Yuan-Fu Deng

Monomeric and polymeric nickel complexes of malate: X-ray crystal structure of polymeric homochiral S-malato nickel(II), [Δ-Ni(S-Hmal)(H2O)2]n·nH2O

Abstract Polymeric S-malate nickel(II) [Δ-Ni(S-Hmal)(H2O)2]n·nH2O (1) was prepared from the reaction of nickel chloride and malate salt. By prolonging the reaction time and heating, the kinetic monomeric product cis-[Ni(S-H2mal)2(H2O)2]·2H2O (2) can be converted into the thermodynamic polymeric product 1. The coordination polymer is linked strongly by the tetradentate malate ligand, forming an homochiral zigzag chain. It is proposed that the chiral metal center of the complex may also be involved in the enantioselective synthesis as well as the chiral ligand.

The first structural examples of tricitratotitanate [Ti(H2cit)3]2− dianions

The crystal structures of the mixed-cation compounds KMg½[Ti(H2cit)3]·6H2O and (NH4)Mg½[Ti(H2cit)3]·6H2O (H4cit = citric acid), which were synthesized by a modified Pechini process, feature three bidentate [(HO2CCH2)2C(CO2–)O–] citrato groups that chelate to the titanium atom through their negatively-charged α-alkoxyl and α-carboxyl oxygen atoms; the other two β-carboxylic acid groups are free.