Three new acylamideligands formed in situ and their application in constructing metal–organic frameworks

Abstract

Reported here are three previously unobserved acylamide ligands used in the preparation of metal–organic frameworks. Interestingly, in this work these acylamide ligands are formed in situ, rather than pre-prepared and three novel metal–organic frameworks are obtained. Their formulae are listed as follows: {Cd(H₂O)(bpy)(ip)₂Cd(bpy)(HL)(ip)₂}_n (1, H₂ip = isophthalic acid, bpy = 2,2′-bipyridine, HL = 4-(pyridin-3-ylcarbamoyl)benzoic acid), {Zn(L1)₂}_n (2, HL1 = 4-(pyridin-3-ylcarbamoyl)-1-naphthoic acid), {Cd(L2)(bdc)_0.5(L3)}_n (3, H₂bdc = terephthalic acid, L2 = N4,N4′-di(pyridin-3-yl)-[1,1′-biphenyl]-4,4′-dicarboxamide, HL3 = 4′-(pyridin-3-ylcarbamoyl)-[1,1′-biphenyl]-4-carboxylic acid). Their structures can be described as a 2D supramolecular net, a 3D CdSO₄ net with two-fold interpenetration, and a 3D dia or alternatively α-Po net, respectively. Notably, in the cases of polymers 1 and 3, three distinct organic ligands coexist and coordinate with one metal center, where such concordant coordination competition around one metal center among three distinct organic ligands, to the best of our knowledge, is rare. Moreover, as observed in the literature, the spontaneous resolution producing chiral compounds from achiral source is also observed in polymer 2. Furthermore, we also explored their thermostability and luminescence properties.