DOI: 10.1080/10426507.2019.1688812

Theoretical calculations of the chemical shifts of cyclo[n]phosphazenes for n = 2, 3, 4 and 5 (X₂PN)_n with X = CH₃, F, Cl and Br: the effect of relativistic corrections

Di, tri, tetra and pentacyclophosphazenes substituted on the phosphorus atoms by CH3, F, Cl and Br atoms corresponding to (X2PN)n structures have been studied theoretically at the B3LYP/6-311++G(d,p) level. After a brief discussion of their geometries comparing them to those of the conjugated carbocycles, (CH)n, of the same size, the absolute shieldings calculated with the GIAO and ZORA approximations will be reported. For the Cl and mainly for the Br substituted cyclo[n]-phosphazenes, relativistic corrections are absolutely necessary for 31P and useful for 15N chemical shifts.