After a brief introduction of the reaction patterns of N3P3Cl6 and N4P4Cl8 with monofunctional nucleophilic reagents, the reactions of these two chlorocyclophosphazenes with difunctional, trifunctional and tetrafunctional nucleophilic reagents are surveyed. These reagents contain aliphatic and aromatic hydroxyl and primary and secondary amino groups. Spiro, ansa, dangling and bridging units have been observed as well as a combination of these. The stability of the various ring systems is discussed. Crystal structures and 1H, 13C and 31P n.m.r. spectroscopic studies are reported.

The reactions of phosphazenes with difunctional and polyfunctional nucleophilic reagents

In the solid state, OP[N(H)Me]3 (1a) and OP[N(H)tBu]3 (1b) have hydrogen-bonded structures that exhibit three-dimensional and one-dimensional arrays, respectively. The lithiation of 1b with 1 equiv of nBuLi generates the trimeric monolithiated complex (THF){LiOP(NtBu)[N(H)tBu]2}3 (4), whereas reaction with an excess of nBuLi produces the dimeric dilithium complex {(THF)2Li2OP(NtBu)2[N(H)tBu]}2 (5). Complex 4 contains a Li2O2 ring in an open-ladder structure, whereas 5 embraces a central Li2O2 ring in a closed-ladder arrangement. Investigations of the lithiation of tris(alkyl or arylamido)thiophosphates, SP[N(H)R]3 (2a, R = iPr; 2b, R = tBu; 2c, R = p-tol) with nBuLi reveal interesting imido substituent effects. For the alkyl derivatives, only mono- or dilithiation is observed. In the case of R = tBu, lithiation is accompanied by P−S bond cleavage to give the dilithiated cyclodiphosph(V/V)azane {(THF)2Li2[(tBuN)2P(μ-NtBu)2P(NtBu)2]} (9). Trilithiation occurs for the triaryl derivatives EP[N(H)Ar]3 (E = S, ...

Lithiation of tris(alkyl- and arylamido)orthophosphates EP[N(H)R]3 (E = O, S, Se): imido substituent effects and P=E bond cleavage.

This review describes the reactivity and structural aspects of cyclophosphazenes. The reactions of halogenocyclophosphazenes with a variety of monofunctional and difunctional reagents are described. The mechanisms of the reactions involved are discussed in light of kinetic evidence and product analysis. Reactions involving main-group and transition-metal reagents and halogenocyclophosphazenes are also described. The chemistry of hydridophosphazenes containing a P-H bond is described in more detail. Some of the rearrangement reactions including cis-trans isomerism and tautomerism which are common to some cyclophosphazene derivatives have been discussed. The coordination chemistry involving cyclophosphazenes as ligands via endocyclic and/or exocyclic coordination sites resulting in several types of derivatives including metallocenyl cyclophosphazenes, metal clusters and carboranyl cyclophosphazenes has been critically evaluated. The structural aspects of cyclophosphazenes have been reviewed with particular emphasis on multinuclear NMR and single crystal X-ray methods. Bond angle-bond length variations in X-ray structures of cyclophosphazenes have been explained based on the theories of bonding prevalent in these molecules.

Recent aspects of the structure and reactivity of cyclophosphazenes

The reactions of octachlorocyclotetraphosphazatetraene, N4P4CI8, with ethane diol did not yield any characterised products. Those with 1,3-propanediol and 1.4-butanediol gave the following isolated and characterised derivatives, N4P4Cl8–2x[O(CH2)nO]x: x = 1, n = 3, 4; x = 2, n = 3, 4 (2 isomers of each); x = 3, n = 3,4; x = 4, n = 4. 31P, 1H and 13C n.m.r. spectroscopic investigations showed all derivatives to have spiro structures. The isomeric bis derivatives have 2,2,4,4- and 2,2,6,6-structures.

Phosphorus-nitrogen compounds. part 611. the reactions of octachlorocyclotetra-phosphazatetraene with ethanediol, 1,3-propanediol and 1,4-butanediol. synthetic and nuclear magnetic resonance spectroscopic investigations

Reactions of 1-(dichlorophosphinyl)-2,2,2-trichlorophosphazene, Cl2P(O).N[dbnd]PCl3, with an excess of pyrrolidine led to the isolation of the acyclic pyrro-lidino-derivative, (H8C4N)2P(O).N[dbnd]P(NC4H8)3, and bis(pyrrolodinophosphinoyl) ∼ amine, [(H8C4N)2P(O)]2NH. N',N'-tetramethyleneacetamidiniumchloride, [CH3 ∼ (H8C4N)C[dbnd]NH]. HCl, was formed from CH3CN, pyrrolodine and HCl evolved during the reactions in CH3CN. The reactions of N3P3Cl6, N4P4Cl8, and N4P4(NHEt)2Cl6 with an excess of pyrrolidine in CH3CN gave the above mentioned amidinium salt and some known phosphazene derivatives. The phosphazene compounds promote the formation of the amidinium salt. The reaction of N3P3(NH2)2Cl4 with an excess of dimethylamine gives the free base, N3P3(NH2)2(NMe2)4, and its salt, N3P3(NH2)2(NMe2). HCl, but no amidinum salt, [Me(Me2N)C[dbnd]NH]. HCl could be separated as a stable product. The basicities of these phosphazene derivatives in nitrobenzene solution are reported. Possible reaction mechanisms fo...

Phosphorus-Nitrogen Compounds. I. Reactions of Cl 2 P(O).N[dbnd]PCl 3 with an Excess of Pyrrolidine: Isolation of an Acycylic Phosphazene, (H 8 C 4 N) 2 P(O).N[dbnd]P(NC 4 H 8 ) 3 , Bis (Pyriolidinophosphinoyl)Amine, [H 8 C 4 N) 2 P(O)] 2 NH and Amidinium Salt, [CH 3 (H 8 C 4 N)C[dbnd]NH]. HCl

The reactions of geminal N3P3Ph2Cl4 and N3P3(NHBut)2Cl4 with difunctional reagents have been investigated. The N.M.R. spectra of the derivatives are reported. The basicity of these products in nitrobenzene solution is reported and the basicity substituent constants evaluated. X-ray crystallographic data are presented.

THE REACTIONS OF GEMINAL N3P3Ph2Cl4 AND N3P3(NHBut)2Cl4 WITH DIFUNCTIONAL REAGENTS. X-RAY CRYSTALLOGRAPHY, NMR SPECTROSCOPY AND BASICITY OF THE PRODUCTS

X-ray crystallographic and35cl n.q.r. spectroscopic studies on chlorocyclophosphazenes

Methods of preparation and likely reaction mechanisms of the formation of [PhP(S)NR]2 from PhP(S)Cl2 and NH2R are discussed. These cyclodiphosph(V)azanes were investigated by means of N.M.R. spectroscopy and X-ray crystallography. The initial reaction products appear to be the trans-iso-mers. Cis-trans isomerisation is discussed.

Leyl S. Shaw

Papers

THE REACTIONS OF GEMINAL N3P3Ph2Cl4 AND N3P3(NHBut)2Cl4 WITH DIFUNCTIONAL REAGENTS. X-RAY CRYSTALLOGRAPHY, NMR SPECTROSCOPY AND BASICITY OF THE PRODUCTS

X-ray crystallographic and35cl n.q.r. spectroscopic studies on chlorocyclophosphazenes

The structures and mode of formation of some cyclodiphosph(v)azanes and their cis-trans isomerisation