Search results for "BIP"
showing 10 items of 1908 documents
Organoelement derivatives of steroids: Synthesis and structural features of organosilicon, -tin and -lead derivatives of cholesterol and desoxycholic…
1987
Some organo-Main-Group-IV-element compounds of steroids of the type R3M(COL), R2Sn(COL)2 and (R3M)2(HDCA) (where R = Me or Ph; M = Si, Sn and Pb; HCOL = cholest-5-en-3β-ol; H3DCA = 3α, 12α-dihydroxy-5β-cholan-24-oic acid), have been synthesized. The structures of these compounds have been investigated by vibrational, mass, NMR (1H, 13C, 29Si, 119Sn and 207Pb) and 119Sn Mossbauer spectroscopy. For Me3Sn(COL) both in solution and in the solid state an associated structure with distorted trigonal bipyramidal geometry around tin and three-coordinated oxygen atoms is postulated. Discrete tetrahedral geometries are assigned to Ph3M(COL) complexes and to R2Sn(COL)2 complexes in solution. The latte…
Structural analysis and magnetic properties of the copper(II) dicyanamide complexes [Cu2(dmphen)2(dca)4], [Cu(dmphen)(dca)(NO3)] and [Cu(4,4′-dmbpy)(…
2004
Abstract The preparation, crystal structures and magnetic properties of three copper(II) compounds of formulae [Cu2(dmphen)2(dca)4] (1), [Cu(dmphen)(dca)(NO3)]n (2) and [Cu(4,4′-dmbpy)(H2O)(dca)2] (3) (dmphen=2,9-dimethyl-1,10-phenanthroline, dca=dicyanamide and 4,4′-dmbpy=4,4′-dimethyl-2,2′-bipyridine) are reported. The structure of 1 consists of discrete copper(II) dinuclear units with double end-to-end dca bridges whereas that of 2 is made up of neutral uniform copper(II) chains with a single symmetrical end-to-end dca bridge. Each copper atom in 1 and 2 is in a distorted square pyramidal environment: two (1) or one (2) nitrile-nitrogen atoms from bridging dca groups, one of the nitrogen…
Geometric isomeric pairs: synthesis, structure, thermal decomposition and magnetic properties of cis- and trans-[Cr(mal)(bpy)(H2O)2][NO3]·xH2O (H2mal…
2001
Abstract Procedures are given for the preparation and isolation of cis-[Cr(mal)(bpy)(H2O)2][NO3]·3H2O (I) and trans-[Cr(mal)(bpy)(H2O)2][NO3]·H2O (II) (H2mal=malonic acid, bpy=2,2′-bipyridine). The single crystals X-ray structure of cis-compound reveals that the cations and anions as well as cations between cations are linked into hydrogen-bonded chains. Unfortunately, little structural information is available for the trans compound II (only isotropic cation refinement), nevertheless, from this result is observed that there also exists a hydrogen-bonded network between anion units. Thermal analysis and magnetic behaviour for both compounds were studied.
Tetrakis(1-ethyl-1H-1,2,4-triazole-κN4)bis(nitrato-κO)copper(II) and bis(nitrato-κO)tetrakis(1-propyl-1H-1,2,4-triazole-κN4)copper(II)
2005
The copper(II) environments for tetrakis(1-ethyl-1,2,4-triazole)dinitratocopper(II), [Cu(NO 3 ) 2 (C 4 H 7 N 3 ) 4 ], and tetrakis-(1-propyl-1,2,4-triazole)dinitratocopper(II), [Cu(NO 3 ) 2 (C 5 -H 9 N 3 ) 4 ], are distorted square bipyramidal. Both structures are centrosymmetric, with the copper(II) ions located at inversion centers coordinated by four N atoms of four triazole molecules and by two O atoms of two nitrate ions in an elongated octahedral geometry. This elongation is a result of the Jahn-Teller effect. The largest distortion is that of the N-Cu-O angles, which differ from 90 by 5.68 (10)° in the ethyl and 5.59 (8)° in the propyl derivative.
Heterobimetallic complexes of cobalt(IV) porphyrin-corrole dyads. Synthesis, physicochemical properties, and X-ray structural characterization.
2005
The synthesis of a novel family of heterobinuclear cofacial biphenylene (B), anthracene (A), 9,9-dimethylxanthene (X), or dibenzofuran (O) bridged porphyrin-corrole complexes, (PCY)MClCoCl, is reported, M being either an iron(III) or manganese(III) ion. Each complex was characterized by electrochemistry, mass spectrometry, UV-vis, IR, and electron spin resonance spectroscopy. Unlike previously examined biscobalt porphyrin-corrole dyads, the cobalt ion of the corrole moiety is present in a high-valence +4 oxidation state, as proven by electrochemistry, spectroelectrochemistry, and an X-ray diffraction study of (PCB)FeClCoCl, which shows the presence of a bound Cl- anion on the cobalt corrole…
Azide bridged dicopper(II), dicobalt(II) complexes and a rare double μ-chloride bridged ferromagnetic dicobalt(II) complex of a pyrazolyl-pyrimidine …
2012
Abstract Two new dinuclear copper(II) complexes [Cu2(PymPz)2(N3)2Cl2] (1), [Cu2(PymPz)2(N3)4] (2) and two new dinuclear cobalt(II) complexes [Co2(PymPz)2Cl4] (3), [Co2(PymPz)2(N3)4] (4) [PymPz = 2-(3,5-dimethyl-1H-pyrazol-1-yl)-4,6-dimethylpyrimidine] have been synthesized and characterized crystallographically and spectroscopically. In each of the complexes 1, 2 and 4 the two adjacent metal centers are bridged by a pair of μ-1,1 azide groups whereas in 3 the metal centers are bridged by a pair of chloride ions. In the complexes, all the metal centers are pentacoordinated. In 1 and 2 the copper(II) centers have distorted square pyramidal geometry (τ = 0.18 for 1 and 0.091 for 2) but in 3 an…
Coordination abilities of l-glutamic acid γ-monohydroxamic acid towards copper(II) in the absence and presence of some aliphatic amines
2012
Abstract Solution equilibrium studies on the Cu 2+ –(A)–(Glu-γ-ha) ternary systems ((A) = polyamine: ethylenediamine (en), diethylenetriamine (dien), N , N , N ′, N ″, N ″-pentamethyldiethylenetriamine (Me 5 dien); (Glu-γ-ha) = l -glutamic-γ-hydroxamic acid) have been performed by pH-potentiometry, UV–Vis spectrophotometry and EPR methods. The obtained results suggest the formation of the heteroligand complexes with [Cu(A)(Glu-γ-ha)] + stoichiometry in all studied systems. Our spectroscopic results indicate the tetragonal geometry for the [Cu(en)(Glu-γ-ha)] + species in which Glu-γ-ha acts as a tridentate ligand, the geometry slightly deviated from square pyramidal for [Cu(dien)(Glu-γ-ha)]…
Mössbauer study of the solid state configuration of triorganotin derivatives with intramolecular coordination
1980
Triorganotin bromides with intramolecular nitrogen-to-tin coordination (I-VIII, Fig. 1) have been structurally investigated by Mossbauer and infrared spectroscopy. Mossbauer-Zeeman spectra have been measured for I and VIII in order to obtain the sign of the nuclear quadrupole splitting ΔE and the value of the asymmetry parameter η. Point-charge model values of ΔE and η have been calculated for environments of tin atoms in I-VIII which are plausible in view of the results of previous investigations. From trends of experimental ΔE in the series, and from the agreement between experimental and calculated Mossbauer parameters it is concluded that the compounds I-VIII all have trigonal bipyramid…
Insertion Reactions of Neutral Phosphidozirconocene Complexes as a Convenient Entry into Frustrated Lewis Pair Territory
2016
International audience; Neutral phosphidozirconocene complexes [Cp2Zr(PR2)Me] (Cp=cyclopentadienyl; 1a: R=cyclohexyl (Cy); 1b: R=mesityl (Mes); 1c: R=tBu) undergo insertion into the Zr-P bond by non-enolisable carbonyl building blocks (O=CRR), such as benzophenone, aldehydes, paraformaldehyde or CO2, to give [Cp2Zr(OCRRPR2)Me] (3-7). Depending on the steric bulk around P, complexes 3-7 react with B(C6F5)(3) to give O-bridged cationic zirconocene dimers that display typical frustrated Lewis pair (FLP)/ambiphilic ligand behaviour. Thus, the reaction of {[Cp2Zr(-OCHPhPCy2)][MeB(C6F5)(3)]}(2) (10a) with chalcone results in 1,4 addition of the Zr+/P FLP, whereas the reaction of {[Cp2Zr(-OCHFcPCy…
Synthesis, spectroscopic characterization and in vitro antimicrobial activity of diorganotin(IV) dichloride adducts with [1,2,4]triazolo-[1,5-a]pyrim…
2006
Abstract The heterocyclic ligands [1,2,4]triazolo-[1,5-a]pyrimidine (tp) and 5,7-dimethyl-[1,2,4]triazolo-[1,5-a]pyrimidine (dmtp), react with diorganotin dichlorides giving the addition compounds Me2SnCl2(tp)2, Et2SnCl2(tp)2, Me2SnCl2(dmtp)2, Et2SnCl2(dmtp)2, Bu2SnCl2(dmtp), Ph2SnCl2(dmtp). The organotin:ligand stoichiometry goes from 1:2 to 1:1 by increasing the steric hindrance of the organic groups bound to tin. The compounds have been characterized by means of infrared, 119Sn Mossbauer and 1H AND 13C NMR spectroscopy. The ligands presumably coordinate to tin classically through the nitrogen atom at the position 3. The 1:1 complexes adopt trigonal bipyramidal structures, with the organi…