Concomitant Crystallization of Genuine Supramolecular Isomeric Rhombus Grid and Ribbon

Two
genuine Co­(II) supramolecular isomers, a two-dimensional (2-D)
rhombus grid 1 and a one-dimensional (1-D) ribbon 2, that have the same metal fragment and ligand conformations,
were crystallized from the same reaction bath under hydro­(solvo)­thermal
conditions. The formation of supramolecular isomers in this system
is dominated by the bridging orientation of InMe-4-py ligands, which
is mainly influenced by reaction temperature but also weakly swayed
by pH value, reaction time, and counteranion. The major rhombus grid 1 is the thermodynamically favored product, and the minor
ribbon 2 is the kinetically favored product under controlled
conditions, as supported by their relative abundances in functions
of temperature and time. Both polymeric networks of supramolecular
isomers 1 and 2 display a high thermal stability
over 350 °C. Magnetic studies of 1 and 2 indicate that the Co­(II) centers in the 2-D and 1-D networks are
essentially magnetically insulated. The magnetic behavior demonstrates
depopulation of higher energy Kramers doublets to the ground state,
which results from a spin–orbit contribution, of the high-spin
Co­(II) center in Oh configuration upon
a decrease of temperature.