Search

Solid-state materials with adjustable luminescence properties have always been a research hotspot due to their potential applications in optical data recording, display and ink-free printing. Further research on the multiform light-controlled luminescent switches will create a new perspective. We synthesized two isostructural compounds, namely [Me(ipbp)Cl] H2O (ipbp = 1-(3,5-dicarboxyphenyl)-4,4′-bipyridinium, Me = Cd (1), Me = Zn (2)). In the solid-state, they not only show excitation-wavelength-dependent photoluminescence emission in a wide spectral range but also exhibit good time-dependent photoluminescence emission. This study could provide a broad perspective for the development of multiform light-controlled luminescent switches.

Changing N-substituents to modify energy gaps is important for the diverse applications (photochromism, photocatalysis, etc.) of viologen-based compounds. In situ N-substitution using alcohols under solvothermal and acidic conditions is an effective and common synthetic method for viologen-templated metal halides. In this work, we found that replacing alcohols with alkenes could reduce the reaction temperature dramatically to room temperature. A new cis/trans-viologen-templated bromoplumbate with a novel 1-D chain structure built by edge-sharing planar [Pb3Br9]3− oligomers was successfully obtained. This bromoplumbate hybrid has a narrower energy gap compared with bulk PbBr2, which has been well explained by linear optical response spectra calculations and PDOS analysis.

Photoluminescent coordination compounds have appealing applications in light-emitting and photoactive materials, but there exist some difficulties in the tuning and domination of luminescence by changing the structures. In this work, diverse luminescence was realized by the rational design and controllable construction of a series of Zn(II)/Cd(II) coordination compounds from an isolated binuclear moiety, a 1D zigzag chain, a 1D ladder-like chain and a 3D 3,4-connected topology network based on a flexible semi-rigid tetrazole–viologen ligand. Especially, the isolated binuclear compound shows an interesting photochromic molecular system that involves electron transfer from the N3− ions and Cl atoms to the tetrazole–viologen ligand and exhibits fluorescence and second-order nonlinear optical property variation upon ultraviolet light irradiation.

Rare tetranuclear Zn clusters were successfully embedded into 3D energetic metal–organic framework channels by an enhanced extended hook method. The obtained metal–organic framework exhibits not only high enthalpy of combustion and low sensitivity but also strong green fluorescence.

An alternative approach to fabricate color-tunable and white-light-emitting lanthanide(III) coordination polymers (LnCPs) is demonstrated by employing a selective light-emitting tetrazolate–dicarboxylate ligand, which displays different color emissions when coordinated to different lanthanide(III) ions. The emission colour of the obtained LnCPs can be modulated from orange to white by simply adjusting the excitation wavelengths. White-light emissions, with high color rendering index and favorable correlated color temperature, have been successfully realized in new 2D single-component Sm(III) and two-component Eu(III)-doped Gd(III) coordination polymers excited at specific excitation wavelengths.

Herein, we report a novel high-dimensional I3O3 organic–inorganic hybrid framework, namely [Cd3(OH)2(tza)2]n (1) (H2tza = 1H-tetrazolate-5-acetic acid), where a rare pure ths inorganic connectivity of Cd–Ohydroxyl is observed. Meanwhile, 1 displays blue emission and high thermal stability up to 370 °C.

The rational design and synthesis of ternary two-dimensional alloy nanocrystals with a non-layered structure are still a challenge. Here, we show, for the first time, the synthesis of homogeneous ternary ZnS1−xSex nanosheets by thermal decomposition of lamellar inorganic–organic hybrid precursors. The morphology, composition and crystal structure of ZnS1−xSex nanosheets have been thoroughly investigated. We also found that the lattice constants and bandgaps of ZnS1−xSex nanosheets could be easily tuned via alteration of the Se/S ratio. Our work provides a facile and effective strategy to synthesize homogeneous multinary non-layered chalcogenide nanosheets with tunable compositions and bandgaps.

Hydrothermal reaction of cadmium salts with HATZ in the presence of R4NBr (R = Et, Pr) led to two organic cation templated Cd(II) MOFs, (Et4N)[Cd6Br5(ATZ)8]·H2O (1) and (Pr4N)[Cd4Br5(ATZ)4] (2) (HATZ = 5-amino-tetrazolate, Et = ethyl and Pr = propyl), which are the first examples of tetraalkylammonium cations templated N-heterocyclic ligand based MOFs. These two MOFs have been fully characterized by single crystal X-ray diffraction, XRD, TGA, IR, elemental analysis, photoluminescence spectra and combustion heat measurement. The anionic frameworks of 1 and 2 are three- and two-dimensional, respectively. Topological analyses show that compound 1 exhibits an unprecedented binodal (4,10)-connected network, which is a subnet of the (12,12)-connected tcj net, and compound 2 is a 2-D uninodal four-connected network when the Cd6 clusters in these two MOFs are viewed as nodes. Moreover, compound 1 maybe have potential application as an energetic material due to its high enthalpy of formation.

Two bifunctional 1H-tetrazolate-5-carboxylate ligands with different flexibilities, H2tza (1H-tetrazolate-5-acetic acid) and H2tzf (1H-tetrazolate-5-formic acid), were employed in the construction of zinc(II) complexes in the presence/absence of secondary ligands such as 2,2′-bipy and 4,4′-bipy. Three tza coordination polymers and two tzf dinuclear complexes, namely [Zn(tza)(H2O)]n (1), [Zn3(tza)2Cl2(2,2′-bipy)2(H2O)2]n (2), [Zn2(tza)2(4,4′-bipy)]n (3), [Zn(tzf)(H2O)3]2·2H2O (4) and [Zn(tzf)(2,2′-bipy)(H2O)]2·H2O (5), were hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Polymer 1 is a 3-D two-fold interpenetrating diamond-like network with tetranuclear [Zn(COO)]4 clusters as tertiary building units (TBUs) and µ3-κN3:κO2:κO1,N1 bridging tza as linkers. Polymer 2 presents a 2-D structure formed by the linkage of 1-D Zn-carboxylate [Zn(COO)]n helical chains and µ3-κN4:κO2:κO1,N1 bridging tza. In 3, 2-D (4,4) nets are built up with dinuclear [Zn(COO)]2 clusters and µ3-κN4:κO2:κO1,N1 bridging tza, which are pillared through 4,4′-bipy to gain a 3-D self-penetrating LB-1 (446108) topology. In dinuclear complexes 4 and 5, two Zn(II) atoms are bridged by a tzf ligand in a µ2-κN2:κO1,N1 fashion. The results denote that tetrazolate-5-carboxylate ligands can adopt variable coordination modes in the formation of the complexes, and different Zn-carboxylate aggregates can serve as tertiary building units (TBUs). The effects of the nature of tetrazolate-5-carboxylate ligands and secondary ligands, and hydrothermal reaction conditions on the structural topologies of the obtained complexes have been investigated. The photoluminescent properties and thermal stabilities of 1–5 have also been discussed.

Hydrothermal reaction of cyano-substituted viologen derivatives and NaN3 with corresponding metal salts in the presence/absence of H2PTA (H2PTA = p-phthalic acid) yielded three azide-based polynuclear coordination polymers: [Co4(N3)4(PTA)3(4-CV)2]n·2nH2O 3D (1), [Co4(N3)4(PTA)3(3-CV)2]n·nH2O 3D (2), and [Cu6(N3)14(4-CV)2]n 2D (3) (3/4-CV+ = 4,4′-bipyridinium-N-methyl-3/4-benzonitrile). The azido bridges are employed to construct two types of polynuclear cluster units: tetranuclear [Co4(μ1,1-N3)4] and hexanuclear [Cu6(μ1,1-N3)6(μ1,1,1-N3)4]. Polymers 1 and 2 are isostructural, and exhibit similar 3D frameworks constructed by unprecedented linear tetranuclear CoII4 units with a four-connected 65·8 topology. Polymer 3 features a 2D (4,4) topological network built up by hexanuclear CuII6 segments. The azide anion exhibits diverse coordination modes: μ1,1-N3 in 1 and 2, and μ1,1-, μ1,3-, μ1,1,1- and μ1,1,3-N3 in 3. Variable-temperature magnetic susceptibility data denote that 1 and 2 display a weak antiferromagnetic interaction in CoII4 units and 3 shows a dominant ferromagnetic exchange in CuII6 units.

A novel inorganic–organic hybrid [Cu(2,2′-bipy)2I]2n(PbI3)2n·nDMF·nH2O (1), which exhibits diplex single-crystal-to-single-crystal transformation, can transform to a guest molecule released compound [Cu(2,2′-bipy)2I]n(PbI3)n (1a) by thermal induction, or to both a guest molecule released and ligand exchanged compound [Cu(2,2′-bipy)3]n(Pb2I6)n (1b) by solvent induction.

A series of one-dimensional (1-D) N-succinopyridine-based complexes: [Cu(L−)(H2O)2]Cl·2H2O (1), [Pr(L−)(H2O)4]Cl2 (2), [Ln(L−)(H2O)5]Cl2·3H2O (Ln = Eu (3), Gd (4)), and [Er(L−)(H2O)4]Cl2·H2O (5) (HL = N-succinopyridine (−OOC–CH(N+C5H5)–CH2–COOH)) have been prepared and characterized by single-crystal X-ray diffraction. The frameworks of complexes 1, 2 and 5 constructed from dinuclear metal building blocks exhibit 1-D double-strand loop-like chains; these chains are further connected to each other by hydrogen bonds forming a 3-D supramolecular architecture. Whereas complexes 3 and 4 feature hydrogen bonding 2-D supramolecular networks assembled from 1-D chains that are constructed from mononuclear metal building blocks. The effects of different metal ions, steric hindrance and coordination diversities of HL on the polymeric architectures have been discussed. In addition, thermogravimetric and magnetic properties of these complexes were also investigated in this paper.

We investigate the impact of different derivatives of 1,4-diazabicyclo[2.2.2]octane on the crystal structures of iodoplumbates by systematically increasing the size of the same organic amine, and present two new 1-D iodoplumbates. Optical studies reveal the semiconductor characteristics of all as-synthesized iodoplumbate hybrids.

Hydrothermal reaction of N-(2-cyanoethyl)glycine and NaN3 with corresponding metal salts yielded three energetic coordination polymers: [Zn(tzeg)]n1 and [M(tzeg)(H2O)]n (M = Cd2+ for 2, Cu2+ for 3) (H2tzeg = N-[2-(1H-tetrazol-5-yl)ethyl]glycine), which were characterized by single-crystal X-ray diffraction. Nitrogen-rich tzeg2− ligand is a new in situ generated organic compound through [2 + 3] cycloaddition reaction of nitrile and azide, which adopts two different coordination modes in 1–3. Polymer 1 features an achiral 3D network built up by interweaving of left/right-handed helical channels. Isostructural 2 and 3 exhibit an achiral 2D network formed alternately by left/right-handed helical chains. As nitrogen-rich energetic materials, 1 and 3 possess higher enthalpies of combustion (ΔHc), which are −12.054 and −11.583 kJ g−1, respectively, than the classical energetic compounds 1,3,5-trinitro-1,3,5,-triazine (RDX, −9.6 kJ g−1) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX, −9.44 to −9.88 kJ g−1). The solid-state excitation and emission spectra for 1–3 were investigated at room temperature, which reveals ligand-centered luminescent emissions in the intensity order of 2 > 1 > 3. Variable-temperature magnetic susceptibility data show that 3 displays a weak antiferromagnetic interaction mainly resulting from magnetic exchange coupling between Cu2+ ions through double tetrazolato bridges.

Four Zn(II) tetrazolate coordination compounds have been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction. They are formulated as [Zn(3-tzbd)2]n·nH2O (1), [Zn2(3-tzbd)2(OH)2(4,4′-bipy)]n·nH2O (2), [Zn2(3-tzbd)3(N3)(4,4′-bipy)2]n·nH2O (3) and Zn2(3-tzbd)4(phen)2 (4), where 3-Htzbd = 3-(5H-tetrazol)benzaldehyde. The 3-tzbd− ligand, which was in situ generated through a [2 + 3] cycloaddition reaction of nitrile and azide, displays diverse coordination modes. Compound 1 exhibits a (4,4)-connected two-dimensional (2D) layer generated by the linkage of dinuclear units of [Zn2(μ2-3-tzbd)2] and μ2-3-tzbd− ligands. In 2, Zn(II) atoms are connected by μ2-3-tzbd− ligands and μ3-OH− anions to form unusual double-stranded stair-like chains, which are further linked by 4,4′-bipy to create a 2D sheet. Compound 3 features an unprecedented one-dimensional (1D) four-legged, triple-ladder chain composed of tetranuclear units [Zn4(μ2-3-tzbd)4(μ2-N3)2]. Two Zn(II) atoms in 4 are bridged by μ2-3-tzbd− ligands to result in an isolated dinuclear structure. In addition, the luminescent properties of 1–4 were investigated in the solid state at room temperature. The relevant density of states (DOS) calculation results show that their photoluminescence mainly originates from ligand-centered emission and is dependent on the organic ligand incorporated into the compounds.

Two fluorescent cadmium complexes, [HL][CdCl2(H2O)2] (1) and [HL][CdBr2(H2O)2] (2) (HL = N-succinopyridine), have been prepared and characterized by single-crystal X-ray diffraction. Complex 1 contains a unique μ2-Cl bridged neutral 2D inorganic layer, which is further connected to isolated HL molecules by hydrogen bonds forming a hamburger-like OIO 2D supramolecular architecture. Complex 2 features a 3D supramolecular network assembly from 1D inorganic chains and discrete organic molecules through hydrogen bonds. Thermogravimetric, luminescent properties and theoretical calculations of 1 and 2 are also discussed. Moreover, UV-to-Vis tunable emissions for N-succinopyridine and 1 as well as blue-to-green tunable emission for 2 are observed.

A novel quaternary mercury and cadmium chalcogenidehalide, (Hg2Cd2S2Br)Br (1), has been prepared by solid-state reaction and structurally characterized by single crystal X-ray diffraction analysis. The structure of 1 is composed of parallel slabs stacking with -ABAB- mode via linearly coordinated Hg atoms to form a 3D cationic network with the channels being occupied by discrete Br anions, in which the slab consists of interlinks of linear (HgS2Br2) tetrahedral chains and (CdS2Br) trigonal chains. The optical properties were investigated in terms of the diffuse reflectance and Fourier transform infrared spectra. The electronic band structure along with density of states (DOS) calculated by DFT method indicates that the present compound is a semiconductor with an indirect band gap, and that the optical absorption is mainly originated from the charge transitions from Br-4p and S-3p to Cd-5s and Hg-6s states.

A new carboxylate-introduced 1,2,3-triazole, 1-(3,5-dicarboxyphenyl)-4-carboxy-1H-1,2,3-triazole (H3dcpct), was synthesized by 1,3-dipolar cycloaddition of a terminal alkyne to azide in the presence of a Cu(II) salt. Hydrothermal reaction of H3dcpct and Mn(NO3)2·6H2O or Co(NO3)2·6H2O in different NaOH/H3dcpct molar ratios afforded four new coordination polymers [Mn(dcpt)(H2O)2]·0.25H2O 1, [Mn(dcpt)(H2O)] 2, [Co(dcpt)(H2O)2]·H2O 3 and [Co(H2O)6][Co2(dcpct)2(H2O)6]·2H2O 4 (H2dcpt = 1-(3,5-dicarboxyphenyl)-1H-1,2,3-triazole). The in situ hydrothermal decarboxylation of H3dcpct into H2dcpt in 1–3 was found and its possible mechanism is proposed. In 1 and 3, dcpt2− ligands bridge Mn(II) and Co(II) ions, respectively, to give two similar 2D layered structures with a (6,3)-connected network topology. Polymer 2 displays a whole achiral 3D open framework with both chiral and achiral channels in the same direction and possesses an unprecedented (3,6)-connected (4·82)(42·812·10) network topology. The structure of 4 features a 1D chained net, in which no decarboxylation occurred. Variable-temperature magnetic susceptibility data show that 1 exhibits a weak ferromagnetic interaction and 2 manifests an overall antiferromagnetic interaction between their respective Mn(II) ions, while 3 and 4 display an antiferromagnetic interaction between Co(II) ions and/or spin-orbital coupling. The thermal stabilities of all obtained polymers have also been examined.

Hydrothermal reaction of ZnCl2, NCCH2CH2COONa and NaN3, in the absence/presence of auxiliary ligand 2,2′-bipy/4,4′-bipy, gave birth to three novel coordination polymers, namely, [Zn(tzp)]n (1), [Zn2(tzp)(N3)(OH)(2,2′-bipy)]n (2) and [Zn2(tzp)2(4,4′-bipy)]n (3) (H2tzp = 1H-tetrazolate-5-propionic acid). The tzp2− ligand was in situ generated through the [2 + 3] cycloaddition reaction of nitrile and azide, which was first untilized to synthesize coordination compounds. Polymer 1 behaves as a three-dimensional (3-D) network built up by the fusion of one-dimensional (1-D) pseudo-channels formed by the linkage of tzp2− ligands and tetrahedral Zn nodes. When the chelating 2,2′-bipy was introduced into the reaction system, a two-dimensional (2-D) puckered network 2 was constructed, where 1-D pseudo-channels, similar to those in 1, are bridged by azide ions in an end-on (EO) mode. Employment of the linear bridging 4,4′-bipy ligand as the auxiliary ligand resulted in the formation of an unusual 3-D polymer 3, where the connection of Zn and tzp2− produces a 2-D network, which are further joined by 4,4′-bipy. The tzp2− ligands in 1–3 show the flexible conformations and different coordination modes, with the tetrazolate group being the 1,4-N mode and the carboxylate group being the syn–anti, syn–syn and monodentate mode, respectively. The results suggest that the flexible nature of the tzp2− ligand as well as the introduction of auxiliary ligands is responsible for the formations of 1–3. Their photoluminescent properties and thermal stabilities have also been discussed.

Two novel halogeno(cyano)argentates(I), [Et4N]3[Ag6(CN)3.39Br5.61] (1) and [Pp4N]3[Ag8(CN)4I7] (2) (Et4N = tetra-ethylammonium, Pp4N = tetra-n-propylammonium), were obtained by the solvothermal reaction of silver(I) cyanide with tetraalkylammonium salts in anhydrous THF. Complex 1 presents a 2-D grid-like sheet built by [Ag6Br5]+ clusters bridged by cyanide groups. Complex 2 is the first example of 3-D halogeno(cyano)argentates(I), and displays a porous framework with fluorite (flu) topology based on [Ag4I4] and an unprecedented [Ag8I6]2+ cluster, respectively, as 4-connected and 8-connected nodes. The optical and luminescent properties of the two complexes have been investigated. On the basis of Time-dependent Density Functional Theory calculations, the emission spectrum of 1 can be assigned as metal-centred (MC) transitions, while the luminescence behavior for 2 is assumed to arise from metal-to-ligand charge-transfer (MLCT) transitions.

The stabilization of the (SnS4)4− anion in the coordination of [Mn(phen)]2+ complexes brings about a novel compound {[Mn(phen)]2(SnS4)}n·nH2O (1), in which an unprecedented link mode of the (SnS4)4− anion is observed. Theoretical calculations indicate that TM complexes with big π-conjugated ligands, such as [Mn(phen)]2+, can serve as an excellent electron reservoir to stabilize the (SnS4)4− anion in 1, despite its strong condensation tendency. Magnetic measurements show the presence of strong antiferromagnetic interactions between the Mn2+ ions in 1.

Using cyanide anions and sulfur simple substance as precursors of thiocyanate groups, three desired luminescent halogeno-thiocyano-d10 metal complexes, namely, [Me4N][Cu(SCN)Br] (1) with a 1-D to 2-D architecture constructed through C–H⋯Br hydrogen bonds, [Me4N][Cu(SCN)I] (2) with a 1-D to 3-D framework constructed through C–H⋯I hydrogen bonds, and [Me4N][Ag2(SCN)2Cl] (3) with a special 3-D nanoporous structure constructed by µ-chloride atoms connecting the 2-D neutral ∞2[Ag2(SCN)2] layers, have been solvothermally synthesized and all exhibit efficient luminescence. The luminescent behavior of the three complexes was illustrated through the density functional theory.

NSF of China [20701037, 20801026]; NSF for Distinguished Young Scientist of China [20425104]; 973 program [2009CB939801]; Key Project from the CAS [KJCX2.YW.M10]; NSF of Fujian Province [2008I0026]