Phosphorus–fluorine chemistry. Part XVI. Phosphorus–phosphorus coupling constants, 2J(PMP′) in ethylaminobisdifluorophosphine complexes of chromium, molybdenum, and tungsten carbonyls

Abstract

Ethylaminobisdifluorophosphine complexes of chromium, molybdenum, and tungsten EtN(PF₂)₂M(CO)₄(M = Cr, Mo, W) have been synthesised by displacement of norbornadiene from the corresponding olefin–metal carbonyl complex. ¹⁹F and ³¹P N.m.r. spectra, analysed as XX′AA′X″X‴ spin systems, enable accurate values for ¹J(PF), ³J(PF′), ²J(PMP′), and ⁴J(FF′)(two types) to be obtained. The n.m.r. studies confirm the bidentate nature of the ligand and phosphorus to metal co-ordination.