THE STRUCTURE OF ORGANOPHOSPHORUS COMPOUNDS .43. THE MOLECULAR-STRUCTURE OF CIS-LAMBDA-3-AMINO-2,4,6-TRI(TERT-BUTYL)PHENYLIMINOPHOSPHINES AND TRANS-LAMBDA-3-AMINO-2,4,6-TRI(TERT-BUTYL)PHENYLIMINOPHOSPHINES

An x-ray diffraction structural analysis was carried out for new lambda(3)-aminoiminophosphines, 2,4,6-(t-Bu)3-C6H2N = P-NR2, where R = Me (I) and i-Pr (II) using lambda-Mo radiation. Sets of 2498 and 4730 reflections were measured for I and II, respectively. The final R values were 0.050 and 0.063 for I and II, respectively. The unit cell parameters for the monoclinic crystals of I are as follows: a = 6.268, b = 12.801, c = 13.067 angstrom, beta = 94.40-degrees, V = 1045.5 angstrom 3, d(calc) = 1.06 g/cm3, Z = 2, space group P2(1). The unit cell parameters of the monoclinic crystals of II are as follows: a = 11.118, b = 11.288, c = 19.838 angstrom, beta = 94.82-degrees, V = 2480.8 angstrom 3, d(calc) = 1.05 g/cm3, Z = 4, space group P2(1)/c. We are the first to report that the cis isomer is favored for aminoiminophosphines 2,4,6-(t-Bu)3--C6H2N = P-NR2 in the case of nonbulky substituents R, while the trans isomer is more favorable when R is bulky. The features of the molecular structures of cis and trans isomers are discussed. The major geometrical parameters of I are as follows: P = N, 1.539(3); P-N, 1.651(3) angstrom; NPN, 115.9(3); PNC, 140.7(4); CNPN, -4.9(7)-degrees. The major geometrical parameters of II are as follows: P = N, 1.555(2); P-N, 1.656(2) angstrom; NPN, 105.6(1), PNC, 129.6(2), CNPN, 179.9(3)-degrees. The benzene ring is twisted relative to the CNPN group by 89.9(2) and 87.37(8)-degrees in I and II, respectively.