Isolation, n.m.r. spectra, and X-ray crystal structures of two isomeric N₃P₃Cl₂[O(CH₂)₃O]₂derivatives. The first example of dispiro/spiro–ansa isomerism in phosphazene chemistry

Abstract

From the reaction of N3P3C16 with 1,3-dihydroxypropane two isomeric N3P3C12[O(CH2)30]2 derivatives were isolated, whose n.m.r. spectra suggest, and crystal structures prove, that they represent an example of dispirokpiro-ansa isomerism, the first of its kind in phosphazene chemistry.

4,4,6,6-Tetrachloro-2,2-(2,2-dimethylpropane-1,3-diyldioxy)-1,3,5,2λ5,4λ5,6λ5-triazatriphosphorine

“…This pattern is slightly different from the patterns observed in analogous monospirocyclic cyclotriphosphazenes (Contractor et al, 1985;Kumaraswamy et al, 1999), wherein a long±short±long pattern for the ring PÐN bond lengths was noted. The PÐCl bond lengths are within the normal range observed for analogous compounds (Contractor et al, 1984;Kumaraswamy et al, 1999).…”

“…Since the most readily accessible among these, N 3 P 3 Cl 6 , (I), has six reactive Cl atoms that can affect its utility, we wished to reduce the number of functionalities. One of the easiest ways to do this is to treat (I) with a suitable difunctional reagent and obtain`spiro' or`ansa' type products (Contractor et al, 1984;Kumaraswamy et al, 1999;Chandrasekhar & Thomas, 1993). Since tetracoordinate P V compounds with six-membered rings at the P atom are more stable to hydrolysis than those with ®ve-membered rings, the diol 2,2-dimethyl-1,3-propanediol, which is cheaper than 1,3-propanediol, was used as the starting material.…”

The structural and stereogenic properties of pentaerythritoxy-bridged cyclotriphosphazene derivatives: spiro–spiro, spiro–ansa and ansa–ansa isomers

“…The spiro-ansa compound, N 3 P 3 Cl 2 [O(CH 2 ) 3 O] 2 (4) (Scheme 1), was the first ansa derivative of a cyclotriphosphazatriene to be crystallographically 4) puckers into a chair form with a strictly alternating positive/negative torsion angle sequence around the ring and each ring component in a gauche conformation with respect to its neighbour. The crystal structures of the mono-spiro (5) 24 and di-spiro (6) 21 1,3-propanedioxy derivatives of cyclophosphazenes are also available in the literature and, for comparison purposes, the crystal structure of the mono-ansa 1,3-propanedioxycyclophosphazene (7) has been determined in this work. The X-ray crystallographic data of (7) are summarized in (Table 3) and the molecular structure is shown in (Fig.…”

Synthesis and spectroscopic properties of geminal-bis(tertbutylamino) phosphazenes obtained by the reaction of spiro and ansa phenoxyphosphazenes with the tert-butylamine and the crystal structure of 2,2-[2,2’-metheylenebis(4-chlorophenoxy)]-4,4-bis(tert-butylamino)-6,6-dichlorocyclo- 2λ5,4λ5,6λ5-triphosphazatriene

“…The determined P-Cl bond lengths are in good agreement with the expected values. 5,[27][28][29] The crystal structure is stabilized by a weak intermolecular hydrogen bond and the molecules are stacked via weak C-H…π ring interactions in compound 3. …”