MOLECULAR-TRANSFORMATIONS IN THE SOLID-STATE - CRYSTALLOGRAPHIC RESOLUTION OF THE SPIN ISOMERS OF TRIS(2-PICOLYLAMINE)IRON(II) DICHLORIDE AND THE STRUCTURAL RELATIONSHIP BETWEEN THE METHANOL AND ETHANOL SOLVATES

Multiple temperature crystallographic analysis has provided a detailed structural and thermodynamic description of the spin-state transformation in the methanol solvate of tris(2-picolylamine)iron(II) dichloride. Iron-nitrogen distances in the crystallographically resolved spin isomers are in excellent agreement with those obtained in the high- and low-temperature limits. Thermodynamic parameters obtained crystallographically agree well with those obtained spectroscopically. A two-dimensional hydrogen-bonding network links all amine hydrogen atoms of the complexes, the noncoordinating chloride ions, and the methanol molecule. Low-temperature structural analysis of the ethanol solvate of this salt reveals the same hydrogen-bonding network but a different space group. Crystal data, Fe(2-pic)3Cl2•MeOH, 115 K: space group Pbna, Z = 8, a = 11.359 (2) Å, b = 18.582 (3) Å, c = 21.873 (4) Å, V = 4617 (1) Å3, R = 0.037, Rw = 0.046 for 3107 reflections. Fe(2-pic)3Cl2-EtOH, 115 K: space group P21/a (c unique), Z = 4, a = 11.389 (5) Å, b = 10.768 (5) Å, c = 21.654 (8) Å, γ = 117.18 (3)°, V = 2362 (2) Å3, R = 0.051, Rw = 0.061 for 3627 reflections. © 1979, American Chemical Society. All rights reserved.