Syntheses, Structures, and Magnetic Properties of Inorganic−Organic Hybrid Cobalt(II) Phosphites Containing Bifunctional Ligands

Seven new cobalt(II) phosphites, [Co(HPO3)(C14H14N4)(H2O)2]·2H2O (1), [Co(HPO3)(C22H18N4)]·H2O (2), [Co2(HPO3)2(C22H18N4)2H2O]·H2O (3), [Co2(HPO3)2(C12H10N4)1.5H2O]·1.5H2O (4), [Co(HPO3)(C14H14N4)0.5]·H2O (5), [Co(HPO3)(C18H16N4)0.5] (6), and [Co(HPO3)(C18H16N4)0.5] (7) were synthesized in the presence of 1,2-bis(imidazol-1-ylmethyl)benzene (L1), 1,4-bis(benzimidazol-1-ylmethyl)benzene (L2), 1,3-bis(benzimidazol-1-ylmethyl)benzene (L3),
1,4-bis(1-imidazolyl)benzene (L4), 1,4-bis(imidazol-1-ylmethyl)benzene (L5), 1,4-bis(imidazol-1-ylmethyl)naphthalene
(L6), and 1,5-bis(imidazol-1-ylmethyl)naphthalene (L7), respectively, and their structures were determined by X-ray
crystallography. Compound 1 is a molecular compound in which two cobalt(II) ions are held together by double
μ-O linkages. The inorganic framework of compounds 2 and 3 are composed of vertex-shared CoO2N2/CoO3N2
and HPO3 polyhedra that form four rings; these are further linked by an organic ligand to generate 2D sheets.
Compounds 4 and 5 both have 1D inorganic structures, with the bifunctional ligands connected to each side of the
ladder by coordination bonds to give 2D hybrid sheets. A 3D organically pillared hybrid framework is observed in
6 and 7. In 6, the stacking of the interlayer pillars gives rise to a small hydrophobic channel that extends through
the entire structure parallel to the sheets. The temperature-dependent magnetic susceptibility measurements of
these compounds show weak interactions between the metal centers, mediated through the μ-O and/or O−P−O
linkages.