Structure, magnetic properties and spin density of two alternative Mn (ii)coordination polymers based on 1, 4-bis (2'-carboxyphenoxy)benzene

Two novel manganese coordination polymers [Mn2(?2-bcpb)(?4-bcpb)(2,2?-bipy)2]n (1)and [Mn2(?3-bcpb)2(2,2?-bipy)2(H2O)]n (2)(H2bcpb = 1,4-bis(2?-carboxylato phenoxy)-benzene; 2,2?-bipy = 2,2?-bipyridine), have been synthesized successfully from the same reactants. This unusual selectivity was corroborated by X-ray powder diffraction. Single crystal X-ray diffraction analysis of complex 1 reveals that neighboring Mn(II)ions are linked via two bcpb2? anions to form a dinuclear Mn(II)subunit [Mn2(?1,1-COO)2]2+ with a Mn?Mn distance of 3.3758 (6)Å. And ??? interactions between aromatic rings of the bcpb2? and 2,2?-bipy ligands stabilize the two-dimensional extended coordination network with the unprecedented Schläfli symbols {4·62}2{42·62·82}. In the [Mn2(?1,3-COO)2]2+ subunit of 2, two linking bcpb2? ligands subtend an interaction distance of 4.4048(6)Å. Intermolecular O-H?O hydrogen bonds involving oxygen atoms of carboxylic acid and coordinated water molecules connect adjacent 1D chain molecules into a 2D network. Experimental temperature-dependent magnetic susceptibility measurements and spin density analyses by DFT disclose that compounds 1 and 2 display different magnetic properties.