Insight into the Reaction of a Dinuclear Phosphinidene Complex with Nitriles

Abstract

The phosphinidene complex [Cp*P{W(CO)5}2] (1; Cp*=C5 Me5 ) reacted with malononitrile to give the 1,2-dihydro-1,3,2-diazaphosphinine derivative 2. The reaction of 1 with 1,4-benzodinitrile gave [1,4-{{W(CO)5}2 P-N=C(Cp*)}2 (C6 H4)] (3), the first example of a cumulene-like aminophosphinidene complex. The reaction of 1 with aniline gave the aminophosphinidene complex [(Ph)N(H)P{W(CO)5}2] (4). To compare the reactivity of benzonitrile and aniline with 1, the phosphinidene complex 1 was reacted with three different isomers of aminobenzonitrile (2-, 3-, and 4-aminobenzonitrile). These reactions gave an insight into the reaction pathway of 1 with benzonitrile derivatives. Compounds 5, 6 a, 6 b, and 7, which are derivatives of 1,2-dihydro-1,3,2-diazaphosphinine or benzo-2H-1,2-azaphospholes, were, as well as all other products, characterized by mass spectrometry, NMR and IR spectroscopy, and X-ray structure analysis.

Phosphinidene-bridged binuclear complexes

“…The reaction of the phosphinidene complex 5 towards aniline and 1,4-benzodinitrile yielded two new phosphinidene complexes after formation of new PN bonds (Scheme 29) [57]. In the first reaction, HCp* is eliminated to give the aminophosphinidene complex 55, while the second reaction involves nitrile insertion into the PCp* bond to eventually yield the tetranuclear complex 56.…”

“…The reactivity of the ditungsten complex 5 towards molecules containing multiple CN bonds such as nitriles [57,102], isocyanides [103], carbodiimides [104] and carboimidophosphenes [105] has been examined in detail (Schemes 72 and 73). Reaction with acetonitrile proceeded at 293 K to give a 1,2-dihydro-1,3,2-diazaphosphinine derivative 147a following from double NCMe insertion into the PC bond of the phosphinidene ligand, with CC bond formation and subsequent migration of βH atoms of one acetonitrile to the N atoms.…”

“…In contrast, reaction with malononitrile in refluxing toluene led to a derivative of type 147 now bearing two Cp* substituents, along with other thermolysis products (Scheme 72). The reactions of 5 with malononitrile and acetonitrile represent the first examples in which two nitriles form a -diketiminate assisted by a phosphinidene complex [57].…”

Exploring Differences between Bis(aldimino)- and amino-aldimino-N,C,N-Pincer-Stabilized Pnictinidenes: Limits of Synthesis, Structure, and Reversible Tautomerization-Controlled Oxidation

“…They represent very reactive R–E molecules (E = P, As, Sb or Bi); therefore, their synthesis is not trivial and still remains a challenging task. For a long time, these compounds could not be isolated and were studied especially as very reactive intermediates or as ligands for transition metals that often exhibit interesting reactivity. , Lighter pnictinidenes, especially phosphinidenes, could be generated in situ from suitable metastable precursors and transferred to other substrates in a controlled manner as well …”

Structural investigations on bridging stibinidene complexes with Cu Kβ radiation: a comparison

“…The bridging pentelidene complexes [Cp*E{W(CO) 5 } 2 ] (Cp* = pentamethylcyclopentadienyl, E = P, As) have been a subject of interest in our group for almost 20 years and thus their reaction behavior towards nucleophiles such as phosphines [1][2] and nitriles [3] has been investigated thoroughly. In contrast, since their discovery in 1978 [4], trigonal-planar stibinidene complexes have not been investigated much [5].…”