PUB - Publikationen an der Universität Bielefeld

Via the reaction of bis-(pentamethylcyclopentadienyl)diphosphene [Cp*P=PCP*, 1] and 1-(pentamethylcyclopentadienyl)-2-(2,4,6-tri(t)butylphenyl)-diphosphene [Cp*P=PMes*, 2] with the diazomethanes N2CHR [R=H, Si(CH3)3] the four new diphosphiranes Cp*PPCp*CHSi(CH3)3, 4a, Cp*PPMes*CHSi(CH3)3, 4b, Cp*PPCp*CH2, 5a, Cp*PPMes*CH2, 5b, are obtained. The formation of 4a results via a 2 + 3-cyclo-addition product, which could be proved by nmr spectroscopy. The reaction of As-(pentamethylcyclopentadienyl)P-(2,4,6-tri(t)butylphenyl)arsaphosphene [Cp*As=PMes*, 3] with diazomethane leads to 1-(pentamethylcyclopentadienyl)-2-(2,4,6-tri(t)butylphenyl)-1-arsa-2-pho sphacyclopropane [phospharsiran, Cp*AsPMes*CH2, 61. Analysis of the structures by nmr spectroscopy gives clear evidence for a trans-orientation of the substituents at the El-P bond (El=As, P) in all of the three membered ring systems. For the diphosphirane Cp*PPCp*CH2 (5a) a Cp*-phosphorus bond cleavage by thermolysis cannot be observed. From the reaction of compound 5a with Cr(CO),thf one obtains 1-(pentacarbonylchrom)-1,2-bis(pentamethylcyclopentadienyl)-1,2-diphosph acyclopropane, 7.