Search results for "Spectral"
showing 10 items of 3116 documents
Infrared and quantum-chemical studies of the structure and vibrations of methyldisilylamine
2002
Abstract Infrared spectra are reported from labelled species of methyldisilylamine (N(CH 3 )(SiH 3 ) 2 ) in the gas and solid phase. Quantum-chemical (QC) calculations of structure and force field have been carried out at HF, MP2 and B3LYP levels using 6-31G ∗ and 6-311G ∗∗ basis sets. The equilibrium structure belongs to the point group C s with the plane of symmetry at right angles to the NSi 2 angle and a slight non-planarity of the CNSi 2 moiety ( C s ,⊥ ). Spectra in the ν SiH region however suggest an effective C 2 v structure, with two distinct types of SiH bond. Two strong SiH bonds lie in the skeletal plane, eclipsing each other. The single ν is CH band in the CHD 2 species suggest…
SYNTHESIS, LASER-RAMAN, INFRARED AND PROTON MAGNETIC RESONANCE SPECTRA OF (CH3)3PtX2- 3 IONS (X = Cl−, Br−) AND (CH3)3Ptiv ISOCYANIDE COMPLEXES
1976
Abstract The novel ionic complexes [(C6H5)4As]2 [(CH3)3PtX3](X = Cl− and Br−) and [(CH3)3Pt(bipy)L]+[B(C6H5)4]− (bipy = 2,2′-bipyridine, L = aliphatic and aromatic isocyanide) have been prepared. The structure of the complex ions has been inferred from Laser-Raman and infrared spectra in the solid state and 1H NMR in solution. These data are consistent with a facial configuration of the organometallic moiety. Trends in vibrational frequencies ν(Pt-C) and ν(Pt-X) indicate a “trans” influence sequence for the ligands, which in the case of (CH3)3PtX2- 3 is related with that found for (CH3)2AuX− 2 ions.
Complexes of organothallium(III) with Cis-1,2-dicyanoethylenedithiolate ion and a ‘tripod’ ligand. Synthesis, infrared and proton magnetic resonance …
1980
Abstract The reaction of cis-1,2-dicyanoethylenedithiolate ion (mnt2− with organothallium(III) derivatives has been examined. The complexes [(CH3)2Tl]2mnt and [(C4H9)4N] [(C6H5)2Tl mnt] have been synthesized. The results seem to indicate a trend in reactivity similar to that of arylmercury(II) derivatives towards chelating agents with nucleophilic character. In addition, the complex [(CH3)2Tl(tren)] [BPh4] has been obtained as a test of the complexing ability of 2,2′, 2″-triaminotriethylamine(tren) towards organometallic moieties. I.r. and 1H n.m.r. are presented and discussed.
Antimony-121 mössbauer and infrared spectral study on halophenylantimonate(III) Compounds
1981
Abstract The synthesis and the 121 Sb Mossbauer and infrared spectra of halophenylantimonates(III) M[PhSbX 3 ] (M Me 4 N, Ph 4 As;X Cl, Br, I) are reported, and the spectral data are discussed and compared with those of SbX 4 and other related systems. The results are in accord with the participation of the antimony 5s electrons in the SbPh bond. In the interpretation of the electric field gradient, the contributions to V zz from both the lone pair and the SbPh bond electron densities are assumed to be dominant.
Kristallstruktur, thermische Ausdehnung und Farbwechsel von (Me3Ge)2Sb-Sb(GeMe3)2 und anderen Distibanen
1989
Abstract Single crystals of the distibanes (Me3M)4Sb2 (1: M = Si, 2: M = Ge) are obtained by the oxidation in air of (Me3M)3Sb. The crystal structure of 2 is reported. 2 forms linear chains of distibane molecules in trans conformation with Sb ··· Sb contacts of 386 pm at −110°C and 390 pm at 22°C. The thermal expansion of crystals of 2 and (Me3Sn)4Sb2 (3) has been determined. UV-VIS spectra of 1–3, Me4Sb2 (4), Et4Sb2 (5), and Ph4Sb2 (6) in different phases have been recorded. The spectra of 1–5 are consistent with the visible colour changes.
Copper(II) Complexes with Derivatives of Barbiturate
1984
Abstract NaCuL2(OH).1,5H2O, KCuP2(OH).1H2O, Na2CuL4 and K2CuP4-8H2O (HL=Phenobarbitone and HP=Methyl Phenobarbitone) were prepared and characterized by elemental analysis, IR and electronic spectral data and magnetic susceptibility measurements. The ESR spectra show and octahedral environment for the Cu(II) ion.
Synthesen mit substituierten Malondialdehyden, XI. γ‐Formyl‐tetramethinmerocyanin‐, γ‐Formyl‐pentamethincyanin‐ und [2.2.2]Heptamethincyanin‐Farbstof…
1972
Durch Kondensation des Formylmalondialdehyds (Triformylmethan) 5 mit heterocyclischen Imoniumsalzen 4 werden je nach Reaktionsbedingungen neuartige γ-Formyl-tetramethinmerocyanin-(6), γ-Formyl-pentamethincyanin-(8) und trinucleare symmetrische [2.2.2]Heptamethincyanin-Farbstoffe (9) dargestellt. Die Isolierung der Mono- (6) und Dikondensationsprodukte (8) des Formylmalondialdehyds ermoglicht die Darstellung unsymmetrischer Farbstoffe 8 und 9 mit verschiedenen Endgruppen. — Die trinuclearen [2.2.2]Heptamethincyanine 9 lassen sich in Analogie zu den phenylogen Guanidiniumionen (Triphenylmethanfarbstoffe) als methinyloge Guanidiniumkationen 3 (n = 3) auffassen. — Die spektroskopischen Eigensch…
X‐ray Absorption Spectra of Cu II and Cu III Complexes of N , N ′ ‐1,2‐Phenylenebis(2‐mercapto‐2‐methylpropionamide)
2005
The X-ray absorption spectra of Cu I I and Cult complexes of N,N'-1,2-phenylenebis(2-mercapto-2-methylpropionamide) were recorded and analysed in solid phase. The EXAFS spectra of the two samples were refined with full multiple scattering path. Geometry optimisations on the Cu I I and Cu I I I complexes were performed by the B3LYP density functional method, with the 6-31G(d,p) basis set, considering different spin multiplicities. The singlet state of the Cu I I I complex was shown to be more stable than the triplet state, and a good agreement between the calculated and the corresponding experimental structure was found. Further single-point calculations on the optimised geometry were carrie…
Lactones. Part 15: Synthesis of chiral spirolactones with a carane system—insect feeding deterrents
2002
Abstract Starting from (+)-3-carene 1 several spirolactones with carane backbone were synthesized. δ-Hydroxy-γ-lactone 5 was obtained by acidic lactonization of a γ,δ-epoxy ester. Iodolactone 8 and bromolactone 9 were products of iodolactonization of γ,δ-unsaturated acid 7 and bromolactonization of γ,δ-unsaturated ester 3 respectively. The halo lactones were subjected to reductive dehalogenation with tributyltin hydride and dehydrohalogenation with DBU. The structures of the lactones obtained were confirmed by X-ray analysis and spectral data.
Synthesis and spectral studies ofN-2-pyridinylcarbonyl-2-pyridinecarxoximidate copper(II) complexes
1987
Dimeric and polymeric copper(II) complexes containing BPCA (N-2-pyridinylcarbonyl-2-pyridinecarboximidate), having general formulae Cu(BPCA)X·nH2O (X=Cl, Br, NCS, NCO, N3, or CN) and Cu2(BPCA)2-X·nH2O [X=oxalate anion (OX), chloranilate anion (CA) or the dianion of 2,5-dihydroxy-1,4-benzoquinone (DHBQ)] have been synthesized by the copper(II)-assisted hydrolysis of 2, 4, 6-tris(2-pyridyl)-1, 3, 5-triazine. Spectroscopic results indicate five-coordinate, approximately square-pyramidal, geometry around the copper(II) ion. Half-field absorption in the ΔMs=±2 region of the X-band e.p.r. powder spectra has been observed for the dimeric species.