Pyridin-Borabenzol und Pyridin-2-Boranaphthalin als Liganden von Metallen der Chromgruppe / Pyridine-borabenzene and Pyridine-2-boranaphthaline as Ligands of Group 6 A Metals

1985 ◽  
Vol 40 (10) ◽  
pp. 1327-1332 ◽  
Author(s):  
Roland Boese ◽  
Norbert Finke ◽  
Thomas Keil ◽  
Peter Paetzold ◽  
Günter Schmid
Keyword(s):  
Membered Ring ◽  
X Ray ◽  
Group 6 ◽  
Structure Determinations

Pyridine-borabenzene (1) and pyridine-2-boranaphthalene (2) can be coordinated to group 6A metals M to form compounds of the type (OC)3M·1 and (OC)3M·2, respectively. X-ray structure determinations prove the ligands to be η6-bonded to the metal via the boron-containing six-membered ring.

Funktionelle Trimethylphosphanderivate, XXVI [1]. Silylsubstituierte Phosphinomethane und Lithiumphosphinomethanide / Functional Trimethylphosphine Derivatives, XXVI [1] Silyl-substituted Phosphinomethanes and Lithiumphosphinomethanides

1988 ◽  
Vol 43 (11) ◽  
pp. 1416-1426 ◽  
Author(s):  
Hans H. Karsch ◽  
Armin Appelt ◽  
Brigitte Deubelly ◽  
Karin Zellner ◽  
Jürgen Riede ◽  
...  
Keyword(s):  
Membered Ring ◽  
Marked Influence ◽  
X Ray ◽  
Phosphorus Forms ◽  
Twist Conformation ◽  
Structure Determinations

The lithium phosphinomethanides LiCH(X)(PMe2) (X = H, PMe2 SiMe3) react with Me3SiCl to give silylsubstituted phosphinomethanes CH(X)(PMe2)(SiMe3). The latter are metalated by LiR (R = tBu, nBu). This metalation is facilated by the presence of Me2NCH2CH2NMe2 (TMEDA). X-ray structure determinations of {(TMEDA)Li[CH(PMe2)(SiMe3)]}2 (3b) and (TMEDA){Li[C(PMe2)(SiMe3)2]}2 (5b) show the marked influence of increasing silyl substitution on the structures of lithium phosphinomethanides: the Li-C contacts are weakened, whereas phosphorus forms additional (bridging) Li···P contacts to the second Li atom in the dimeric arrangements. In 3b, a six-membered ring in twist conformation is formed by head-to-tail dimerization. Likewise, 5b forms a six-membered ring, in this case by head-to-head dimerization. however, which may be regarded as a complex of a chelating phosphinomethyl lithiate ligand to [(TMEDA)Li]+ .

Cyclische Diazastannylene, XXX [1] Symmetrisch und asymmetrisch substituierte German- und Stannandiyle mit Amid-, Alkoholat- und Thiolat-Liganden, Teil I [2] / Cyclic Diazastannylenes, XXX [1] Symmetrically and Asymmetrically Substituted Germane- and Stannanediyls with Amide, Alcoholate and Thiolate Ligands, Part I [2]

1989 ◽  
Vol 44 (9) ◽  
pp. 1067-1081 ◽  
Author(s):  
M. Veith ◽  
P. Hobein ◽  
R. Rösler
Keyword(s):  
Chelate Ring ◽  
Membered Ring ◽  
Aluminium Atom ◽  
X Ray ◽  
Thiolate Ligands ◽  
Trigonal Bipyramidal ◽  
Tetrahedral Environment ◽  
Homologous Compounds ◽  
Structure Determinations ◽  
Tert Butylamine

Chelates of Ge(II) and Sn(II)Symmetrically and unsymmetrically substituted germane- and stannanediyls as well as chelated bis(amino)- or aminooxogermanium- and -tinmonohalides have been obtained from cyclic bis(amino)germane- and stannanediyls by treatment with tert-butylamine, tert-butanol and tert-butylmercaptane. The following compounds have been synthesized: GeX2 (X = OtBu (5), StBu (6)), Sn(StBu), (9), GeXCl (X = N(H)tBu (21), OtBu (22)), SnXCl (X = N(H)tBu (23), OtBu (24), StBu (25), OMe (28)) and Sn(OtBu)Br (27). In the series of the chelates Me2Si(NtBu)(NHtBu)GeCl (13), Me2Si(NtBu)(OtBu)SnX (X = Cl (18), OMe (19)) and the bischelate [Me2Si(NtBu)(OtBu)]2Sn (20) have been prepared. When 18 is allowed to react with aluminiumtrimethyl Me2Si(NtBu)(OtBu)AlClMe is formed, a compound with a center of chirality at the aluminium atom. X-ray structure determinations have been performed on single crystals of 6, 8, 9, 13, 22 and 24. 6, 8, 22 and 24 form molecular dimers with c.n. of 3 at the Ge or Sn atoms, resp. While the tBu-S ligands are syn with respect to the central Ge2S2 ring in 6 (symmetry approaching C2v), the tBu-O ligands are anti to the central Sn2O2 ring in 8 (symmetry Ci). 9 forms a coordination polymer with all Sn atoms in a Ψ-trigonal-bipyramidal and all S atoms in a Ψ-tetrahedral environment. The germanium atom in 13 is coordinated by a chlorine, a λ3- and a λ4-nitrogen atom, the two nitrogen atoms being connected by as dimethylsilyl group. The hydrogen and chlorine atom of 13 are found at the same side of the four-membered chelate ring. The two unsymmetrically substituted, homologous compounds Ge(O/tBu)Cl (22) and Sn(OtBu)Cl (24) are found to form dimers via O→Ge resp. O→Sn bonds. While the chlorine atoms in 22 are syn with respect to the four-membered ring, they are anti in the case of molecule 24.

Alternant Bond Distances in Octaethylporphyrin π-Cation Radicals

2017 ◽  
Vol 21 (04-06) ◽  
pp. 273-286 ◽  
Author(s):  
W. Robert Scheidt ◽  
Beisong Cheng ◽  
K. Venugopal Reddy ◽  
Kristin E. Brancato
Keyword(s):  
Nickel Complex ◽  
Bond Distance ◽  
Solvent System ◽  
Membered Ring ◽  
The Other ◽  
X Ray ◽  
Cation Radicals ◽  
Structure Determinations ◽  
Jahn Teller ◽  
Ring Pair

The possible appearance and nature of alternant bond distance patterns in the inner 16-membered ring of several octaethylporphyrin [Formula: see text]-cation radicals has been investigated. This study was made possible by recognizing an unexpected solvent system, namely dichloromethane/chloroform, even though the [Formula: see text]-cation species have extremely limited solubility in chloroform. A total of six [M(OEP[Formula: see text]][Formula: see text] derivatives were studied by single-crystal X-ray structure determinations. Two new zinc derivatives display, quantitatively, the same alternant pattern observed previously. A new nickel complex shows a smaller but now probably significant alternant pattern. However, a copper derivative, independently analyzed twice, shows no evidence for an alternant pattern. The importance of ring–ring interactions on the energy of the top two orbitals is shown by two distinct magnesium derivatives. The derivative with strongly overlapped rings displays an alternant bond distance pattern, whereas the other, with a modestly overlapped ring pair, does not. This suggests the importance of strong ring–ring interactions in leading to a pseudo-Jahn-Teller state; this hypothesis is also supported by other prior results.

Sterisch belastete cyclische Phosphanborane / Sterically Crowded Cyclic Phosphine-Boranes

1993 ◽  
Vol 48 (9) ◽  
pp. 1248-1256 ◽  
Author(s):  
Gerhard Müller ◽  
Joachim Lachmann
Keyword(s):  
Solid State ◽  
Coordination Mode ◽  
Conclusive Evidence ◽  
Membered Ring ◽  
X Ray ◽  
Butyl Group ◽  
Tert Butyl Group ◽  
Structure Determinations ◽  
New Compounds ◽  
Boron Center

The anionic phosphine o-(diphenylphosphinomethyl)phenyl L has been used to prepare the sterically crowded cyclic phosphine-boranes BL3, tBuBL2, and tBu2BL by reaction of the lithiated ligand LiL with B(OMe)3, tBuB(OMe)2, and tBu2BOMe, respectively. In the new compounds tBuBL2 and tBu2BL one ligand L is bonded to the boron center by both its carbanionic and its phosphino function with formation of five-membered rings. In solution 11B and 31P NMR spectroscopy does not indicate substantial B—P dissociation, i.e., the existence of threecoordinate boron. The steric bulk of L in BL3 leads to the formation of oligomers in solution, presumably by a bridging coordination mode of L to two boron centers. No conclusive evidence as to the monomeric or oligomeric nature of BL3 in the solid state can be given, however. Five-membered ring formation is proven for the solid state by X-ray structure determinations of tBuBL2 and tBu2BL which in addition confirm that the steric bulk of L is superior to that of a tert. butyl group.

Synthesis, characterization and X-ray studies of new chiral five-six-membered ring, [4.3.0] heterobicyclic system of monomeric boronates

2011 ◽  
Vol 696 (11-12) ◽  
pp. 2420-2428 ◽  
Author(s):  
José María Rivera ◽  
Susana Rincón ◽  
Norberto Farfán ◽  
Rosa Santillan
Keyword(s):  
Membered Ring ◽  
X Ray

Bestimmung von innermolekularen Torsionswinkeln aus Hyperfeinstruktur-Aufspaltungen und g-Faktoren

1965 ◽  
Vol 20 (9) ◽  
pp. 1117-1121 ◽  
Author(s):  
K. Möbius
Keyword(s):  
Electron Diffraction ◽  
Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Small Amplitude ◽  
Membered Ring ◽  
Radical Ions ◽  
Hydrogen Atoms ◽  
Stereochemical Structure ◽  
X Ray ◽  
Phenyl Rings

The stereochemical structure of aromatic hydrocarbons in solution being overcrowded with hydrogen atoms is not known with certainty, because the conventional X-ray and electron diffraction methods are suitable only for samples in the crystalline and vapor phase. Using EPR spectroscopy for the aromatic hydrocarbon radicals biphenyl (—), phenanthrene (—) and pentaphenylcyclopentadienyl (PPCPD) innermolecular twist and bond angles could be determined by means of hfssplittings and g-factors. Stably solvated biphenyl radical ions are found to have twist angles of 38 ±2°; phenanthrene ions turn out to be planar but change their angles of hybridization at particular positions; in the PPCPD radical the phenyl rings oscillate with small amplitude around planes orthogonal to the five-membered ring.

Preparations, X-ray crystal structure determinations, and base strength measurements of substituted tritylamines

2000 ◽  
pp. 85-92 ◽  
Author(s):  
Moisés Canle L. ◽  
William Clegg ◽  
Ibrahim Demirtas ◽  
Mark R. J. Elsegood ◽  
Howard Maskill
Keyword(s):  
Crystal Structure ◽  
X Ray ◽  
Structure Determinations ◽  
Base Strength
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