Catena-Poly[[diaqua-rubidium(I)](?(2)-3-carboxy-pyrazine-2-carboxyl-ato)(?(2)-pyrazine-2,3-dicarboxylic acid)].

ABSTRACT: The structural unit of the title compound, [Rb(C(6)H(3)N(2)O(4))(C(6)H(4)N(2)O(4))(H(2)O)(2)](n), consists of one rubidium cation, one hydrogen pyrazine-2,3-dicarboxyl-ate anion, one pyrazine-2,3-dicarboxylic acid mol-ecule and two water mol-ecules. This formulation is repeated twice in the asymmetric unit as the rubidium cation lies on an inversion centre. Each anion or acid mol-ecule is linked to two rubidium cations, while the rubidium cation has close contacts to four symmetry-equivalent organic ligands, with two different coordination modes towards this cation. In addition, each rubidium cation is coordinated by two water O atoms, raising the coordination number to eight. One of the carboxyl groups of the acid holds its H atom, which forms a hydrogen bond to a coordinated water mol-ecule. The other carboxyl group is deprotonated in half of the ligands and protonated in the other half, taking part in a strong O-H?O hydrogen bond disordered over an inversion centre. The stabil-ization of the crystal structure is further assisted by O-H?O and O-H?N hydrogen-bonding inter-actions involving the water mol-ecules and carboxyl-ate O atoms.

SUBMITTER: Tombul M 

PROVIDER: S-EPMC2968173 | biostudies-literature | 2009 Jan

REPOSITORIES: biostudies-literature