Three Novel Metal-Organic Frameworks with Different Topologies Based on 3,3′-Dimethoxy-4,4′-biphenyldicarboxylic Acid: Syntheses, Structures, and Properties

Abstract

A series of three novel metal-organic frameworks, [CdL] n (1), [ZnL] n (2), and [Cu 2 L 2 (DMF) 2 ] 3 6H 2 O (3), were successfully prepared by a solvothermal method using 3,3 0 -dimethoxy-4,4 0 -biphenyldicarboxylic acid (H 2 L) as the ligands. X-ray crystallography analysis reveals that complex 1 exhibits a 3D framework with sra topology and a rare eight-coordinated Cd(II) with two bound methoxy groups as secondary building unit (SBU). For complex 2, a 2D coordination network with a four-coordinated Zn(II) as SBU was observed. Complex 3 also shows a 2D layered architecture with 4 4 square lattice topology and a paddle-wheel Cu 2 (-CO 2 ) 4 as SBU. 113 Cd NMR spectrum of 1 showed that the chemical shift of eight-coordinated Cd(II) appeared at δ -108.9 ppm. In addition, both 1 and 2 are robust coordination polymers with high thermal stabilities (>380 °C). Fluorescence measurements of 1 and 2 display medium strong emission peaks at 403 and 401 nm, respectively. Magnetic study of 3 exhibits a strong antiferromagnetic interaction between two Cu(II) ions with -2J = 286 cm -1 .

Topological identification of the first uninodal 8-connected lsz MOF built from 2,2′-difluorobiphenyl-4,4′-dicarboxylate pillars and cadmium(II)–triazolate layers

“…Although topological analyses of MOF networks have been greatly aided by searchable databases and computer programs (O'Keeffe et al, 2017;Ramsden et al, 2017), the design and construction of low-symmetry high-connected MOFs with a novel topology still remains a major challenge. Our current interest is to utilize the symmetrically substituted biphenyldicarboxylic acids (H 2 BPDC) as organic linkers for building highconnected MOFs and analyze the resulting network topology (Wang, Zhu et al, 2010;Gao et al, 2012;Luo et al, 2014). For example, an unprecedented (3,20)-connected binodal three-dimensional MOF has been constructed successfully from 2,2 0dimethoxy-BPDC as a linker and a nano-sized [Ln 4 @Ln 4 ] 'matryoshka' tetrahedron as a node (Zhao et al, 2016).…”

From molecules to materials: Molecular paddle-wheel synthons of macromolecules, cage compounds and metal–organic frameworks

“…Wang,104 Maji, 105 and Zhu 106. In 1998, Yaghi et aldescribed the synthesis of a microporous metal-organic framework [Zn(bdc)·(DMF)(H 2 O)].…”

Reversible Structural Flexibility and Sensing Properties of a Zn(II) Metal–Organic Framework: Phase Transformation between Interpenetrating 3D Net and 2D Sheet

“…The 2D sheet [Cu 2 L 2 (DMF) 2 ]· 6H 2 O (Cu phase) was prepared by a solvothermal reaction of Cu(NO 3 ) 2 ·3H 2 O and H 2 L in DMF/H 2 O at 80°C. 26 This structure is quite different from 1 (Zn phase) with the 3-fold interpenetration. To examine the mutual transformation between Zn and Cu phases, the Zn phase was immersed in a 0.04 M Cu 2+ solution and treated under reaction conditions identical to that used for the synthesis of the Cu phase.…”

“…3,3′-Dimethoxybiphenyl-4,4′-dicarboxylic acid (H 2 L) was prepared according to the literature procedure. 26 All the other chemicals and solvents in the synthesis were of reagent grade and used as received. All manipulations were performed under aerobic conditions.…”