pz)3 (2) have been prepared starting from HC(pz)3 and HOCH2C(pz)3. The molecular structure of compound 1 has been determined by X-ray diffraction studies, which show a propeller-like conformation of the pyrazolyl rings. Compound 2 has been found to be useful for the synthesis of [Mo(CO)3{Me3SiOCH2C(pz)3}] (3), [TiCl2(NtBu){Me3SiOCH2C(pz)3}] (4), and [PdCl2{Me3SiOCH2C(pz)3}] (5), through ligand exchange reactions. The characterization of the new complexes is compatible with a tridentate coordination of the ligands in complexes 3 and 4, and a bidentate coordination in 5 as confirmed by an X-ray analysis carried out with the palladium complex. The procedure has been extended for the synthesis of the carbosilane G1,[OCH2C(pz)3]4 (6) and the tetrametallic compound G1,[OCH2C(pz)3Mo(CO)3]4 (7) (G1 = Si(CH2CH2CH2Me2Si)4,). (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source] Novel Synthetic Strategy towards the Efficient Synthesis of Substituted Bis(pyrazolyl)(2-pyridyl)methane Ligands,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2010Alexander Hoffmann Abstract A general one-pot synthesis of new substituted heteroscorpionate ligands is presented. These mixed-functionality ligands were obtained in a catalyzed Peterson rearrangement starting from the substituted pyrazole, thionyl chloride, and an aldehyde. Thus, the synthesis of polyfunctional tridentate ligands is enabled, and they contain, besides the two pyrazole groups, other functionalities relevant for coordination chemistry. Additionally, the steric hindrance is easily defined in the ligands by the substitution of the pyrazole rings. By combination of the versatility in donor function and steric demand, a systematic tuning of the properties of the bis(pyrazolyl)methane ligands is possible. The synthesis and full characterization of 11 bis(pyrazolyl)methane ligands are reported. Two of these were structurally characterized as well. [source] Copper Complexes with Neutral N4 Tripodal Ligands: Influence of the Number of Nitrogen Donors on Their Structures, Properties, and Reactivity,EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 26 2009Kiyoshi Fujisawa Abstract Copper coordination complexes of the neutral tetradentate nitrogen-containing ligands tris(3,5-dimethylpyrazol-1-ylmethyl)amine (L0N4) and tris(3,5-diisopropylpyrazol-1-ylmethyl)amine (L1N4), namely the copper(II) chlorido complexes [CuII(L0N4)Cl2] (1) and [CuII(L1N4)Cl2] (2), the copper(II) nitrato complexes [CuII(L0N4)(NO3)](NO3) (3) and [CuII(L1N4)(NO3)](NO3) (4), and the copper(II) sulfato complexes [CuII(L0N4)(SO4)] (5) and [CuII(L1N4)(SO4)] (6), and the copper(I) complexes [CuI(L0N4)](PF6) (7) and [CuI(L0N4)(PPh3)](ClO4) (8), have been systematically synthesized in order to investigate the influence of the number of nitrogen donors on their structures, properties, and reactivity. All copper(II) complexes were fully characterized by X-ray crystallography and by IR/far-IR, UV/Vis absorption, and ESR spectroscopy. Although the structure of 7 was not determined by X-ray crystallography, this complex and the structurally characterized copper(I) triphenylphosphane complex 8 were fully characterized by IR/far-IR and NMR spectroscopy. A comparison of the copper(II) complexes with two tris(pyrazol-1-ylmethyl)amine ligands with different bulkiness of the pyrazolyl rings has allowed us to evaluate the second coordination sphere effects of the ligands. Moreover, the structures and physicochemical properties of these complexes are compared with those of related complexes containing the neutral tridentate tris(pyrazolyl)methane ligand and the neutral bidentate bis(pyrazolyl)methane ligand. Finally, the relative stability of the copper(I) complexes is discussed. The influence of the number of nitrogen donors in copper complexes is observed from these systematic results.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] A New Synthesis of Charge-Neutral Tris-Pyrazolyl and -Methimazolyl Borate LigandsCHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2010Philip Abstract The dimethylamine in the adducts [(HNMe2)B(azolyl)3] (azolyl=methimazolyl, pyrazolyl), obtained by reaction of the azole with B(NMe2)3, can readily be substituted with a range of nitrogen donors to provide new charge-neutral, tripodal ligands in high yield. This observation has led to a revision of an earlier interpretation of the mechanism of the formation of these species. The donor properties of the ligands [(nmi)B(azolyl)3] (nmi=N -methylimidazole) have been compared with their anionic analogues [HB(azolyl)3], by synthesis of their manganese(I),tricarbonyl complexes and comparison of their infrared ,CO energies. This comparison indicates that the new neutral ligands are only marginally weaker donors than the corresponding anionic hydrotris(azolyl)borate ligands. This may be explained by the ability of the attached nmi ring to stabilize a positive charge remotely from the coordinated metal, which may also account for the fact that the [(nmi)B(pyrazolyl)3] ligand is a substantially stronger donor than the similarly neutral tris(pyrazolyl)methane ligand. [source] Novel Synthetic Strategy towards the Efficient Synthesis of Substituted Bis(pyrazolyl)(2-pyridyl)methane Ligands,EUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 21 2010Alexander Hoffmann Abstract A general one-pot synthesis of new substituted heteroscorpionate ligands is presented. These mixed-functionality ligands were obtained in a catalyzed Peterson rearrangement starting from the substituted pyrazole, thionyl chloride, and an aldehyde. Thus, the synthesis of polyfunctional tridentate ligands is enabled, and they contain, besides the two pyrazole groups, other functionalities relevant for coordination chemistry. Additionally, the steric hindrance is easily defined in the ligands by the substitution of the pyrazole rings. By combination of the versatility in donor function and steric demand, a systematic tuning of the properties of the bis(pyrazolyl)methane ligands is possible. The synthesis and full characterization of 11 bis(pyrazolyl)methane ligands are reported. Two of these were structurally characterized as well. [source] catena -Poly[[dinitratocadmium(II)]bis[,-bis(2-methyl-1H -imidazol-1-yl)methane-,2N3:N3,]]ACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2007Chuan-Ming Jin The title compound, [Cd(NO3)2(C9H12N4)2]n, has a one-dimensional double-bridged chain polymer structure with a 16-membered macrometallacyclic tetragonal structural motif. The CdII ion occupies a crystallographic inversion centre and is coordinated by four equatorial N atoms from four distinct bis(2-methylimidazol-1-yl)methane ligands and two apical nitrate O atoms to form a slightly distorted octahedral coordination geometry. [source] | ||||||||||