A new halocadmium/methyl viologen hybrid (MV)4(Cd2I6)(Cd2I7)2 (1) (MV2+ = methyl viologen) has been structurally determined. In 1, two kinds of dimeric halocadmium clusters constructed from edge/vertex-sharing CdI4 tetrahedra respectively, i.e., Cd2I62− and Cd2I7− dimmers were observed, which were templated by methyl viologen cation (MV2+). A highly interesting feature of 1 is the presence of mixed type dimeric halocadmium clusters in one crystal lattice templated by one kind of cation. 1 displays photoluminescences, and its thermochromism behavior is observed, whose mechanism was verified by theoretical calculations.

Alkali metals were introduced into heavy main-group iodometallates to get two new IA/IVAheterometallic frameworks [PbI3K(pdon)(H2O)2]n (1) and {[Pb3I9K2(pdon)2(H3O)] ⋅H2O}n (2) (pdon =1,10-phenanthroline-5,6-dione), which were obtained as single phases by hydrothermal method at different pH values. Compounds 1 and 2 are three-dimensional heterometallic frameworks constructed from the linkage of pdon ligand between iodometallate chains and potassium oxides/iodide clusters. Specially, these two heterometallic frameworks exhibit broadened absorption bands at 700 and 750 nm compared with those of bulk PbI2 and pdon ligand. The band gap of 2 is wider than that of 1, which is due to the absence of π⋯π interaction in 2. Their thermal stabilities are also discussed.

Two new methyl viologen halocadmium charge-transfer salts with isostructures, [(MV)(CdI4)]2·3H2O (1) and (MV)(CdI4)·H2O (2) (MV = methyl viologen, i.e., 1,1′-dimethyl-4,4′-bipyridinium), have been structurally determined. 1 and 2 consist of CdI42− clusters, MV2+ dications, lattice waters with isostructures, and C–H···I hydrogen bonds are presented in 1 but absent in 2, furthermore, their relative stabilities based on were investigated by DFT calculations. Both compounds display photoluminescences in the visible region under visible-light excitations, and their thermochromism effects are observed. But their photoluminescence and thermochromic behaviors differ greatly with the presence or absence of hydrogen bonds. Moreover, their absorption spectra have also been discussed.

We extend our efforts to investigate the influence of ligand spacers on iodoargentate hybrids templated by cationic SDAs [structure-directing agents, BPB2+ (1,4-bis(pyridinium)butane), BPO2+ (1,8-bis(pyridinium)octane)] possessing both rigidity and flexibility and two iodoargentate hybrids [(BPB)(Ag5I7)]n (1), [(BPO)(Ag5I7)]n (2) have been synthesized in polar organic solvents. 1 exhibits a 3-D network with BPB2+ cations trapped in the 3-D (Ag5I7)n2− cavities and 2 contains one-dimensional infinite polymeric anions accompanied by discrete SDA cations. Interestingly, judging from structural analysis and DFT calculations, we find that the rigidity/flexibility competition will achieve a balance when the ligand spacer n is 4, where the most versatile structure and stable confirmation can be presented. Their adsorption and fluorescent spectra are also discussed.

A 3-D supramolecular hybrid {[La(EPC)3(H2O)3]2(Pb6I18)}n (EPC+ = N-ethyl-pyridium-4-carboxylate) (1) has been structurally determined, which assume significance for its incorporating lanthanide metal-carboxylic coordination polycation into polymeric iodoplumbate to get heterometallics. 1 consists of 1-D (Pb6I18)n6n- zigzag-like anion chains with lanthanide metalcarboxylic [La(EPC)3(H2O)3]n3n+ polycations, which arrange in a criss-cross configuration. C–H⋯I and C–H⋯O hydrogen bonds among inorganic anions and polycations contribute to the formation of a 3-D supramolecular framework. Moreover, the framework displays an absorption edge at 2.46 eV which is comparable to PbI2’s absorption edge.Highlights► Incorporating lanthanide metal-carboxylic coordination polycation into polymeric iodoplumbate to get heterometallic. ► (Pb6I18)n6n- anion chains and lanthanide metal-carboxylic [La(EPC)3(H2O)3]n3n+ polycations are in criss-cross configuration. ► semiconductor nature with optical gap of 2.46 eV.

Two new lanthanide–bismuth heterometallic hybrids, [Dy(DMF)8](Bi2I9) (1) and [Er(DMF)8](Bi2I9) (2) (N,N’-dimethylformamide (DMF)) have been synthesised by solution processes, which assume significance for their first incorporation lanthanide metals into bismuth iodides to get heterometallics. Two hybrids are isostructures containing (Bi2I9)3− halobismuthate dimers and lanthanide metal complexes [M(DMF)8]3+ (M = Dy, Er) cations, and it is noteworthy that the dimers and lanthanide metal complexes cations connect with each other by C–H···I hydrogen bonds to achieve the structural extending from 0-D to 1- or 2-D. Their absorption spectra and fluorescence’s were discussed, and energy band gaps of 2.19 eV indicate their narrow-gap semiconductor natures.

The hydrothermal reaction of Gd(NO3)3·6H2O with 2,2′-bipyridyl-4,4′-dicarboxylic acid(H2BPDC) ligand results in the formation of a new Gd(III) polymer: {[Gd2(BPDC)3(H2O)3]·H2O}n..(1). The central gadolinium ion is coordinated by eight oxygen atoms to give a dicapped triangular prism geometry. Based on the versatile coordination modes of BPDC2− ligand, together with hydrogen bonds and π···π stacking interactions, a 3-D network is presented. DFT calculation was executed to probe the electronic structure of 1.

A new hybrid coordination polymer {[Cu(II)(2,2′-bipy)3][Pb2I6]}n (1) was synthesized by the reaction of Cu(NO3)2, 2,2′-bipy, PbI2 and NaI in DMF/DMSO mixed solvent. As revealed by X-ray structural analysis, 1 consists of [Pb2I6]n2n− polyanions and discrete [Cu(II)(2,2′-bipy)3]2+ structure-directing agent cations. The polymeric negative chain [Pb2I6]n2− is built up by face-sharing of PbI6 octahedra. Structure-directing reagent cations and polymeric negative chains are in combination with each other by static attracting force to form so-called hybrid structure. Experimental and theoretical optical property investigations indicate that 1 possesses semiconductor property. DFT calculation was executed to probe the electronic structure of 1. To our interest, when using both second metal and π system as electronic tuning species, conjugated system is more preferable.