The ubiquitous paddle-wheel building block in two-dimensional coordination polymers with square grid structure

• Published in: Journal of coordination chemistry Vol. 69; no. 11-13; pp. 1957 - 1969
• Main Authors: Pariyar, Anand, Stansbery, Joseph, Patel, Rajankumar L., Liang, Xinhua, Choudhury, Amitava
• Format: Journal Article
• Language: English
• Published: Abingdon Taylor & Francis 02.07.2016; Taylor & Francis Ltd
• Subjects: 1,4-benzenedicarboxylate; 2-D coordination polymer; Coordination polymers; Crystal structure; Ligands; paddle-wheel; Pyrazines; Pyridines; square grid topology; Surface area; Surface chemistry; Topology; transition metal
• ISSN: 0095-8972; 1029-0389
• DOI: 10.1080/00958972.2016.1190839

This work describes design of a series of new paddle-wheel binuclear clusters containing 2-D coordination polymers based on ditopic carboxylate linkers, 1,4-benzenedicarboxylate (BDC) or 2-amino,1,4-benzenedicarboxylate (Am-BDC). The strategic use of strongly coordinating base/solvent as blocking ligand to restrict the structure in 2-D space is explored, and the role of organic base on the overall structure formation is further elaborated. The isostructural [Zn(BDC)(Py)] n (1) and [Co(BDC(Py)] n (2) were formed by the use of strong base pyridine (Py) as a blocking ligand whereas reaction using N-methylimidazole (Mim) in place of pyridine gives [Co(BDC)(Mim)] n (3) with similar topology and coordination environment. The use of weak/non-coordinating base such as 2-chloropyrimidine, pyrazine, and tetramethylammoniumhexafluorophosphate [(CH 3 ) 4  N(PF 6 )] gives the DMF-coordinated 2-D frameworks, [Cu(BDC)(DMF)] n (4), [Zn(BDC)(DMF)] n (5), and [Zn(AmBDC)(DMF)] n (6). All the structures crystallize in monoclinic crystal system yielding 2-D nets with square grid 4 4 topology and solid state 3-D structure via extensive non-covalent supramolecular interactions. Surface area analysis via N 2 adsorption of three representative 2-D coordination polymers, 1, 4, and 6, indicate that 4 has a surface area of 450 m 2  g −1 which is a signature of microporosity, while 1 and 6 have moderate (161.6 m 2  g −1 ) and negligible (33 m 2  g −1 ) surface areas, respectively.