TY - JOUR
T1 - Bis(dimethylmethylenephosphoranyl)dihydroborato(1-) Complexes of Manganese(II) and Cobalt(II)
T2 - Stable, Homoleptic Tetraalkyls of Paramagnetic Transition-Metal Centers
AU - Müller, Gerhard
AU - Neugebauer, Dietmar
AU - Geike, Walter
AU - Köhler, Frank H.
AU - Pebler, Jürgen
AU - Schmidbaur, Hubert
PY - 1983/2
Y1 - 1983/2
N2 - Treatment of tetrahydrofuran solutions of lithium bis(dimethylmethylenephosphoranyl)dihydroborate (Li+Lr), prepared from bis(trimethylphosphane)dihydroboron(III) bromide and 2 mol equiv of tert-bu-tyllithium, with anhydrous MnBr2 or CoCl2 in the molar ratio 2:1 at -20 °C results in the formation of binary metal ylide complexes MnL2 and CoL2, respectively. The magnetic moments, measured in solution at 300 K for both CoL2 and MnL2 and in the solid state beween 4.2 K and 300 K for CoL2, correspond to a normal high-spin configuration of strongly paramagnetic d5 and d7 metal ions in a tetrahedral environment. The Curie-Weiss law is obeyed throughout this temperature range. This structure also follows from IR measurements. These spectra show close similarities for MnL2 and CoL2 and with the spectra of the corresponding Zn(II), Cd(II), and Hg(II) complexes. There are pronounced discrepancies, however, especially in the low wavenumber region, with the spectra of the complexes of diamagnetic d8 analogues NiL2, PdL2, and PtL2 for which the square-planar coordination of the metal centers has been proven by X-ray crystallography. Paramagnetic 1H NMR spectra, obtained in benzene solution, reveal the two ligands to be equivalent. X-ray precession photographs show crystals of both complexes to be isomorphous (space group P2j/c; Z = 4; MnL2, a = 8.386 (3) A, b = 11.286 (5) A, c = 23.880 (10) A, β = 94.87 (3)° CoL2, a = 8.38 (1) A,b = 11.24 (1) A, c = 23.61 (2) A, /3 = 94.8 (1)°). A complete single-crystal X-ray diffraction study of the manganese complex establishes the proposed structure. The manganese atom is almost perfectly tetrahedrally surrounded by four carbon atoms, with angles averaging at 109.53°. They form a spirobicyclic structure of two six-membered rings in a chair conformation joined by the manganese atom. The homologous boron-alkylated ligand L'~ is prepared by conversion of bis(trimethylphosphane)dimethylboron(III) bromide into its lithium derivative. LiL’ is reacted further with the bis(trimethylphosphane) adduct of NiCl2 to form the diamagnetic yellow organonickel(II) species NiL'2 whose composition and structure have been determined by analytical and spectroscopic mean. Its general properties resemble those of its BH2 congener NiL2.
AB - Treatment of tetrahydrofuran solutions of lithium bis(dimethylmethylenephosphoranyl)dihydroborate (Li+Lr), prepared from bis(trimethylphosphane)dihydroboron(III) bromide and 2 mol equiv of tert-bu-tyllithium, with anhydrous MnBr2 or CoCl2 in the molar ratio 2:1 at -20 °C results in the formation of binary metal ylide complexes MnL2 and CoL2, respectively. The magnetic moments, measured in solution at 300 K for both CoL2 and MnL2 and in the solid state beween 4.2 K and 300 K for CoL2, correspond to a normal high-spin configuration of strongly paramagnetic d5 and d7 metal ions in a tetrahedral environment. The Curie-Weiss law is obeyed throughout this temperature range. This structure also follows from IR measurements. These spectra show close similarities for MnL2 and CoL2 and with the spectra of the corresponding Zn(II), Cd(II), and Hg(II) complexes. There are pronounced discrepancies, however, especially in the low wavenumber region, with the spectra of the complexes of diamagnetic d8 analogues NiL2, PdL2, and PtL2 for which the square-planar coordination of the metal centers has been proven by X-ray crystallography. Paramagnetic 1H NMR spectra, obtained in benzene solution, reveal the two ligands to be equivalent. X-ray precession photographs show crystals of both complexes to be isomorphous (space group P2j/c; Z = 4; MnL2, a = 8.386 (3) A, b = 11.286 (5) A, c = 23.880 (10) A, β = 94.87 (3)° CoL2, a = 8.38 (1) A,b = 11.24 (1) A, c = 23.61 (2) A, /3 = 94.8 (1)°). A complete single-crystal X-ray diffraction study of the manganese complex establishes the proposed structure. The manganese atom is almost perfectly tetrahedrally surrounded by four carbon atoms, with angles averaging at 109.53°. They form a spirobicyclic structure of two six-membered rings in a chair conformation joined by the manganese atom. The homologous boron-alkylated ligand L'~ is prepared by conversion of bis(trimethylphosphane)dimethylboron(III) bromide into its lithium derivative. LiL’ is reacted further with the bis(trimethylphosphane) adduct of NiCl2 to form the diamagnetic yellow organonickel(II) species NiL'2 whose composition and structure have been determined by analytical and spectroscopic mean. Its general properties resemble those of its BH2 congener NiL2.
UR - http://www.scopus.com/inward/record.url?scp=8844255554&partnerID=8YFLogxK
U2 - 10.1021/om00074a009
DO - 10.1021/om00074a009
M3 - Article
AN - SCOPUS:8844255554
SN - 0276-7333
VL - 2
SP - 257
EP - 263
JO - Organometallics
JF - Organometallics
IS - 2
ER -