Synthesis and X-ray structural studies of new spiro-cyclotriphosphazenes

<p>The series of four cyclotriphosphazenes containing biphenyl and phenyl groups, N3P3(C12H8)3-nPh 2n, where n = 0-3, (1-4 respectively), has been completed by the synthesis of two new C-bonded spiro-cyclotriphosphazenes, N3P3(C12H8)2Ph 2 2 and N3P3(C12H8)Ph4 3. They have been fully characterised and X-ray structural analysis shows that both compounds have a planar cyclotriphosphazene ring with less overall molecular rigidity compared to the trispirocyclic analogue, 1.</p>