Hydrated manganese(II) cyanato complexes of 3- and 4-acetyl, carbomethoxy-, carboethoxy- and benzoylpyridine derivative ligands and crystal structure of trans-dicyanato-bis(4-acetylpyridine)diaquamanganese(II) ; [Mn(4-acetylpyridine)2(NCO)2(H2O)2]

Article abstract of DOI:10.1016/S0277-5387(97)00016-8

A series of 1:2 manganese(II) cyanato complexes of 3-, 4-acetyl-, 3- and 4-benzoylpyridines, methyl and ethyl nicotinate and isonicotinates has been prepared and characterized. Except for L = ethyl isonicotinate, all other complexes crystallize with two water molecules. In the case of ethyl isonicotinate the complex crystallizes with two ethanol molecules, the IR and Raman spectral lines of diagnostic value are given and discussed, suggesting terminal N-bonded cyanato ligands and aqua molecules or bonded ethanol molecules in these manganese(II) complexes. The structure of [Mn(4-acetylpyridine)₂(OCN)₂(H₂O)₂] as determined by crystallographic methods features six-coordinate manganese (II) centres, pairs of trans aqua molecules [Mn - O = 2.202(3) A], N-bonded cyanato ligands [Mn - N = 2.116(3) A] and monodentate N-bonded carbonyl pyridine ligands [Mn-N = 2.322(3) A]. The structure is further consolidated by hydrogen bonds between aqua oxygen atoms of acetyl groups or terminal oxygen atoms of cyanato ligands. These hydrogen bonds connect the polyhedra along the cb plane to form a layer-type structure. The EPR spectra of powder samples and solvent solutions at room temperature were recorded and discussed.