Diverse coordination of Schiff bases based on 2-(aminomethyl)pyridine or 2-acetylpyridine at Mo(IV) centre: Synthesis, crystal structures and physicochemical properties

作者：Jurowska Anna^*; Szklarzewicz Janusz; Kurpiewska Katarzyna; Tomecka Monika

来源：Polyhedron, 2014, 75: 127-134.

DOI：10.1016/j.poly.2014.03.021

• Molybdenum
• Schiff bases
• Complexes
• X-ray diffraction
• Pyridine

The reaction of Schiff bases formed in reaction of 2-(aminomethyl)pyridine and aliphatic ketones (acetone, dihexyl ketone, 2- and 4-heptanone) or 2-acetylpyridine and 2-aminoethanol with K3Na[Mo(CN)(4)O-2]center dot 6H(2)O in water-ethanol solution results in isolation of two new complexes of formulae: (PPh4)[Mo(CN)(3)O(ampy)]center dot 2H(2)O (1) (ampy = 2-(aminomethyl)pyridine) and (PPh4)[Mo(CN)(3)O(aceamet)]center dot 2H(2)O (2) (aceamet = 2-([1-(pyridin-2-yl)ethyl]amino)ethanol). The isolated salts were characterized by elemental analysis, single crystal X-ray structure measurements, IR and UV-Vis spectroscopy and cyclic voltammetry. The complexes crystalize in monoclinic (1) or triclinic (2) space group with very distorted geometry of the anion with almost identical Mo=O distance (1.674 and 1.673 angstrom for 1 and 2, respectively). The energy of intense MLCT transitions in visible part of the spectra were found to be dependent on pyridine ring position (cis in 1 and trans in 2) to Mo=O bond and show strong solvatochromic effect dependent on the nature of the solvent. The very unusual position of pyridine ring in 2 as well as coordination of only 2-(aminomethyl)pyridine in 1 is discussed in terms of the reaction scheme in which for both salts only Schiff base ligand components [chelating 2-(aminomethyl)pyridine or 2-acetylpyridine] are coordinated at first reaction step. The results presented in paper indicate, that the Schiff bases cannot be treated as typical stable organic ligands, but rather as a complex system. The metal (or complex) determine which element of this system and in what sequence is coordinated.

• 出版日期2014-6-17