A variety of metal–organic and supramolecular networks constructed from a new flexible multifunctional building block bearing picolinate and terephthalate functionalities: hydrothermal self-assembly, structural features, magnetic and luminescent properties

• Published in: RSC advances Vol. 5; no. 106; pp. 87484 - 87495
• Main Authors: Shao, Yong-Liang, Cui, Yan-Hui, Gu, Jin-Zhong, Kirillov, Alexander M., Wu, Jiang, Wang, Ya-Wen
• Format: Journal Article
• Language: English
• Published: 01.01.2015
• Subjects: Bearing; Coordination polymers; Ligands; Networks; Optical properties; Self assembly; Three dimensional; Two dimensional
• DOI: 10.1039/C5RA16580F
• ISSN: 2046-2069

A novel flexible multifunctional building block (H 3 L) bearing picolinate and terephthalate functionalities was designed and applied for the hydrothermal self-assembly generation of a series of coordination compounds [Co(H 2 L) 2 (H 2 O) 2 ] ( 1 ), [M(HL)(H 2 O)] n {M = Cd ( 2 ) and Mn ( 3 )}, {[Mn 1.5 (L)(phen)(H 2 O) 2 ]·H 2 O} n ( 4 ), [Zn 3 (L) 2 (H 2 O) 6 ] n ( 5 ), and {[Zn 3 (L) 2 (py) (H 2 O) 4 ]·4H 2 O} n ( 6 ) {wherein H 3 L = 2-(4-carboxypyridin-3-yl)-terephthalic acid, phen = 1,10-phenanthroline, py = pyridine}. All the obtained products 1–6 were fully characterized by IR spectroscopy, elemental, thermogravimetric, powder and single-crystal X-ray diffraction analyses. By adjusting the molar ratio of NaOH and H 3 L ligand, the latter becomes partially deprotonated to form the H 2 L − blocks in 1 and HL 2− moieties in 2 and 3 , or completely deprotonated to create the L 3− units in 4–6 . The structures of the obtained compounds range from a discrete 0D monomer 1 and 1D coordination polymers 4 and 5 to 2D coordination polymers 2 and 3 , and an intricate 3D metal–organic framework 6 ; their detailed topological classification was also performed. The structures of 1–5 are further extended [0D → 3D ( 1 ), 1D → 3D ( 4 , 5 ), and 2D → 3D ( 2 , 3 )] into supramolecular networks by means of multiple hydrogen bonds. The results reveal that the nature of metal( ii ) ion, molar ratio between NaOH and H 3 L ligand, and the presence (optional) of auxiliary ligand play a significant role in determining dimensionality, topology and other structural features of the obtained products. Magnetic susceptibility measurements indicate that compounds 3 and 4 have dominating antiferromagnetic couplings between metal centers. Furthermore, luminescent properties of 2 , 5 , and 6 were also investigated.