142159-55-5Relevant academic research and scientific papers
SOME NEW POLY-PHOSPHA-BENZENES AND -CYCLOOCTATETRAENES
Schmidbaur, Hubert,Gamper, Siegfried
, p. 221 - 224 (2007/10/02)
Based on the cyclisation of 1,1-bis(diphenylphosphanylmethyl)ethene with appropiate reagents several new (hetero-)phosphabenzenes and -cyclooctatetraenes have been prepared and characterized by analytical, spectroscopic, and diffraction methods.The series includes 2-aza-, 2-phospha-, and 2-borata-1,3-diphosphabenzenes, as well as the corresponding cyclooctatetraenes.For several of these heterocycles the ligand properties towards transition metal centers have also been investigated.The allylic anion part of the molecules is found to be a powerful donor function, complemented by the bis(onium)methylide moiety, where applicable.These results confirm the conclusions draw from spectroscopic data which indicated that the heterocycles are best described as onium-allylides with phosphorus atoms as conjugation barriers for the ?-systems.
2-Hetero-1λ5,3λ5-diphosphabenzenes as ligands in molybdenum complexes
Gamper, Siegfried F.,Schmidbaur, Hubert
, p. 2863 - 2867 (2008/10/08)
Treatment of (2,5-norbornadiene)molybdenum tetracarbonyl with 5-methyl-1,1,3,3-tetraphenyl-1λ 5-phospha-3-phosphonia-2-boratabenzene (1) results in the formation of a complex 1·Mo(CO)4 (4). Likewise, the reaction of (cycloheptatriene) molybdenum tricarbonyl with 5-methyl-1,1,3,3-tetraphenyl-1λ5,3λ5-diphosphabenzene (2) gives a complex 2·Mo(CO)3 (5). Complexes 4 and 5, obtained in high yields, have been characterized on the basis of their IR and 1H, 13C{1H}, and 31P{1H} NMR spectra, as well as by mass spectrometry and elemental analysis. Ocher-yellow crystals of composition 4·THF were grown from tetrahydrofuran/hexane and studied by X-ray crystallography: space group C2/m, a = 23.343 (4) A?, b = 14.016 (1) A?, c = 13.352 (2) A?, β = 122.90 (1)°, V = 3667.83 A?3, Z = 8/2. Bright yellow crystals of composition 5·0.5THF were obtained by crystallization from THF: space group Pbca, a = 16.687 (2) A?, b = 17.375 (2) A?, c = 22.929 (3) A?, V = 6647.96 A?3, Z = 8. Compounds 4 and 5 feature zero-valent molybdenum centers in a pseudooctahedral coordination sphere with the heterocycles 1 and 2 bound as four-electron donors via their methallylic functions and the semiylidic function PCHP as an additional two-electron donor in 5.
