Bis(N-2-propylsalicylideneamino-N,O)cobalt(II)

Abstract

The title complex, bis [2-(2-propylirninomethyl) 2435lic derivatives (Pahor, Calligaris, Delise, Dodic, Nardin & Randaccio, 1976); metal complexes of Schiff bases in general have been extensively studied (Calligaris, Nardin & Randaccio, 1972). We describe here the structure of the bis(N-isopropylsalicylideneamino)cobalt(II), (I), complex and compare it with related compounds having different substituents.The two bidentate ligands are coordinated to the Co" ion through their N and O atoms. The geometry around cobalt is somewhat distorted from ideal tetrahedal, mainly as a consequence of the restricted bite of the chelate ligands (reducing intra-ligand O---CO-N angles) and steric repulsion of the isopropyl groups (increasing the N---Co---N angle). The dihedral angle between the two Schiff base ligands, excluding the isopropyl groups, is 82.88 (5) °, so that the two ligands are almost perpendicular, the deviation from an ideal value ) showing the atom-labelling scheme and 50% probability displacement ellipsoids (ORTEPII;.of 90 ° also being due to the isopropyl groups. Geometric differences between the two ligands are minor. The sum of the bond angles at the two N atoms is 360.0 (2) ° in each case, which is appropriate for sp 2 hybridization. The coordination geometry is very similar to that found for corresponding complexes in which the isopropyl groups are replaced by either n-butyl or tert-butyl groups, these complexes retaining the distorted tetrahedral coordination (Bahron, Larkworthy, Marecaux, Povey & Smith, 1994); the mean Co----O and Co-N distances in the present structure are 1.906 (5) and 1.992 (8),~, respectivel)~, with corresponding values of 1.894 (4) and 1.968 (4) A for the averages of the n-butyl and tert-butyl structures. In contrast, linking the two ligands by a two-carbon bridge between the N atoms forces an approximate square-planar coordination geometry in which the Co---O bonds are shorter by about 0.06 and the CoN bonds are drastically shortened by about 0.13 ,~, (Pahor et al., 1976;Hiller, Nishinaga, Tsutsui & Rieker, 1993). Octahedral coordination of Co "I by three similar salicylideneamino ligands gives mean Co----O. and Co--N bond lengths of 1.893 (3) and 1.948 (4)A, respectively, the smaller intrinsic size of the Co I" ion being largely compensated for, as is generally observed, by an increase in the effective size with a larger coordination number (Elerman, Kabak, Svoboda & Geselle, 1994). Experimental Salicylaldehyde (0.2 mmol) and isopropylamine (1 ml) were dissolved in acetonitrile (50 ml). COC12.6H20 (0.1 mmol) in boiling methanol (30 ml) was added and the solution refluxed for 48 h. Suitable crystals were obtained on cooling. ReferencesBahron, H., Larkworthy, L. F., Marecaux, A., Povey, D. C. & Smith, G. W. (1994). J. Chem. Crystallogr. 24, 145-150. Calligaris, M., Nardin, G. & Randaccio, L. (1972). Coord. Chem. Rev. 7, 385--403. Elevman, Y., Kabak, M., Svoboda, I. & Geselle, M. (1994). ActaCryst. C50, 1694-1696. Enraf-Nonius (1993 Ankara, Turkey. E-mail: dulku@...

Bis[2-(cyclopentyliminomethyl)-4-nitrophenolato-κ2N2,O]cobalt(II)

“…The tetrahedral coordination sphere of Co II atom in the complex is formed by two imino N atoms and two phenolate O atoms from two Schiff base ligands. The coordinate bond distances are typical and comparable with the values in other similar cobalt(II) complexes with Schiff bases (Bahron et al, 1994;Elerman et al, 1996). The coordinate bond angles are in the range 96.06 (14)-123.0 (2)°, indicating a distorted tetrahedral geometry.…”

“…For the Schiff base complexes we have reported, see: Wei et al (2008); Wang et al (2007). For similar cobalt(II) complexes with Schiff bases, see: Bahron et al (1994); Elerman et al (1996).…”

Bis{1-[3-(cyclohexylamino)propyliminomethyl]naphth-2-olato}cobalt(II) tetrahydrate

“…The Co II atom is six-coordinated by two O and four N atoms from the two Schiff base ligands, forming a slightly distorted octahedral coordination. The Co-O and Co-N bond lengths (Table 1) are comparable with the corresponding values observed in the structures of similar Schiff base cobalt(II) complexes (You, 2005;Iyere et al, 2004;Elerman et al, 1996;Akitsu et al, 2004). The three trans angles at the Co II centre are 180 , by symmetry, and all other angles are close to 90 , ranging from 89.50 (13) to 90.50 (13) .…”

Bis[2-(cyclohexyliminomethyl)-4-nitrophenolato]cobalt(II)

“…The Schiff base acts as a bidentate ligand and ligates to the metal via the phenolate O and imine N atoms. All the bond lengths (Table 1) around the metal center are comparable to those in similar complexes (Fun et al, 1999;Iyere et al, 2004;Elerman et al, 1996).…”