Cyano and isocyano derivatives of the octahydrotriborate anion; Molecular and crystal structures of the [(Ph 3P) 2N] + salts of [B 3H 7NCBH 3] −, [(B 3H 7) 2CN] − and [Ag(CNB 3H 7) 2] −

Abstract

[Ph 3P) 2N][B 3H 7NCBH 3] is triclinic, P 1 , with 2 ion pairs in a cell of dimensions a = 9.832(3), b = 11.490(3), and c = 16.889(2) Å, α = 105.66(2), β = 92.43(2), and γ = 101.59(2)° at 185 K. Using 5255 amplitudes the structures has been refined to R = 0.059. There are 4 ion pair of [(Ph 3P) 2N][B 3H 7) 2CN] in a monoclinic unit cell, a = 17.003(4), b = 11.823(9), and c = 19.519(8) Å, β = 108.78(3)°, space group P2 1/a. R = 0.066 for 4840 reflections, again measured at 185 K. For [(Ph 3P) 2N][Ag(CNB 3H 7 2] the unit cell is a = 17.976(6), b = 11.559(3), and c = 19.20(3) Å β = 94.30(6)°, space group P2 1/c, and Z = 4.3742 reflections measured at 185 K have been used to refine to R = 0.074. The arrangements of hydrogen atoms in four of the five B 3H 7 moietes contained within these three crystal structures is common, there being one bridging-H across the B-B connectivity not involving the substituted atom.