The Hexacyanotitanate Ion: Synthesis and Crystal Structure of [NEt₄]₃[Ti^III(CN)₆]·4MeCN

Abstract

The hexacyanotitanate salt, [Et4N]3[Ti(CN)6]·4MeCN, has been prepared by addition of tetraethylammonium cyanide to the titanium(III) triflate salt Ti(O3SCF3)3(MeCN)3. The orange crystalline product has been characterized by X-ray diffraction, and the d1 anion is only slightly distorted from ideal Oh symmetry. The anion resides on a center of symmetry and is characterized by the following parameters: Ti−C = 2.195(2), 2.197(3), and 2.213(3) Å; C−N (av) = 1.141(4) Å; C−Ti−C (cis) = 88.01(9), 88.02(9), 89.02(9), and 89.78(9)°; C−Ti−C (trans) = 180°. In addition to the crystallographic study, details of the IR (νCN = 2071 cm-1), EPR, and UV−vis spectra (Δo = 22800 cm-1) are given. Crystal data for [Et4N]3[Ti(CN)6]·4MeCN are as follows: monoclinic, space group I2/a, a = 18.171(6) Å, b = 12.200(4) Å, c = 20.989(5) Å, β = 91.17(2)°, V = 4652(2) Å3, Z = 4, wR2 = 0.2054 for 3831 data, 27 restraints, and 318 parameters.