Supramolecular architectures based on various macrocyclic metallic tectons with 1,3,5-triazine-2,4,6-triamine hexaacetic acid ligand

Abstract

Reactions of series of macrocycle derivatives [Ni(hto)]Cl₂·2H₂O (1) (hto = 1,3,6,9,11,14-hexaazatri-cyclo[12.2.1.1^6,9]octadecane), [Ni(CHA)](ClO₄)₂ (2) (CHA = 1,3,6,8,11,14-hexaazatri-cyclo[12.2.1.1^8,11]octadecane), [Ni(PCHA)](ClO₄)₂ (3) and [Cu(PCHA)](ClO₄)₂ (4) (PCHA = 4-methyl-1,3,6,8,11,14-hexaazatri-cyclo[12.2.1.1^8,11]octadecane), with a flexible hexapodal ligand H₆TTHA (H₆TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid) resulted in eight supramolecular coordination polymers (SCPs), formulated as α-[Ni(hto)][H₄TTHA]·5H₂O (5), β-[Ni(hto)][H₄TTHA]·4H₂O (6), [Ni(CHA)][H₄TTHA]·2H₂O (7), [Ni(PCHA)][H₄TTHA]·3H₂O (8), [Cu(PCHA)][H₄TTHA]·1.5H₂O (9), [Ni(PCHA)][H₅TTHA](ClO₄)·4H₂O (10), [Ni(PCHA)][H₄TTHA]·DMSO·H₂O (11) and [Ni(PCHA)][H₄TTHA]·DMF (12). These compounds are structurally characterized by X-ray diffraction analyses. The predominant driving forces that connect macrocyclic metallic tectons with hexaacetic acid ligand in compounds 5–12 are hydrogen bonds, by which the compounds assemble into SCPs with versatile structures. The single-crystal X-ray diffraction analysis reveals that compounds 5 and 6 contain a rhombic 2-D layer network structure constructed of hydrogen bonds. Compound 7 exhibits a 3-D supramolecular network with 12 × 10.4 Ų 1-D brick wall net structure along the c-axis, and all the water molecular guests adorned the brick wall net. Compounds 8 and 9 show a nonporous 3-D framework also stabilized by the hydrogen bonds. Tuning by solvents, in compound 10, an elliptical 2-D network was found to accommodate water molecules and perchlorate in the channels, with grid dimensions of 11 × 10 Ų; compounds 11 and 12 show 2-D honeycomb-like networks with diameter 12 Å. In conclusion, the crystal structures and regulatory effect of thev N-donor on the macrocyclic ligands in these compounds are discussed.