Iminophosphanes: Unconventional Compounds of Main Group Elements

Abstract

Dedicated to Professor R o y Appel on the occasion of his 70th birthdayThe large number of known stable compounds in which phosphorus has a low coordination number makes it clear that such compounds can no longer be regarded as "exotic" in main group chemistry. While the rich chemistry of P-C multiply bonded systems makes clear their affinity to their organic congeners, iminophosphanes in particular are also of increasing importance. The linkage of a phosphinidine fragment with an imine fragment via a multiple bond gives rise to a class of compounds with an unusually wide range of structural types. This in turn leads to a broad spectrum of chemical behavior which makes iminophosphanes extremely useful synthetic building blocks in organoelement chemistry.

Terminal, Anionic Carbide, Nitride, and Phosphide Transition‐Metal Complexes as Synthetic Entries to Low‐Coordinate Phosphorus Derivatives

“…[49] The extensive chemistry of iminophosphanes has been reviewed. [50] Both (Me 3 Si) 2 N-P=NR systems have 31 P NMR spectroscopy chemical shifts (d = 330 ppm, R = tBu; [51] 325 ppm, R = SiMe 3 [52] ) similar to that observed for the monomeric iminophosphinimide complex [(tBuN = PN)Nb(NtBuAr) 3 ]. The lack of dimerization of (Me 3 Si) 2 N-P = NtBu has been attributed to the enhanced steric protection afforded by the tBu substituent, relative to SiMe 3 .…”

A fluoroaryl substituent with spectator function: Reactivity and structures of cyclic and acyclic HF4C6-substituted phosphanes

“…To lower the required temperature for the silyl elimination, chlorine may be replaced by fluorine minimizing the possibility of thermally induced dimerization or polymerization. By contrast, the trend is just the opposite for lithium halide elimination (T Br < T Cl < T F ) [23].…”

“…The synthetic strategy towards iminophosphanes usually involves the elimination of LiCl in the first step forming an aminophosphane [23]. If a lithium amide of a primary amine is used (route a, Scheme 2), the second step proceeds either via lithiation of RPCl-NHR 0 followed by further LiCl elimination or via dehydrohalogenation with non-nucleophilic bases.…”

On the equilibrium between monomeric and dimeric iminochlorophosphanes R–N=P–Cl

“…This group can be further classified according to the structural features given in Scheme 1 analogous to the known phosphorus-carbon compounds [24,25].…”