Hydrothermal reactions of rare earth (Nd, Sm, Eu, and Tb) and l- or d-lactic acid are used to construct four pairs of homochiral metal–organic frameworks (HMOFs) with polymetallic building blocks, namely, {[Nd2(L)2(H2O)3]·4H2O}n (1-r)/(1-s) and {[Ln2(L)2(H2O)2]·4H2O}n {Ln = Sm (2), Eu (3), Tb (4)} (n-r)/(n-s). The eight complexes were characterized by single-crystal X-ray diffraction, infrared spectra, elemental analysis, thermogravimetric analysis, electronic circular dichroism (ECD) spectra, and powder X-ray diffraction measurements. The complexes 1–4 featuring a 3D porous metal–organic framework crystallize in chiral space groups, and their chirality is proven by the solid-state ECD spectra. Moreover, the second-harmonic generation (SHG) investigation reveals that the complexes 1-r, 2-r, 3-r, and 4-r have medium SHG eficiencies. The complexes 2, 3, and 4 exhibit relatively high luminescence properties, which could be ascribed to ligand-centered emission. The luminescence of complex 4-r could be quenched by nitrobenzaldehyde, which may be used for molecular sensing and recognition.

Three isomorphic chiral coordination polymers, namely, [M(cpca)·(H2O)]2·H2O (M = Zn (1), Cd (2), and Co (3)), based on a new homochiral dicarboxylic acid ligand, have been synthesized under hydro(solvo)thermal conditions and characterized by single X-ray diffractions, elemental analyses, infrared spectra, thermogravimetric analysis, powder X-ray diffractions, and circular dichroism spectroscopy. The three compounds featured two-dimensional layer structures with one-dimensional pseudo-nanotubes connected together by weak intermolecular interactions, exhibiting a new topological structure with a point symbol of (43·62·8). The influence of ionic radii in tuning the pore size of the coordination polymers is discussed. Furthermore, second harmonic generation (SHG) activity, luminescence and sensing, and asymmetric catalytic properties of all these three chiral coordination polymers have also been studied. All the three complexes show different SHG activities. The luminescence of the complexes could be quenched by nitrobenzaldehyde, which may be used for molecular sensing and recognizing. The three complexes also demonstrate asymmetric catalysis activities toward Henry reactions of nitroaldehyde.

•Self-assembly of oxomolybdate and 3,5-di(4H-1,2,4-triazol-4-yl)benzoic acid results in [(Mo2O6)L]·CH3OH·3H2O (1).•Complex 1 exhibits an unreported 3D topological structure with a point symbol of (32;42;53;62;7)2(32;83;9).•Luminescent analysis of 1 reveals that the MoVI ions are able to tune the luminescent emission of the L ligand.•The electrochemical analysis shows that the work electrode of 1 exhibits a surface-controlled redox process.A new complex namely, [(Mo2O6)L]·CH3OH·3H2O (1), based on oxomolybdate and 3,5-di(4H-1,2,4-triazol-4-yl)benzoic acid (L) was synthesized under hydrothermal condition, which shows a new three-dimensional supramolecular framework with unreported topological structure. In addition, the luminescent and electrochemical behaviors of complex 1 were investigated.A triazole-MoIV complex is hydrothermally synthesized with interesting 3D supramolecular framework with unreported topological structure and fluorescence and electrochemical properties.

To investigate the construction of novel chiral coordination polymers and the effect of N-donor ligands with different lengths as the second ligand, five new chiral zinc(II) coordination polymers based on (R)-4-(4-(1-carboxyethoxy)phenoxy)-3-fluorobenzoic acid (H2cpfa), namely, [Zn(cpfa)] (1), [Zn2(cpfa)2(biim-4)2]·2H2O (2), [Zn2(cpfa)2(bix)2]·2H2O (3), [Zn2(cpfa)2(bix)2]·CH3OH·H2O (4), and [Zn2(cpfa)2(bimb)2]·CH3OH·H2O (5) (where biim-4 = 1,1′-(1,4-butanediyl)bis(imidazole), bix = 1,4-bis(imidazole-1-ylmethyl) benzene, bimb = 4,4′-bis((1H-imidazol-1-yl)methyl)biphenyl), have been synthesized under hydro(solvo)thermal conditions. Their structures are determined by single crystal X-ray diffraction and further characterized by infrared spectra (IR), elemental analyses, powder X-ray diffraction (PXRD), circular dichroism spectra (CD), and thermogravimetric (TG) analyses. Complex 1 features a three-dimensional (3D) rhombic right-handed structure with a rare topology of 5,5T2. Complexes 2–5 involving N-donor ligands with different lengths display similar two-dimensional (2D) sq1 networks. Complex 2 is a 2D 4-connected undulated layer with (H2O)2 dimers filling in the cavities. Similar 2D undulated layers in complex 3 are connected via O–H···O hydrogen-bonds between cpfa2– anions and lattice water molecules to generate a 3D supramolecular structure. In complex 4, 2D (4,4)-sq1 sheets with large cavities form a 2-fold interpenetrated sq1 network, with the two adjacent layers stacking in an ABAB fashion. Complex 5 exhibits a structure very similar to 4, except with double right-handed helical chains available. The structures of above chiral complexes based on H2cpfa could be affected by the combined N-donor ligands’ tuning ability to the coordination number of the Zn(II) center and the coordination configuration of the H2cpfa ligand. Furthermore, the second-order nonlinear optical properties of complexes 1–5 are also studied, and the second-harmonic generation efficiencies of the complexes could be tuned by the introduction of second N-donor ligands.

A series of novel organic–inorganic complexes based on trivalent lanthanides and 1,3-C6H4[CH2P(O)(OH)2]2 (H4L) formulated as Ln(HL)(H2O)2 (Ln = La, 1; Pr, 2; Nd, 3; Sm, 4; Eu, 5; Gd, 6; and Tb, 7) have been obtained as single phases by regulating the pH under hydrothermal conditions. Complexes are isostructural and feature a network in which the LnO7 polyhedra are interconnected by bridging CPO3 tetrahedra into inorganic layers. These layers are further stacked with the benzyl groups of ligands via C–H⋯π interaction into a laminar framework architecture. Luminescent measurements indicate that complexes 4, 5 and 7 show strong metal-centered emission bands in yellow, red and green light regions, respectively. Magnetic properties of 2 and 7 have also been studied.

A novel complex, [CuI2L2]2[Mo8O26] (1), was hydrothermally synthesized by using ammonium molybdate, copper nitrate and 1,3-bis(imidazol-l-yl-methyl)benzene. Complex 1 exhibits a new 3D (3,4,6)-connected topological structure with a Schlafli symbol of (4·6·8)2(42·64·83·102·123)(44·62)2, which is constructed by [Mo8O26]4− anions linking a [4 + 4] metallomacrocycle.

A series of novel organic–inorganic complexes based on trivalent lanthanide and HOOC–C6H4–CH2PO(OH)(OC2H5) (H2L′) formulated as Ln(HL)(H2L)(H2O) (H3L = HOOC–C6H4–CH2PO(OH)2, Ln = La, 1; Ce, 2; Pr, 3; Nd, 4; Sm, 5; Eu, 6; Gd, 7; and Tb, 8) have been obtained as single phases by regulating the pH values under hydrothermal conditions. They are isomorphous and feature a network in which the LnO7 polyhedra are interconnected by bridging CPO3 tetrahedra into inorganic layers. These layers are further cross-linked by hydrogen bonds of the carboxyl acid groups of ligands into a S-shape pillared framework architecture. Luminescent measurements indicate that complexes 1–5 and 7 exhibit ligand-centered blue light emission bands. Complexes 6 and 8 display Ln-centered strong red and green luminescence, respectively. To elucidate the energy transfer process between ligands and metal ions, the energy levels of the relevant electronic states have been estimated. Simultaneously Eu3+ and Tb3+ were observed to accept energy with their several different 5Dj, resonance levels depending on the lowest triplet state energy level of the ligand. Magnetic properties of 7 and 8 have also been studied.

Highlights•Two novel metal organic frameworks have been synthesized and characterized.•Complexes 1 and 2 show pcu and uoc framework respectively.•Coordination polymers show diverse interpenetrating networks.•The thermal and fluorescence properties of polymers have been studied.To investigate the construction of interpenetrating frameworks, two novel coordination polymers [Co(bimb)3](NO3)2·2H2O (1) and [Co(bimb)(bdc)]·H2O (2) [bimb = 4,4′-bis(1H-imidazol-1-yl-methyl)biphenyl; H2bdc = 1,2-benzenedicarboxylic acid] were hydrothermally synthesized and characterized by elemental analysis, IR, PXRD and TGA. Complex 1 shows a 2-fold pcu interpenetrating framework. However, complex 2 exhibits a rare 2-fold uoc interpenetrating framework due to the introduction of bdc anion. The results indicate that the presence of the second ligand could tune the product structures. Photoluminescence properties of complexes 1 and 2 reveal the cobalt ion disturbed ligand emission.Graphical abstractTo investigate the construction of interpenetrating frameworks, tow novel coordination polymers were hydrothermally synthesized. The results indicate that the coordination polymers based on long spacer bimb ligand are inclined to form interpenetrating structures, which can be tuned by 1,2-benzenedicarboxylic acid as the second ligand from 2-fold interpenetrating pcu framework to 2-fold interpenetrating uoc framework.

Two flexible V-shape ligands, namely, 1,3-bis(pyridine-4-ylmethoxy)benzene (4-bpmb) and 1,3-bis(pyridine-2-ylmethoxy)benzene (2-bpmb), have been synthesized and employed for constructing eight novel coordination polymers, {[Zn(4-bpmb)(H2O)(NO3)2]·(4-bpmb)}n (1), {[Cd(4-bpmb)(H2O)(NO3)2]·(4-bpmb)}n (2), {[Hg(4-bpmb)(H2O)(NO3)2]·(4-bpmb)}n (3), {[Zn4(2-bpmb)4Cl8]·C5H5N}n (4), {[Hg(2-bpmb)Cl2]·2H2O}n (5), [Cu4(μ-CH3COO)8(2-bpmb)2]n (6), [Ag(2-bpmb)(NO3)]n (7), {[Cu(2-bpmb)(H2O)2]·(NO3)2}n (8). These complexes were characterized by elemental analyses and IR spectra and structurally determined by powder and single crystal X-ray diffraction analyses. The photoluminescence properties of complexes 1−3 are studied. The results revealed that the 4-bpmb ligands react with II B group transitional metallic nitrates to give three isostructural 1D wavelike chains (complexes 1−3), which are further decorated by equimolar 4-bpmb molecules to form the wavelike double-stranded chain structures via hydrogen bonds. In the packing model of complex 3, a 2D layer network is observed considering the interaction between mercury atoms and nitrate anions from the adjacent chains. The 2-bpmb ligands reacting with the corresponding transition metal salts generate three 1D helical chains, as expected (complexes 4−6). Complex 7 has a 2D layer structure produced by nitrate anions bridging with 1D opposite homohanded helical chains. Complex 8 displays a straight chain due to the coordination of two O atoms of each 2-bpmb ligand with copper cations.

A novel organomercury complex, [Hg2(μ-CH3COO)(CH3COO)(L)]n (L = 1,3-bis(pyridine-2-ylmethoxy)benzene) 1, has been synthesized. Complex 1 has a one-dimensional chain structure formed by acetate anions bridging Hg(II) atoms in crystallographical c-axis. The orthomercuration of the ligand takes place at C-4 and C-6 of benzene ring rather than C-2 position. It shows intense fluorescent emission by solid-state luminescent analysis.A novel organomercury complex has been synthesized, [Hg2(μ-CH3COO)(CH3COO)(L)]n, which is a one-dimensional chain formed by acetate anions bridging Hg(II) atoms in c-axis. The orthomercuration of the ligand takes place at C-4 and C-6 of benzene ring rather than C-2 position.