Synthesis, structure, and redox properties of crowded triarylphosphines carrying 2,6-diarylphenyl substituents
摘要:
Crowded triarylphosphines carrying 2,6-diarylphenyl and 2,4,6-trialkylphenyl groups were synthesized by the reaction of arylcopper(I) reagent with the chlorophosphines. The triarylphosphines had large bond angles and lengths around the phosphorus and were reversibly oxidized at significantly low potentials. X-ray crystallography of bis(2,4,6-triisopropylphenyl)[4-methyl-2,6-di(1-naphthyl)phenyl]phosphine revealed that two 1-naphthyl groups took anti conformation in the crystal. (C) 2004 Elsevier Ltd. All rights reserved.
NOVEL ISOLABLE C,C-DICHLOROPHOSPHAALKENES RP=CCl2 OWING TO THE USE OF NEW HUGE STABILIZING GROUPS
摘要:
Three new C,C-dichlorophosphaalkenes RP=CCl2 18-20 have been synthesized from the corresponding dichlorophosphines RPCl2 11-13. Compounds 18-20 are stabilized owing to the use of thr very bulky new groups R-1 [2,6-bis(4-methylphenyl)-4-methylphenyl] and R-3 [2;6-bis(2-methoxyphenyl)-4-methylphenyl] and the known 2,6-dimesityl-4-methylphenyl (R-2). The compounds with a R-3 group ((RI)-I-3: 4, (RPCl2)-P-3: 13, (RPH2)-P-3: 17 and (RP)-P-3=CCl2: 20) exist in the form of two conformational isomers on the NMR time scale. A H-1 and P-31 NMR dynamic study (for 4 and 13 respectively) allowed the determination of the Delta G* of this phenomenon, respectively 18.5 and 18.2 kcal/mol.