Synthesis and crystal structure of d–f heteronuclear Gd(III)–Co(II) system

Some aspects of the formation and structural features of low nuclearity heterometallic carboxylates

Heterometallic carboxylate complexes are of paramount interest in pure and applied coordination chemistry. Despite that plurality of such type compounds have been published to date, synthetic aspects of their chemistry often remain in the shadow of intriguing physical properties manifesting by these species. Present review summarizes reliable data on direct synthesis of low nuclearity molecular compounds as well as coordination polymers on their base with carboxylate-bridged {M2Mg} (M = Co2+, Ni2+, Cd2+), {M2Li2} (M = Co2+, Ni2+, Zn2+, VO2+), {M2Ln2} and {M2Ln} (M = Cu2+, Zn2+, Co2+) metal cores. Structural features and stabilization factors are considered and principal outcomes are confirmed by quantum-chemical calculations. Particular attention is paid to consideration of ligand-exchange reactions that allow controllable modification of heterometallic metal core under mild conditions giving diverse molecular complexes with modified ligand environment or Metal-Organic Frameworks with permanent porosity.

Bis(2,2'-bipyridine)-1κN,N';3κN,N'-hexa-μ-methacrylato-1:2κO:O';2:3κO:O'-(nitrato-2κO,O')-1,3-dicobalt(II)-2-terbium(III)

In the title trinuclear cobalt–terbium complex, [Co₂Tb(C₄H₅O₂)₆(NO₃)(C₁₀H₈N₂)₂], the central Tb^III and each of the Co^II ions are bridged by three carboxyl­ate groups of the methacrylate anions. The Tb^III cation is coordinated by six O atoms from six methacrylate anions and two O atoms from a chelating nitrate anion in a distorted square-anti­prismatic geometry. Each Co^II ion is coordinated by three O atoms from three methyl­acrylate anions and two N atoms of a 2,2′-bypiridine ligand in a distorted square-pyramidal geometry. In the crystal structure, π–π stacking between the pyridine rings [centroid–centroid distances = 3.682 (8) and 3.760 (8) Å] is observed and weak inter­molecular C—H⋯O hydrogen bonding is also present.