The role of auxiliary solvents in the formation of MOFs has been investigated for a series of MnII-based framework systems. Reactions of 4,4′,4″-nitrilotribenzoic acid (H3L) with MnII through varying auxiliary solvents of the medium resulted in the formation of diversified multinuclear MnII subunits in four new coordination polymers: [Mn3(L)(HCOO)3(DEF)3] (1), [Mn3(L)2(EtOH)2]·DMF (2), [Mn5(L)4(H2O)2]·2(H2NMe2)+·4DMF·2H2O (3), and [Mn3(L)2(py)4(H2O)]·H2O (4) (H3L=4,4′,4′-nitrilotribenzoic acid, DMF=dimethylformamide, DEF=N,N-diethylformamide, py=pyridine). These four compounds were fully characterized by single-crystal X-ray diffraction, showing interesting SBUs variations. For compound 1, it displays a (3,6)-connected kgd net with wheel [Mn6] cluster serving as SBU, whereas in 2, the sequence of Mn3(COO)9(EtOH)2 is repeated by inversion centers located between Mn1 and Mn3 to form an infinite Mn-carboxylate chain, which are further interlinked by L3− ligands to form a 3D architecture. In 3, the pentanuclear Mn5(CO2)12 clusters are interlinked to form a layer, which are further pillared by L3− to generate a 3D network. Compound 4 has a (3,6)-connected network in which the SBU is a linear trimeric Mn3(COO)6(py)4(H2O) cluster. In addition, the thermal stabilities, X-ray powder diffraction of all the compounds were studied, photoluminescence behaviors of compounds 1, 3 and 4 are discussed.Supramolecular assembly of C3-symmetric ligand 4,4′,4″-nitrilotribenzoic acid (H3L) with MnII through varying auxiliary solvents of the medium resulted in the formation of diversified multinuclear MnII subunits in four new coordination polymers. The results exhibit the structures of Mn-SBUs in these MOFs largely depend on the ancillary solvents involved in the reactions.

A new three-dimensional (3D) metal–organic framework (MOF), [Zn3L2(DMF)2]·2DMF (1-Zn), was prepared by the reaction of 5-(4-carboxybenzoylamino)-isophthalic acid (H3L) with Zn(NO3)2·6H2O under solvothermal conditions. Interestingly, the zinc ions in the zinc–carboxylate chains of complex 1-Zn could be exchanged with copper ions via direct single-crystal to single-crystal transformation (SC-SC). The complete and irreversible exchange of the metal ions from Zn2+ to Cu2+ and retention of the framework structure were verified by powder X-ray diffraction (PXRD), ICP-AES and SEM-EDS. Solid state photoluminescence measurements showed metal-specific properties.

•A new 3D porous NbO-type MOF with inserted acylamide units was synthesized.•This complex shows large CO2-uptake capacity and high selectivity toward CO2/N2.•This complex exhibits catalytic activity in Knoevenagel condensation reaction.•This work will enrich the chemistry of functional MOFs via inserting polar units.•This work will facilitate research of MOFs with high performance in the future.A dual functional three-dimensional porous NbO-type metal–organic framework with inserted acylamide units was solvothermally synthesized, which exhibits large CO2-uptake capacity (160 cm3 g− 1 at 1 bar), high selectivity toward CO2/N2 (41.6 at 273 K) and satisfied catalytic activity in Knoevenagel condensation reaction.A dual functional three-dimensional porous NbO-type metal–organic framework with inserted acylamide units exhibits large CO2-uptake capacity, high selectivity toward CO2/N2 and satisfied catalytic activity in Knoevenagel condensation reaction.

Solvothermal reactions of a tricarboxylate ligand 5-(4-carboxybenzoylamino)-isophthalic acid (H3L), dipyridyl linkers (bpe, bpa and bpy) and divalent metal ions (Co2+, Cd2+, Zn2+ and Ni2+) provided a highly efficient approach to the syntheses of multi-dimensional framework materials containing interesting structural motifs: [Co3L2(bpe)4]·2DMF·2H2O (1), [Cd3L2(bpe)4]·3H2O (2), [Zn2L(OH)(bpe)]·5.5H2O (3), [Co7L4(bpa)2(OH)2(H2O)4]·4H2O (4), Ni(HL)(bpa)(H2O) (5) and [Zn2(HL)2(bpy)2(H2O)2]·(bpy)·6H2O (6) (bpe = 1,2-bis(4-pyridyl)ethene, bpa = 1,2-bis(4-pyridyl)diazene, bpy = 4,4′-bipyridine). Solids 1 and 2 are isostructural and each features a three-dimensional (3D) pillar-layer architecture generated from bpe-pillared M-L3− layers. Complex 3 has a 3D structure in which the secondary building unit (SBU) is a rare example of a tetranuclear Zn4(μ3-OH)2(COO)6(bpe)4 unit, whereas 4 exhibits an interesting sandwich-shaped architecture with a trimeric unit [Co3(COO)4(OH)(N2)] serving as the SBU. Complex 5 provides an unusual example of a (4,4) grid layer structure bearing free carboxylic acid (–COOH) units. The layered structure of 6 is generated from hydrogen bonded [Zn(HL)(bpy)(H2O)] chains, with free bpy and guest water molecules accommodated inside. Furthermore, the thermal behavior, powder X-ray diffraction (PXRD) and solid state photoluminescence properties correlated with the corresponding structural features were investigated.

Assembly reactions of acylamide-containing dicarboxylate ligand 4,4′-(carbonylimino)dibenzoic acid (H2L) with corresponding divalent metal ions resulted in the formation of seven new coordination polymers, namely Cd(L)(H2O) (1), Zn(L)(H2O) (2), Zn5(L)2(OH)6 (3), [Ni(L)(H2O)2]·H2O (4), [Cd(L)(py)(H2O)]·(DMF)·(C6H5Cl) (5), [Cd(L)(py)2]·2CH3OH (6) and [Mn (HL)2(py)2]·2DMF (7). In complex 1, the double chains composed CdII and L2− are connected by interlayer Cd–O bonds to form a three-dimensional architecture. Complex 2 exhibits a three-dimensional supramolecular architecture extended by hydrogen bonds involving O–H⋯O and N–H⋯O types. Complex 3 displays a three-dimensional framework consisting of zinc-hydroxide layers and L2− pillars. Complex 4 is also a supramolecular three-dimensional network generated from linkage of Ni–O chains via versatile hydrogen bonds. Complex 5 exhibits an interdigitated network in which the cavities are occupied by guest DMF and C6H5Cl molecules. In complex 6, two-dimensional square-grid network was generated by linkage of Cd2 units with L2− ligands. Mono-depronated ligand presents in complex 7. The adjacent [Mn(py)(HL)] chains are arranged parallel to each other by forming hydrogen bonding between the acylamide groups and guest DMF molecules. The stability properties of 2, 3, 4, 6 and 7 have been presented. In addition, photoluminescence properties of complexes 2, 3, 5 and 6 are investigated.Supramolecular assembly of acylamide-containing dicarboxylate ligand 4,4′-(carbonylimino)dibenzoic acid (H2L) with divalent zinc, nickel, cadmium and manganese ions were investigated. The combination of coordination bond, hydrogen bond and π–π stacking leads to a series of coordination polymers showing interesting solid-state structures.

The employment of different Lewis bases pyridine and 3,5-DMpy under solvothermal conditions gave rise to two isostructural three-dimensional metal-organic frameworks: Co2(py)2(L)(DMA)2 (1) and Co2(L)(DMA)4 (2) (H4L = 5-(3,5-dicarboxybenzoylamino)-isophthalic acid, py = pyridine, DMA = N,N-dimethylacetamide, 3,5-DMpy = 3,5-dimethylpyridine). Single-crystal X-ray analysis has shown that 1 furnishes two different types of one-dimensional channels occupied by bridging DMA and terminal pyridine molecules. Changing pyridine to 3,5-DMpy in the assembly procedure affords 2, in which the channels are filled with bridging and terminal DMA molecules exclusively.Lewis bases pyridine and 3,5-DMpy were employed to tune the pores of two isostructural MOFs: Co2(py)2(L)(DMA)2 (1) and Co2(L)(DMA)4 (2). The results suggest that the employment of noncoordinating base 3,5-DMpy instead of pyridine under similar reaction conditions will contribute to the enhancement of porosity.Highlights► New tetracarboxylate ligand H4was first developed. ► Catenation was circumvented via the use of H4. ► Controlover the porosity of the two MOFs was achievedvia use of Lewis bases. ► The results of this enrich the of synthesis of MOFs.

4,4′,4″-[1,3,5-Benzenetriyltris(carbonylimino)]trisbenzoic acid (H3L), a C3-symmetric ligand, was found to self-assemble into an interesting core-rosette structure driven by intermolecular hydrogen-bonding interactions. Reactions of this ligand with Zn2+, Co2+ and Cd2+ under solvothermal conditions resulted in the formation of four new coordination polymers with interesting structural motifs: [Zn2(L)(OH)(H2O)(DMF)]·DMF·H2O (1), [Co3(L)2(DMF)(H2O)]·DMF·3CH3OH (2), [Co1.5(L)(H2O)(DMF)]·DMF (3), and [Cd1.5(L)(H2O)(DMF)]·DMF (4). Single-crystal structural analysis revealed that complex 1 exhibits a rare example of twofold interpenetrating two-dimensional CdI2-type structure with tetranuclear Zn4(μ3-OH)2(COO)6(H2O)(DMF) serving as secondary building unit (SBU), whereas in 2, the μ3-oxo-tricobalt basic carboxylate SBUs are connected by L3− ligands, leading to a twofold interpenetrating three-dimensional (3,6)-net framework. The isomorphous complexes 3 and 4 each has a (4,4)-grid layered architecture in which the SBU is a linear Co3/Cd3 cluster. The four coordination polymers were all further characterized by IR, thermogravimetric and powder X-ray diffraction (PXRD).Supramolecular assembly of C3-symmetric 4,4′,4″-[1,3,5-benzenetriyltris(carbonylimino)]trisbenzoic acid (H3L) and its ligand behavior toward divalent zinc, cobalt and cadmium ions were investigated. The results exhibit a rosette-type hydrogen-bonded network of the free acid and metal coordination polymers of L3− bearing interesting structural motifs.