Search results for "X-Ray"

Equilibria involved in the diorganotin(IV) and triorganotin(IV) phosphomycin interaction in aqueous solution

2007

Four new diorganotin(IV), (R = Me, Bu), and triorganotin(IV), (R = Me, Ph), derivatives of the phosphomycin disodium salt antibiotic[(1R,2S)-1,2-epoxypropylphosphonate]Na2 have been synthesized and their solid state configuration studied by X-ray crystallography, FT-IR, Mossbauer, UV–Vis spectroscopies. The X-ray diffraction investigation, performed on the bis[trimethyltin(IV)]- phosphomycin, showed that the coordination geometry at all the Sn atoms is trigonal bipyramidal. The structure of the complex forms an unusual polymeric zig-zag planar network. The FT-IR and the 119Sn Mo¨ssbauer studies supported the formation of trigonal bipyramidal (Tbp) molecular structures, both in the diorganot…

Synthesis and Unusual NMR-Spectroscopic Behavior of a Strained Bicyclic Ammonium Salt

2018

Cyclometallation reactions in complexes of the type Rh(oq)(CO)(P(o-BrC6F4)Ph2)

1986

Abstract The complex [uRh(oq)Br(P( o -Cu 6 F 4 )Ph 2 )(H 2 O)] 2 is obtained by refluxing a solution of Rh(oq)(CO)(P( o -BrC 6 F 4 )Ph 2 ) (oq = 8-oxyquinolinate) in toluene. The structure of this compound has been determined by X-ray diffraction and refined to R = 0.061 and R w = 0.065 factors. The cell has monoclinic symmetry, space group P 2 1 / n ; a 19.513(2), b 17.049(1), c 16.898(1) A and β 99.69(1)°. The structure consists of two independent Rh(oq)Br(P( o -C 6 F 4 )Ph 2 )H 2 O) units linked by hydrogen bonds between the coordinated water molecules and oq ligands to form a distorted boat (six atom ring of junction between the two units). In each unit the metal atom has a distorted oc…

Structure and fluxional behaviour of heptaleneirontricarbonyl and heptalenebis (Irontricarbonyl)

1987

Abstract The synthesis of heptaleneirontricarbonyl ( 4 ) is described. The structures of 4 and of the closely related heptalenebis(irontricarbonyl) ( 3 ) are elucidated by NMR spectroscopy ( 1H and 13C) and by X-ray crystallography. Compounds 3 and 4 are shown by dynamic NMR to undergo an isodynamic 1 ,2-migration of the Fe(CO3)-groups as well as a carbonyl scrambling. The relevant kinetic data allow for a mechanistic discussion of the dynamics and a comparison with other irontricarbonyl complexes.

Geometric and electronic structure of dithiapyranylidine: evolution upon oxidation

1993

Abstract We present a theoretical investigation of the modifications that successive oxidation induces on the geometric and electronic structures of the π-electron donor dithiapyranylidene. The lengthening of the double bonds and the shortening of the single bonds calculated as the molecular charge increases indicate a gain of aromaticity with oxidation. Both the geometricand the electronic structure of dithiapyranylidene show a clear evolution towards those of biphenyl as oxidation takes place.

Synthesis, characterization, and complexation of tetraarylborates with aromatic cations and their use in chemical sensors.

2005

Five aromatic borate anions, namely tetrakis(4-phenoxyphenyl)borate (1), tetrakis(biphenyl)borate (2), tetrakis(2-naphthyl)borate (3), tetrakis(4-phenylphenol)borate (4), and tetrakis(4-phenoxy)borate (5), have been prepared and tested as ion-recognition sites in chemical sensors for certain aromatic cations and metal ions. To gain further insight into the complexation of the cations, some complexes have been prepared and structurally characterized. The complexation behavior of 1 and 2 towards N-methylpyridinium (6), 1-ethyl-4-(methoxycarbonyl)pyridinium (7), tropylium (8), imidazolium (9), and 1-methylimidazolium (10) cations has been studied, and the stability constants of the complexes o…

Synthesis and structural studies on Ni(II) dithiocarbamates : Exploring intramolecular Ni···H-C interactions

2017

Abstract Five new Ni(II) dithiocarbamates with NiS4, NiS2PN and NiS2PCl coordination spheres, viz. [Ni(bupmbzdtc)2] (1), [Ni(bupmbzdtc)(PPh3)(NCS)] (2), [Ni(bupmbzdtc)(PPh3)Cl] (3), [Ni(4-dpmpzdtc)(PPh3)Cl] (4) and [Ni(pbbzbudtc)(PPh3)(NCS)] (5), where bupmbzdtc = N-butyl(p-methylbenzyl)dithiocarbamato anion, 4-dpmpzdtc = 4-(diphenylmethyl)piperazinecarbodithioato anion, pbbzbudtc = N-(p-bromobenzyl)butyl-dithiocarbamato anion and PPh3 = triphenylphosphine, were synthesized and characterized by UV, IR, NMR and single crystal X-ray diffraction methods. Spectral results suggest a square planar geometry around the Ni(II) metal center for all the synthesized complexes. Single crystal X-ray stru…

First tetrathiafulvalene (TTF) cation-radical salt containing the inorganic polyoxometalate β-[Mo8O26]4⊖

1993

Tetrazine Click Chemistry for the Modification of 1-Hydroxy-1,1-methylenebisphosphonic Acids: Towards Bio-orthogonal Functionalization of Gold Nanopa…

2016

Inverse electron demand Diels-Alder (iEDDA) was evaluated for the functionalization of gold nanoparticles. The reaction was first modelled with the free coating molecule 1-hydroxy-1,1-methylenebisphosphonate bearing an alkene functionality (HMBPene). A model tetrazine 3,6-dipyridin-2-yl-1,2,4,5-tetrazine (pyTz) was used, kinetic of the reaction was calculated and coupling products were analysed by NMR and HRMS. The reaction was then transposed at the nanoparticle surface. Gold nanoparticles bearing an alkene functionality were obtained using a one-pot methodology with HMBPene and the tetrazine click chemistry was evaluated at their surface using pyTz. The successful coupling was assessed by…

Buildup of ultrathin multilayer films by a self-assembly process: III. Consecutively alternating adsorption of anionic and cationic polyelectrolytes …

1992

A solid substrate with a positively charged planar surface is immersed in a solution containing an anionic polyelectrolyte and a monolayer of the polyanion is adsorbed. Since the adsorption is carried out at relatively high concentrations of polyelectrolyte, a large number of ionic residues remain exposed to the interface with the solution and thus the surface charge is effectively reversed. After rinsing in pure water the substrate is immersed in the solution containing a cationic polyelectrolyte. Again a monolayer is adsorbed but now the original surface charge is restored. By repeating both steps in a cyclic fashion, alternating multilayer assemblies of both polymers are obtained. The bu…