Organic Inorganic Hybrid Compound Research Articles

Syntheses and performance study of three POM-viologen compounds with photo- and electric-stimulation response

In recent years, stimulus responsive materials have received widespread attention. Under solvothermal conditions, three polyoxometalates-viologen organic–inorganic hybrid compounds were successfully constructed by combining a viologen ligand 1-(3-Nitro-benzyl)-[4,4′]bipyridinyl-1-ium bromide (1,3-nibipy·Br) with octamolybdate, namely [Cu2(1,3-nibipy)4(H2O)2(β-Mo8O26)2]·2H2O (1), [Cu2(1,3-nibipy)4(H2O)4(β-Mo8O26)]·(β-Mo8O26) (2) and (1,3-Hnibipy)2·(β-Mo8O26) (3). These three compounds can exhibit color changing properties under both light and electrical stimulation. Through characterizations of PXRD, FT-IR, UV–vis spectra, XPS, EPR, CV, and other tests, the photochromic and electrochromic properties of these three compounds are caused by the generation of viologen radicals. Compounds 1–3 have a rapid photoresponse efficiency and can be made into mixed matrix films for use as ultraviolet detectors. In addition, coated filter paper synthesized from acetonitrile and compounds can serve as an innovative erasable ink-free printing material medium, which is suitable for various erasable ink-free printing and anti-counterfeiting fields. We further investigated the electrochromic devices prepared from compounds 1–3, which achieved color change at a voltage of around −0.2 V and exhibited good stability after 500 cycles.

Designing Zero-Dimensional Cadmium-Based Organic-Inorganic Hybrids: The Role of Halogen Doping in Modulating Multifunctional Properties.

Advances in materials science are increasingly dependent on the development of multifunctional materials capable of improving system efficiency and reducing the environmental impact. In this study, two zero-dimensional (0D) cadmium-based organic-inorganic hybrid materials (BEMPD)2CdBr4 (BEMPD-Br, 1) and (BEMPD)2CdBr2Cl2 (BEMPD-ClBr, 2) (BEMPD = 1-(2-bromoethyl)-1-methylpiperidine) were prepared by halogen doping. Compound 2 is a mixed halide in which there are two halogen sites, Cl and Br, and in a disordered state, which has a regulatory effect on the structural distortion and properties of the compound. The Curie temperatures of compounds 1 and 2 are 348 and 390 K, respectively, and the UV-vis absorption spectra showed that the direct band gaps of compounds 1 and 2 were 4.68 and 4.8 eV, respectively. In addition, room-temperature photoluminescence experiments show broadband emission peaks at 717 and 683 nm for compounds 1 and 2, respectively, with fluorescence lifetimes of 2.414 and 3.915 μs. These 0D hybrids provide an avenue for the development of smart materials and optoelectronic devices, and also provide positive clues for manipulating the properties of organic-inorganic hybrid compounds.

Innovative hybrid and bifunctional rare earth complexes as corrosion inhibitors for AA2024 Alloy: Electrochemical and surface analysis enhanced by DFT/MD simulation

The hybrid inorganic–organic compounds, RE-thioglycolates (RE = Ce, Nd, Sm), were analyzed as effective green corrosion inhibitors of AA2024 alloy in 0.1 M NaCl solution. Utilizing Electrochemical Impedance Spectroscopy the protective inhibitory film on the alloy’s surface was affirmed, alongside the persistence of a natural oxide layer over time. These complexes demonstrated notable corrosion inhibition efficiency over immersion from 1 h to 3 days, with Sm-thiog retaining the high inhibition efficiency of over 95 % during 72 h. All RE-thioglycolates are mixed-type inhibitors, imparting resistance against both general and pitting corrosion.The presence of a protective inhibitory film on the AA2024 surface in NaCl solution has been substantiated through various analytical techniques including FTIR, SEM/EDS and XPS. A detailed examination of the differential inhibition exhibited by these bifunctional complexes is elucidated through theoretical calculations. The smallest difference of HOMO and LUMO orbitals for Sm-thiog of 3.21 eV indicates that this inhibitor attains the strongest donor–acceptor interactions with the metal surface. Predictions generated by Density Functional Theory/Molecular Dynamics simulations suggest the potential formation of diverse inhibitory species within the electrolyte. The corrosion inhibition mechanism proposed for RE-thioglycolates is grounded in electrochemical and theoretical insights, and subsequently validated through surface analysis methods.

Isostructural phase transition and dielectric reversibility in a cobalt thiocyanate complex incorporating an organic-inorganic hybrid compound: (C5H7N2)2[Co(NCS)]4

In this study, a novel inorganic-organic hybrid crystalline material (C5H7N2)2[Co(NCS)4] (compound 1) was obtained by adopting the natural evaporation method using cobalt(II) chloride hexahydrate, ammonium thiocyanate, and 4-aminopyridine as raw materials. The structure and properties of the compounds were characterized by variable-temperature infrared spectroscopy, single-crystal X-ray diffraction (XRD), thermogravimetric analysis (TGA), powder XRD, differential scanning calorimetry (DSC), and dielectric tests. The results revealed P21/c as the space group of compound 1, wherein one-dimensional chains and a two-dimensional mesh structure were formed via combined hydrogen bonding and π···π interactions between the cobalt thiocyanate complex and the protonated 4-aminopyridine, exhibiting noticeable telescopic motions with changes in temperature. The DSC results showed that the compound generated a reversible phase-transition thermal energy peak near 240 K, with the reversible dielectric cycling changes being consistent with the thermal energy changes. This finding highlighted the isostructural phase transition and dielectric reversibility attributes of the herein synthesized compounds, accentuating their multifunctionality and excellent electrochemical properties.

Characterization of new hybrid material based on 5-amino-3-methyl-1-phenyl-1H-1,2,4-triazole and bismuth: Hydrothermal synthesis, structural analysis, thermal behavior, vibrational and optical properties, and Hirshfeld surface calculations

The new interesting organic-inorganic hybrid compound with the title (C9H12N4)2[BiBr6].Cl.4H2O was synthesized and grown using the hydrothermal method. Single-crystal X-ray diffraction analysis revealed that the new supramolecular compound adopts the non-centrosymmetric space group Pmn21 in the orthorhombic system. The unit cell parameters are as follows: a = 20.1193 (2) Å, b = 10.7704 (10) Å, c = 7.8356 (10). The crystalline structure of the new compound was solved using Direct methods and refined using the least squares method to achieve final values of R1 = 0.0239 and wR2= 0.0628.The purpose of conducting Hirshfeld surface analysis was to investigate the interactions between molecules and the 2D fingerprint plots associated with them, confirming the existence of hydrogen bond interactions and indicating that the Br⋯H/H⋯Br interaction is the most dominant, accounting for 50 % of the total interactions. FTIR spectroscopy and Raman scattering were used to identify the functional and molecular groups present in the crystal by analyzing their vibration modes. The energy gap value for the titled compound was calculated and confirmed by the DOS spectrum. Finally, the thermal behavior of the compound was characterized by thermogravimetry (TGA) analysis.

Lead‐Free halide perovskites for optoelectronic application: Investigation of structural, optical, electric and dielectric behaviors

Lead-free all-inorganic perovskite single crystals (SCs) are currently the subject of a lot of research because of their enhanced material stability and lower biological toxicity. These advancements are essential for removing major obstacles to the real-world implementation of device applications. The lead-free hybrid organic-inorganic compound (CH3NH3)2MnCl4 was synthesized in this work at room temperature employing the slow evaporation solution growth approach. Investigating its structural, optical, and electric characteristics was the key objective of the study. The (CH3NH3)2MnCl4 compound crystallises in the orthorhombic system (Pccn space group). For the compound under study, the UV–visible spectroscopy spectrum shows the direct band-gap value of ∼3.6 eV, indicating that it is a semiconductor material. The electric studies were conducted in a wide frequency range from 10−1 Hz–106 Hz and a temperature range from 348 to 388 K. Nyquist plots revealed only a semicircle in the whole impedance spectra due to the effect of interior grains. The obtained results were analyzed by fitting the experimental data to an equivalent circuit model R//C//CPE. The Alternating current conductivity (σAC) follows Jonscher's power law. The fitting of σAC curves reveals that the activation energy is equal to 0.706 eV. The dominant transport mechanism is the CBH model in the temperature range from 348 to 388 K. Studies of the dielectric constant permittivity ε*(ω) confirmed that the relaxation process was thermally activated.

Synthesis, Structural characterization and complex impedance analysis of a novel organic-inorganic hybrid compound based on Mercury (II) chloride

The organic-inorganic hybrid compounds are promising materials due to their electro-optical and semiconducting properties. In this study, a single crystal of (C6H16N)2[HgCl4] has been synthesized and characterized using single-crystal X-ray diffraction at room temperature, SEM/EDS and complex impedance spectroscopy. The crystal structure is centrosymmetric with the monoclinic system (P21/c space group). It consists of isolated tetrahedral anions [HgCl4]2− and protonated amines (C6H16N) +. SEM/EDS analyses proved the composition of the title compound. The frequency-dependent electrical and dielectric properties were analyses using complex impedance spectroscopy in the frequency range of 10−1 Hz – 1 MHz. The Nyquist plots (-Z’’ vs Z’) was characterized by the appearance of a single semicircle arc, indicating a non-Debye type relaxation process in the (C6H16N)2[HgCl4] material. The AC conductivity followed Jonscher law, and the variation of frequency exponent s with temperature suggested that non-overlapping small polaron tunneling (NSPT) is the dominant electrical transport mechanism. So, this work will be very beneficial to the further development of the (C6H16N)2[HgCl4] compound and its potential electrical applications.

Synthesis of binder-free hydrated vanadium oxide-polyaniline electrodes via in situ polymerization for high-performance aqueous zinc-ion batteries

Hydrated vanadium oxide, a kind of layered electrode material with high theoretical specific capacity, has great potential for developing high-performance, low-cost, and eco-friendly aqueous zinc-ion batteries. However, its characteristics of poor electronic conductivity, vanadium dissolution, and unstable structure lead to poor electrochemical performance, such as low specific capacity, poor rate performance and short cycle life. Combining PANI with layered hydrated vanadium oxide is expected to overcome the shortcomings and achieve high zinc storage performance. In this work, binder-free hydrated vanadium oxide-polyaniline inorganic–organic hybrid compounds deposited on carbon cloth (VOH-PANI/CC) are developed by combination of layer-by-layer and in-situ polymerization process. Benefiting from synergistic effect between polyaniline and hydrated vanadium pentoxide, the hybrid electrode (VOH-PANI/CC) delivers high capacities of 290 mA h/g at 0.5 A/g and 165 mA h/g at 4 A/g. In contrast, the specific capacities of VOH/CC are only 185 and 70 mA h/g at 0.5 and 4 A/g, respectively. This in-situ polymerization of aniline via layer-by-layer strategy on hydrated vanadium oxide provides a novel synthesis scheme for the use of vanadium oxide as cathode material for aqueous zinc-ion batteries.

Continuous wave laser-assisted evaporation of halide perovskite thin films from a single stoichiometric source

We report continuous wave laser-assisted evaporation (CLE), a thin film deposition technique that yields phase-pure and stoichiometric thin films of halide perovskites (HaPs) from stoichiometric HaP targets. We use methylammonium lead bromide (MAPbBr3) to demonstrate the ability to grow with CLE well-oriented and smooth thin films on various substrates. Further, we show the broader applicability of CLE by preparing films of several other 3D HaP compounds, viz., methylammonium lead iodide, formamidinium lead bromide, and a 2D one, butylammonium lead iodide. CLE is a single-source, solvent-free, room-temperature process that needs only roughing pump vacuum; it allows the deposition of hybrid organic-inorganic compound films without needing post-thermal treatment or an additional organic precursor source to yield the intended product. The resulting films are polycrystalline and highly oriented. All these features, and the fact that one stoichiometric source serves as the target, make for an attractive, potentially scalable dry deposition approach.

Structural and Optical Characterization of a New Tetra- and Hexa-Coordinated Cd-Based Hybrid Compound with White Light Emission

The present paper deals with a new two-in-one zero-dimensional (0D) organic–inorganic hybrid compound namely (C6H10N2)4[CdBr6][CdBr4]2. This molecular crystal structure contains isolated CdBr4 tetrahedra and CdBr6 octahedra. The optical characterization by UV–Vis–NIR spectroscopy shows that the (C6H10N2)4[CdBr6][CdBr4]2 exhibits a large gap energy of 4.97 eV. Under UV excitation, this hybrid material shows a bright cold white light emission (WLE) at room temperature. The photoluminescence (PL) analysis suggests that the WLE originates from the organic molecules. Density of states (DOS) analysis using the density functional theory (DFT) demonstrates that the calculated HOMO(Br)→LUMO(organic) absorption transition (4.1 eV) does not have significant intensity, while, the transition involving the valence band (VB) and the second and third conduction bands (CB) around 5 eV are allowed, which is in good agreement with the experimental gap value. The interesting theoretical result is that the LUMO(organic)→HOMO(Br) emission is allowed, which confirms the important role of the organic molecule in the emission mechanism, in good agreement with the experimental PL analysis.

Exploring the semiconductor characteristics of a polyoxometalate-based organic-inorganic hybrid dimer and its photocatalytic applications

Polyoxometalate-based organic-inorganic hybrid compounds have been widely used in the field of photocatalysis, photoelectrocatalysis, interfacial materials of semiconductor device. However, their intrinsic semiconductor characteristics such as carrier diffusion lengths and carrier mobility are still unclear. Herein, we first unravel the carriers diffusion length and carrier mobility of the novel POM-based dimeric compound, {(HBW12O40)[Cu(2,2′-bipy)2]2[CuO(2,2′-bipy)(H2O)]}2·2H2O (1), which is successfully synthesized through co-assembly of binuclear Cu(II)-complex and BW12 in hydrothermal reaction. Space charge-limited currents (SCLC) method shows that the holes carriers mobility (μh) of this compound reached 0.84 cm2V−1s−1, which is more 30 times than that of raw BW12 (2.6 × 10−2 cm2V−1s−1). The calculated carrier diffusion lengths of compound 1 is 82 nm, which is almost 3 time higher than that of BW12 (25 nm), indicating that photogenerated carriers are more easily separated and diffused in compound 1. Furthermore, the semiconductor properties of compound 1 have been demonstrated by the measurements of photocurrent response, VB-XPS spectrum and band gap (Eg) values. In addition, its applications of photocatalysis indicate the excellent activities of compound 1 with 71 % degradation rate for photodegradation of methylene blue (MB) and 67 % degradation rate for photocatalytic reduction of Cr(VI).

Constructing a P2W18O626--Containing Hybrid Photocatalyst via Noncovalent Interactions for Enhanced H2 Production.

Polyoxometalates (POMs) have gained significant research attention because of their excellent properties in photocatalytic (PC) hydrogen production. Exploring POM-based compounds for heterogeneous photocatalysis is an ongoing task. Here, we obtain a water-insoluble inorganic-organic hybrid compound, (P2W18O62)3(C12N3H10)6(C12N3H11)6·9.5H2O (P-PW), formed by Dawson-type POM P2W18O626- (P2W18) anions and protonated 2-(pyridin-4-yl)-1H-benzo[d]imidazole (PHB) cations via noncovalent interactions. In the presence of the sacrificial agent triethanolamine, P-PW exhibits a PC H2 generation rate of 0.418 mmol/g/h, surpassing that of P2W18 and PHB by 15 and 17 times, respectively. This enhancement in PC performance of P-PW can be attributed to its band structure change from the precursor compounds, leading to increased light absorption and therefore more efficient PC hydrogen production.

Two 2D inorganic—organic hybrid compounds containing Anderson—type polyoxometalate for electrocatalytic and capacitive performances

For constructing the compounds containing polyoxometalate with electrochemical properties, to employ 3,5 − di − [1,2,4]triazol − 1 − yl − benzonitrile (DTCN) as organic ligand, Anderson − type polyoxometalate {TeMo6O24}6− as inorganic building block, two inorganic–organic hybrid compounds were synthesized under hydrothermal condition, formulated as {M(H2O)4(DTCN)2}[M2(H2O)2(DTCN)2{TeMo6O24}]·2H2O [M = Co (1), Ni (2)]. Structural analysis indicated that two compounds have 2D structures. The {TeMo6O24}6− polyoxoanions were each other aggregated through paired transition metal centers to generate a 1D inorganic chain. The DTCN ligand played a role of bidentate linker, utilizing the nitrogen atoms of two triazole groups to link these inorganic chains into a 2D grid − like layer. Another kind of metal − organic fragments {M(H2O)4(DTCN)2}2+ were arranged in the grids. Compounds 1 and 2 displayed not only electrocatalytic activities for the reduction of Cr(VI), but also sensing activities with the limit of detection of 0.011 μM for 1 and 0.019 μM for 2, as well as capacitive performances with specific capacitances of 1297F·g−1 for 1 and 968F·g−1 for 2 at a current density of 1 A·g−1. The results might provide a potential approach for preparing polyoxometalate − based inorganic–organic hybrid compounds used as electrochemical materials.

Solvent-Induced Bright Emission in Lead-Free Organic-Inorganic Antimony Bromides with Reversible Transformation.

Lead-free low-dimensional organic-inorganic metal halides have gained increasing attention in a wide range of applications due to their low toxicity, outstanding optical performance, and structural tunability. In this work, a general method of incorporating organic molecule into sodium antimony bromides is introduced. The 1D Na3SbBr6(C2H6OS)6 and Na3SbBr6(C4H8OS)6 single crystals exhibit bright yellow and orange emission with PL peaks at 610 and 664nm, and high photoluminescence quantum yields (PLQYs) of 85% and 60%, respectively. These two compounds can be reversibly converted into each other by the removal and addition of the organic components. Their exceptional luminescent performance enables them to be used as solid-state phosphors for the fabrication of yellow and orange down-conversion LEDs. A white LED with a high color rendering index (CRI) of 95 is also fabricated by using Na3SbBr6(C2H6OS)6 as the yellow phosphor. The universality of this method is demonstrated by synthesizing other members of this family with diverse A-groups, including methylammonium (MA) and formamidinium (FA). This work provides an effective strategy for the development of diverse lead-free and high-performance organic-inorganic hybrid materials and indicates these organic-inorganic hybrid compounds are promising luminescent materials for lighting or displays.

A series of viologen/POM materials with discoloration properties under the stimulation of X-ray, UV, electricity, and organic amines

At present, viologen-based compounds can undergo reversible chemical/physical changes under external stimuli such as light and electricity. This makes these compounds have potential applications in smart windows, displays, and sensors. In order to obtain such materials, three viologen-POM inorganic–organic hybrid compounds have been successfully synthesized by a hydrothermal method, namely {[Cu2(cybpy)8(α-P2W18O62)2}·18H2O (1), (Hbpy)·(cybpy)·[H4(α-P2W18O62)]}·32H2O (2) and {(Hcybpy)2(β-Mo8O26)}·2H2O (3) (cybpy·Br = 1-cyclobutylmethyl-[4,4′]bipyridinyl-1-ium bromide, bpy = 4,4′-bipyridine). Three compounds exhibit good discoloration behaviors under various external stimuli, especially under the stimulation of X-ray, UV, electricity, and organic amines. In addition, in order to promote the compounds in the actual production of more applications, they were doped into the polymer matrix to construct hybrid films, which not only have the same response to external stimulation but also increase the repeatability of the photochromic process. Moreover, 1–3 powder samples in ethanol solution were ultrasonic treated and deposited on filter paper, which can be successfully used in erasable inkless printing.

Two new polyoxomolybdate-based organic–inorganic hybrid compounds with copper ions and bridging ligands

Two new polyoxomolybdate-based organic–inorganic hybrid compounds with copper ions and bridging ligands were prepared in a hydrothermal reaction system, and the chemical formulas are [Cu2(L1)4S][Mo6O19] (1) and [CuIICuI 2(L2)5][β-Mo8O26] (2) (L1 = 1,2-bis(iminazole-1-ylmethyl)benzene, L2 = 1,4-bis(1,2,4-triazol-1-ylmethyl)benzene). Complexes 1 and 2 were characterized by elemental analysis, IR spectra, TG analyses and single-crystal X-ray diffraction analyses. Compound 1 exhibits 2-D layers with honeycomb-like cavities, further stacking into a 3-D supramolecular framework with the [Mo6O19]2- polyoxoanions as guest templates in the honeycomb-like cavities. Compound 2 possesses an overall 3D(2D/3D) framework constituted by the undulating 2-D motifs and the 3D sqp framework. The photocatalytic activities of 1 and 2 under UV light were investigated based on the degradation of methylene blue (MB). Both compounds exhibit efficient catalytic activity for the degradation of MB.

Fine Tuning Ag(I)-Sb(III) Hybrid Iodides for Light Detection.

Lead-free hybrid double perovskite iodides (HDPIs) have piqued increasing research interest due to their environmental friendliness and high stability. However, such antimony-based HDPIs with strong photocurrent response are currently very limited. Here, we successfully design and construct five Ag(I)-Sb(III)-based HDPIs using two types of cyclic aliphatic amines as A-site templates. Interestingly, these Ag(I)-Sb(III) HDPIs exhibit relatively narrow band gaps, preferred orientation, and high stability after being processed into thin films on the indium tin oxide (ITO) substrate. Notably, under illuminations of a xenon lamp, all HDPIs exhibit considerable photocurrent responses, reaching a maximum difference of 17 μA·cm-2 for ASI 1, which is the highest among lead-free halogen-based organic-inorganic hybrid compounds to date. Combining the considerable photocurrents and the high stability, the optoelectronic applications of two-dimensional Ag(I)-Sb(III) HDPIs can be expected.

Phase Transition and Switchable Dielectric Properties of a Three-Dimensional Hydrogen-Bonding Framework Based on Cobalt (Ⅲ), o-Bromoaniline, and 18-Crown-6

The organic–inorganic hybrid compound, (o-BrAH)[H2Co(CN)6]0.5·(18-crown-6)0.5·H2O, was synthesized and characterized by variable-temperature X-ray diffraction, single-crystal diffraction, infrared spectroscopy, elemental analysis, thermogravimetric analysis, differential scanning calorimetry, and dielectric measurements. Single-crystal X-ray diffraction revealed a three-dimensional cage-like structure formed through the hydrogen bonds of cobalt hexacyanide, supermolecular cations, and water molecules. Temperature variation triggered an abrupt change in the cage structure and simultaneously caused dynamic oscillation of the supramolecules within the framework of [Co(CN)6]3−, inducing a phase transition accompanied by a step-like change in the dielectric physical properties.

Synthesis, crystal structure, BFDH morphology, Hirshfeld surface analysis and electrical characterization of the new bi-(2-amino-5-methylpyridinium) hexa-chlorostannate compound

The Organic–inorganic hybrid compounds have attracted considerable attention for their scientific and technological potential according to their wide field application. In this paper, we describe the preparation of a new hybrid crystal, with the structural formula [C6H9N2]2SnCl6, of which crystallographic, BFDH morphology, Hirshfeld and complex impedance spectroscopy have been studied and analyzed. The X-ray diffraction analysis revealed that the title compound crystallized in the centrosymmetric space group P21/c of the monoclinic system. The powder XRD is used to confirm the phase purity of the sample and the crystalline nature of the powder.The [C6H9N2]2SnCl6 crystal morphologies are simulated from the Laue symmetry (2/m), and from the space group symmetry (P21/c), which highlighted the effect of the screw axe 21 and the glide plane c in reducing the Importance morphology in the constructed model considering the space group symmetry. The intermolecular interactions studied using Hirshfeld surfaces showed the important contribution of H⋯Cl/Cl⋯H intercontacts (67.1 %) in the [C6H9N2]2SnCl6 crystal packing.The analysis of real and imaginary parts impedance spectra shows that the electrical properties are heavily dependent on frequency and temperature, indicating a relaxation phenomenon and semiconductor-type behavior. The Nyquist plot (-Z″ vs Z′) showed only one semicircular arc, representing the grain effect in the electrical conduction. The obtained results were analyzed by fitting the experimental data to an equivalent circuit model R/CPE/C. The Alternating current conductivity (σAC) follows Jonscher's power law. The latter confirmed that the conduction is insured by the non-overlapping small polaron tunneling model (NSPT) model, which has been studied in depth.

Metal ion-dependent structural phase transition and impact of Jahn-Teller effect in two organic-inorganic hybrid compounds

Two new molecule-based organic-inorganic hybrid compounds, (H2dabco)[M(H2O)6][SiF6]2 (dabco = 1,4-diazabicyclo [2.2.2] octane, M = Mn2+ & Cu2+), affected by the different metal ions and Jahn-Teller effect of Cu2+, exhibiting metal...