Catenation control in the two-dimensional coordination polymers based on tritopic carboxylate linkers and azamacrocyclic nickel(ii) complexes

Abstract

Four new coordination polymer frameworks, namely [(NiL(1))(3)(BTB)(2)]·6H(2)O, [(NiL(2))(3)(BTB)(2)]·6H(2)O, [(NiL(3))(3)(BTB)(2)]·6H(2)O and [(NiL(2))(3)(BTC)(2)]·10.25H(2)O (L(1) = 1,4,8,11-tetraazacyclotetradecane, L(2) = 3-methyl-1,3,5,8,12-pentaazacyclotetradecane, L(3) = 3,10-dimethyl-1,3,5,8,10,12-hexaazacyclotetradecane, BTC(3-) = benzene-1,3,5-tricarboxylate, BTB(3-) = 4,4',4''-benzene-1,3,5-triyl-tribenzoate) were prepared in water-N,N-dimethylformamide solutions. The molecular and crystal structures of these compounds are compared to the related coordination polymers formed by nickel(II) macrocyclic cations to examine the effect of carboxylate linker size on the framework architecture. Luminescent properties of the complexes based on the BTB(3-) bridging ligand are also discussed.

Synthesis and crystal structure of bis[trans-diaqua(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)] trans-(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N

“…Usually, the modification of this bridge through the substitution of the carboxylic groups by para-carboxybenzyl fragments (the ligand H 3 BTB, 4,4 0 ,4 00 -benzene-1,3,5-triyltribenzoic acid) does not affect the coordination properties of the carboxylate groups or the topological characteristics of polymeric nets but results in the enlargement of the hexagonal structural unit of the coordination polymers allowing interpenetration of the subnets (Lampeka et al, 2012;Gong et al, 2016). Compared to carboxylates, linkers with other coordinating functions, in particular oligophosphonates, have been studied to a much lesser extent (Gagnon et al, 2012;Firmino et al, 2018;Yu ¨cesan et al, 2018), though one can expect that the substitution of a mono-anionic carboxylic group by a di-anionic phosphonate group with distinct acidity, number of donor atoms and spatial directivity of coordination bonds will strongly influence the composition and topology of the coordination nets.…”

Syntheses and structural characterizations of the first coordination polymers assembled from the Ni(cyclam)2+ cation and the benzene-1,3,5-tricarboxylate linker

“…Their interactions with different oligocarboxylates as the most common bridging ligands (Rao et al, 2004) usually result in coordination polymers, the dimensionalities of which are dependent on the number of carboxylic groups present in the linker. As was shown formerly for a number of macrocyclic Ni 2+ complexes of aza-and diazacyclam derivatives, which are the closest structural analogues of L (azacyclam = 1, 3,5,8,12-pentatetraazacyclotetradecane, diazacyclam = 1,3,5,8,10,12-hexaazazacyclotetradecane), the coordination of the simplest tridentate aromatic ligand benzene-1,3,5-tricarboxylate (btc 3-) in the trans-axial coordination positions of the metal ion leads to the formation of two-dimensional coordination polymers with hexagonal nets of 6 3 topology (Choi et al, 2001;Meng et al, 2011;Choi & Suh, 1998;Ryoo et al, 2010;Lu et al, 2001;Lu et al, 2002;Lampeka et al, 2012). Surprisingly, for the Ni(L) 2+ cation itself, only ionic compounds built on the transdiaqua [Ni(L)(H 2 O) 2 ] 2+ cation and the non-coordinated btc 3À anion have been described to date (Choi et al, 1999;Parsons et al, 2006;Tadokoro et al, 2015).…”

“…All of them are highly hydrated (18-29 water molecules of crystallization) ionic complexes containing the trans-diaqua [Ni(L)(H 2 O) 2 ] 2+ dication and non-coordinated btc 3trianions. At the same time, a number of two-dimensional coordination polymers built on parent 14-membered derivatives of Ni(azacyclam) (CAXMIZ, Lampeka et al, 2012) and Ni(diazacyclam) (IPOZIW, Choi et al, 2001;IWESIN and IWESOT, Meng et al, 2011;JEDQIS and JEDQOY, Choi & Suh, 1998;UJUHUD, Ryoo et al, 2010;VOQSAV, Lu et al, 2001;and WUJDEK, Lu et al, 2002) bearing different substituents at the non-coordinated distal nitrogen atom(s) have been structurally characterized. In addition, two compounds with other structures have been described.…”

Influence of the Molar Ratio and Solvent on the Coordination Modes of 1,7-Dibenzyl-4,10-bis(pyridin-4-ylmethyl)cyclen

“…Azamacrocycles have attracted much attention because of their application for ion recognition, catalysis, and adsorption in supramolecular chemistry. − Metal ions are incorporated into the cavity of the azamacrocycles, resulting in a very stable structure. To improve the efficacy of various applications of azamacrocycles, the preparation of high-dimensional coordination polymers based on azamacrocycles has been attempted. − As a method for increasing the coordination ability, azamacrocycles as coligands are used in the reaction with organic ligand linkers and a metal ion, − or substituents capable of metal coordination, such as carboxylates, are introduced. − Despite some literature reporting on the preparation of functional coordination polymers based on azamacrocycles, few attempts have been made to systematically demonstrate the effect of control factors on the self-assembly of such coordination polymers. − …”