Single-Crystal X-Ray Structure and Reactivity of a Triphenylphosphinazine, (C₆H₅)₃P˭N‒N˭C(H)(C₆H₄NO₂-p)

Abstract

Phosphinazines with "PNNC" framework comprise a novel class of compounds owing to the presence of both phosphinimino and ketimino moieties. There are very few known examples in this set and their utility toward exploring the chemistry is little known. We have embarked on a systematic investigation on this important class of compounds for delineating their coordination behaviour. Here we report the X-ray structure of free phosphinazine and its intrinsic functionality as a synthon to inorganic heterocycles and ligand in coordination chemistry. The p-nitrobenzaldehyde triphenylphosphoranylidenehydrazone (C 6 H 5 ) 3 P N N C(H)(C 6 H 4 NO 2 -p) molecules are arranged in a monoclinic lattice having P2 1 /n spatial arrangement with unit cell dimensions a = 8.7574(14) Å, b = 15.610(2) Å, c = 16.6566(12) Å, β = 104.828(8) • , and Z = 4. The analysis reveals trans orientation for the P N and C N moieties in the PNNC fragment. Extensive π conjugation starting from one of the phenyl rings on phosphorus to the p-nitrophenyl ring on carbon stabilizes the entire strip of the molecule. The reactions with S 4 N 4 , S 3 N 3 Cl 3 , and S 3 N 2 Cl 2 gave rise to the formation of six-membered cyclotrithiazene and other five-membered inorganic heterocycles. The coordination reactions with Mo(CO) 6 in the ratios 1:1 and 2:1 led to the formation of [Mo(CO) 5 L] and trans-[Mo(CO) 4 L 2 ], where L is the title phosphinazine.