Karl Hensen

Coordinative interactions in chelated complexes of boron and silicon: VI. Multinuclear magnetic resonance of 1,2,3,4,-tetrahydro-1,10-phenanthroline-boron and -silicon complexes

Abstract The 1H, 13C, 29Si, and natural abundance 15 N NMR spectra have been measured for a series of 1,2,3,4-tetrahydro-1,10-phenanthroline-boron and -silicon complexes which have methyl and/or halogen substituents on the central atom. The 29Si spectra for four analogous naphtholesilicon and hydroxyquinolinesilicon complexes have been recorded for comparison. The variation of chemical shifts in the series of compounds indicates a transfer of electron density from the ligand moiety to the central atom as a result of intramolecular coordinative interaction. In the series of the silicon complexes there is a transition from four- to five-fold coordination when the methyl substituents at the central Si atom are replaced by halogens.

Darstellung von N-BZW. O-chlormethylsilyl-derivaten der amine 1,2,3,4-tetrahydro-1,10-phenanthrolin und 8-hydroxychinolin

Abstract The reaction of N- or O-lithium salts of 1,2,3,4-tetrahydro-1,10-phenanthroline and 8-hydroxyquinoline with chloromethylsilanes MenSiCl4-n (n = 0, 1, 2, 3) leads to substitution of chlorine at the silicon atom by the nitrogen- or oxygen-bonded amine. In the case of tetrahydrophenanthroline (C12H12N2) the compounds (C12H11N2)SiMenCl3-n (n = 0, 1, 2, 3) were isolated. Depending on the number of chlorine atoms in the silane the lithium salt of 8-hydroxyquinoline (C9H7NO) reacts by single or double exchange of chlorine to give (C9H6NO)SiMenCl3-n (n = 2, 3) and (C9H6NO)2SiMenCl2-n (n = 0, 1).

Spektroskopische und theoretische Untersuchungen am Borazolmolekül und seinen Bortrihalogenoderivaten

Hückel-MO calculations are performed for Borazine and the B-Trihalogenoborazines; the parameters used are calibrated with the UV-spectra, which had either been measured here or obtained from the literature. The calculated π-electron densities compare favorably well with the 11B- and 14N-nuclear magnetic resonances determined for the above mentioned compounds.ZusammenfassungEs werden Hückel-MO-Rechnungen am Borazol und den B-Trihalogenoborazolen durchgeführt und die entsprechenden Parameter an den teils bekannten und teils gemessenen UV-Spektren geeicht. Die für diese Verbindungen bestimmten chemischen Verschiebungen der 11B- und 14N-Kernresonanz lassen sich mit den berechneten π-Elektronendichten erklären.RésuméLe borazole et les B-trihalogenoborazoles sont calculés par la méthode de Hückel en utilisant des paramètres calibrés sur les spectres U.V. mesurés ou obtenus dans la littérature. Les densités électroniques π sont en bon accord avec le déplacement chimique de N.M.R. de 11B et 14N déterminé pour les composés cidessus.

Statistische Modellrechnungen an den Molekülen CH4, SiH4, GeH4, SnH4 und PbH4 nach der Einzentrenmethode

OCE-calculations are reported for ground state energies and bond distances of the hydrides CH4, SiH4, GeH4, SnH4 and PbH4. The statistical atom model (Gombás and Ladányi [1]) is connected with the noble gas model (Hartmann and Gliemann [2]). The results are in good agreement with known experimental values. Bond distance and ground state energy of PbH4 are presented for the first time.ZusammenfassungMit einem Einzentren-Ansatz werden Bindungsabstände und Gesamtenergien der Moleküle CH4, SiH4, GeH4, SnH4 und PbH4 berechnet. Die statistische Betrachtungsweise der Elektronen nach Gombás und Ladányi [1] wird mit der Edelgas-Modellvorstellung nach Hartmann und Gliemann [2] verknüpft. Die Ergebnisse liegen in guter Übereinstimmung mit den vorliegenden experimentellen Daten. Bindungsabstand und Gesamtenergie des Moleküls PbH4 werden erstmals berechnet.

Umsetzung von gemischten Siliciumhalogeniden und von Halogendisilanen mit Pyridin und 1,10-Phenanthrolin

ZusammenfassungDie Reaktion gemischter Siliciumhalogenide mit Pyridin (=py) oder 1,10-Phenanthrolin (=phen) führte zu den Additionsverbindungen SiClBr3(py)2, SiClBr3(phen), SiCl3Br(py)2, SiCl3Br(phen), SiCl2J2(py)4, SiCl2J2(phen), SiCl3J(py)3 und SiCl3J(phen). Eine Dismutation der gemischten Siliciumhalogenide wurde dabei nicht beobachtet. Ihre Darstellung erfolgte durch Umsetzung von ClSi(Net2)3, Cl2Si(Net2)2 und Cl3Si(Net2) (et=C2H5) mit HBr oder HJ. Si2Cl6 reagierte mit 3py zu SiCl4(py)2 und 1/n [SiCl2(py)]n, Si2Br6 analog zu SiBr4(py)2 und 1/n [SiBr2(py)]n, Si3Cl8 mit 4py zu SiCl4(py)2 und 2/n [SiCl2(py)]n.AbstractThe reactions of mixed silicon halogenides with pyridine (=py), or 1.10-phenanthroline (=phen) resulted in the addition compounds SiClBr3(py)2, SiClBr3(phen), SiCl3Br(py)2, SiCl3Br(phen), SiCl2I2(py)4, SiCl2I2(phen), SiCl3I(py)3 and SiCl3I(phen). Dismutation of the mixed silicon halogenides in these reactions was not observed. Their preparation was achieved by cleaving of Si−N-bonds in ClSi(Net2)3, Cl2Si(Net2)2 and Cl3Si(Net2) (et=C2H5) with HBr or HI. Si2Cl6 reacted with 3py forming SiCl4(py)2 and 1/n [SiCl2(py)]n. The analogous reaction of Si2Br6 resulted in SiBr4(py)2 and 1/n [SiBr2(py)]n. Si3Cl8 and 4py formed SiCl4(py)2 and 2/n [SiCl2(py)]n.

Reaktionen der Siliciumtetrahalogenide mit 2,2′-Dipyridyl und mit 1,10-Phenanthrolin

In den Systemen Siliciumtetrahalogenid/2,2′-Dipyridyl und Siliciumtetrahalogenid/1,10-Phenanthrolin bilden sich unter Warmeentwicklung weise bis leicht getonte rontgenkristalline Additionsverbindungen des Typs Hlg4Si(dipy) bzw. Hlg4Si(phen) mit SiHlg4=SiCl4, SiHCl3 und SiBr4. Mit SiJ4 waren analog die gelben Verbindungen J4Si(dipy) und J4Si(phen)2 zu erhalten. Methylchlorsilane reagieren mit den beiden Heterocyclen nicht. Pyrazin setzte sich nur mit SiJ4 um, offensichtlich zu gelbem J4Si(pyz)4.

Röntgenstrukturbestimmung von AlCl3-Pyridin-Addukten: Der strukturelle Aufbau im trans-Dichlorotetrakis(pyridin)aluminium(III)- Tetrachloroaluminat(III) und im Trichlorotris(pyridin)aluminium(III) / X-ray Diffraction Study of AICl3-Pyridine Adducts: The Crystal Structure of trans-Dichlorotetrakis(pyridine)aluminium(III)tetrachloroaluminat(III) and of Trichlorotris(pyridine)aluminium(III)

Abstract Crystals of [Al(C5H5N)4Cl2][AlCl4] are orthorhombic, Pna21, Z = 4, a = 18.522(7), b = 15.141(5), c = 9.593(3) Å, V = 2690(2) Å3 , Dc = 1.440 g/cm3 . The structure has been solved from 5968 diffractometer measured intensities and refined by full-matrix least squares to Rw(F) = 0.032. The crystal structure shows the complex to be trans-dichloro-tetrakis(pyridine)aluminium(III) tetrachloroaluminat(III). The mean trans Al-Cl-and trans Al-N-distances in the octahedron are 2.279(3) and 2.070(4) Å, respectively. Crystals of Al(C5H5N)3Cl3 are monoclinic, P21/c, Z = 4, a = 7.261(2), b = 29.961(4), c = 8.624(1) Å, β = 98.12(2)°, V -1857(1) Å3 , DC = 1.326 g/cm3 . The structure has been solved from 4707 diffractometer measured intensities and refined to Rw(F) = 0.028. The crystal structure shows octahedral complexes AlCl3·3 (C5H5N) with trans geometry. The Al-N-distance trans to chlorine (2.096(2) Å) is significantly longer than the two other Al-N-distances (mean 2.072(2) Å).

Complexes of silicon tetrabromide with pyridine and 3,5-dimethylpyridine

The crystal structures of trans-tetrabromobis(pyridine)silicon (1) and trans-tetrabromobis(3,5-dimethylpyridine)silicon (2) have been determined: (1) crystallizes in the monoclinic space group C2/m with cell dimensions a = 14.4250(2) Å, b = 7.3055(1) Å, c = 7.2839(1) Å,β = 117.660(1)°, (2) crystallizes in the monoclinic space group C2/m with cell dimensions a = 16.013(3) Å, b = 7.316(1) Å, c = 8.179(2) Å, β = 113.19(1)°. Both molecules, with D2h symmetry, have crystallographic C2h site symmetry. The environment about the Si atoms can be described as a slightly distorted octahedron with the pyridyl ligands occupying axial positions and the four bromo ligands in the equatorial plane.

cis-bis(2,2'-bipyridyl-N-N')dichlorosilicon diiodide

The crystal and molecular structure of the title compound, C20H16Cl2N4Si2+·2I−, has been determined at 173 K. To our knowledge, this is the first crystal structure of a silicon tetrahalide complex with a bidentate base as a ligand. The two chloro ligands are cis relative to each other. The Si—N bonds trans to a chloro ligand are longer than the Si—N bonds trans to an Si—N bond. This feature is observed for the majority of M(bipy)2Cl2 (M = metal and bipy = 2,2′-bipyridyl) complexes, but it does not hold for all structures retrieved from the Cambridge Structural Database. The two pyridyl rings of each bipyridyl unit are nearly coplanar, whereas the bipyridyl units are almost perpendicular to each other. The two I− ions are more than 5 A from the silicon centre. As a result, the compound can definitely be described as ionic. The crystal packing is stabilized by short C—H⋯I contacts.

trans-Tetrabromobis(3,5-dimethylpyridine)germanium(IV), a non-merohedral twin

The structure of the title compound, [GeBr 4 (C 7 H 9 N) 2 ], is the first example of an addition compound of GeBr 4 with two aromatic nitrogen bases. The molecule, with D 2h symmetry, has crystallographic C 2h site symmetry. The environment around the Ge atom can be described as a slightly distorted octahedron with the dimethylpyridine ligands occupying axial positions and the four bromo ligands in the equatorial plane. The crystal structure is a non-merohedral twin composed of two overlapping monoclinic domains, simulating an orthorhombic symmetry.