TY - JOUR A1 - Finze, Maik A1 - Reiss, Guido J. T1 - Trimethyl­sulfonium 1-amino-6-fluoro-2,3,4,5,7,8,9,10,11,12-decaiodo-1-carba-closo-dodeca­borate N2 - no abstract available KW - Chemie KW - single-crystal X-ray study KW - T = 100 K KW - wR factor = 0.052 KW - data-to-parameter ratio = 20.8 Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75397 ER - TY - JOUR A1 - Finze, Maik A1 - Reiss, Guido J. A1 - Frohn, Hermann-Josef T1 - 2,3,5,6-Tetrafluoro-1,4-bis(trimethylsilyl)benzene N2 - no abstract available KW - Chemie KW - single-crystal X-ray study KW - T = 199 K KW - R factor = 0.027 KW - wR factor = 0.068 KW - data-to-parameter ratio = 14.0. Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-75401 ER - TY - JOUR A1 - Braunschweig, Holger A1 - Arnold, Thomas A1 - Gruss, Katrin T1 - cyclo-Tri-mu-oxido-tris{[(eta 5,eta 5)-1,2-bis(cyclopentadienyl)-1,1,2,2-tetramethyldisilane]zirconium(IV)}: atrimeric disila-bridged oxidozirconocene N2 - no abstract available KW - Chemie KW - single-crystal X-ray study KW - T = 174 K KW - R factor = 0.027 KW - wR factor = 0.069 KW - data-to-parameter ratio = 23.6. Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-74737 ER - TY - JOUR A1 - Bringmann, Gerhard A1 - Hartung, Thomas A1 - Goebel, Lothar A1 - Schupp, Olaf A1 - Ewers, Christian L. J. A1 - Schoener, Bernd A1 - Zagst, Rainer A1 - Peters, Karl A1 - Von Schnering, Hans Georg A1 - Burschka, Christian T1 - Novel concepts in directed biaryl synthesis, IX: Synthesis and structure of benzonaphthopyranones, useful bridged model precursors for stereoselective biaryl syntheses N2 - A practicable two-step procedure for the preparation of a series of lactone-type bridged biaryls 7 as favorable substrates for subsequent atropisomer-selective ring-opening reactions is described. Due to the efficiency of the coupling step, which tolerates even a telt·butyl group next to the biaryl axis and avoids problems of regioselectivity, a variety of differently substituted representatives is prepared. These cover a broad range of steric hindrance and thus molecular distortion. The structures are investigated mainly by NMR spectroscopy and X-ray diffraction, showing the lactones 7 to be helically distorted, depending on the size of the residues R. KW - Chemie Y1 - 1992 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-46635 ER - TY - JOUR A1 - Bringmann, Gerhard A1 - Zagst, Rainer A1 - Schöner, Bernd A1 - Busse, Holger A1 - Hemmerling, Martin A1 - Burschka, Christian T1 - Acetogenic Isoquinoline Alkaloids. XXIII. Structure of the Naphthyl Isoquinoline Alkaloid Dioncophylline A N2 - No abstract available KW - Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31331 ER - TY - JOUR A1 - Kaupp, Martin A1 - Schleyer, P. v. R. A1 - Stoll, H. A1 - Preuss, H. T1 - Pseudopotential Approaches to Ca, Sr and Ba Hybrides. Why are some Alkaline Earth MX\(_2\) Compounds Bent? N2 - Quasirelativistic and nonrelativistic lo-valence-electronp seudopotentialsf or Ca, Sr, and Ba are presented. Results of calculations with 6s6p5d basis sets for MH, MH\(^+\) , and MH\(_2\), are compared with all-electron and 2-valence-electron pseudopotential calculations with and , without core-polarization potentials. The lo-valence-electron pseudopotential approach agrees well with all-electron calculations. It circumvents problems for the 2-valence-electron pseudopotentials arising from an incomplete separation of valence and subvalence shells in polar molecular systems due to strongly contracted occupied (n - 1 )-d orbitals. All higherlevel calculations show SrH\(_2\) and BaII\(_2\), to be bent with angles of - 140° and 120°, respectively, while CaH\(_2\) is linear with a flat potential-energy surface for the bending motion. The use of a core-polarization potential together with the 2-valence-electronp seudopotentiala pproach allows an investigation of the relative importance of core-polarization vs direct d-orbital bonding participation as reasons for the bent structures. The calculations strongly suggest that both contribute to the bending in SrH\(_2\) and BaII\(_2\). Even at the Hartree-Fock level of theory lovalence- electronp seudopotentialc alculations given reasonablea nglesw hen the potentialenergy surface is not exceedingly flat, and only moderately contracted basis sets including both compact d functions and diffuse p functions are used. The effect of core-valence correlation and the importance off functions also are discussed. KW - Chemie Y1 - 1991 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31646 ER - TY - JOUR A1 - Ries, Wolfgang A1 - Albright, Thomas A1 - Silvestre, Jerome A1 - Bernal, Ivan A1 - Malisch, Wolfgang A1 - Burschka, Christian T1 - Unusual structural features of a siloxane N2 - Crystals of the R, S diastereoisomer of [Cp(CO)\(_2\)-FeSiCH\(_3\)F]\(_2\)O are monoclinic, space group ndc (No. 14), with a = 846.0(3) [836.4(1»), b = 768.0(3) [757.1(1»), c = 1548.5(4) [1522.3(2)] pm, {3 = 97.34(3t [97.47(3t] at 300 K [120 K] with Z = 2. Even at 120 K the Si-O-Si fragment is found to be strictly linear due to crystallographically imposed symmetry. To explain the unusual electron distribution derived from the X-ray data collected, several types of possible disorders are discussed, none of which leads to a satisfying explanation. Retaining the Ci symmetry (linear Si-O-Si fragment in the final model) the important bond lengths are Fe-Si 226.7(1) [226.5(1)] pm, Si-F 160.9(2) [161.8(2)] pm, Si-O 160.3(1) [161.1(1)] pm, Si-C 185.0(3) [185.6(3)] pm. The electronic features of this compound were probed via molecular orbital calculations of the extended Hiickel type. It was found that the lone pairs on the siloxane oxygen were tipped away from cylindrical symmetry. The tipping was directed toward the fluorine substituents on the silicon atoms and away from the CpFe(CO)\(_2\) units. A pertubational approach was utilized to rationalize this effect. KW - Chemie Y1 - 1986 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31925 ER - TY - JOUR A1 - Kuehn, A. A1 - Burschka, Christian A1 - Werner, H. T1 - Synthesis and molecular structure of C\(_5\)H\(_5\)(P-/-Pr\(_3\))Pd(η\(^1\), η\(^3\)-C\(_3\)H\(_4\))Pd(P-/-Pr\(_3\))Br: a compound formed through insertion of allene into a metal-metal bond\(^1\) N2 - No abstract available KW - Chemie Y1 - 1982 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-46592 ER - TY - JOUR A1 - Peach, Michael E. A1 - Burschka, Christian T1 - Metal carbonyl complexes of some aromatic ortho bis(methylthio)ethers N2 - Various complexes of the type M(CO)4L and [M(CO)4lzL, M = Cr, Mo, W, have been prepared and characterized. A series of aromatic ortho bis(methylthio)ethers were used as the ligand L. The crystal structures of the free ligand C6(SCH)6 and of the complex Cr(CO)4C6(SCH)6 are reported. N2 - On a prepare divers complexes du type M(CO)4L et [M(CO)4]2L, ou M = Cr, Mo, W, et on les a identifies. On a utilise une serie d'ortho bis (methylthio) ethers aromatiques comme ligand L. On rapporte la structure cristalIine du ligand libre C6(SCH)6 et celle du complexe Cr(CO)4C6(SCH)6. KW - Chemie Y1 - 1982 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31964 ER -