Series of TM-OFs as a Platform for Efficient Catalysis and Multifunctional Luminescence Sensing.

Three novel porous transition-metal-organic frameworks (TM-OFs), formulated as [Co3(DCPN)2(µ2-OH2)4(H2O)4](DMF)2 (1), [Cd3(DCPN)2(µ2-OH2)4(H2O)4](DMF)2 (2), and [CdK(DCPN)(DMA)] (3), have been successfully prepared via solvothermal conditions based on a 5-(3',6'-dicarboxylic phenyl) nicotinic carboxylic acid (H3DCPN) ligand. 1 and 2 both have the same porous 3D network structure with the point symbol of {410·614·84}·{45·6}2 based on trinuclear ({Co3} or {Cd3}) clusters, indicating a one-dimensional porous channel, and possess excellent water and thermal stability; 3 also displays a porous 3D network structure with a 4-connected sra topology based on the heteronuclear metal cluster {CdK}. Complex 1 can be used to load Pd nanoparticles (Pd NPs) via a wetness impregnation strategy to obtain Pd@1. The reduction of nitrophenols (2-NP, 3-NP, 4-NP) by Pd@1 in aqueous solution shows outstanding conversion, excellent rate constants (k), and remarkable cycling stability due to the synergistic effect of complex 1 and Pd NPs. Luminescence sensing tests confirmed that 2 is a reliable multifunctional chemical sensor with high selectivity and sensitivity for low concentrations of Fe3+, Cr2O72-, CPFX, and NFX. Specifically, 2 shows a fluorescence enhancement behavior toward fluoroquinolone antibiotics (CPFX and NFX), which has not been reported previously in the literature. Moreover, the rational mechanism of fluorescence sensing was also systematically investigated by various detection means and theoretical calculations.

2-Amino-4-[4-(dimethyl-amino)-phen-yl]-5-oxo-5,6,7,8-tetra-hydro-4H-chromene-3-carbonitrile.

In the title mol-ecule, C(18)H(19)N(3)O(2), the fused cyclo-hexenone and pyran rings adopt sofa conformations. Inter-molecular N-H⋯N and N-H⋯O hydrogen bonds link mol-ecules into corrugated layers parallel to the bc plane.

2-Amino-4-(4-meth-oxy-phen-yl)-5-oxo-5,6,7,8-tetra-hydro-4H-chromene-3-carbonitrile.

The title compound, C(17)H(16)N(2)O(3), crystallizes with two independent mol-ecules in the asymmetric unit. In both mol-ecules, the fused cyclo-hexenone ring adopts a sofa conformation. In the crystal, N-H⋯N and N-H⋯O hydrogen bonds link the mol-ecules into corrugated layers parallel to the (101) plane.

1-(1-Phenyl-ethyl-idene)carbonohydrazide.

The title compound, C(9)H(12)N(4)O, crystallizes with two independent mol-ecules in the asymmetric unit. In the crystal, inter-molecular N-H⋯O and N-H⋯N hydrogen bonds link the mol-ecules into paired ribbons propagated in [100]. The crystal studied was a twin (twin law 00/00/001) with a minor component of 25%.

(3-Hydroxy-2-{[1-(2-oxidophenyl)ethyl-idene]amino-κO,N}propanoato-κO)diphenyltin(IV).

In the title compound, [Sn(C(6)H(5))(2)(C(11)H(11)NO(4))], the tin(IV) atom is penta-coordinated in a distorted trigonal-bipyramidal SnC(2)NO(2) geometry. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers. Weak C-H⋯O inter-actions further link the dimers into chains extending in [010].

1,5-Bis(1-phenyl-ethyl-idene)carbonohydrazide.

In the title mol-ecule, C(17)H(18)N(4)O, the two phenyl rings form a dihedral angle of 18.15 (17)°. In the crystal, pairs of inter-molecular N-H⋯O hydrogen bonds link the mol-ecules into centrosymmetric dimers. Weak inter-molecular C-H⋯O inter-actions further link the dimers into chains running along [010].

Dibromido{2-hydr-oxy-N'-[phen-yl(2-pyrid-yl)methyl-ene]benzohydrazide}copper(II).

In the title complex, [CuBr(2)(C(19)H(15)N(3)O(2))], the metal ion is coordinated by the N,N',O-tridentate 2-hydr-oxy-N'-[phen-yl(2-pyrid-yl)methyl-ene]benzohydrazide ligand and two bromide ions, resulting in a distorted CuN(2)OBr(2) square-based pyramidal coordination geometry with one bromide ion in the apical site. An intra-molecular N-H⋯O hydrogen bond occurs in the ligand. In the crystal, mol-ecules are connected by inter-molecular C-H⋯O, C-H⋯Br and O-H⋯Br inter-actions.

Bis(dicyanamido-κN)bis-[2-(2-hydroxy-ethyl)pyridine-κN,O]nickel(II).

In the title complex, [Ni{N(CN)(2)}(2)(C(7)H(9)NO)(2)], the Ni(II) ion (site symmetry ) adopts a distorted trans-NiO(2)N(4) octa-hedral geometry. In the crystal, inter-molecular O-H⋯N hydrogen bonds link the mol-ecules, forming a chain along the c axis.

N'-Cyclo-hexyl-idenebenzohydrazide.

In the title compound, C(13)H(16)N(2)O, the cyclo-hexane ring adopts a chair conformation. In the crystal structure, inter-molecular N-H⋯O and C-H⋯O hydrogen bonds link the mol-ecules into chains propagating in [001].

(E)-N'-[(2-Hydroxy-1-naphthyl)methyl-ene]benzohydrazide monohydrate.

In the title compound, C(18)H(14)N(2)O(2)·H(2)O, the dihedral angle between the benzene ring and the naphthalene system is 5.18 (10)°. Intra-molecular N-H⋯O hydrogen bonds influence the molecular conformation. In the crystal, inter-molecular N-H⋯O and O-H⋯O hydrogen bonds are observed as well as π-π inter-actions between the phenyl ring and the substituted ring of the naphthalene [centroid-centroid distance = 3.676 (11) Å].

Benzaldehyde thio-semicarbazone.

The title compound, C(8)H(9)N(3)S, contains two mol-ecules in the asymmetric unit. One mol-ecule is close to being planar (r.m.s. deviation from the mean plane = 0.06 Šfor the non-H atoms), while the other exhibits a dihedral angle of 21.7 (1)° between the benzene ring and the mean plane of the thio-semicarbazone unit. Inter-molecular N-H⋯S hydrogen bonds link the mol-ecules into layers parallel to the (010) plane.

Synthesis and characterization of novel donor-acceptor type neutral green electrochromic polymers containing an indolo[3,2-b]carbazole donor and diketopyrrolopyrrole acceptor.

Indolocarbazole bearing donor-acceptor type polymers have rarely been reported in the electrochromic field despite them having considerable development in the applications of organic photoelectric devices. In this paper, two novel soluble electrochromic polymers, namely PDTCZ-1 and PDTCZ-2, were prepared by chemical polymerization including indolo[3,2-b]carbazole (IC) units as the donor, diketopyrrolopyrrole (DPP) units as the acceptor and bithiophene units as the bridging group. Through diverse characterization techniques such as cyclic voltammetry (CV), scanning electron microscopy (SEM), UV-vis spectroscopy and thermogravimetric analysis (TGA), it was found that PDTCZ-1 and PDTCZ-2 exhibited saturated green in the neutral state and pale green in the oxidized state with optical band gaps of 1.44 eV and 1.39 eV, respectively, as well as demonstrating fast switching speed, satisfactory coloration efficiency and favorable thermal stability. In addition, the proportion of donors to acceptors definitely exerted an influence on the electrochromic properties of the polymers. As the thiophene/IC/DPP ratio changed from 4/3/1 (PDTCZ-1) to 5/4/1 (PDTCZ-2), meaning an increase of the donor ratio, the polymer showed a reduced onset oxidation potential, decreased optical band gap and different dynamic parameters. The positive results suggest that PDTCZ-1 and PDTCZ-2 could be promising candidates as neutral green electrochromic materials and deserve more attention and penetrating research.

Synthesis and characterization of novel donor-acceptor type electrochromic polymers containing diketopyrrolopyrrole as an acceptor and propylenedioxythiophene or indacenodithiophene as a donor.

A range of low band gap donor-acceptor conjugated polymers (P1-P3) with backbones composed of diketopyrrolopyrrole (DPP), propylenedioxythiophene (ProDOT) and indacenodithiophene (IDT) units were designed and synthesized using the Stille coupling reaction. The optical, electrochemical and electrochromic properties of the resultant polymers were thoroughly characterized. These polymers showed exceptional solubility in common organic solvents and displayed thermal stability at a high temperature. The optical and electrochemical measurements revealed slight variations in the maximum absorptions and oxidation peaks depending on the intrinsic D-A ratio in each polymer, and narrow band gaps lower than 1.60 eV were found for these polymers. Upon oxidation, the polymer films exhibit distinct color changes (pale violet-red to dark gray for P1, rosy brown to silver for P2, atrovirens to light grey for P3) in the VIS and NIR regions. Moreover, the electrochromic switching studies indicated that these polymers have favorable switching properties, such as rapid response speed and high optical contrast and coloration efficiency, and are outstanding candidates for electrochromic applications.

Soluble Electrochromic Polymers Incorporating Benzoselenadiazole and Electron Donor Units (Carbazole or Fluorene): Synthesis and Electronic-Optical Properties.

A series of π-conjugated polymers containing alternating benzoselenadiazole (BSe)-bi(thiophene derivative)-carbazole or benzoththiadiazole (BSe)-bi(thiophene derivative)-fluorene units were designed and synthesized. Thiophene derivatives, namely 3-hexylthiophene, 3,4-bihexyloxythiophene, and 3,4-bioctyloxythiophene, were used as the π-bridges of the polymers. The polymers were characterized in detail in terms of their thermal stabilities, cyclic voltammograms, UV-Vis absorption, spectroelectrochemistry, dynamic switching property and so forth. The alkoxy thiophene π-bridged polymers have lower onset oxidation potentials and bandgaps than that of their corresponding alkyl thiophene π-bridged polymers. The selection of the donor units between the carbazole and the fluorene units has nearly no effect on the bandgaps and colors as well as the onset oxidation potentials of the polymers. The increase in the length of the side alkyl chains on the thiophene ring caused a slight increase in the polymer bandgap, which may be caused by the space hindrance effect. The dynamic switching abilities of the polymers were obtained by the chronoabsorptometry method, and the results also suggested that the alkoxy thiophene-containing polymers (as π-bridges) have higher contrast ratios than the corresponding alkyl thiophene-containing polymers. Furthermore, the increase in the length of the side alkyl chain might have a detrimental effect on the optical contrast ratios of the polymers.

Effects of Fluoro Substitution on the Electrochromic Performance of Alternating Benzotriazole and Benzothiadiazole-Based Donor⁻Acceptor Type Copolymers.

Two new donor⁻acceptor type electrochromic copolymers containing non-fluorinated and di-fluorinated benzothiadiazole analogues, namely P(TBT-TBTh) and P(TBT-F-TBTh), were synthesized successfully through chemical polymerization. Both polymers were measured by cyclic voltammetry, UV-vis spectroscopy, colorimetry and thermogravimetric analysis to study the influence of fluoro substitution on the electrochromic performance. The results demonstrated that the two polymer films displayed well-defined redox peaks in pairs during the p-type doping, and showed distinct color change from dark gray blue to light green for P(TBT-TBTh) with the band gap of 1.51 eV, and from gray blue to celandine green for P(TBT-F-TBTh) with the band gap of 1.58 eV. P(TBT-F-TBTh) presented lower highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, and better stability than P(TBT-TBTh). It was found that the two fluorine atoms participated in not only inductive effects but also mesomeric effects in the P(TBT-F-TBTh) backbone. In addition, the polymers exhibited high optical contrasts, short response time, and favorable coloration efficiency, especially in the near infrared region. The characterization results indicated that the two reported polymers can be the potential choice as electrochromic materials.

The Availability of Neutral Cyan, Green, Blue and Purple Colors from Simple D⁻A Type Polymers with Commercially Available Thiophene Derivatives as the Donor Units.

In this paper, the Stille coupling reaction was used to prepare four donor⁻acceptor⁻donor (D⁻A⁻D) type monomers. For this purpose, 2,3-bis(4-methoxyphenyl) quinoxaline was used as the acceptor unit, and thiophene derivatives (3,4-ethylenedioxythiophene, or EDOT; 3-methoxythiophene, or MOTh; 3-methylthiophene, or MTh; and thiophene, or Th) were used as the donor units. The monomers were polymerized to the corresponding polymers by the cyclic voltammetry (CV) or potentiostatic method. The band gaps and the adsorption profiles of the polymers were finely tuned with the incorporation of the different thiophene units. All four polymers have low band gaps, and switched between the colored neutral states and the highly transmissive oxidized state. We were successfully able to obtain the valuable neutral colors of cyan, green, blue, and violet for the polymers employing EDOT, MOTh, MTh, and Th as the donor unit, respectively. Furthermore, electrochromic kinetic investigations showed that all four polymers displayed excellent optical contrasts (ΔT%), fast switching times, high coloration efficiencies, and robust stabilities, indicating that these four polymers are probably promising choices for developing electrochromic devices.

Synthesis, Characterization and Application of Four Novel Electrochromic Materials Employing Nitrotriphenylamine Unit as the Acceptor and Different Thiophene Derivatives as the Donor.

In this study, four novel donor⁻acceptor systems, 4-(2,3-dihydrothieno[3,4-b][1,4]dioxin -5-yl)-N-(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)phenyl)-N-(4-nitrophenyl)aniline (NETPA), 4- (4-methoxythiophen-2-yl)-N-(4-(4-methoxythiophen-2-yl)phenyl)-N-(4-nitrophenyl)aniline (NMOTPA), 4-(4-methylthiophen-2-yl)-N-(4-(4-methylthiophen-2-yl)phenyl)-N-(4-nitrophenyl) aniline (NMTPA) and 4-nitro-N,N-bis(4-(thiophen-2-yl)phenyl)aniline (NTTPA), were successfully synthesized by Stille coupling reaction and electropolymerized to obtain highly stable conducting polymers, PNETPA, PNMOTPA, PNMTPA and PNTTPA, respectively. The polymers were characterized using cyclic voltammetry (CV), step profiling and UV⁻Vis⁻NIR spectroscopy. The band gaps (Eg values) were 1.34, 1.59, 2.26, and 2.34 eV, for PNETPA, PNMOTPA, PNMTPA and PNTTPA, respectively. In addition, electrochromic switching showed that all polymers exhibit outstanding optical contrasts, high coloration efficiencies and fast switching speeds in the near-infrared region (NIR). These properties make the polymers suitable materials for electrochromic applications in NIR region.

Multichromic Polymers Containing Alternating Bi(3-Methoxythiophene) and Triphenylamine Based Units with Para-Protective Substituents.

Two novel triphenylamine-based thiophene derivative monomers, 4-cyano-4',4″-di(4-methoxythiophen-2-yl)triphenylamine and 4-methoxy-4',4″-di(4-methoxythiophen-2-yl)triphenylamine, were successfully synthesized. The corresponding polymers including poly (4-cyano-4',4″-di(4-methoxythiophen-2-yl)triphenylamine) and poly (4-methoxy-4',4″-di(4-methoxythiophen-2-yl)triphenylamine) were electrochemically synthesized and characterized by multiple test method. The electrochemical measurements and spectroelectrochemical analyses revealed that both of the two polymers had quasi-reversible redox behavior and multi-electrochromic properties. The two polymer films showed reversible electrochemical oxidation, excellent optical contrasts in NIR region (62% at 1070 nm for the first polymer, and 86% at 1255 nm for the second polymer), satisfactory coloration efficiencies and fast switching times. The research on the application of the as prepared polymer in the fabrication of electrochromic device was also conducted, employing PCMTPA or PMMTPA as the anodically coloring materials.