@article{LazarevaShainyanKleinpeter2010,
  author    = {Lazareva, Nataliya F. and Shainyan, Bagrat A. and Kleinpeter, Erich},
  title     = {4-Alkyl-2,2,6,6-tetramethyl-1,4,2,6-oxaazadisilinanes : synthesis, structure, and conformational analysis},
  issn      = {0894-3230},
  doi       = {10.1002/Poc.1605},
  year      = {2010},
  abstract  = {4-Alkyl-2,2,6,6-tetramethyl-1,4,2,6-oxaazadisilinanes RN[CH2Si(Me)2]2O [R = Me (1), i-Pr (2)] were synthesized by two methods which provided good yields up to 84\%. Low temperature NMR study of compounds (1) and (2) revealed a frozen ring inversion with the energy barriers of 8.5 and 7.7 kcal/mol at 163 and 143 K, respectively, which is substantially lower than that for their carbon analog, N-methylmorpholine. DFT calculations performed on the example of molecule (1) showed that N-Meax conformer to exist in the sofa conformation with the coplanar fragment C-Si-O-Si-C, and its N-Meeq conformer in a flattened chair conformation.},
  language  = {en}
}
@article{KleinpeterBoelkeKoch2010,
  author    = {Kleinpeter, Erich and Boelke, Ute and Koch, Andreas},
  title     = {Subtle Trade-off Existing between (Anti)Aromaticity, Push-Pull Interaction, Keto-Enol Tautomerism, and Steric Hindrance When Defining the Electronic Properties of Conjugated Structures},
  issn      = {1089-5639},
  year      = {2010},
  language  = {en}
}
@article{KirpichenkoKleinpeterShainyan2010,
  author    = {Kirpichenko, Svetlana V. and Kleinpeter, Erich and Shainyan, Bagrat A.},
  title     = {Conformational analysis of 3,3-dimethyl-3-silathiane, 2,3,3-trimethyl-3-silathiane and 2-trimethylsilyl-3,3- dimethyl-3-silathiane{\`u}preferred conformers, barriers to ring inversion and substituent effec},
  issn      = {0894-3230},
  year      = {2010},
  abstract  = {The first conformational analysis of 3-silathiane and its C-substituted derivatives, namely, 3,3-dimethyl-3- silathiane 1, 2,3,3-trimethyl-3-silathiane 2, and 2-trimethylsilyl-3,3-dimethyl-3-silathiane 3 was performed by using dynamic NMR spectroscopy and B3LYP/6-311G(d,p) quantum chemical calculations. From coalescence temperatures, ring inversion barriers ;G; for 1 and 2 were estimated to be 6.3 and 6.8;kcal/mol, respectively. These values are considerably lower than that of thiacyclohexane (9.4;kcal/mol) but slightly higher than the one of 1,1- dimethylsilacyclohexane (5.5;kcal/mol). The conformational free energy for the methyl group in 2 (;;G°;=;0.35;kcal/mol) derived from low-temperature 13C NMR data is fairly consistent with the calculated value. For compound 2, theoretical calculations give ;E value close to zero for the equilibrium between the 2-Meax and 2-Meeq conformers. The calculated equatorial preference of the trimethylsilyl group in 3 is much more pronounced (;;G°;=;1.8;kcal/mol) and the predominance of the 3-SiMe3 eq conformer at room temperature was confirmed by the simulated 1H NMR and 2D NOESY spectra. The effect of the 2-substituent on the structural parameters of 2 and 3 is discussed.},
  language  = {en}
}
@article{KleinpeterKoch2010,
  author    = {Kleinpeter, Erich and Koch, Andreas},
  title     = {Identification of benzenoid and quinonoid structures by through-space NMR shieldings (TSNMRS)},
  issn      = {1089-5639},
  year      = {2010},
  language  = {en}
}
@article{KleinpeterBoelkeKreicberga2010,
  author    = {Kleinpeter, Erich and Boelke, Ute and Kreicberga, Jana},
  title     = {Quantification of the push-pull character of azo dyes and a basis for their evaluation as potential nonlinear optical materials},
  issn      = {0040-4020},
  year      = {2010},
  abstract  = {The push-pull characters of a large series of donor-acceptor substituted azo dyes{\`u}71 structures in all{\`u}have been quantified by the NN double bond lengths, dNN, the 15N NMR chemical shift differences, ;;15N, of the two nitrogen atoms and the quotient, ;*/;, of the occupations of the antibonding ;*, and bonding ; orbitals of this partial NN double bond. The excellent correlation of the occupation quotients with the bond lengths strongly infers that both ;*/; and dNN are excellent parameters for quantifying charge alternation in the push-pull chromophore and the molecular hyperpolarizability, ;0, of these compounds. By this approach, selected compounds can be appropriately considered as viable candidates for nonlinear optical (NLO) applications.},
  language  = {en}
}
@article{FettkeKramerKleinpeter2010,
  author    = {Fettke, Anja and Kramer, Markus and Kleinpeter, Erich},
  title     = {Lectin-bound conformations and non-covalent interactions of glycomimetic analogs of thiochitobiose},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2010.04.012},
  year      = {2010},
  abstract  = {The bound conformations of five S-glycoside analogs of N,N'-diacetylchitobiose as well as their non- covalent interactions with two lectins, Phytolacca americana lectin (PAL) and wheat germ agglutinin (WGA), are reported. The conformations of the ligands were examined by trNOESY experiments and compared with the free, solution-state conformations and molecular modeling data obtained by force field calculations. In the case of S-aryl, S-glycosides with exclusively S-glycosidic linkages, similar free and lectin-bound conformations and non-covalent interactions were found, whereas they differed for mixed glycosides and for a thiazoline derivative. In addition, STD (saturation transfer difference) NMR magnetization transfer efficiencies at three different temperatures were determined and assessed with respect to the structural differences of these pseudosaccharides. The binding epitopes of each substrate with PAL and WGA were also determined.},
  language  = {en}
}
@article{deAraujoChaconCarneiroetal.2010,
  author    = {de Araujo, Martha T. and Chacon, Eluzir P. and Carneiro, Jos{\´e} W. de M. and Koch, Andreas and Kleinpeter, Erich},
  title     = {Analysis of anisotropic effects in trinuclear metal carbonyl compounds by visualization of through-space NMR shielding},
  issn      = {1610-2940},
  doi       = {10.1007/s00894-010-0662-3},
  year      = {2010},
  abstract  = {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.},
  language  = {en}
}
@article{KihampaNkunyaJosephetal.2010,
  author    = {Kihampa, Charles and Nkunya, Mayunga H. H. and Joseph, Cosam C. and Magesa, Stephen M. and Hassanali, Ahmed and Heydenreich, Matthias and Kleinpeter, Erich},
  title     = {Antimosquito and antimicrobial clerodanoids and a chlorobenzoid from Tessmannia species},
  issn      = {1934-578X},
  year      = {2010},
  abstract  = {The clerodane diterpenoids trans-kolavenolic acid, 18-oxocleroda-3,13(E)-dien-15-oic acid, ent-(18- hydroxycarbonyl)-cleroda- 3,13(E)-dien-15-oate, 2-oxo-ent-cleroda-3,13(Z)-dien-15-oic acid and trans-2-oxo-ent-cleroda- 13(Z)-en-15-oic acid, and the chlorobenzenoid O-(3-hydroxy-4-hydroxycarbonyl-5-pentylphenyl)-3-chloro-4-methoxy-6-pentyl- 2-oxybenzoic acid were isolated from Tessmannia martiniana var pauloi and T. martiniana var matiniana. Structures were established based on interpretation of spectroscopic data. Some of the compounds exhibited significant antimosquito, antifungal and antibacterial activities.},
  language  = {en}
}
@article{KleinpeterKoch2010,
  author    = {Kleinpeter, Erich and Koch, Andreas},
  title     = {Probing the exohedral magnetic properties of C20 derivatives by through space NMR shieldings (TSNMRS)},
  issn      = {0166-1280},
  doi       = {10.1016/j.theochem.2009.09.018},
  year      = {2010},
  abstract  = {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.},
  language  = {en}
}
@article{KramerKleinpeter2010,
  author    = {Kramer, Markus and Kleinpeter, Erich},
  title     = {STD-DOSY : a new NMR method to analyze multi-component enzyme/substrate systems},
  issn      = {1090-7807},
  doi       = {10.1016/j.jmr.2009.11.007},
  year      = {2010},
  abstract  = {A new approach to analyze multi-component Saturation Transfer Difference (STD) NMR spectra by combining the STD and the DOSY experiment is proposed. The resulting pulse sequence was successfully used to simplify an exemplary multi- component protein/substrate system by means of standard DOSY processing methods. Furthermore, the same experiment could be applied to calculate the ratio of saturated substrate molecules and its saturation rate in the case of competitive interactions. This ratio depends on the strength of this interaction between the substrates and the protein, so that this kind of information could be extracted from the results of our experiment.},
  language  = {en}
}
@article{BaranacStojanovicKlaumuenzerMarkovicetal.2010,
  author    = {Baranac-Stojanovic, Marija and Klaumuenzer, Ute and Markovic, Rade and Kleinpeter, Erich},
  title     = {Structure, configuration, conformation and quantification of the push pull-effect of 2-alkylidene-4- thiazolidinones and 2-alkylidene-4,5-fused bicyclic thiazolidine derivatives},
  issn      = {0040-4020},
  doi       = {10.1016/j.tet.2010.09.040},
  year      = {2010},
  abstract  = {Structures of a series of push-pull 2-alkylidene-4-thiazolidinones and 2-alkylidene-4,5-fused bicyclic thiazolidine derivatives were optimized at the B3LYP/6-31G(d) level of theory in the gas phase and discussed with respect to configurational and conformational stability. Employing the GIAO method, C-13 NMR chemical shifts of the C-2, C-2', C-4 and C-5 atoms were calculated at the same level of theory in the gas phase and with inclusion of solvent, and compared with experimental data. Push-pull effect of all compounds was quantified by means of the quotient pi*/pi, length of the partial double bond, C-13 NMR chemical shift difference (Delta delta(C=C)) and H-1 NMR chemical shifts of olefinic protons. The effect of bromine on donating and accepting ability of other substituents of the push- pull C=C double bond is discussed, too.},
  language  = {en}
}
@article{StarkeKammerHoldtetal.2010,
  author    = {Starke, Ines and Kammer, Stefan and Holdt, Hans-J{\"u}rgen and Kleinpeter, Erich},
  title     = {Stability of disubstituted copper complexes in the gas phase analyzed by electrospray ionization mass spectrometry},
  issn      = {0951-4198},
  doi       = {10.1002/Rcm.4519},
  year      = {2010},
  abstract  = {A series of nitrogen ligand (L)/copper complexes of the type [(CuL)-L-I](+), [(CuL)-L-II(X)](+) and [(CuL2)-L- I](+) (X = Cl-, BF4-, acac(-), CH3COO- and SO3CF3-) was studied in the gas phase by electrospray ionization mass spectrometry. The following ligands (L) were employed: 1,12-diazaperylene (dap), 1,1'-bisiso-quinoline (bis), 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 2,11-disubstituted 1,12-diazaperylenes (dap), 3,3'- disubstituted 1,1'-bisisoquinoline (bis), 5,8-dimethoxy-substituted diazaperylene (meodap), 6,6'-dimethoxy- substituted bisisoquinoline (meobis) and 2,9-dimethyl-1,10-phenanthroline (dmphen). Collision-induced decomposition measurements were applied to evaluate the relative stabilities of the different copper complexes. The influence of the spatial arrangement of the ligands, of the type of substituents and of the counter ion of the copper salts employed for the complexation was examined. Correlations were found between the binding constants of the [ML2](+) complexes in solution and the relative stabilities of the analogous complexes in the gas phase. Furthermore, complexation with the ligands 2,11-dialkylated 1,12-diazaperylenes [alkyl = ethyl (dedap) and isopropyl (dipdap)] was studied in the solvents CH3OH and CH3CN.},
  language  = {en}
}