TY  - JOUR
A1  - de Araujo, Martha T.
A1  - Chacon, Eluzir P.
A1  - Carneiro, José W. de M.
A1  - Koch, Andreas
A1  - Kleinpeter, Erich
T1  - Analysis of anisotropic effects in trinuclear metal carbonyl compounds by visualization of through-space NMR shielding
N2  - Through-space NMR shieldings were calculated for trinuclear metal-carbonyl compounds [M-3(CO)(12)] (M = Fe, Ru, Os), employing the nucleus-independent chemical shift approach. The through-space shieldings were visualized as a contour plot of iso-chemical shielding surfaces, and were applied to quantify the overall anisotropic effect of the carbonyl groups, as well as to identify the influence of the transition metal on the scopes of the corresponding anisotropy cones. The shielding surfaces show that the anisotropic effect of the carbonyl groups at equatorial positions changes depending on the metal. This effect was associated with pi-backdonation from the metal to the carbonyl groups in that position, in agreement with geometric data as well as calculated NMR parameters. Therefore, visualization of the through-space NMR shieldings of trinuclear metal-carbonyl compounds of group 8 is able to reflect the distinct arrangements of the carbonyl groups in these organometallic compounds.
Y1  - 2010
UR  - http://www.springerlink.com/content/100529
U6  - https://doi.org/10.1007/s00894-010-0662-3
SN  - 1610-2940
ER  - 
TY  - JOUR
A1  - Awad, Duha Jawad
A1  - Conrad, Franziska
A1  - Koch, Andreas
A1  - Schilde, Uwe
A1  - Poeppl, Andreas
A1  - Strauch, Peter
T1  - 1,10-phenanthroline-dithiolate mixed ligand transition metal complexes : synthesis, characterization and EPR spectroscopy
N2  - A series of new N2S2 mixed ligand transition metal complexes, where N-2 is phenanthroline and S-2 is 1,2- dithiooxalate (dto) or 1,2-dithiosquarate (dtsq), has been synthesized and characterized. IR spectra reveal that the 1,2- dithiolate ligands are coordinated via the sulfur atoms forming a N2S2 coordination sphere. The copper(II) complex [Cu(phen)(dto)] was studied by EPR spectroscopy as a diamagnetically diluted powder. The diamagnetic dilution resulted from doping of the copper complex into the isostructural host lattice of the nickel complex [Ni(phen)(dto)]. The electronic situation in the frontier orbitals of the copper complex calculated from the experimental data is compared to the results of EHT and DFT calculations. Furthermore, one side product, chlorobis(1,10-phenanthroline)copper(I) ethanol solvate hydrate [(phen)(2)CuCl]center dot C2H5OH center dot H2O, was formed by a reduction process and characterized by X-ray diffraction. In the crystal packing one-dimensional columns of dimers are formed, stabilized by significant pi-pi interactions.
Y1  - 2010
UR  - http://www.sciencedirect.com/science/journal/00201693
U6  - https://doi.org/10.1016/j.ica.2010.01.021
SN  - 0020-1693
ER  - 
TY  - JOUR
A1  - Awad, Duha Jawad
A1  - Conrad, Franziska
A1  - Koch, Andreas
A1  - Friedrich, Alwin
A1  - Poeppl, Andreas
A1  - Strauch, Peter
T1  - 2,2'-Bipyridin-1,2-dithiolat Gemischtligand-Komplexe : Systhese, Charakterisierung und EPR-Spektroskopie
N2  - A series of new 2 2'-bipyridine/1 2-dithiolate transition metal complexes has been synthesised and characterised As 1,2-dithiolate ligands 1,2 dithiooxalate (dto) and 1 2-dithiosquarate (dtsq) were used It follows from the IR spectra that the multidentate dithiolate ligands coordinate exclusively via their sulfur atoms forming an MN2S2 coordination sphere The central metal ions (M) are Cu2+ Ni2+ Pd2+ Pt2+, and Zn2+ The complex [Cu-II(bpy)(dto)] could be studied by EPR spectroscopy and was measured as powder diamagnetically diluted in the isostructural [Ni-II(bpy)(dto)] host structure The spin density contribution calculated from the experimental parameters is compared with the electronic situation in the frontier orbitals namely in the semi occupied SOMO of the copper complex derived from quantum chemical calculations on different levels (EHT and DFT)
Y1  - 2010
UR  - http://www.znaturforsch.com/b.htm
SN  - 0932-0776
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Boelke, Ute
A1  - Koch, Andreas
T1  - Subtle Trade-off Existing between (Anti)Aromaticity, Push-Pull Interaction, Keto-Enol Tautomerism, and Steric Hindrance When Defining the Electronic Properties of Conjugated Structures
Y1  - 2010
SN  - 1089-5639
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - Identification of benzenoid and quinonoid structures by through-space NMR shieldings (TSNMRS)
Y1  - 2010
SN  - 1089-5639
ER  - 
TY  - JOUR
A1  - Kleinpeter, Erich
A1  - Koch, Andreas
T1  - Probing the exohedral magnetic properties of C20 derivatives by through space NMR shieldings (TSNMRS)
N2  - The through space NMR shieldings (TSNMRS) of dodecahedrane C20H20, of the isomeric hydrocarbons C20H12, of the ions C20H122+ and C20H122- of the fluxional fullerene C20 and of its dication C202+ have been ab initio calculated employing the NICS concept on basis of MP2/6-31G* geometries and visualized as iso-chemical-shielding/deshielding surfaces (ICSSs). TSNMRS values were employed to study the exohedral magnetic properties of the compounds studied. Hereby, the curved It-conjugation in the compounds studied could be quantified.
Y1  - 2010
UR  - http://www.sciencedirect.com/science/journal/01661280
U6  - https://doi.org/10.1016/j.theochem.2009.09.018
SN  - 0166-1280
ER  -