Molecular structure of 1-(2,4,6-tri-tert-butylphenyl)-4,4-bis(dimethylamino)-1-aza-2,3 lambda(3)-phosphabutadiene-1,3

The crystal and molecular structure of 1-(2,4,6-tri-tert-butylphenyl)-4,4-b is (dimethylamino)-1-aza-2,3 lambda (3)-phosphabutadiene-1,3, Ttb-N=P-P=C(N Me2)(2), has been determined (crystal data of C23H41N3P, C2/c; Z = 8, monoc linic, a = 17.252(7), b = 9.014(3), c = 32.095(8) Angstrom, beta = 94.00(3) degrees). The main geometrical parameters of I are: N=P 1.582(5), P-P 2.130 (3), P=C 1.808(6) Angstrom, CNP 123.8(4), NPP 111.6(2), PPC 94.1(2), CNPP - 0.7, NPPC 176.8 degrees. Peculiarities of the molecular structure 1 (in par ticular. significant shortening of P-P single bond and realization of C-N=P -P bonds system in sterically unfavourable cis-form) are discussed on the b asis of ab initio calculations of the model phosphabutadiene systems.