TY - JOUR A1 - Kleinpeter, Erich A1 - Koch, Andreas T1 - (Anti)aromaticity of dehydroannulenes of various ring size proved by the ring current effect in H-1 NMR spectra JF - Tetrahedron N2 - The spatial magnetic properties (Through-Space NMR Shieldings-TSNMRS) of already synthesized dehydro[n]annulenes of various ring size (from C-12 to C-20) have been computed, visualized as Isochemical Shielding Surfaces (ICSS) of various size and direction, and were examined subject to present (anti)aromaticity. For this purpose the thus quantified ring current effect of the macro cycles on proximate protons in proton NMR spectra was employed. KW - Dehydro[n]annulenes KW - (Anti)aromaticity KW - TSNMRS KW - H-1 NMR spectroscopy KW - Anisotropic effect KW - Theoretical calculations KW - ICSS Y1 - 2013 U6 - https://doi.org/10.1016/j.tet.2012.12.019 SN - 0040-4020 VL - 69 IS - 5 SP - 1481 EP - 1488 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Kammer, Stefan A1 - Starke, Ines A1 - Pietrucha, Andreas A1 - Kelling, Alexandra A1 - Mickler, Wulfhard A1 - Schilde, Uwe A1 - Dosche, Carsten A1 - Kleinpeter, Erich A1 - Holdt, Hans-Jürgen T1 - 1,12-Diazaperylene and 2,11-dialkylated-1,12-diazaperylene iridium(III) complexes [Ir((CN)-N-boolean AND)(2)((NN)-N-boolean AND)]PF6: new supramolecular assemblies JF - Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry N2 - A series of new monocationic iridium(III) complexes [Ir((CN)-N-boolean AND)(2)((NN)-N-boolean AND)]PF6 with "large-surface" alpha,alpha'-diimin ligands (NN)-N-boolean AND (dap = 1,12-diazaperylene, dmedap = 2,11-dimethyl-1,12-diazaperylene, dipdap = 2,11-diisopropyl-1,12-diazaperylene) and different cyclometalating ligands (CN)-N-boolean AND (piq = 1-phenylisoquinoline, bzq = benzo[h]quinoline, ppz = 1-phenylpyrazole, thpy = 2-(2-thienyl)pyridine, ppy = 2-phenylpyridine, meppy = 2-(4-methylphenyl)pyridine, dfppy = 2-(2,4-difluorophenyl)pyridine) were synthesized. The solid structures of the complexes [Ir(piq)(2)(dap)]PF6, [Ir(bzq)(2)(dap)]PF6, [Ir(ppy)(2)(dipdap)]PF6, [Ir(piq)(2)(dmedap)]PF6, [Ir(ppy)(2)(dap)]PF6 and [Ir(ppz)(2)(dap)]PF6 are reported. In [Ir(piq)(2)(dap)]PF6, the dap ligand and one of the piq ligands of each cationic complex are involved in pi-pi stacking interactions forming supramolecular channels running along the crystallographic c axis. In the crystalline [Ir(bzq)(2)(dap)]PF6 pi-pi stacking interactions between the metal complexes lead to the formation of a 2D layer structure. In addition, CH-pi interactions were found in all compounds, which are what stabilizes the solid structure. In particular, a significant number of them were found in [Ir(piq)(2)(dap)]PF6 and [Ir(bzq)(2)(dap)]PF6. The crystal structures of [Ir(ppy)(2)(dipdap)]PF6 and [Ir(ppy)(2)(dmedap)]PF6 are also presented, being the first examples of bis-cyclometalated iridium(III) complexes with phenanthroline-type alpha,alpha'-diimin ligands bearing bulky alkyl groups in the neighbourhood of the N-donor atoms. These ligands implicate a distorted octahedral coordination geometry that in turn destabilized the Ir-N-N boolean AND N bonds. The new iridium (III) complexes are not luminescent. All compounds show an electrochemically irreversible anodic peak between 1.15 and 1.58 V, which is influenced by the different cyclometalated ligands. All of the new complexes show two reversible successive one-electron "large-surface" ligand-centred reductions around -0.70 V and -1.30 V. Electrospray ionisation mass spectrometry (ESI-MS) and collision induced decomposition (CID) measurements were used to investigate the stability of the new complexes. Thereby, the stability agreed well with the order of the Ir-N-N boolean AND N bond lengths. Y1 - 2012 U6 - https://doi.org/10.1039/c2dt30412k SN - 1477-9226 VL - 41 IS - 34 SP - 10219 EP - 10227 PB - Royal Society of Chemistry CY - Cambridge ER - TY - JOUR A1 - Shainyan, Bagrat A. A1 - Kirpichenko, Svetlana V. A1 - Kleinpeter, Erich A1 - Shlykov, Sergey A. A1 - Osadchiy, Dmitriy Yu A1 - Chipanina, Nina N. A1 - Oznobikhina, Larisa P. T1 - 1,3-Dimethy1-3-silapiperidine - synthesis, molecular structure, and conformational analysis by gas-phase electron diffraction, low temperature NMR, IR and Raman Spectroscopy, and quantum chemical calculations JF - The journal of organic chemistry N2 - The first Si-H-containing azasilaheterocycle, 1,3-dimethyl-3-silapiperidine 1, was synthesized, and its molecular structure and conformational properties were studied by gas-phase electron diffraction (GED), low temperature NMR, IR and Raman spectroscopy and quantum chemical calculations. The compound exists as a mixture of two conformers possessing the chair conformation with the equatorial NMe group and differing by axial or equatorial position of the SiMe group. In the gas phase, the SiMeax conformer predominates (GED: ax/eq = 65(7):35(7)%,Delta G = 0.36(18) kcal/mol; IR: ax/eq = 62(5):38(5)%,Delta G = 0.16(7) kcal/mol). In solution, at 143 k the SiMeeq conformer predominates' in the frozen equilibrium (NMR: ax/eq = 31.5(1.5):68.5(1.5)%, Delta G = -0.22(2) kcal/mol). Thermodynamic parameters of the ring inversion are determined (Delta G(double dagger) = 8.9-9.0 kcal/mol, Delta H-double dagger = 9.6 kcal/mol, Delta S-double dagger = 2.1 eu). High-level quantum chemical calculations :(MP2, G2, CCSD(T)) nicely reproduce the experimental geometry and the predominance of the axial conformer in the gas phase. Y1 - 2013 U6 - https://doi.org/10.1021/jo400289g SN - 0022-3263 VL - 78 IS - 8 SP - 3939 EP - 3947 PB - American Chemical Society CY - Washington ER - TY - JOUR A1 - Shainyan, Bagrat A. A1 - Suslova, Elena N. A1 - Tran Dinh Phien, A1 - Shlykov, Sergey A. A1 - Heydenreich, Matthias A1 - Kleinpeter, Erich T1 - 1-Methylthio-1-phenyl-1-silacyclohexane: Synthesis, conformational preferences in gas and solution by GED, NMR and theoretical calculations JF - Tetrahedron N2 - 1-Methylthio-1-phenyl-1-silacyclohexane 1, the first silacyclohexane with the sulfur atom at silicon, was synthesized and its molecular structure and conformational preferences studied by gas-phase electron diffraction (GED) and low temperature C-13 and Si-29 NMR spectroscopy (LT NMR). Quantum-chemical calculations were carried out both for the isolated species and solvate complexes in gas and in polar medium. The predominance of the 1-MeSaxPheq conformer in gas phase (1-Ph-eq :1-Ph-ax = 55:45, Delta G degrees = 0.13 kcal/mol) determined from GED is consistent with that measured in the freon solution by LT NMR (1-Ph-eq:1-Ph-ax = 65:35, Delta G degrees = 0.12 kcal/mol), the experimentally measured ratios being close to that estimated by quantum chemical calculations at both the DFT and MP2 levels of theory. (C) 2019 Elsevier Ltd. All rights reserved. KW - 1-Methylthio-1-phenyl-1-silacyclohexane KW - Conformational analysis KW - Gas phase electron diffraction KW - Low-temperature C-13 and Si-29 NMR KW - DFT and MP2 calculations Y1 - 2019 U6 - https://doi.org/10.1016/j.tet.2019.130677 SN - 0040-4020 VL - 75 IS - 46 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Pihlaja, Kalevi A1 - Sinkkonen, Jari A1 - Stajer, Geza A1 - Koch, Andreas A1 - Kleinpeter, Erich T1 - 1-Oxo-1,3-dithiolanes - synthesis and stereochemistry JF - Magnetic resonance in chemistry N2 - 1-Oxo-1,3-dithiolane (4) and its cis- and trans-2-methyl (5,6), -4-methyl (7,8) and -5-methyl (9,10) derivatives were prepared by oxidizing the corresponding 1,3-dithiolanes (1-3) with NaIO(4) in water. The oxides were purified and their isomers separated using thin layer chromatography. The structural characterization was carried out with (1)H and (13)C NMR spectroscopy and molecular modelling. The sulfoxides 4-6 and 8-10 attain two S(1) type envelopes (sometimes slightly distorted) the S=O(ax) envelope greatly dominating. Cis-4-methyl-1-oxo-1,3-dithiolane is a special case exhibiting both two closely related S=O(ax) (30 and 27%) as well as S=O(eq) (21 and 22%) forms [S(1) and C(4) envelopes, respectively]. The relative energies of these conformations, the values of (1)H-(1)H coupling constants and (1)H and (13)C chemical shifts were estimated by computational methods and they support well the conclusions based on the experimental data. KW - NMR KW - (1)H NMR KW - (13)C NMR KW - sulfur heterocycles KW - conformational analysis KW - computational chemistry Y1 - 2011 U6 - https://doi.org/10.1002/mrc.2764 SN - 0749-1581 VL - 49 IS - 7 SP - 443 EP - 449 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Pihlaja, Kalevi A1 - Sinkkonen, Jari A1 - Stájer, Gezá A1 - Koch, Andreas T1 - 1-Oxo-1,3-dithiolanesùsynthesis and stereochemistry N2 - 1-Oxo-1,3-dithiolane (4) and its cis- andtrans-2-methyl (5,6), -4-methyl (7,8) and -5-methyl (9,10) derivatives were prepared by oxidizing the corresponding 1,3-dithiolanes (1-3) with NaIO4 in water. The oxides were purified and their isomers separated using thin layer chromatography. The structural characterization was carried out with 1H and 13C NMR spectroscopy and molecular modelling. The sulfoxides 4-6 and 8-10 attain two S(1) type envelopes (sometimes slightly distorted) the S=Oax envelope greatly dominating. Cis-4-methyl-1-oxo-1,3-dithiolane is a special case exhibiting both two closely related S=Oax (30 and 27%) as well as S=Oeq (21 and 22%) forms [S(1) and C(4) envelopes, respectively]. The relative energies of these conformations, the values of 1H-1H coupling constants and 1H and 13C chemical shifts were estimated by computational methods and they support well the conclusions based on the experimental data. Y1 - 2011 SN - 0749-1581 ER - TY - JOUR A1 - Thomas, Steffen A1 - Brühl, Iris A1 - Heilmann, Dieter A1 - Kleinpeter, Erich T1 - 13 C NMR Chemical shift calculations for some substituted pyridines - a comparative consideration Y1 - 1997 ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Koch, Andreas A1 - Fischer, G. A1 - Askolin, C.-P. T1 - 13 C NMR, 15 N NMR and quantum-chemical study of the tautomerism of 2-substituted 5-ME-7-OH-1,2,4-triazolo[1,5- a]pyrimidines Y1 - 1997 ER - TY - JOUR A1 - Kleinpeter, Erich A1 - Thomas, Steffen A1 - Fischer, G. T1 - 13C and 15N NMR study of 1,2,4-Triazolo[1,5-a]pyrimidines with one tautomerism-introducing substituent Y1 - 1995 ER - TY - BOOK A1 - Pihlaja, Kalevi A1 - Kleinpeter, Erich T1 - 13C NMR chemical shifts in structural and stereochemical analysis T3 - Methods in stereochemical analysis Y1 - 1994 PB - VCH CY - New York ER -