@article{KleinpeterKoch2013, author = {Kleinpeter, Erich and Koch, Andreas}, title = {(Anti)aromaticity of dehydroannulenes of various ring size proved by the ring current effect in H-1 NMR spectra}, series = {Tetrahedron}, volume = {69}, journal = {Tetrahedron}, number = {5}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2012.12.019}, pages = {1481 -- 1488}, year = {2013}, abstract = {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.}, language = {en} } @article{KammerStarkePietruchaetal.2012, author = {Kammer, Stefan and Starke, Ines and Pietrucha, Andreas and Kelling, Alexandra and Mickler, Wulfhard and Schilde, Uwe and Dosche, Carsten and Kleinpeter, Erich and Holdt, Hans-J{\"u}rgen}, title = {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}, series = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, volume = {41}, journal = {Dalton transactions : a journal of inorganic chemistry, including bioinorganic, organometallic, and solid-state chemistry}, number = {34}, publisher = {Royal Society of Chemistry}, address = {Cambridge}, issn = {1477-9226}, doi = {10.1039/c2dt30412k}, pages = {10219 -- 10227}, year = {2012}, abstract = {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.}, language = {en} } @article{ShainyanKirpichenkoKleinpeteretal.2013, author = {Shainyan, Bagrat A. and Kirpichenko, Svetlana V. and Kleinpeter, Erich and Shlykov, Sergey A. and Osadchiy, Dmitriy Yu and Chipanina, Nina N. and Oznobikhina, Larisa P.}, title = {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}, series = {The journal of organic chemistry}, volume = {78}, journal = {The journal of organic chemistry}, number = {8}, publisher = {American Chemical Society}, address = {Washington}, issn = {0022-3263}, doi = {10.1021/jo400289g}, pages = {3939 -- 3947}, year = {2013}, abstract = {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.}, language = {en} } @article{ShainyanSuslovaTranDinhPhienetal.2019, author = {Shainyan, Bagrat A. and Suslova, Elena N. and Tran Dinh Phien, and Shlykov, Sergey A. and Heydenreich, Matthias and Kleinpeter, Erich}, title = {1-Methylthio-1-phenyl-1-silacyclohexane: Synthesis, conformational preferences in gas and solution by GED, NMR and theoretical calculations}, series = {Tetrahedron}, volume = {75}, journal = {Tetrahedron}, number = {46}, publisher = {Elsevier}, address = {Oxford}, issn = {0040-4020}, doi = {10.1016/j.tet.2019.130677}, pages = {9}, year = {2019}, abstract = {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.}, language = {en} } @article{PihlajaSinkkonenStajeretal.2011, author = {Pihlaja, Kalevi and Sinkkonen, Jari and Stajer, Geza and Koch, Andreas and Kleinpeter, Erich}, title = {1-Oxo-1,3-dithiolanes - synthesis and stereochemistry}, series = {Magnetic resonance in chemistry}, volume = {49}, journal = {Magnetic resonance in chemistry}, number = {7}, publisher = {Wiley-Blackwell}, address = {Malden}, issn = {0749-1581}, doi = {10.1002/mrc.2764}, pages = {443 -- 449}, year = {2011}, abstract = {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.}, language = {en} } @article{KleinpeterPihlajaSinkkonenetal.2011, author = {Kleinpeter, Erich and Pihlaja, Kalevi and Sinkkonen, Jari and St{\´a}jer, Gez{\´a} and Koch, Andreas}, title = {1-Oxo-1,3-dithiolanes{\`u}synthesis and stereochemistry}, issn = {0749-1581}, year = {2011}, abstract = {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.}, language = {en} } @article{ThomasBruehlHeilmannetal.1997, author = {Thomas, Steffen and Br{\"u}hl, Iris and Heilmann, Dieter and Kleinpeter, Erich}, title = {13 C NMR Chemical shift calculations for some substituted pyridines - a comparative consideration}, year = {1997}, language = {en} } @article{KleinpeterKochFischeretal.1997, author = {Kleinpeter, Erich and Koch, Andreas and Fischer, G. and Askolin, C.-P.}, title = {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}, year = {1997}, language = {en} } @article{KleinpeterThomasFischer1995, author = {Kleinpeter, Erich and Thomas, Steffen and Fischer, G.}, title = {13C and 15N NMR study of 1,2,4-Triazolo[1,5-a]pyrimidines with one tautomerism-introducing substituent}, year = {1995}, language = {en} } @book{PihlajaKleinpeter1994, author = {Pihlaja, Kalevi and Kleinpeter, Erich}, title = {13C NMR chemical shifts in structural and stereochemical analysis}, series = {Methods in stereochemical analysis}, journal = {Methods in stereochemical analysis}, publisher = {VCH}, address = {New York}, year = {1994}, language = {en} }