Syntheses and structures of heterobicyclic bis(tert-butylamido)cyclodiphosph(III)azane compounds having phosphorus(III) and arsenic(III) centers

Syntheses and single-crystal X-ray diffraction studies of heterobicyclic cyclodiphosphazanes having central phosphorus(III) and arsenic(III) atoms are described. Interaction of PCl3 or AsCl3 with cis-[((BuNP)-Bu-t)(2)(tBuNLi . THF)(2)] produced the isomorphous {[((BuNP)-Bu-t)(2)((BuN)-Bu-t)(2)]ECl}; E = P(1), As(4), respectively. These C-s-symmetric molecules crystallize with two molecules in the monoclinic space group P2(1)/m. Unit cell dimensions of 1 are (293 K) a = 9.777(1) Angstrom, b = 11.745(1) Angstrom, c = 9.986(2) Angstrom, and beta = 97.44(1)degrees; those of 4 are (213 K) a = 9.688(3) Angstrom, b = 11.873(3) Angstrom, c = 9.975(3) Angstrom, and beta = 97.80(3)degrees. When {[((BuNP)-Bu-t)(2)((BuN)-Bu-t)(2)]PCl} was treated with NaN3 or LiN-(SiMe3)(2), {[((BuNP)-Bu-t)(2)((BuN)-Bu-t)(2)]PN3}(2) and {[((BuNP)-Bu-t)(2)((BuN)-Bu-t)(2)]PN(SiMe3)(2)}(3), respectively, were obtained. Compound 2 crystallizes in the monoclinic space group P2(1)/m and has unit-cell dimensions (213 K) of a = 9.496(7) Angstrom, b = 12.455(7) Angstrom, c = 10.043(6) Angstrom, and beta = 97.23(4)degrees, Z = 2.