Molecule-based crystalline materials with angle-dependent polarized emission have attracted considerable attention owing to their extensive applications in displays and anticounterfeiting. Herein, one anionic metal-organic framework (MOF) {[Zn2.5(µ3-OH)(NDC)2(HNDC)](HPIM)}n was constructed on the basis of an excellent photoactive ligand naphthalene-1,4-dicarboxylic acid (H2NDC). The protonated 2-propylimidazole (HPIM) guests residing in the nanochannels of MOF can be exchanged by a D-π-A cationic dye. The resulted host-guest system shows a rare example of ratiometric fluorescent polarizations and highly enhanced photoelectron performance in comparison with the pristine MOF.
Three lanthanide compounds have been synthesized, namely, {[Dy2(bpda)3(H2O)3]4·2H2O}(Dy-1), {[Sm(bpda)2·(H2O)]·H2O} n (Sm-2) and {[Tb2(bpda)3(H2O)3]4·2H2O} (Tb-3) (H2bpda = 2,2'-bipyridine-6,6'-dicarboxylic acid). Their structures were determined by single crystal X-ray diffraction and characterized by elemental analysis, infrared spectroscopy and thermogravimetric analysis. Dy-1 and Tb-3 are isostructural with a conjugate bimolecular four-nuclear cluster structure constructed with intramolecular hydrogen bonds and they form a 3D supramolecular structure with intermolecular hydrogen bonding. Sm-2 is a one-dimensional chain structure and is further connected by intricate hydrogen bonds into a three-dimensional supramolecular structure. These three compounds exhibit significant characteristic luminescence from the ligand to the central Ln(iii) ion, which is found by solid-state photoluminescence measurement. Sm-2 exhibits a long luminescence lifetime and high fluorescence quantum yield. A slow relaxation phenomenon is observed for the dysprosium compound by measuring the alternating-current susceptibility at low temperature and the underlying mechanism was further confirmed by theoretical calculations.
[This corrects the article DOI: 10.1039/C9RA10975G.].
Room temperature phosphorescence of Mn(ii) and Zn(ii) based coordination polymers (Mn-CP and Zn-CP) with a different mechanism was confirmed by experiments and theory calculations. The Mn-CP exhibits high photoelectron response performance while Zn-CP can generate frequency tunable alternating current when the period of on-off illumination is changed.
Two pH-stable luminescent metal-organic frameworks (LMOFs), {[Ln2(L)2(OH)(HCOO)]·[H2O]}n (Ln = Eu 1, Tb 2), based on a new π-conjugated organic building block involving both carboxylate and terpyridine groups were rationally synthesized under a combination of hydro/solvothermal and ionothermal conditions (H2L = 4'-(4-(3,5-dicarboxylphenoxy)phenyl)-4,2':6',4''-terpyridine). 1 and 2 are isostructural and feature noninterpenetrated open 3D condensed frameworks constructed by rod-shaped lanthanide-carboxylate building units. Their excellent water-stability and pH-stability allow them to be used in aquatic systems. 1 and 2 both exhibit selective and sensitive aqueous phase detection of the well-known nitroaromatic explosive environmental pollutant 2,4,6-trinitrophenol (TNP), which is highly desirable for practical applications. The presence of a free pyridine group on the LMOF particle surface was strategically utilized for the purpose of exclusive TNP-sensing.
Two series of Cd(II) coordination polymers (CPs), {[Cd(bimm)2(H2O)2][(3,4-tdc)2][H2O]2}n (1a), [Cd(3,4-tdc)(bimb)]n (2a), [Cd(3,4-tdc)(bimpy)(H2O)]n (3a) and [Cd(2,3-Htdc)2(bimm)2]n (1b), {[Cd(2,3-tdc)(bimb)](H2O)}n (2b), [Cd(2,3-tdc)(bimpy)(H2O)]n (3b) where H2tdc = thiophenedicarboxylic acid, bimm = 1,2-bis(imidazol-1'-yl)methane, bimb = 1,2-bis(imidazol-1'-yl)butane and bimpy = 3,5-bis(imidazol-1'-yl)pyridine, have been synthesized by using Cd(II) acetate with H2tdc and N-donor ligands under hydrothermal conditions. Two related isomeric thiophenedicarboxylic acids were chosen to examine the positional isomeric effect on the construction of these CPs with distinct dimensionality and connectivity. The structure of 1a is a one-dimensional (1D) cationic double chain further forming a two-dimensional (2D) supramolecular network via hydrogen-bonding interactions, while 1b exhibits a neutral double chain structure. Interestingly, a three-dimensional (3D) 4-connected cds network for 2a as well as a 1D neutral double chain structure for 2b were obtained in the presence of bimb. When the rigid tripodal bimpy was introduced, isomorphous 3a and 3b with 3D (3,5)-connected (6(2)·8) (6(7)·8(3)) nets were constructed. The structural diversity of 1a-2b mainly stems from the positional isomeric effect of thiophenedicarboxylate, while 3a and 3b are well regulated by rigid bimpy. Moreover, the thermal stability and photoluminescence of 1a-3b are investigated.
The title compound [Cd(C(8)H(11)N(2)O(3)S)(2)](n), is a two-dimensional coordination polymer based on a Cd(2+) atom and deprotonated 2-(2-pyridylmethyl-amino)ethanesulfonic acid (Hpmt). The complex has mol-ecular symmetry C(i) as a consequence of the Cd(II) being located on an inversion centre. Two N atoms of each pmt(-) ligand coordinate to the Cd(2+) ion and its sulfonate O atom bonds to an adjacent Cd(2+) ion. 24-membered (-Cd-N-C-C-S-O-)(4) rings are formed between neighbouring Cd(2+) ions; these are inter-connected, forming a two-dimensional layer structure. In respect to stereogenic amino N atom and the inversion symmetry of the complex, the compound is a 1:1 racemate. The crystal packing is stabilized by inter-molecular N-Hâ¯O hydrogen bonds and further connected by π-π stacking inter-actions between the pyridyl rings [average inter-planar distance and centroid-centroid separation = 3.582â (1) and 3.634â (1)Å, respectively], forming a three-dimensional supra-molecular architecture.
