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The self-assembly of three MOFs with a series of structure differences in framework charge, metal nodes, topolpgy nets and porosity, not only demonstrates the great potential of mixed-ligands strategy to create novel high-porosity crystalline solids, but also highlights the structural directional effect of 3d metal ions based on varied coordination geometry preference. [Display omitted] • Two new and highly porous mixed-ligands MOFs were synthesized from H 3 btb and H 2 bdc. • The metal ions induced structural orientation and differentiation in mixed-ligands MOFs. • Two-steps gate-opening in gas sorption was found for flexible Mn(II) mixed-ligands MOFs. Mix-ligands strategy is highly efficient for the rational construction of MOFs with particular structure motifs and high porosity, yet challenging and requiring matching in hierarchical coordination assembly and synergetic crystallization. The solvothermal reactions of 1,3,5-tris[4-carboxyphenyl]benzene (H 3 btb) and 1,4-benzenedicarboxylic acid (H 2 bdc) with different 3d metal ions, generated highly porous mixed-ligands MOFs of [(CH 3) 2 NH 2 ] 2 [Mn 3 (btb) 2 (bdc)]·12DMF·3MeOH (Mn-btb-bdc) having anionic 3D frameworks constructed from linear [Mn 3 (COO) 8 ] nodes, [Co 4 (btb) 2 (bdc)(H 2 O) 3 ]·15DMF·7H 2 O (Co-btb-bdc) processing neutral frameworks constituted by linear [Co 3 (COO) 6 (H 2 O) 4 ] and paddle-wheel [Co 2 (COO) 4 (H 2 O) 2 ] nodes, as well as one single-ligand MOFs of [(CH 3) 2 NH 2 ][Cd(btb)(H 2 O)]·8DMF (Cd-btb-2fold) exhibiting 2-fold interpenetrated ths net frameworks due to the unsuccessful introduce of the coexisted bdc ligand. Two new topology net of 2,3,8-connected net with point symbol of (42·6) 2 (44·66·812·105·12)(6) and 2,3,4,6-connected net with Point Symbol of (4·82) 4 (42·811·102) 2 (84·122)(82) were found for Mn-btb-bdc and Co-btb-bdc. All these three MOFs are highly porous with void fractions of 60.9%, 52.2% and 61.4%, stemming from 3D-penetrated, 3D-penetrated and 1D channels, respectively. Such structural differentiations are attributed to the diversified electronic structure and coordination preference of different 3d metal ions, as well as the solvent template and temperature effects. Two-steps gate-opening behaviour in gas sorption isotherms was found in the flexible Mn-btb-bdc MOFs. [ABSTRACT FROM AUTHOR]

By adopting mixed‐ligand strategy, three Co(II)/Cd(II) metal–organic frameworks were prepared by hydrothermal reactions of Co(II)/Cd(II) acetate with 1,2‐phenylenediacetic acid or 1,3‐phenylenediacetic acid(1,2‐H2phda/1,3‐H2phda) combining with two imidazolyl/trazol/pyridyl‐type tectons, namely, {[Co(1,2‐phda)(bip)(H2O)2]·0.25H2O}n (1), {[Cd0.5(1,2‐phda)0.5(bip)0.5(H2O)0.5]·0.5H2O}n (2) and [Cd2(1,3‐phda)2(itmb)2]n (3) (bip = 3,5‐bis(1‐imidazoly)pyridine and itmb = 1‐(imidazo‐1‐ly)‐4‐(1,2,4‐trazol‐1‐ylmethyl)benzene). The single‐crystal X‐ray diffraction analyses show that three compounds contain various metal(II)‐carboxylate motifs, including carboxylate mononuclear (1), carboxylate chain (2), and carboxylate layer (3), which are further extended by two kinds of coligands to afford a vast diversity of the structures from 3‐connected {63}‐hcb topology (1), (4,4) grids layer (2) to 6‐connected {412·63} pcu topology (3). Furthermore, the photoluminescences of both Cd(II) complexes exhibit highly selective sensing of Fe3+ ion through fluorescence quenching, and may be used as a potential Fe3+ sensor material. [ABSTRACT FROM AUTHOR]

We reported the design and synthesis of mixed ligands Cu-metal organic frameworks (MOFs), MOFs-2 and MOFs-3, and their application as the transport vehicles for the delivery of Ibuprofen (IBU) and doxorubicin hydrochloride (DOX). The unique MOFs with mixed ligands, 1,3,5-benzene tricarboxylate (BTC) and isophthalic acid (IPA), were easily prepared by hydro-thermal method, and their structures were well characterized by XRD, FTIR, and SEM imaging analysis. Single ligand MOFs with BTC or IPA only were also prepared and characterized as the control group. The biocompatibility of synthesized MOFs towards human cells, HEK 293A was evaluated by MTT assay. To demonstrate the practical applications of the prepared MOFs as the transport vehicles for drugs, the capability of loading and controlled release of IBU and DOX by MOFs-1, MOFs-2, MOFs-3, and MOFs-4 were then examined. In addition, the drug delivery efficiency of various MOFs with different ligands was investigated. [ABSTRACT FROM AUTHOR]

Abstract: ZIF-78 is a prototypical mixed-ligand compound among metal–organic frameworks (MOFs), with the composition of divalent zinc cations bridging by 2-nitroimidazolate (nIm) and 5-nitrobenzimidazolate (nbIm) anions. ZIF-78 belongs to hexagonal space group (P63/mmc) with a GME topology. Owing to the anisotropic pore structure and good affinity to CO2, ZIF-78 has potential applications in adsorption and separation fields. Herein, morphological control of ZIF-78 crystals was achieved via solvothermal synthesis. XRD, SEM, NMR, and adsorption characterizations were performed to study the crystalline phase, morphology, composition and adsorption behavior of obtained crystals, respectively. ZIF-78 micro-crystals with shape of the hexagonal rods were prepared with the assistance of triethylamine. The size and the aspect ratios of ZIF-78 microrods were manipulated from the “slender” to the “squat” via varying the nutrient concentration, the ligand concentration or relative molar ratio of nIm to nbIm. [Copyright &y& Elsevier]