Search results for " Spectroscopy"
showing 10 items of 6851 documents
Field-Induced Slow Magnetic Relaxation in a Mononuclear Manganese(III)-Porphyrin Complex
2015
We report on a novel manganese(III)-porphyrin complex with the formula [Mn(III) (TPP)(3,5-Me2 pyNO)2 ]ClO4 ⋅CH3 CN (2; 3,5-Me2 pyNO=3,5-dimethylpyridine N-oxide, H2 TPP=5,10,15,20-tetraphenylporphyrin), in which the Mn(III) ion is six-coordinate with two monodentate 3,5-Me2 pyNO molecules and a tetradentate TPP ligand to build a tetragonally elongated octahedral geometry. The environment in 2 is responsible for the large and negative axial zero-field splitting (D=-3.8 cm(-1) ), low rhombicity (E/|D|=0.04) of the high-spin Mn(III) ion, and, ultimately, for the observation of slow magnetic-relaxation effects (Ea =15.5 cm(-1) at H=1000 G) in this rare example of a manganese-based single-ion ma…
Biomimetic Mn-catalases based on dimeric manganese complexes in mesoporous silica for potential antioxidant agent
2015
Two new structural and functional models of the Mn-catalase with formula [{Mn(III)(bpy)(H2O)}(μ-2-MeOC6H4CO2)2(μ-O){Mn(III)(bpy)(X)}]X, where X = NO3 (1) and ClO4 (2) and bpy = 2,2'-bipyridine, were synthesized and characterized by X-ray diffraction. In both cases, a water molecule and an X ion occupy the monodentate positions. The magnetic properties of these compounds reveal a weak antiferromagnetic behavior (2J = -2.2 cm(-1) for 1 and -0.7 cm(-1) for 2, using the spin Hamiltonian H = -2J S1·S2) and negative zero-field splitting parameter DMn (-4.6 cm(-1) and -3.0 cm(-1) for 1 and 2, respectively). This fact, together with the nearly orthogonal orientation of the Jahn-Teller axes of the M…
DNA binding, nuclease activity, DNA photocleavage and cytotoxic properties of Cu(II) complexes of N-substituted sulfonamides.
2013
Abstract Ternary copper(II) complexes [Cu(NST)2(phen)] (1) and [Cu(NST)2(NH3)2]·H2O (2) [HNST = N-(4,5-dimethylthiazol-2-yl)naphthalene-1-sulfonamide] were prepared and characterized by physico-chemical techniques. Both 1 and 2 were structurally characterized by X-ray crystallography. The crystal structures show the presence of a distorted square planar CuN4 geometry in which the deprotonated sulfonamide, acting as monodentate ligand, binds to the metal ion through the thiazole N atom. Both complexes present intermolecular π–π stacking interactions between phenanthroline rings (compound 1) and between naphthalene rings (compound 2). The interaction of the complexes with CT DNA was studied b…
Organozin- und organobleiderivate von N-(2,4-dinitrophenyl)glycin
1982
Abstract Organotin and organolead derivatives of N -(2,4-dinitrophenyl)glycine (HDNG), R 3 MDNG (M = Sn, Pb; R = CH 3 , C 6 H 5 ) and (C 6 H 5 ) 2 Pb(DNG) 2 , have been prepared from R 3 MOH or [(C 6 H 5 ) 2 PbO] n and HDNG, respectively. (CH 3 ) 3 PbDNG was also obtained from (CH 3 ) 3 PbBr and TlDNG. According to spectroscopic data R 3 M groups in R 3 MDNG are essentially planar and are bridged by bidentate carboxylate groups of DNG. NH does not coordinate to M. Penta-coordination is also indicated by Mossbauer data of R 3 SnDNG. Also for (C 6 H 5 ) 2 Pb(DNG) 2 a chain structure but with hexacoordination of Pb is proposed. The compounds are monomeric in solution.
Organometallic complexes with biological molecules, IV. Di- and tri-organotin(IV) amoxicillin derivatives: Solid-state and solution-phase spectroscop…
1995
Novel di- and tri-organotin(IV) derivatives of amoxicillin (amoxicillin - =Amox - =6-[D(-)-β-amino-p-hydroxyphenylacetamido] penicillinate) have been prepared. The isolated compounds showed stoichiometries of the type R 2 SnClAmox.2H 2 O, R 3 SnClAmoxNa.2H 2 O and R 2 SnAmox 2 .2H 2 O (R=Me, Bu, Ph). The infrared spectra suggest that Amox − , in both R 2 SnClAmox.2H 2 O and R 2 SnAmox 2 .2H 2 O, behaves as a monoanionic bidentate ligand, coordinating the tin(IV) atom through the ester-type carboxylate, as well as through the lactamic carbonyl. In R 3 SnClAmoxNa.2H 2 O, Amox - coordinates the organotin(IV) moieties through the lactamic carbonyl. In all of the compounds, water molecules are n…
Complexes of (CH3)2AuIII: synthesis, PMR and IR spectra
1975
Abstract The syntheses and reactivity of dimethylgold(III) complexes with multidentate ligands as TRIPHOS (i.e., 1,1,1-tris(diphenylphosphinomethyl)ethane) and TREN (i.e. 2,2′,2″-triaminotriethylamine) have been examined. I.r. spectra for the compounds in the solid state, conductivity and PMR data for solutions, lead to the assignment of an ionic formula [CH 3 ) 2 Au TRIPHOS] + [(CH 3 ) 2 AuCl 2 ] − where the gold(III) atoms are presumably four-coordinate. The complex (CH 3 ) 2 AuCl TREN in DMSO solution undergoes a reductive elimination reaction, as found for analogous dimethylgold(III) derivatives.
Polypyridyl-functionalizated alkynyl gold(i) metallaligands supported by tri- and tetradentate phosphanes
2017
A series of alkynyl gold(I) tri and tetratopic metallaligands of the type [Au3(CuC-R)3(μ3-triphosphane)] (R = 2,2'-bipyridin-5-yl or C10H7N2, 2,2':6',2''-terpyridin-4-yl or C15H10N3; triphosphane = 1,1,1-tris(diphenylphosphanyl) ethane or triphos, 1,3,5-tris(diphenylphosphanyl)benzene or triphosph) and [Au4(CuC-R)4 (μ4-tetraphosphane)] (R = C10H7N2, C15H10N3; tetraphosphane = tetrakis(diphenylphosphanylmethyl)methane or tetraphos, 1,2,3,5-tetrakis(diphenylphosphanyl)benzene or tpbz, tetrakis(diphenylphosphaneylmethyl)-1,2- ethylenediamine or dppeda) were obtained in moderate to good yields. All complexes could be prepared by a Q4 reaction between the alkynyl gold(I) polymeric species [Au(Cu…
Structural characterization of triorganotin(IV) complexes with sodium fusidate and DFT calculations
2010
Abstract Three new complexes of the steroid sodium fusidate (sodium 2-[(1 S ,2 S ,5 R ,6 S ,7 S ,10 S ,11 S ,13 S , 14 Z ,15 R ,17 R )-13-(acetyloxy)-5,17-dihydroxy-2,6,10,11-tetramethyl tetracyclo[8.7.0.0 2,7 .0 11,15 ] heptadecan-14-ylidene]-6-methylhept-5-enoate = (NaFusidate, Na FA )]), with triorganotin(IV) moieties have been prepared and investigated by conventional techniques as FTIR, Mossbauer, ESI-MS and NMR spectroscopy. The isolated compounds showed stoichiometries organotin(IV)/fusidate 1/1, R 3 Sn(IV) FA (R = Me, FA1 ; Bu, FA2 ; Ph, FA3 ). The ligand coordination sites were determined by FTIR spectroscopic measurements. In the complexes, the carboxylate group of the fusidate li…
Organometallic complexes with biological molecules. IX. Diorgano- and triorgano-tin(IV)[meso-tetra (4-sulfonatophenyl)porphinate] derivatives: solid-…
1997
Diorgano- and triorgano-tin(IV) derivatives of meso-tetra(4-sulfonatophenyl)porphine (H4TPPS) with general formula (R2Sn)2TPPS and (R3Sn)4TPPS (TPPS4−=[meso-tetra(4-sulfonatophenyl)porphinate]4−, R=Me, Bu, Ph) have been obtained and their solid-state configuration inferred on the basis of IR and Mossbauer spectroscopy, while solution-phase studies have been carried out by 1H and 13C NMR in DMSO-d6, together with determination of the in vivo cytotoxicity of the new derivatives towards embryonic development of Ciona intestinalis. In particular, octahedral and trigonal-bipyramidal eq-R3Sn polymeric configurations are proposed, in the solid state, respectively for (R2Sn)2TPPS and (R3Sn)4TPPS co…
Preparation and structural studies on the tBu2Sn(IV) complexes with aromatic mono- and dicarboxylic acids containing hetero {N} donor atom
2004
Nine complexes of 'Bu2Sn(IV)(2+) were obtained in the solid state with ligands containing -COOH group(s) and aromatic (N) donor atom. The binding sites of the ligands were identified by FT-IR spectroscopic measurements. It was found that in most cases the -COO- groups are co-ordinated in monodentate manner. Nevertheless, in some of our complexes, the -COO- group forms bridges between two central {Sn} atoms resulting in the formation of an oligomeric structure, a motif that is characteristic only to the nicotinate compound. These pieces of information and the rationalisation of the experimental Sn-119 Mossbauer nuclear quadrupole splittings, Delta, - according to the point charge model forma…