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 [Mn-2(mu(2)-bcpb)(mu(4)-bcpb)(2,2'-bipy)(2)](n) (1) and [Mn-2(mu(3)-bcpb)(2)(2,2'-bipy)(2)(H2O)](n) (2) (H(2)bcpb = 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 bcpb(2-) anions to form a dinuclear Mn(II) subunit [Mn-2(mu(1,1)-COO)(2)](2+) with a Mn center dot center dot center dot Mn distance of 3.3758 (6) angstrom. And pi center dot center dot center dot pi interactions between aromatic rings of the bcpb(2-) and 2,2'-bipy ligands stabilize the two-dimensional extended coordination network with the unprecedented Schlafli symbols {4.6(2)}(2){4(2).6(2).8(2)}. In the [Mn-2(mu(1,3)-COO)(2)](2+) subunit of 2, two linking bcpb(2-) ligands subtend an interaction distance of 4.4048(6) angstrom. Intermolecular O-H center dot center dot center dot 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.

Automated summary

Two novel manganese coordination polymers have been successfully synthesized using the same reactants. X-ray diffraction analysis confirms their structures. Experimental results reveal that these compounds exhibit different magnetic properties.