TY - JOUR
T1 - Divalent manganese, cobalt and nickel chloride complexes with neutral N2- and N3-based ligands derived from 2-pyridinecarbaldehyde: Synthesis, structural features and spectroscopic studies
AU - Buvaylo, E.A.
AU - Melnyk, A.K.
AU - Trachevsky, V.V.
AU - Vassilyeva, O.Y.
AU - Skelton, Brian
PY - 2016/2/17
Y1 - 2016/2/17
N2 - © 2015 Elsevier Ltd. All rights reserved. A series of dihalide M(II) mononuclear complexes in a cis configuration, Mn(HL1)2Cl2·CH3OH·H2O (1), Co(HL1)2Cl2·CH3OH·H2O (2), Ni(HL1)2Cl2·2H2O (3) and CoL2Cl2·0.5dmf (4) (HL1 - Schiff base ligand 4-N-(2′-pyridylimine)benzoic acid; L2 - pyridin-2-yl(3-(pyridin-2-yl)imidazo[1,5-a]pyridin-1-yl) methanone, both formed in situ from 2-pyridinecarbaldehyde), have been obtained as single crystals and characterized by elemental analysis, IR and EPR spectroscopy, and single-crystal X-ray diffraction techniques. The neutral M(L1)2Cl2 and CoL2Cl2 molecules in 1-3 and 4, respectively, show no crystallographically imposed symmetry with the metal atoms in a MN4Cl2 distorted octahedral (1-3) and CoN3Cl2 (4) elongated trigonal-bipyramidal geometries. In the crystal lattice molecules of 1-3 are arranged in columns propagating along the c axis; the structure of 4 can be described as layers of CoL2Cl2 and dmf molecules alternating along the a axis. The minimum M⋯M separations in a column (1-3) and inside a layer (4) are above 8 Å. The X-band solid-state EPR spectra of 1 at room temperature and 77 K exhibit broad fine structure signals at 1600 and 3000 G (geff ∼ 4.14 and 2.22, respectively) resulting from ZFS of the spin states for the high-spin d5 metal ion. The solid-state EPR spectra of 2 are temperature dependent showing a wide unresolved line at geff ∼ 2.09 at room temperature and a very broad signal (ΔHpp = 2500 G) at geff ∼ 4.21 at 77 K. The Ni analogue 3 is EPR-silent. The EPR spectra of 4 at both temperatures show a broad asymmetrical signal centred at g ∼ 2 suggesting the low-spin configuration; the line width is nearly independent of temperature.
AB - © 2015 Elsevier Ltd. All rights reserved. A series of dihalide M(II) mononuclear complexes in a cis configuration, Mn(HL1)2Cl2·CH3OH·H2O (1), Co(HL1)2Cl2·CH3OH·H2O (2), Ni(HL1)2Cl2·2H2O (3) and CoL2Cl2·0.5dmf (4) (HL1 - Schiff base ligand 4-N-(2′-pyridylimine)benzoic acid; L2 - pyridin-2-yl(3-(pyridin-2-yl)imidazo[1,5-a]pyridin-1-yl) methanone, both formed in situ from 2-pyridinecarbaldehyde), have been obtained as single crystals and characterized by elemental analysis, IR and EPR spectroscopy, and single-crystal X-ray diffraction techniques. The neutral M(L1)2Cl2 and CoL2Cl2 molecules in 1-3 and 4, respectively, show no crystallographically imposed symmetry with the metal atoms in a MN4Cl2 distorted octahedral (1-3) and CoN3Cl2 (4) elongated trigonal-bipyramidal geometries. In the crystal lattice molecules of 1-3 are arranged in columns propagating along the c axis; the structure of 4 can be described as layers of CoL2Cl2 and dmf molecules alternating along the a axis. The minimum M⋯M separations in a column (1-3) and inside a layer (4) are above 8 Å. The X-band solid-state EPR spectra of 1 at room temperature and 77 K exhibit broad fine structure signals at 1600 and 3000 G (geff ∼ 4.14 and 2.22, respectively) resulting from ZFS of the spin states for the high-spin d5 metal ion. The solid-state EPR spectra of 2 are temperature dependent showing a wide unresolved line at geff ∼ 2.09 at room temperature and a very broad signal (ΔHpp = 2500 G) at geff ∼ 4.21 at 77 K. The Ni analogue 3 is EPR-silent. The EPR spectra of 4 at both temperatures show a broad asymmetrical signal centred at g ∼ 2 suggesting the low-spin configuration; the line width is nearly independent of temperature.
U2 - 10.1016/j.poly.2015.12.025
DO - 10.1016/j.poly.2015.12.025
M3 - Article
SN - 0277-5387
VL - 105
SP - 238
EP - 245
JO - Polyhedron
JF - Polyhedron
ER -