Organoamine-induced isomerism of calixarene-based complexes: from 1D to 2D

Two isomers of the calixarene-based cobalt complex [Co₄Cl(TC4A)(BCPT)₂]⁻ (H₄TC4A = p-tert-butylthiacalix[4]arene; H₂BCPT = 3,5-bis (4′-carboxy-phenyl)-1,2,4-triazole) were obtained under the solvothermal conditions with tetramethylammonium/tetraethylammonium hydroxide (CIAC-236) and triethylamine (CIAC-237). Single crystal X-ray diffraction reveals that CIAC-236 has a 1D zigzag aggregate constructed by bridging the shuttlecock-like Co₄–TC4A secondary building units (SBUs) with two pairs of opposite V-shaped BCPT ligands while CIAC-237 possesses a 2D layer assembly with each Co₄–TC4A SBU bonded by four BCPT ligands in a same direction (clockwise or counterclockwise), which indicates that different shapes of the organoamines lead to different assembly of the BCPT ligands and the formation of different extended aggregates. For comparison, only the 1D structure ([Fe₄Cl(TC4A)](BCPT)₂]⁻, CIAC-238) was obtained for the iron complexes with all these three organoamines, which would be attributed to different property and coordination of iron element. Magnetic properties of all these three compounds were studied.

Two isomers of the calixarene-based cobalt complex, 1D aggregate and 2D network, were obtained with different organoamine templates.