Search results for "BIP"
showing 10 items of 1908 documents
Electronic Structure Study of Seven-Coordinate First-Row Transition Metal Complexes Derived from 1,10-Diaza-15-crown-5: A Successful Marriage of The…
2005
A detailed study of the electronic structure of seven-coordinate Mn(II), Co(II), and Ni(II) complexes with the lariat ether N,N'-bis(2-aminobenzyl)-1,10-diaza-15-crown-5 (L(1)) is presented. These complexes represent new examples of structurally characterized seven-coordinate (pentagonal bipyramidal) complexes for the Mn(II), Co(II), and Ni(II) ions. The X-ray crystal structures of the Mn(II) and Co(II) complexes show C(2) symmetries for the [M(L(1))](2+) cations, whereas the structures of the Ni(II) complexes show a more distorted coordination environment. The magnetic properties of the Mn(II) complex display a characteristic Curie law, whereas those of the Co(II) and Ni(II) ions show the …
A two-dimensional magnetic architecture with bridging polynitrile and 2,2′-bipyrimidine ligands
2004
cited By 7; International audience; A new polymeric, two-dimensional compound [Co2(bpym)(dcne) 4 (H2O)2] (1) (dcne = [(CN)2CC(O) OEt)]- = 2,2-dicyano-1-ethoxyethenolate anion and bpym = 2,2'-bipyrimidine) has been synthesized and characterized by X-ray crystallography. The structure is monoclinic space group P21/a and consists of two-dimensional networks of octahedrally coordinated Co(II) ions, bridged by bis-bidentate 2,2'-bipyrimidine and μ2-dcne anions. Magnetic measurements revealed a broad maximum in the xm vs T plot at 20 K which is characteristic of antiferromagnetic exchange between the high spin cobalt(II) centres. © EDP Sciences.
Synthesis and characterization of triphenyltin(IV) 5-[(E)-2-(aryl)-1-diazenyl]-2-hydroxybenzoates. Crystal and molecular structures of Ph3Sn{O2CC6H3-…
2005
Abstract Triphenyltin 5-[(E)-2-(4-methylphenyl)-1-diazenyl]-2-hydroxybenzoate, Ph3SnL2H, has been prepared and characterized, its structure determined by X-ray crystallography, and the structure compared with those of its homologues. Two polymorphs were isolated from the same crystallization attempt. The reactivity of tetrahedral Ph3SnL1H (L1H = 5-[(E)-2-(2-methylphenyl)-1-diazenyl]-2-hydroxybenzoate) towards 2,2′-bipyridine (bipy) has been investigated to ascertain the ability of bipy to coordinate to the Sn-complex and the resultant changes in the molecular architecture. The crystal structure of the product revealed that the bipy moiety does not coordinate to the Sn atom, but forms a cycl…
Synthesis of polymeric alkoxides from dialkyltin(IV) oxides and chloral, and their characterization by mössbauer and infrared spectroscopy
1979
Abstract The reaction of (Alk2SnO)n with OCH·CCl3 gives compounds of elemental formula Alk2SnOCH- (CCI3)O (Alk = Bun, Octn), probably by addition of the Sn-O bond to the carbonyl group. Mossbauer parameters suggest the occurrence of five-coordinated Sn, and polymeric structures with bridging three- coordinating oxygens are proposed. The assumption that C2SnO3 units with trigonal bipyramidal type structures are present is consistent with point-charge model rationalization of the quadrupole splitting. Infrared spectra are in keeping with the proposed structures, suggesting, inter alia, bent C Sn C skeletons, but the analysis of possible ν(Sn-O) modes does not provide conclusive evidence for t…
Intramolecular versus intermolecular exchange pathways in the binuclear complex [Cu2(H2tea)2(4,4′-bipy)](ClO4)2·3H2O (H3tea=triethanolamine and 4,4′-…
2001
Abstract The binuclear copper(II) complex of formula [Cu2(H2tea)2(4,4′-bipy)](ClO4)2·3H2O (1) (H3tea=triethanolamine and 4,4′-bipy=4,4′-bipyridine) has been isolated and characterized by X-ray diffraction. Its structure consists of dinuclear [Cu2(H2tea)2(4,4′-bipy)]2+ cations, uncoordinated perchlorate anions and crystallization water molecules. Each copper atom exhibits a trigonal-bipyramidal environment with the three triethanolamine-oxygen atoms building the equatorial plane, and the triethanolamine-nitrogen and one of the 4,4′-bipy nitrogen atoms defining the three-fold axis. The 4,4′-bipy molecule acts as a bismonodentate bridging ligand, the copper–copper separation across it being 11…
Long-distance magnetic coupling in dinuclear copper(II) complexes with oligo-para-phenylenediamine bridging ligands
2010
Abstract Two novel dinuclear copper(II) complexes of formulae [Cu2(tren)2(bpda)](ClO4)4 (2) and [Cu2(tren)2(tpda)](ClO4)4 (3) containing the tripodal tris(2-aminoethyl)amine (tren) terminal ligand and the 4,4′-biphenylenediamine (bpda) and 4,4″-p-terphenylenediamine (tpda) bridging ligands have been synthesized and structurally, spectroscopically, and magnetically characterized. Their experimentally available electronic spectroscopic and magnetic properties have been reasonably reproduced by DFT and TDDFT calculations. Single crystal X-ray diffraction analysis of 2 shows the presence of dicopper(II) cations where the bpda bridging ligand adopts a bismonodentate coordination mode toward two …
An intramolecular antiferromagnetically coupled pentanuclear homoleptic Mn(II) cluster: Synthesis, crystal structure, spectral and magnetic property
2013
Abstract A pyrazole based ditopic ligand 5(E)-5-methyl-N′-(pyridin-2-ylmethylene)-1H-pyrazole-3-carbohydrazide (PzOPyH), prepared by the reaction between 5-methylpyrazole-3-carbohydrazide and pyridine-2-carbaldehyde, reacts with Mn(ClO4)2·6H2O to form a self-assembled, antiferromagnetically coupled alkoxide bridged pentanuclear Mn(II) homoleptic cluster complex [Mn5(PzOPy)6](ClO4)4 (1). The complex has a central Mn5(μ-O6) core involving six ligand molecules. This pentanuclear core has a trigonal bipyramidal arrangement of Mn(II) atoms, where, the axial metal centers (Mn2 and Mn_2) have a N3O3 chromophore and the equatorial centers (Mn1, Mn_1 and Mn3) have N4O2 chromophore with distorted oct…
Organometallic Complexes with Biological Molecules: VIII. Synthesis, Solid State andin vivo Investigation of Triorganotin(IV) Derivatives ofL-Homocys…
1997
Several new triorganotin(IV) derivatives of L-homocysteic acid (L-HCAH) with formula R3Sn(L-HCA) (R=Me, nBu, Ph) have been synthesized. Their solid-state configurations were determined by IR and Mossbauer spectroscopy. The tin(IV) atom is five-coordinated in all the complexes, with the L-homocysteic acid behaving as a monoanionic bidentate ligand coordinating the tin(IV) atom through a chelating or bridging carboxylate group. The sulfonate (SO3−) and NH3+ groups of L-homocysteic acid maintain their free acid configuration and hence do not participate to the coordination of the tin(IV) atom. Coordination hypotheses have been checked through the correlation between the Mossbauer parameter iso…
Synthesis and structural studies of 2-stannyl-substituted ferrocenylmethylamine and -phosphine derivatives 2-Me2RSnFcCH2Y (RMe, Cl; YNMe2, PPh2, P(…
1995
Abstract 2-(Trimethylstannyl)ferrocenylmethyldiphenylphosphine, 2-Me3SnFcCH2PPh2 (2a), was synthesized from 2-Me3SnFcCH2NMe2 (1a) and Ph2PH. Compound 2a is oxidized with H2O2 to 2-Me3SnFcCH2P(O)Ph2 (3a). Halogenation of 1a and 2a with Me2SnCl2 and 3a with HCl-diethyl ether yields the organotin monochlorides 2-Me3(Cl)SnFcCH2Y ( 1b , Y = NMe 2 ; 2b , Y = PPh 2 3b , Y = P ( O ) Ph 2 ) . Both crystal structure determinations and multinuclear magnetic resonance studies in solution reveal for 1b–3b molecular structures in which the tin atom approaches a trigonal bipyramidal pentacoordination as a consequence of an intramolecular Y Sn interaction. The donor strength of Y increases in the order PPh2
Electronic structure and energy decomposition analyses as a tool to interpret the redox potential ranking of naphtho-, biphenyl- and biphenylenequino…
2016
By calling on modelling approaches we have performed a comparative study on the redox properties of various naphtho-, biphenyl- and biphenylene-quinone isomers. These different compounds exhibit as a whole a redox potential range between 2.09 and 2.90 V vs. Li+/Li. A specific methodology was used to decrypt the interplay among isomerism, aromaticity and antiaromaticity modifications and the stabilization/destabilization effects due to other molecular components on this key electrochemical feature for electrode materials of batteries. In particular, energy decomposition analysis, within the Quantum Theory of Atoms in Molecules, along with the electron and electron spin population changes upo…