Search results for "Octahedron"
showing 10 items of 405 documents
Organometallic complexes with biological molecules. XI. Solid state and in vivo investigations of some diorganotin(IV)-chloramphenicol and cycloserin…
1998
Abstract Diorganotin(IV) derivatives of chloramphenicol, {=D-(-)threo-2,2-dichloro-N-[ β -hydroxy- α -(hydroxymethyl)- β -(4-nitrophenyl)ethyl]acetamide (=Hchloramph)}, and D-cycloserine, {=(R)-4-amino-3-isoxazolidone [=Hcyclos]} have been prepared. The stoichiometries of the obtained compounds were R 2 SnClantib and R 2 Snantib 2 (antib −1 =chloramph −1 , R=methyl and phenyl; antib −1 =cyclos −1 , R=methyl). The solid state configuration of the complexes was investigated by I.R. and Mossbauer spectroscopy, from which structural hypotheses were inferred. In particular, the experimental data suggested monomer structures both for R 2 Sn(IV)Clchloramph and R 2 Sn(IV)chloramph 2 , in which chlo…
Synthesis, crystal structure and magnetic properties of the three-dimensional compound [Na2Ni(mal)2(H2O)6]n (H2mal=malonic acid)
2000
Abstract A new three-dimensional nickel–sodium compound of formula [Na 2 Ni(mal) 2 (H 2 O) 6 ] n (H 2 mal=malonic acid) was prepared and its structure was determined by X-ray diffraction methods. Four malonate–oxygen atoms and two trans -(Ni) or cis -(Na) coordinated water molecules build distorted octahedral surroundings around the metal atoms. The malonate group exhibits bidentate (Ni) and tetrakis-monodentate (Na) coordination modes. The structure can be described as corrugated sheets of malonato-containing Ni(II) and Na(I) cations which grow in the (101) plane, each sheet being linked to the adjacent one in the [101] direction through bis(μ-aqua)disodium(I) units. Within each corrugated…
Tin(IV) and organotin(IV) complexes containing mono or bidentate N-donor ligands
1998
Abstract A series of adducts of the type [(L # ) y R n SnX 4− n ]· z H 2 O (L # =1-methylimidazole, y =1 or 2, R=Me, Et, Bu n or Ph, n =1, 2 or 3, X=Cl, Br or I, z =0, 1/2 or 1) has been characterized in the solid state and in solution by analyses, spectral (IR, 119 Sn Mossbauer, and 1 H, 13 C and 119 Sn NMR) data and conductivity measurements. The molecular weight determinations and the NMR data indicate that these organotin(IV) complexes partly dissociate in chloroform and acetone solution. The donor L # interacts with [(CH 3 ) 3 SnNO 3 ], yielding the 2:1 ionic complex [(L # ) 2 (CH 3 ) 3 Sn]NO 3 . The derivative [(L # ) 2 (CH 3 ) 2 SnCl 2 ] reacts with NaClO 4 , AgNO 3 , NaBPh 4 and KSC…
Exchange Coupling Mediated by N–H···Cl Hydrogen Bonds: Experimental and Theoretical Study of the Frustrated Magnetic System in Bis(o-phenylenediamine…
2012
The title compound crystallizes in the monoclinic P2(1)/c space group with a = 11.2470(3) A, b = 5.9034(2) A, c = 12.0886(3) A, β = 115.143(1)°, and V = 726.58(4) A(3) and consists of discrete monomeric NiCl(2)(o-phenylendiamine)(2) molecules. Each o-phen ligand coordinates in a bidentate mode with the chloride ions occupying trans positions in the resulting tetragonally distorted octahedral coordination sphere. Two discrete sets of N-H···Cl hydrogen bonds link the octahedral molecules into a two-dimensional network, with type 1 interactions linking adjacent monomers along the c axis and type 2 interactions linking monomers along the diagonals in the bc plane. Analysis of the magnetic data …
Bis and tris(oxalato)ferrate(iii) complexes as precursors of polynuclear compounds
2005
The preparation and crystal structure of two oxalato-bridged NaI–FeIII compounds, [Na3Fe(ox)3(H2O)4]·H2O (1) and [FeII(phen)3][NaFe(ox)3(H2O)3]·4H2O (5), two mononuclear FeIII complexes AsPh4[Fe(bipy)(ox)2]·H2O (3) and AsPh4[Fe(phen)(ox)2]·H2O (4) and an oxalato-bridged FeIII compound [AsPh4]4[Fe2(ox)5]·5H2O (2) (ox = oxalate dianion, bipy = 2,2′-bipyridine, phen = 1,10-phenantroline and AsPh4+ = tetraphenylarsonium cation) are reported here. The structure of 1 consists of infinite anionic [NaFe(ox)3]2− layers linked trough centrosymmetric [Na4(H2O)8]4+ tetranuclear units yielding a three-dimensional motif. Crystallization water molecules ensure the cohesion of the crystal lattice in 1. The…
Mössbauer studies on tin(IV) and organotin(IV) diacetylbis(benzoylhydrazone) complexes
1974
Abstract The Mossbauer parameters of Ph 2 SnDB, PhClSnDB and Sn(DB) 2 were determined, where DB 2− is the dianion of the multidentate ligand diacetylbis(benzoylhydrazone). According also to data treatment with the point charge model formalism, the configurations of Ph 2 Sn IV and PhSn IV derivatives appear to be essentially octahedral, with linear CSnC and CSnCl skeletons. As to Sn(DB) 2 , it appears that the electrical charge density at the Sn IV nucleus has a cubic symmetry, which is consistent with both tetrahedral and octahedral configurations around Sn IV .
Nuclearity controlled cyanide-bridged bimetallic CrIII-MnII compounds: synthesis, crystal structures, magnetic properties and theoretical calculation…
2004
The preparation, X-ray crystallography and magnetic investigation of the compounds PPh4[Cr(bipy)(CN)4].2 CH3CN.H2O (1) (mononuclear), [[Cr(bipy)(CN)4]2Mn-(H2O)4].4H2O (2) (trinuclear), [[Cr(bipy)(CN)4]2Mn(H2O)2] (3) (chain) and [[Cr(bipy)(CN)4]2Mn(H2O)].H2O.CH3CN (4) (double chain) [bipy=2,2'-bipyridine; PPh4 (+)=tetraphenylphosphonium] are described herein. The [Cr(bipy)(CN)4]- unit act either as a monodentate (2) or bis-monodentate (3) ligand toward the manganese atom through one (2) or two (3) of its four cyanide groups. The manganese atom is six-coordinate with two (2) or four (3) cyanide nitrogens and four (2) or two (3) water molecules building a distorted octahedral environment. In 4…
[Mn2(bipym)(H2O)8]4+and [Fe(bipy)(CN)4]−as building blocks in designing novel bipym- and cyanide-bridged heterobimetallic complexes (bipym = 2,2′-bip…
2002
Two new cyano complexes, K[Fe(bipy)(CN)4]·H2O (1) and (μ-bipym)[Mn(H2O)3{Fe(bipy)(CN)4}]2[Fe(bipy)(CN)4]2·12H2O (2), have been synthesised and their structures determined by single-crystal X-ray diffraction. Complex 1 is made up of mononuclear [Fe(bipy)(CN)4]− anions, potassium cations and water molecules of crystallization. The iron(III) is six-coordinated, being surrounded by two nitrogen atoms of a chelating bipy and four carbon atoms of four cyanide groups [Fe–N and Fe–C 1.991(3)–1.990(3) and 1.958(5)–1.914(5) A, respectively]. Complex 2 consists of centrosymmetric tetranuclear (μ-bipym)[Fe(H2O)3{Fe(bipy)(CN)4}]22+ cations, [Fe(bipy)(CN)4]− anions and water molecules of crystallization.…
Manganese(II) complexes with croconate and 2-(2-pyridyl)imidazole ligands: Syntheses, X-ray structures and magnetic properties
2009
Abstract The mixed-ligand complexes of manganese(II) of formula [Mn(pyim)2(C5O5)] (1) and [Mn(pyim)(H2O)(C5O5)]n · 2.5nH2O (2) [pyim = 2-(2-pyridyl)imidazole and C 5 O 5 2 - = croconate (dianion of 4,5-dihydroxy-4-cyclopentene-1,2,3-trione)] have been prepared and their structures determined by X-ray crystallographic methods. Compound 1 is a tris-chelated mononuclear complex where the manganese atom is six-coordinate: four nitrogen atoms from two pyim molecules and two oxygen atoms from a croconate group build a somewhat distorted octahedral surrounding around the metal atom. The resulting neutral mononuclear units are linked to each other through double bridges which are constituted by th…
Novel cobalt(II) coordination polymers based on 1,2,4,5-benzenetetracarboxylic acid and extended bis-monodentate ligands
2009
Four new high-spin cobalt(II) complexes of formulae [Co2(bta)(4,4′-bpy)2(H2O)2]n (1), {Hbpe[Co(Hbta)(bpe)(H2O)2]}n (2), {[Co(H2bta)(azpy)(H2O)2]·azpy}n (3) and {[Co2(bta)(bpa)2(H2O)4]·8H2O}n (4) with H4bta = 1,2,4,5-benzenetetracarboxylic acid, 4,4′-bpy = 4,4′-bipyridine, bpe = trans-1,2-bis(4-pyridyl)ethene, azpy = 4,4′-azobispyridine and bpa = trans-1,2-bis(4-pyridyl)ethane, have been prepared and characterized by single crystal X-ray diffraction. Compounds 1–4 exhibit two-dimensional networks where the fully (1 and 4) or partially (2 and 3) deprotonated tetracarboxylic ligand connects two (2 and 3) or four (1 and 4) cobalt(II) ions through two trans-carboxylate (1–3) or all the carboxyla…