RESUMEN
Chirality is a fascinating geometrical concept with widespread applications in biology, chemistry, and materials. Incorporating chirality into hybrid perovskite materials can induce novel physical properties (chiral optical activity, nonlinear optics, etc.). Hybrid lead-free or lead-substituted perovskite materials, as representatives of perovskites, have been widely used in fields such as photovoltaics, sensors, catalysis, and detectors. However, the successful introduction of chirality into hybrid lead-free perovskites, which can enable their potential applications in areas such as circularly polarized light photodetectors, memories, and spin transistors, remains a challenging research topic. Here, we synthesized two new chiral lead-free perovskites, [(R)-2-methylpiperazine][BiI5] and [(S)-2-methylpiperazine][BiI5]. The material possesses a perovskite structure with a one-dimensional (1D) arrangement, denoted as ABX5. This structure is composed of chiral cations, specifically methylpiperazine, and endless chains of [BiI3] along the a-axis. These chains are assembled from distorted coplanar [BiI5]2- octahedra. The testing results revealed that (R)-1 and (S)-1 have narrow band gaps (Eg-R = 2.016 eV, Eg-S = 1.964 eV), high photoelectric response, and long carrier lifetime [R = 4.94 µs (τ), S = 7.85 µs (τ)]. It is worth noting that 1D chiral lead-free perovskites (R)-1 and (S)-1, which are synthesized in this study with narrow band gaps, high photoelectric response, and long carrier lifetime, have the potential to serve as alternative materials for the perovskite layer in future iterations of lead-free perovskite solar cells. Moreover, this research will inspire the preparation of multifunctional, lead-free perovskites.
RESUMEN
Purification of ethylene (C2H4) is an essential and energy-intensive process in the petrochemical industry. Adsorption separation using ethane (C2H6)-selective porous adsorbents is a highly efficient and straightforward method for obtaining polymer-grade C2H4 from a binary C2H6/C2H4 mixture. However, the design and construction of C2H6-selective adsorbents are very challenging tasks. Herein, we demonstrate a microporous heterometal-organic framework, CuIn(ina)4, can preferentially enrich C2H6 than C2H4. Experimental results revealed that CuIn(ina)4 exhibited remarkable separation performance for the C2H6/C2H4 mixture with a high C2H6 loading capacity (3.3 mmol/g), high IAST selectivity (2.3) and separation potential (1578 mmol/L for equimolar C2H6/C2H4 mixture) under ambient conditions. The effectiveness of CuIn(ina)4 for C2H6/C2H4 adsorption separation was confirmed by theoretical calculations and breakthrough experiments.
RESUMEN
Molecular ferroelectric materials are widely applied in piezoelectric converters, non-volatile memorizers, and photovoltaic devices due to their advantages of adjustable structure, lightweight, easy processing, and environmental friendliness. However, designing multifunctional molecular ferroelectrics with excellent properties has always been a great challenge. Herein, a multiaxial molecular ferroelectric is successfully designed by modifying the quasi-spherical cation dabco with CuBr2 to obtain halogenated [Bretdabco]CuBr4 (Bretdabco = N-bromoethyl-N'-diazabicyclo [2.2.2]octane), which crystallizes in polar point groups (C6). Typical ferroelectric behaviors featured by the P-E hysteresis loop and switched ferroelectric domain are exhibited. Notably, the molecular ferroelectric shows a high TC of 460 K, which is rare in the field and could greatly expand the application range of this material. In addition, the band gap is adjustable through the regulation of halogen. Both the UV absorption spectra and theoretical calculations indicate that the molecular ferroelectrics belong to a direct band gap (2.14 eV) semiconductor. This tunable and narrow band gap semiconductor molecular ferroelectric material with high TC can be utilized more effectively in the study of optoelectronics and sensors, including piezoelectric energy harvesters. This research may provide a promising approach for the development of multiaxial molecular ferroelectrics with a tiny band gap and high TC.
RESUMEN
Construction of ferroelectric and optimization of macroscopic polarization has attracted tremendous attention for next generation light weight and flexible devices, which brings fundamental vitality for molecular ferroelectrics. However, effective molecular tailoring toward cations makes ferroelectric synthesis and modification relatively elaborate. Here, the study proposes a facile method to realize triggering and optimization of ferroelectricity. The experimental and theoretical investigation reveals that orientation and alignment of polar cations, dominated factors in molecular ferroelectrics, can be controlled by easily processed anionic modification. In one respect, ferroelectricity is induced by strengthened intermolecular interaction. Moreover, ≈50% of microscopic polarization enhancement (from 8.07 to 11.68 µC cm-2 ) and doubling of equivalent polarization direction (from 4 to 8) are realized in resultant ferroelectric FEtQ2ZnBrI3 (FEQZBI, FEtQ = N-fluoroethyl-quinuclidine). The work offers a totally novel platform for control of ferroelectricity in organic-inorganic hybrid ferroelectrics and a deep insight of structure-property correlations.
RESUMEN
Four novel all-in-one structured cuprous iodide hybrid materials are presented. Isomerization of the alkyl chain on the ligand improved material thermal stability and regulated their luminescence to warm and near-white light emission, with the internal quantum yield increasing from 5% to 83%. This provides a reasonable route for designing white light emitting cuprous iodide materials for solid-state lighting in future.
RESUMEN
Three anionic luminescent metal-organic frameworks (LMOFs; [M(tcbpe)(CH3)2NH2]·H2O; M = In3+, Eu3+, Gd3+; tcbpe = 4',4â´,4â´â³,4â´â´'-(ethene-1,1,2,2-tetrayl)tetrakis[(1,1'-biphenyl)-4-carboxylic acid]) are synthesized by employing the tetraphenylethene core ligand H4tcbpe with M3+ ions. They stack in the similarly 4-fold-interpenetrated three-dimensional porous structure. All give blue emission when excited at 365 nm, with fluorescence quantum yields of 34.8% (MOF-In), 7.1% (MOF-Eu), and 28.1% (MOF-Gd). Somewhat surprisingly, these three complexes are extremely stable both in various solvents and across a broad pH range: MOF-In is stable between pH = 0 and 14, and MOF-Eu and MOF-Gd are stable between pH = 0 and 13. Additionally, they also show good proton conductivities of 2.29 × 10-5 S·cm-1 (MOF-In), 2.02 × 10-4 S·cm-1 (MOF-Eu), and 1.24 × 10-4 S·cm-1 (MOF-Gd) at high temperature under 98% relative humidity. To the best of our knowledge, this is the first reported LMOF series combining aggregation-induced emission behavior with good proton conductivities.
RESUMEN
Herein, we report the synthesis of two new manganese-based luminescent metal-organic frameworks (LMOFs) [Mn0.5(tipe)(1,4-ndc)] n (1) and [Mn(tipe)(1,4-ndc) (H2O)·(DMF)2·(H2O)3] n (2) [tipe = 1,1,2,2-tetrakis(4-(1H-imidazol-1-yl)phenyl)ethene (tipe) and 1,4-ndc = 1,4-naphthalenedicarboxylic acid] constructed from an aggregation-induced emission (AIE) chromophore ligand. Compound 1 can undergo a facile single-crystal-to-single-crystal transformation to form compound 2, which results in an increase in dimensionality from a two-dimensional (2D) network to a three-dimensional (3D) network. Both compounds demonstrate excellent performance for the solution-phase detection of Fe3+ ions through a significant and rapid quench in luminescence emission. Fluorescence titration experiments reveal that compound 2 is more selective toward Fe3+ compared to compound 1 because of its 3D stacking mode. The K sv value for compound 2 (32â¯378 M-1) is twice as large as that for compound 1 (15â¯854 M-1) for the detection of Fe3+ ions. We attribute this significant increase in performance to the increase in dimensionality. In addition, compound 2 demonstrates high selectivity and sensitivity for the detection of Cr3+ cations and Cr2O7 2- anions.
RESUMEN
Through precise and ingenious molecular modification, we successfully obtained a multiaxial ferroelectric, [FEtDabco]ZnI3 (N-fluoroethyl-N'-ZnI3-1,4-diazabicyclo[2.2.2]octonium), with a record high Tc (540 K) among molecular ferroelectrics, which is promising for application under extreme thermal conditions.
RESUMEN
Copper(I) halide complexes are well sought-after materials due to their rich structural diversities and photophysical properties. Profoundly, there is a direct relationship between each structural variation and luminescence of these complexes, for a purported use. In this review, recent publications within the last 2 years about copper(I) halide complexes, centering on their structural dimensionalities with derivatives of nitrogen, phosphorus, and sulfur ligands, have been considered alongside their effects on luminescence.
RESUMEN
Three new luminescent metal-organic frameworks (LMOFs), [Zn(tppa)(ndc)] n (1), [Cd(tppa)(oba)] n (2), [Zn2(tppa)(bpdc)2] n (3) (tppa = tri(4-pyridylphenyl)amine, ndc = 1,4-naphthalenedicarboxylic acid, oba = 4,4'-oxydibenzoic acid, bpdc = 4,4'-biphenyldicarboxylic acid) have been synthesized by solvothermal method. Complexes 1 and 2 are 2-D two-fold interpenetrating structures, aligning into a 3-D structure through C-Hâ¯π stacking interactions, while 3 is a 5-fold interpenetrating three-dimensional structure. The internal quantum yields (IQYs) of complexes 1-3 are 32.7%, 45.7% and 24.0% (λ ex = 365 nm), separately. Furthermore, all the complexes show different luminescence signal changes towards aromatic volatile organic compounds (AVOCs). Complex 1 exhibits a high sensitivity in the detection of both Fe3+ and Cr3+ with large quenching coefficients of K sv 2.57 × 104 M-1 and 2.96 × 104 M-1, respectively. All these results demonstrated potential applications in chemical sensing.
RESUMEN
In the structure of the binuclear title compound, [Cd2(C6H13N2)2Cl6], two Cd(II) atoms are bridged by two Cl(-) ligands, defining a centrosymmetric Cd2Cl2 motif. Each metal cation is additionally coordinated by two Cl(-) ligands and the N atom of a protonated 1,4-di-aza-bicyclo-[2.2.2]octane (H-DABCO)(+) ligand, leading to an overall trigonal-bipyramidal coordination environment with one of the bridging Cl(-) ligands and the N atom at the apical sites. In the crystal, the neutral dimers are linked via N-Hâ¯Cl hydrogen bonds, forming a two-dimensional network expanding parallel to (100).
RESUMEN
The one-dimensional organic-inorganic hybrid compound bis(cyclohexylammonium) tetrachlorocadmate(II) (1), in which the adjacent infinite [CdCl4]n(-) chains are connected to each other though Cd···Cl weak interactions to form perovskite-type layers of corner-sharing CdCl6 octahedra separated by cyclohexylammonium cation bilayers, was synthesized. It undergoes two successive structural phase transitions, at 215 and 367 K, which were confirmed by systematic characterizations including differential scanning calorimetry (DSC) measurements, variable-temperature structural analyses, and dielectric and second harmonic generation (SHG) measurements. A precise structural analysis discloses that the phase transition at 215 K is induced by the disorder-order transition of cyclohexylammonium cations, while the phase transition at 367 K derives from changes in the relative location of Cd atoms. Emphatically, both the dielectric constant and SHG intensity of 1 show a striking change between low and high states at around 367 K, which reveals that 1 might be considered as a potential dielectric and nonlinear optical (NLO) switch with high-temperature response characterization, excellent reversibility, and obvious change of states.
RESUMEN
In the title ion-pair complex, (C12H14N2)[Cu(C4N2S2)2], the complex anion exhibits a highly twisted coordination environment around the tetra-coordinated Cu(II) atom. The dihedral angles between the 1,2-di-cyano-ethene-1,2-di-thiol-ato ligands and between the two pyridine rings in the cation are 37.49â (3) and 29.18â (10)°, respectively. Weak C-Hâ¯N and C-Hâ¯S hydrogen bonds link the cations and anions into a three-dimensional network.
RESUMEN
In the title mol-ecular salt, (C(4)H(10)NO)(2)[CoCl(4)], the morpholinium cations adopt chair conformations and the tetra-chloridocobaltate(II) anion is significantly distorted from regular tetra-hedral geometry [Cl-Co-Cl = 102.183â (19)-117.59â (2)°]. The Co-Cl bond lengths for the chloride ions not accepting hydrogen bonds are significantly shorter than those for the chloride ions accepting such bonds. In the crystal, the components are linked by N-Hâ¯O and N-Hâ¯Cl and bifurcated N-Hâ¯(O,Cl) hydrogen bonds to generate (100) sheets.
RESUMEN
In the title compound, C(13)H(12)ClNO, the dihedral angle between the two benzene ring planes is 68.71â (8)°. In the crystal, mol-ecules are linked by pairs of O-Hâ¯N hydrogen bonds into inversion dimers, which are further linked by intermolecular N-Hâ¯O interactions into a chain running parallel to the a axis.
RESUMEN
In the title compound, C(14)H(15)NO(2), the dihedral angle between the two benzene rings is 71.10â (5)°. In the crystal, mol-ecules are linked by inter-molecular N-Hâ¯O, and O-Hâ¯N hydrogen bonds into a chain running parallel to the b axis.
RESUMEN
Pyridinium-3-carboxylic acid perchlorate was synthesized and separated as crystals. Differential scanning calorimetry (DSC) measurements show that this compound undergoes a reversible phase transition at approximately 135 K with a wide hysteresis of 15 K. Dielectric measurements confirm the transition at approximately 127 K. Measurement of the unit-cell parameters versus temperature shows that the values of the c axis and beta angle change abruptly and remarkably at 129 (2) K, indicating that the system undergoes a first-order transition at T(c) = 129 K. The crystal structures determined at 103 and 298 K are all monoclinic in P2(1)/c, showing that the phase transition is isosymmetric. The crystal contains one-dimensional hydrogen-bonded chains of the pyridinium-3-carboxylic acid cations, which are further linked to perchlorate anions by hydrogen bonds to form well separated infinite planar layers. The most distinct differences between the structures of the higher-temperature phase and the lower-temperature phase are the change of the distance between the adjacent pyridinium ring planes within the hydrogen-bonded chains and the relative displacement between the hydrogen-bonded layers. Structural analysis shows that the driving force of the transition is the reorientation of the pyridinium-3-carboxylic acid cations. The degree of order of the perchlorate anions may be a secondary order parameter.
RESUMEN
In the title compound, C(31)H(25)ClO(3), the central ring of the xanthene core shows a shallow boat conformation, while the outer six-membered rings display envelope conformations. The dihedral angle between the outer aromatic rings is 88.1â (3)° and the dihedral angles between the chloro-benzene ring and the two phenyl rings are 69.5â (2) and 69.6â (2)°.
RESUMEN
In the title salt, (C(20)H(26)N(2)O(2))[FeCl(4)]Cl·H(2)O, the Fe(III) atom exists in a tetra-hedral coordination environment. The cation, anions and water mol-ecules are linked by N-Hâ¯Cl, O-Hâ¯Cl and O-Hâ¯O hydrogen bonds into a layer network.
RESUMEN
In the title compound, C(22)H(20)N(4), the two benzimidazole ring systems are nearly coplanar [dihedral angle = 4.70â (5)°]. Two terminal C atoms of one allyl group are disordered over two sites of equal occupancy. The crystal structure is stabilized by π-π stacking inter-actions, the centroid-centroid distance between nearly parallel [dihedral angle = 19.82â (4)°] benzene and imidazole rings being 3.7885â (15)â Å.
