A Very Short Ruthenium(II) - Nitrogen Heterocycle Bond: The Crystal Structures of Pentaammine(N-methylpyrazinium)ruthenium(II) Iodide and Pentaammine(N-methylpyrazinium)ruthenium(III) p-Toluenesulfonate Pentahydrate

James F. Wishart, Avi Bino and Henry Taube

Inorg. Chem. 25, 3318-3321 (1986)

Abstract:

The crystal structures of [(NH₃)₅Ru(NC₄H₄NCH₃)] I₃ and [(NH₃)₅Ru(NC₄H₄NCH₃)] (CH₃C₆H₄SO₃)₄°5H₂O have been solved to weighted R factors of 0.053 and 0.083, respectively. For the former structure, the space group is Pmma with a = 10.655(2)Å, b = 7.704(1)Å, c = 21.488(3)Å, and Z = 4. The Ru(II)-N(Mepyz) distance of 1.95(1)Å in this complex is the shortest yet reported for a ruthenium(II) to heteroctclic nitrogen bond. A difference of 0.04(1)Å between the cis (2.122(7)Å and 2.136(8)Å) and trans (2.17(1)Å) Ru-N(ammine) bond lengths indicates a strong static trans effect of the N-methylpyrazinium ligand.

For the latter structure, the space group is P1 with cell parameters a = 14.298(2) Å, b = 14.668(2)Å, c = 13.551(2)Å, alpha = 89.94(3)°, beta = 113.21(4)°, gamma = 66.77(3)°, and Z = 2. The Ru(III)-N(Mepyz) bond length is 2.08(1)Å and the five Ru-N(ammine) distances average 2.11Å.