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By using in-site generated formate, 2D HOFs of TCPP, with excellent stability and permanent porosity (BET surface area larger than 560 m2 g−1), have been obtained. The constructed 2D square-like TCPP-HCO2 grid sheets have shown considerable in-plane stability that comparable to the TCPP-based 2D MOFs, that can be exfoliated into atomically thin 2D nanosheets with efficient photocatalytic activity in aqueous system. These results are expected to shed light on the application-orientated one-pot synthesis for new kinds of multi-dimensional HOFs. [ABSTRACT FROM AUTHOR]

Precise revealing the mechanisms of excited‐state intermolecular proton transfer (ESPT) and the corresponding geometrical relaxation upon photoexcitation and photoionization remains a formidable challenge. In this work, the compound (E)‐4‐(((4H‐1,2,4‐triazol‐4‐yl)imino)methyl)‐2,6‐dimethoxyphenol (TIMDP) adopting a D‐π‐A molecular architecture featuring a significant intramolecular charge transfer (ICT) effect has been designed. With the presence of perchloric acid (35 %), TIMDP can be dissolved through the formation of a HClO4–H2O–OH(TIMDP)–N(TIMDP) hydrogen‐bonding bridge. At the ground state, the ICT effect is dominant, giving birth to crystals of TIMDP. Upon external stimuli (e.g. UV light irradiation, electro field), the excited state is achieved, which weakens the ICT effect, and significantly promotes the ESPT effect along the hydrogen‐bonding bridge, resulting in crystals of [HTIMDP]+⋅[H2O]⋅[ClO4]−. As a consequence, the mechanisms of the ESPT can be investigated, which distorted the D‐π‐A molecular architecture, tuned the emission color with the largest Stokes shift of 242 nm, and finally, high photoluminescence quantum yields (12 %) and long fluorescence lifetimes (8.6 μs) have achieved. These results not only provide new insight into ESPT mechanisms, but also open a new avenue for the design of efficient ESPT emitters. [ABSTRACT FROM AUTHOR]

Three salts: 3-amino-1,2,4-triazolinium (1+) hydrogen oxalate ( 1 ), 3-amino-1,2, 4-triazolinium (1+) hydrogen malonate ( 2 ), 3-amino-1,2,4-triazolinium (1+) hydrogen succinate ( 3 ) and one co-crystal: 3-amino-1,2,4-triazole-adipic acid ( 4 ) have been prepared and characterized by differential scanning calorimetry (DSC), thermogravimetric analyses (TGA), IR, Raman, and single-crystal X-ray diffraction. Wherein, supramolecular motif in salts 1 , 3 and co-crystal 4 were dominant by triazole-acid and amino-acid heterosynthon, while salt 2 dominant by amino-triazole homosynthon in addition to triazole-acid heterosynthon, which attribute to the intermolecular hydrogen interactions within hydrogen malonate anion. These results have a close relationship with the ΔpKa between 3-ATZ and alkyl acids, we found that the ΔpKa is grate than 6.9, the formation of salt will be expected, while the formation of co-crystal usually with the ΔpKa less than 6.75. It is interesting that salts 2 and 3 show the phenomenon of proton transfer after melt, which lead to the stepwise sublimation of the two components. The differences between salts and co-crystal were also revealed by the solid-state vibrational spectroscopy (IR and Raman), Hirshfeld surface analysis and UV spectra. [ABSTRACT FROM AUTHOR]

In order to determine the effect of halogen bonding on supramolecular assemblies and photophysical properties of diaryl oxalates, diaryl oxalate itself and its derivatives with fluorine, chlorine, bromine, and iodine substituents in the p-position of phenyl rings were studied and compared. Their single-crystal structures were studied by geometrical analysis and theoretical calculation. The study reveals that different halogen bonds are formed with respect to different halogen atoms, such as C...F and X...X (bromine and iodine atoms) interactions, and molecular stacking modes would be affected by halogen bonds directly. Comparative studies of photophysical properties in dilute solution and solid state indicate that halogen substitutions would not affect the emission processes of diaryl oxalates in dilute solution; this is not the case for their solid state. This work has demonstrated that halogen bonds play an important role in regulating structures and photophysical properties of diaryl oxalates. [ABSTRACT FROM AUTHOR]

Abstract: Fabricating of melamine (MM)‐based multi‐component functional self‐assemblies have been investigated intensively. However, studies on protonated MM still in its infancy. Hence in this work, we studied the self‐assembly of protonated MM in different forms (1⋅ClO4− [MMH+⋅ClO4−⋅H2O], 2⋅Br− [MMH2+⋅2Br−⋅H2O], and 3⋅Cl− [MMH2+⋅2Cl−⋅H2O]) with various oxoanions (SO42−, NO3− and PO43−). Results revealed that the original anions ClO4‐, Br‐, and Cl‐, though not included in these self‐assemblies, are mainly responsible for the spectacular morphologies, from cuboids (1.SO42−) to prismoids (2.SO42−), sheets (3.SO42−), fibers (1.NO3−), rods (2.NO3−, 3.NO3−) and ribbons (1.PO43−, 2.PO43−, 3.PO43−). The crystalline phase and compositions of these self‐assemblies were found to be independent from the original protonated MM and the degree of protonation, while depend on the specific oxoanions. Therefore, the self‐assembly mechanism can be proposed. These results may provide an effective strategy for morphological control, especially for further development in protonated MM‐based functional materials. [ABSTRACT FROM AUTHOR]

Although synthetic efforts to prepare carboxylato-bridged tetranuclear iron(III) clusters have been well preformed, introducing of functional groups on the coordination ligands to tune the structural, spectroscopic and physical properties of the cluster remains unstudied. Using amino functionalized ligands bipy-NH 2 and O 2 CPh-NH 2 , we have prepared a new cluster 1 ([Fe 4 O 2 (O 2 CPh-NH 2 ) 7 (bipy-NH 2 ) 2 ]·HO 2 CPh-NH 2 ·(CH 3 CN) 3 ·C 2 H 5 OH·OH) via a new precise orientated strategy starting from iron(II) compound. The cluster was characterized by UV–Vis, IR and Mossbauer spectroscopy, X-ray crystallography, cyclic voltammetric and magnetic studies. Results have shown that the [Fe 4 (μ 3 -O) 2 ] 8+ core was disposed in a bent “butterfly” arrangement, and the adjacent cores were connected into 1-D chain via hydrogen-bonding contacts involving lattice OH − anion, HO 2 CPh-NH 2 and solvent molecules. This 1D chain exhibits strong antiferromagnetic interactions, and irreversible electron reduction of one iron(III) ion to iron(II) at EP.C = −1.77 V vs SCE. Remarkably, color change from reddish violet to bluish green have been observed for this cluster upon protonating the amino functional groups. [ABSTRACT FROM AUTHOR]

In this study, the potential of oxoanion separation with the ligands N-4-methylbenzyl-4-amino-1,2,4-triazole (L1), N-4-fluorobenzyl-4-amino-1,2,4-triazole (L2), N-4-hydroxy benzyl-4-amino-1,2,4-triazole (L3), and N-3-methoxy-4-hydroxybenzyl-4-amino-1,2,4-triazole (L4) was explored. The salts of sulphate, nitrate, and perchlorate were crystallized in the form of [HL1]+[HSO4]−·H2O, [HL2]+[HSO4]−·H2O, 2[HL3]+[SO4]2−·2(H2O), and 2[HL4]+[SO4]2−·H2O, [HL3]+[NO3]−·H2O and [HL4]+[NO3]−, and [HL3]+[ClO4]− and [HL4]+[ClO4]−, respectively. Competitive crystallization and competitive sulphate-binding experiments demonstrated special recognition of the sulphate–water clusters (in the forms of [HSO4−·H2O]n or [SO42−·H2O]n) via the parallel packed 3-D architectures of HL1+, HL2+, and HL4+ cations, which were far more effective and selective than the non-3-D structure of HL3+ cation. The observed selectivity for sulphate, nitrate, and perchlorate was found to be anti-Hofmeister. In addition, the selective separation of sulphate anions in seawater was investigated, which demonstrated the real-world application of the present strategy. [ABSTRACT FROM AUTHOR]

Three diaryl oxalate derivatives, bis(4-chlorophenyl)oxalate, bis(2, 6-dichlorophenyl)oxalate and bis(2, 4, 6-trichlorophenyl)oxalate, have been synthesized and characterized via X-ray single crystal diffraction, differential scanning calorimetry, thermogravimetric analysis and infrared spectra, for the purpose of studying the influence of chlorine substitution on the crystal structures of diaryl oxalate. This work has demonstrated that, depending on the position and number, chlorine substitution will influence the molecular geometries and stacking modes of diaryl oxalate by tuning the types and numbers of intermolecular interactions. [ABSTRACT FROM AUTHOR]

Investigations of spin-crossover in an iron(II) tris(diimine) system, based on the ligands L 1 (4,5-dimethy-2-(pyridine-2-yl)imidazole) and L 2 (1-acetic ethyl-2-(pyridine-2-yl)-imidazole), have been presented in this paper. The methyl groups at adjacent sites to the donor atoms in the ligand L 1 generated the crossover situation for complexes Fe( L 1 ) 3 (ClO 4 − ) 2 ( 1 ), Fe( L 1 ) 3 (BF 4 − ) 2 ( 2 ), Fe( L 1 ) 3 (PF 6 − ) 2 ( 3 ) and Fe( L 1 ) 3 (SbF 6 − ) 2 ( 4 ), while the acetic ethyl group at the non-coordinating NH site of the ligand L 2 resulted in an increase in the ligand field and generated a low-spin (LS) state for the complex Fe( L 2 ) 3 (ClO 4 − ) 2 ( 5 ). Complexes 1 and 5 were structurally characterized by single-crystal X-ray diffraction at different spin-states, while the phase purity of complexes 2 – 4 was confirmed by PXRD. Raman, IR and UV–Vis absorption spectra and magnetic properties of 1 – 4 were obtained, which revealed the influence of different counter anions on the spin transition temperatures. The blue-shift of IR and Raman spectra, red-shift and decrease in molar absorptivity of UV–Vis absorption spectra all follow the sequence 1 < 3 < 2 < 4 . [ABSTRACT FROM AUTHOR]

Investigation of spin-crossover in iron(II)-di(diamine) system, based on ligands L 1 , 4,5-dimethy-2-(pyridine-2-yl)imidazole, has been presented in this paper. The methyl group at the adjacent sites of the donor atoms in ligand L 1 can generate the crossover situation for the iron(II) tris(diimine) system. While for the iron(II)-di(diamine) system with L 1 , the results are complicated: complex 1 {Fe( L 1 ) 2 (SCN) 2 } displays paramagnetic behavior while 2 {Fe( L 1 ) 2 (SeCN) 2 } is in crossover situation. The difference was attributed to the various ligand field strength of SCN − and SeCN − , which also resulted to the blue-shift of IR and Raman spectra, as well as red-shift and decrease in molar absorptivity of UV–Vis absorption spectrum. [ABSTRACT FROM AUTHOR]

Two iso-structural two-dimensional (2D) porous coordination polymers, which formulated as [Fe(1,3-di(4-pyridyl)propane) 2 (NCX) 2 ] 2 (X = S [ 1 ], Se [ 2 ]) and featured 2-fold interpenetration, have been synthesised and characterized. Crystal structure, Hirshfeld surfaces analysis and magnetic properties of them were described. The basic-unit of 1 and 2 was the 2D rhombic grids [2 × (4, 4)] network, and the intermolecular interactions in the crystals were dominated by C–H…π, H–H and C–H…S (Se) contacts. The stronger ligand field strength of SeCN − than that of SCN − resulted to different magnetic properties: compound 1 shows paramagnetic property while 2 display displays an incomplete SCO transition approximately 30% conversion of high-spin (HS) to low-spin iron(II) sites with transition temperature of 100 K. [ABSTRACT FROM AUTHOR]

The quantitative visualizations and comparisons between the four pyrazinamide (PZA) polymorphs (α, β, γ and δ) have been investigated by graphical tools based on three-dimensional Hirshfeld surfaces and two-dimensional fingerprint plots. The comparisons were performed in terms of crystal structure, d, Shape index, Curvedness and d surfaces, and fingerprint plots. The results revealed that the α and γ forms featured with 1D chains and the π···π stacking motifs belong to γ-motif, rich in π···π interactions and form infinite face-to-face stacks, β and δ forms featured with dimer unit and the π···π stacking motifs belong to γ- and herringbone-motif, respectively, the herringbone motif of δ form rich in C-H···π and edge-to-face interactions. We also correlated the phase transformation points of α, β, and δ PZA forms with the ratio of the percentage surface coverage of the N-H···O hydrogen bonds over that of the N-H···N hydrogen bonds, and found a negative correlation. [ABSTRACT FROM AUTHOR]

Crystal structural investigations and Hirshfeld surface analysis of three methoxy- and methyl-substituted indole-3-acetonitriles (IAN) (4-OCH-IAN, 5-OCH-IAN and 7-CH-IAN) are reported in this work. Their structures were characterized by infrared spectra, elemental analyses, NMR spectra, differential scanning calorimetry, thermogravimetric analyses, and hot stage microscopy. The Hirshfeld surface analysis in terms of intermolecular interactions and π···π stacking motifs of the three substituted IANs was investigated in detail, and the results revealed that the different kinds of substituent groups as well as different substituted positions have a significant effect on the crystal structures, molecular π···π stacking motifs, melting points, and the types of intermolecular interactions. [ABSTRACT FROM AUTHOR]

A new spin crossover coordination polymer (SCO-CPs) of Fe(II)-4,4′-bipyridine (4,4′-bipy) family: {Fe(4,4′-bipy) 2 (H 2 O) 2 }·(4,4′-bipy)· 8(H 2 O)·2(ClO 4 ) ( 3 ), which displays half spin transitions between 100 and 300 K, has been synthesized and structurally characterized. Compound 3 featured with two-dimensional (2-D) grids connected by hydrogen bonds and π … π packing between one-dimensional (1-D) chains, the 2-D grids expand to three-dimensional (3-D) architecture supported by a “S-shaped holder” involving lattice 4-4′-bipy, water molecules and perchlorate anion. We compared 3 with the other two analogous complexes: ({Fe(4,4′-bipy) (H 2 O) 2 (NCS) 2 }·4,4′-bipy, 1 and {Fe(4,4′-bipy) 2 (NCS) 2 }·mSolv, 2 ) through Hirshfeld surfaces analysis, which revealed that the low ligand field strength (NCS − ) and lone-pair…H contacts contribute to the stabilization of HS (high-spin) state of the Fe(II) ion, while the high ligand field strength (4,4′-bipy) and strong intermolecular contacts (hydrogen bonds and π … π packing interactions) make for the LS (low-spin) state. [ABSTRACT FROM AUTHOR]

Guest molecule dependent crystal structures, intermolecular interactions and magnetic properties of an iron (II) coordination polymer ( 2 ) with 4,4′-dipyridyl disulfide (4-DPS) ligand have been investigated. Polymer 2 {[Fe(NCS) 2 (4-PDS) 2 ]·2(2,5-DCP)} n was derived from polymer 1 [Fe(NCS) 2 (4-PDS) 2 ·4H 2 O] n through the change of water molecules by 2,5-dichloropyrazine molecules (2,5-DCP). This substitution leads to the change of the polymer motif from di -triangle to rectangle, and the decrease of longer contacts (S–H, N–H, C–H and H–H) while increase of the π ⋯ π (C–C) contacts in the crystal. These above changes then tuned the electronic structure of the iron (II) ion from high spin (HS) state ( 1 ) to the onset high spin (HS)–low spin (LS) transition ( 2 ), and resulted intermolecular anti-ferromagnetic interactions at lower temperatures. [ABSTRACT FROM AUTHOR]

Crystal structural investigations and Hirshfeld surface analysis of three halogen atoms (4-Cl, 6-Cl and 4-Br) substituted indole-3-acetonitrile (IAN) were reported in this work. The structures of the present three compounds were characterized by Infrared spectra, Elemental analyses, NMR spectra, differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and hot stage microscopy (HSM). The Hirshfeld surfaces analysis in terms of crystal structure, intermolecular interactions and π⋯π stacking motifs were performed. We found that the different kinds of halogen atoms and the different substituted positions have a significant effect on the crystal structures, molecular π⋯π stacking motifs, melting points, and the nature of intermolecular interactions for IANs. [ABSTRACT FROM AUTHOR]

Iron(II)-triazole coordination polymers have attracted considerable interest for their synthetic versatility, which allows tuning their spin-crossover (SCO) properties. Embedding SCO solid particles in sponge matrices is a simple, powerful, and generic approach to construct processable SCO materials. Here, we have studied a series of magnetic frameworks based on partial ligand substitution by using different chemical mixtures of two organic ligands, yielding four isostructural coordination polymers. The integration of the hygroscopic SCO material has endowed the composite sponge with the ability to capture moisture under ambient conditions. In particular, not only does a spin-crossover transition during absorption occur, but also a color variation has been achieved by varying humidity. The consequences of cooperativity and the exposed surface of the composite sponge on the spin transition were evaluated and the most promising materials among them were screened. This work provides guiding significance for the fabrication and practical application of spin-crossover-sponge materials. [ABSTRACT FROM AUTHOR]

CO2 capture and storage have been regarded as promising concepts to reduce anthropogenic CO2 emissions. However, the high cost, inferior adsorption capacity, and higher effective activation temperature of traditional sorbents limit their practical application in efficient CO2 capture. Here, a C‐S‐H@ZIF‐8 (C‐S‐Z) sorbent is fabricated by in situ growth of the ZIF‐8 shell on the C‐S‐H (calcium‐silicate‐hydrate) surface for ultra‐high CO2 adsorption and storage. Among the C‐S‐Z, the outer ZIF‐8 shell acts as a transport channel that promotes CO2 absorption toward the underlying C‐S‐H substrate for accelerated carbonation while preventing nitrogen and water from reaching the interior C‐S‐H. As a consequence, C‐S‐Z possesses the merits of ample pyrrolic nitrogen, porous structure, and ultra‐high surface area (577.18 m2 g−1), that contribute to an ultra‐high CO2 capture capacity, reaching 293.6 mg g−1. DFT calculations show a high CO2 adsorption energy and the mineral carbonation is dominant by the adsorption process. In particular, the advantages of the outstanding adsorption capacity, low cost, and high CO2 selectivity make this C‐S‐H‐based sorbent hold great potential in the practical application for direct air CO2 capture and storage. [ABSTRACT FROM AUTHOR]

Owing to the critical roles it plays for both structure and functionality, hydrogen bonding has high hopes for the orientated applications in hydrogen‐bonded organic frameworks (HOFs). Here in this work, a hydrogen‐bonding strategy is performed for adjusting the structure and functionality of a heme‐like ligand meso‐tetra(carboxy‐phenyl)‐porphyrin (TCPP) with co‐former 1,3‐di(4‐pyridyl) propane (1,3‐DPP). A 3D dynamic HOF TCPP‐1,3–DPP, with permanent porosity is obtained. For this HOF, the two components form novel robust 1D porous stripes, with the 1,3‐DPP molecules acting as the lining for the pores that are confined within the region between adjacent carboxyphenyl moieties of TCPP. This confinement has tuned the affinities of TCPP from hydrophobic into hydrophilic. Interestingly, the 1D stripes are further stacked by weak π...π interactions into a 3D framework, the latter is highly dynamic with 1D stripes sliding back and forth, upon pressurized and water adsorption in the solid‐state under ambient conditions, respectively. The activated TCPP‐1,3–DPP has a Brunauer–Emmett–Teller surface area of 258 m2 g−1, and shows a maximum adsorption capacity about 9.8% for water during the adsorption–desorption cycles, demonstrating a promising candidate for the real‐world application in effective dehydration of industrial gases under ambient conditions. A 3D dynamic hydrogen‐bonded organic framework TCPP‐1,3–DPP, which is composed of 1D porous stripes, shows permanent porosity and highly affinity to water. The activated species exhibit a maximum adsorption capacity about 9.8% for water during the adsorption–desorption cycles, demonstrating a promise for the real‐world application in effective dehydration of industrial gas under ambient condition. [ABSTRACT FROM AUTHOR]

Metal–organic framework nanosheets (MONs) are expected to turn the cornerstone of integrated electronic and optoelectronic devices owing to their unique properties. However, as the premise and guarantee for research applications, adjustable preparation and accurate control of MONs remain a challenge. Here in this work, we demonstrate that the sizes and colors of MONs can be tuned by subtle control of the solution pH (from 3 to 11) during the precursor preparation. Where the variation of the sizes of MONs from nano-scale (lateral size smaller than 200 nm) to micro-scale (lateral size larger than 10 μm) was achieved, which was accompanied by the continuous color variation from green to gray for the solid-state samples, and from orange to pink for the colloidal suspensions. As a result, linear correlations between the sizes and colors of the MONs with the solution pH were established. Laser irradiation experiments further demonstrated the inverse relationship between the fluorescence intensity of MONs and the pH, providing a fairly good strategy for the controlled preparation and color adjustment of MONs. [ABSTRACT FROM AUTHOR]

Photoreversible color‐switching materials, which can reversibly change color in response to external light stimuli, have attracted increasing attention for their applications in time‐sensitive information storage and optical data storage fields. But most of the related materials are dyes or redox compounds with ultraviolet as the light source, dramatically limiting the cycling stability during discoloration processes. To address this problem, a near‐infrared (NIR)‐responsive rewritable paper via doping layered Co‐metal–organic frameworks (MOFs) into the stable polyvinylidene fluoride matrix is reported for the first time. Layered Co‐MOF shows a rapid color‐switching characteristic between orange and black blue upon NIR illumination on/off because of the interlayer spacing changes. Benefiting from the soft network structures of the matrix, Co‐MOF can be homogeneously distributed to deliver an outstanding reversibility performance, including rapid response, coloration in a short period, and decoloration within about 3 min in ambient air. The fabrication of new photoreversible color switching system holds great potential in communication security, which offers a viable pathway to achieve ink‐free photoreversible printing. [ABSTRACT FROM AUTHOR]

Efficient atmospheric water harvesting has been a focal point in the broad spectrum of water collection sources, to alleviate the challenges caused by water shortage. Herein, we report a systematic approach focused on preparing a polymer hydrophobic–hydrophilic gel, doped with super hygroscopic materials (SHMs), enabling high moisture capture, color response, and in situ moisture storage. The hybrid gel quickly achieves a water uptake of 100% under different humidity levels from 43% to 98%. The hybrid gel achieves not only the capture of moisture but also the response of an obvious color change from blue to pink, visible to the naked eye. The interesting properties of the hybrid gel give rise to a wide range of possibilities in design and engineering for humidity capture response and detection application, providing bright prospects for the next generation of atmospheric water harvesting systems. [ABSTRACT FROM AUTHOR]

Humidity visualization is of significant importance across both the living systems and the industrial processes, which remains a huge challenge. Herein, for the first time, a hydrophilic sponge, which is composed of rigid gel and super hygroscopic material, has been demonstrated capable of all‐weather humidity visualization in a portable, convenient, economical, and in situ manner. This promising aspect is attributed to the effective all‐weather humidity capture and various color display as a response to the humidity capture capacity, of the super hygroscopic material; as well as the rapid humidity transport and excellent humidity storage ability provided by the porous rigid gel. As a consequence, combined with a smartphone, the invisible information on the environment's relative humidity levels, on the one hand, can be correlated qualitatively with the specific color display of the sponge; on the other hand, it can be correlated quantitatively with the specific color intensity, providing a pretty good smart model for humidity visualization in various complex environments. The present humidity visualization technology may open up a new avenue for the development of novel humidity sensors with a wide range of practical applications. [ABSTRACT FROM AUTHOR]

Four new complexes based on the 4-(4-carboxyphenyl)-1,2,4-triazole (Hcpt) ligand, {[Co(cpt) 2 (H 2 O) 4 ]·H 2 O}( 1 ), {[Cr(cpt) 2 (H 2 O) 4 ]·10H 2 O}( 2 ), {[Fe(cpt) 2 (H 2 O) 4 ]·10H 2 O}( 3 ), {[Zn(cpt) 2 (H 2 O) 2 ]}( 4 ) have been synthesized and characterized by elemental analysis, single crystal X-ray diffraction and TGA. For complexes 1 , 2 , and 3 , they almost have the same coordination mode that only one nitrogen atom of triazole are involved in the coordination, while in the complex 4 , only the group COO − participates in the coordination. In the crystal structure of 1 , each structural unit[Co(cpt) 2 (H 2 O) 4 ] is linked to another by hydrogen bonding formed by the lattice water molecules, thus forming a one-dimensional chain structure; In the crystal structure of 2 or 3, each structural unit[Cr(cpt) 2 (H 2 O) 4 ] or [Fe(cpt) 2 (H 2 O) 4 ] forms a two-dimensional layered structure by intermolecular hydrogen bonds from the coordinated water molecule and the group COO − . The results of thermogravimetric analysis show that the loss of lattice water and coordinated water molecules in 1 , 2 and 3 is below 120 °C, while the loss of coordinated water molecules in 4 is in the temperature range of 190–260 °C. Hirshfeld surface shows that the N H⋯O hydrogen bonding interaction plays a significant role towards the conformation of the basic structure of these complexes. [ABSTRACT FROM AUTHOR]

Because of the differences in the position and degree of fluorine substitution, four fluorinated DSA (9,10-distyrylanthracene) derivatives, namely 9,10-bis(4-fluorostyryl)anthracene (4-BFSA), 9,10-bis(3-fluorostyryl)anthracene (3-BFSA), 9,10-bis(3,5-difluorostyryl)anthracene (BDFSA) and 9,10-bis(3,4,5-trifluorostyryl)anthracene (BTFSA), display different crystal packing and photophysical properties in the solid state. Furthermore, the photophysical properties in solution have been investigated. The results show that all the four compounds exhibit tunable aggregation-induced enhanced emission (AIEE) properties. Notably, DSA, 4-BFSA, 3-BFSA and BDFSA display solvatochromic properties. The relationship between their structures and photophysical properties was further discussed. This work has demonstrated that depending on the amount and position, fluorine substitution can tune the structures and photophysical properties of DSA effectively. [ABSTRACT FROM AUTHOR]

Two complexes 1 [Cu(L1)2(H2O)2]·2H2O and 2 [Co(L2)2 (H2O)4]·4H2O formed by hetero N- and O-donor ligands 1-methyl-3-imidazole-4-carboxylic acid (L1H) and 2-methyl-5-pyridine carboxylic acid (L2H) have been synthesized and characterized by elemental analysis and single-crystal X-ray diffraction. These two complexes consist of a 2:1 ratio of ligand to metal ion. The analysis of Hirshfeld surfaces and crystal structures reveal that O‒H···O hydrogen bond interactions and C‒H···π intermolecular interactions support the three-dimensional supramolecular structures of complexes 1 and 2. Meanwhile, the coordinated water molecules and lattice water molecules play a key role in the construction of their crystal structures. [ABSTRACT FROM AUTHOR]

Two new mononuclear iron (II) coordination complexes: Fe(L1)2(SCN)2(1, L1:5-dimethylether-4-(4-methylphenyl)-3-(2-pyridinyl)-1,2,4-triazole) and Fe(L2)3(ClO4)2(2, L2:1-ethyl acetate-2-(2-pyridinyl)-imidazole), for the exploration of spin-crossover compounds have been synthesized and characterized. Structural analysis revealed that the framework of complex1is featured with 1-D chain structure connected by weak π···π interactions between the adjacent L1ligands, while complex2featured with various kinds of weak intermolecular hydrogen bonding interactions between Fe(L2)32+cation and ClO4−anion, which lead to a close crystal packing. The intermolecular interactions have shown a significant influence on the physical properties, and magnetic measurements of complexes1and2in the solid state at the room temperature revealed that the weak intermolecular interactions in1resulted in HS (high-spin) state, while the strong interactions in2lead to LS (low-spin) state over the whole temperature range. [ABSTRACT FROM PUBLISHER]

The compound {[Zn(μ-dicyanamide)(pyrazinamide)](pyrazinamide)} has been synthesized and further characterized by elemental analysis, single-crystal X-ray diffraction, and thermogravimetric analysis. Structural analysis revealed that the dicyanamide anion acted as bridging ligand in a μ-1,5 mode, resulting a polymeric 1-D chain structure. The pairwise N3-H3B···N1 and N9-H9B···N7, N3-H3A···O2 and N9-H9A···O1, N3-H3B···N7 and N9-H9B···N1 multiple hydrogen bonding interactions, impart enhanced stability to supramolecular structures. Hirshfeld surfaces and fingerprint plots were applied to arrive at the same conclusion, which is stabilised mainly by H-H, N-H, O-H interactions. DNA binding studies showed that the compound had interacted with DNA. [ABSTRACT FROM AUTHOR]

A series of Fe(II) complexes with (ClO4)−(SeCN)−, (ClO4)−(SCN)−, (Fe2OCl6)2−, and 2(BF4)−counter-anions for complexes1–4, derived from dmbpy (4,4′-dimethyl-2,2′-bipyridine), were prepared. The single-crystal studies and the Hirshfeld surfaces analysis revealed that the (Fe2OCl6)2−anion results more distortional octahedral geometry of the cation than other anions. In particular, the (ClO4)−(SCN)−and (Fe2OCl6)2−anions lead to complexes2and3stabilized via C-H···π interactions and π···π interactions, which were not found in the other two complexes. However, the double-chain structure of complex4was formed by C-H···F and C-H···C hydrogen bonds interactions. Due to the influence of different anions, magnetic susceptibility measurements showed that complex1was in high-spin (HS) state and complex2was in low-spin (LS) state. [ABSTRACT FROM PUBLISHER]

Four novel lanthanide compounds based on the 4-(4-carboxyphenyl)-1,2,4-triazole ligand (Hcpt), {[Pr2(cpt)4(H2O)10]·10H2O·2ClO4} (1), {[Ln(cpt)2(H2O)2(OH)]·4H2O}n (Ln = Er(2), Lu(3)), and {[Sm(cpt)2(CH3CH2OH)(H2O)3]·ClO4}n (4), have been obtained under hydrothermal conditions and further characterized by elemental analysis, single-crystal X-ray diffraction and thermogravimetric analysis. Compound 1 exhibits a discrete dinuclear structure constructed by one cpt− ligand coordinated to two Pr3+ ions and another cpt− ligand coordinated to more than one Pr3+ ion. Compounds 2 and 3 are isomorphous and every cpt− ligand coordinates to two Ln3+ ions, resulting in a polymeric 1-D chain structure. Different from the above compounds, the nitrogen atoms of triazole are also involved in the coordination of compound 4. One cpt− ligand coordinates to two Sm3+ ions and another cpt− ligand coordinates to more than one Sm3+ ion, meanwhile, the nitrogen atoms of triazole coordinate to the third Sm3+ ion, resulting in a 2-D polymeric network structure. The luminescence properties of compound 4 were characterized, and the results revealed that it exhibited characteristic Sm3+ emission in the yellow region. [ABSTRACT FROM AUTHOR]

Four DSA (9,10-distyrylanthracene) derivatives, namely 9,10-bis(4-fluorostyryl)anthracene (BFSA), 9,10-bis(4-chlorostyryl)anthracene (BCSA), 9,10-bis(4-bromostyryl)anthracene (BBSA) and 9,10-bis(4-iodostyryl)anthracene (BISA) have been synthesized and characterized via single crystal X-ray diffraction, powder X-ray diffraction, differential scanning calorimetry, photoluminescence spectroscopy, ultraviolet-visible absorption spectroscopy, solid fluorescence quantum yield measurement and other techniques, for the purpose of studying the influence of halogen atoms on the structures and photophysical properties of 9,10-distyrylanthracene. The results indicate that the introduction of halogen atoms into DSA significantly influences the molecular geometries and stacking modes in the crystals. The photophysical properties in solution and in the crystalline state of the five compounds were comparatively investigated, and the relationship between the crystalline state emissions and crystal structures was further discussed. This work has demonstrated that the introduction of halogen atoms into DSA could influence the molecular packing and molecular geometries in the crystals and endow them with different photophysical properties. [ABSTRACT FROM AUTHOR]

We here reported a series of co-crystal structure of pyrazinamide (PZA) with m-hydroxybenzoic acid (MHBA), p-hydroxybenzoic acid (PHBA) and 3,4-dihydroxy benzolic acid (3,4-DHBA) and obtained three co-crystals (co-crystal 1- 3, respectively) under the same conditions. These crystal structures were characterized by single-crystal X-ray diffraction, IR spectra, thermogravimetric analyses, differential scanning calorimetry, and Raman spectrum analysis. The images of single crystal diffraction revealed that 1 was a 1:1 (PZA:MHBA) co-crystal, 2 was a 1:1 (PZA:PHBA) co-crystal, and 3 was a 1:1 (PZA:3,4-DHBA). The strong O-H···O, N-H···O hydrogen bonding interactions between PZA and hydroxyl-substituted benzoic acid primarily made the structure of co-crystals stabilized. Hirshfeld surface and fingerprint plots of the three co-crystals showed that the structures were stabilized by H···H, O-H···O, N-H···O C-H···π, and π···π intermolecular interactions. [ABSTRACT FROM AUTHOR]

• Establishing a set of models of supramolecular complexes to further study substituent effect on the formation process of co-crystals. • Providing a widely applicable method for modifying industrial raw materials, finished products and auxiliary products. • Co-crystal strategy has been proven to be effective in the field of Spice Modification, improving the stability and release characteristics of traditional flavoring agents. Co-crystallizations of 2,3,5,6-tetramethyl pyrazin (TMP) with different substituted aromatic compounds [3,5-dinitrosalicylic acid (DNS), 5-chlorosalicylic acid (CSA) and 3,5-dichlorosalicylic acid (DCA)] have been performed, resulting in the formation of three co-crystals (TMP : DNS = 1:1 for 1 ; TMP : CSA = 1:2 for 2 ; TMP : DCA = 1:2 for 3). Those newly co-crystals were characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analyses (TGA), UV–Vis spectroscopy and X-ray diffraction (XRD). The Hirshfeld surface analysis revealed that N–H∙∙∙O/O–H∙∙∙N strong hydrogen bonds and other intermolecular interactions such as H∙∙∙H, C–H∙∙∙π, π∙∙∙π and lone-pair∙∙∙π participated in a cooperative way to stabilize the supramolecular structures. Additionally, thermodynamic results indicated that the halogen bonding exerted a positive effect on the stability of co-crystal structures, further improving the release process of pyrazine spices. This work provided a co-crystal strategy for the solidification of liquid pyrazine-related spices for broader applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Developing versatile printing inks with good biocompatibility is essential for the fabrication of functional colored contact lenses. In this work, by employing a new kind of printing ink that shows humidity-induced discoloration, multifunctional colored contact lenses have been constructed. The obtained products have displayed distinct and stable all-weather humidity-triggered discoloration under ambient conditions. More importantly, combined with a smartphone, the quantitative and qualitative relationship between the discoloration of colored contact lenses and environmental humidity has been established, which is expected to realize the early prediction of humidity-related eye diseases in a portable, economical, and in-situ manner. • A new kind of printing ink that shows humidity-induced discoloration has been prepared. • The colored contact lens with all-weather humidity-triggered discoloration has been constructed. • The quantitative and qualitative relationship between the discoloration of colored contact lenses and environmental humidity has been established. [ABSTRACT FROM AUTHOR]

• Efficient mercury capture by ultrathin 2D nanosheets has been presented. • Highly uptake capacity and extremely fast kinetics have been observed. • Practically applicable recycling ability have been demonstrated. • The challenging goal of "turning waste into treasure" has been achieved. The retrieval of toxic heavy metals ions from aqueous resources effectively and facilely, by using low-cost, robust, and efficient technologies, is imperative and of significant environmental and societal importance. Adding on, the comprehensive utilization of the captured heavy metals remains a huge challenge. Herein, we demonstrate that the single-layered sulfur-rich two-dimensional (2D) metal-organic frameworks (MOFs) nanosheets 2D-NCS ({[Co(NCS) 2 (pyz) 2 ]} n) (pyz = pyrazine), which featured with the merits of ultrahigh sulfur content (19.1%), tremendous affinity of thiocyanate group, and fully accessible chelating sites arrayed on the double surfaces of the nanosheets, serving as an ideal adsorbent materials for mercury chloride capture from aqueous solution, with considerable capacity, efficiency, effectivity and recycling ability. The maximum uptake capacity is found to be 1698 mg g−1, accompanied by high affinity (K d value of 2.26 × 106 mL g−1) and extremely fast kinetics (reduce the mercury concentration from 10 ppm to 1 ppb within 15 min). More importantly, 2D-NCS can act as versatile building blocks for the construction of solid three-dimensional porous architecture 2D-NCS@Hg , achieving the challenging goal of "turning waste into treasure". These results have demonstrated the enormous potential of ultrathin 2D MOFs nanosheets for high-performance environmental remediation. [ABSTRACT FROM AUTHOR]

Abstract A new complex [Fe(CN) 2 (bipy-NH 2) 2 ] (2 , bipy-NH 2 = 4, 4′-diamino-2, 2′-bipyridine), which was designed through ligand exchange strategy, has been prepared and characterized. The magnetism properties of 2 have been tuned through protonate the amino groups on bipy-NH 2 ligand with HCl in stoichiometric ratio 2 :HCl below 1:1. Further increase the ratio exceed 1:1 has induced the distortion of the bipy-ammonium moieties in bipy-NH 3 2+ cation, with the dihedral angle involving the mean plane change from 0° to 37°. This distortion, on the one hand, responsible for the decomposition of 2 , on the other hand, take charge the break of the precursor complex 1 ([Fe(H 2 Bpz 2) 2 (bipy-NH 2)]) (pz = pyrazolyl) upon protonation. Graphical abstract Tuning the magnetism properties of a new complex [Fe(CN) 2 (bipy-NH 2) 2 ] (2) through protonation of the ligand bipy-NH 2 with HCl have been investigated with stoichiometric ratio of 2 :HCl below 1:1. While once the ratio larger than 1:1, ligand bipy-NH 2 has distorted with the mean plane of bipy-ammonium moieties to form a dihedral angle large to be 37°. Unlabelled Image Highlights • The protonation of a Fe(II) complex has been investigated. • The mechanism of protonation induced decomposition of Fe(II) complex has been proposed. • The mean plane of bipy-ammonium moieties has been distorted with dihedral angle large to be 37°. [ABSTRACT FROM AUTHOR]

A new complex of the title system ([2(H 3 O + )·18-crown-6]·2[BF 4 − ]), which was induced by external magnetic field, has been prepared and characterized. When compared with other two members of the same system, the proton transfer induced by magnetic field from HBF 4 to H 2 O has leads to the co-plane of six oxygen atoms in the crown and stronger H F and O F intermolecular interactions, which can be attributed to the closer contacts between 18-crown-6, oxonium ion H 3 O + and counterion BF 4 − . In addition, a compression effect of crystals stacking has been observed. These results are of importance for the evaluation the effect of magnetic field on the host–guest systems. [ABSTRACT FROM AUTHOR]

In this work, two new single crystals of copper-tetraphenylporphine (Cu-TPP) (crystals 2 and 3), which were induced by external magnetic fields with strengths of 0.5 and 0.8 T, respectively, have been prepared and characterized by single-crystal X-ray diffraction and Hirshfeld surface analysis. Compared with the original Cu-TPP (crystal 1), crystals 2 and 3 exhibit significant differences in their unit cell parameters, crystalline stacking styles and intermolecular interactions, resulting in a “compressed” crystal packing. Here, the number of closer interactions (H…H, C…H/H…C) increased with the magnetic field strength, accompanied by a decrease in the number of π…π (C…C) interactions as a sacrifice. On considering the results of our previous work, the results here suggest that a magnetic field has a different influence on the crystallization process of mono-component and multi-component materials, which will certainly provide some suggestions for the design of crystallization strategies for other materials with the presence of an external magnetic field. [ABSTRACT FROM AUTHOR]

Two zinc (II) pseudo-halide complexes [Zn( L 1 )(N 3 ) 2 ] n ( 1 L 1 : 1,2-diaminocyclohexane) and Zn( L 2 ) 2 (N 3 ) 2 ( 2 L 2 : 4,5-dimethy-2-(pyridine-2-yl) imidazole) have been synthesized and characterized. Single-crystal X-ray structural analysis revealed that the central Zn II atoms in 1 displays distorted trigonal bipyramidal arrangement with a 1D chain structure bridged by N 3 − anions, while in 2 , the central Zn II atoms incorporating with two bidentate L 2 ligands, and adopts an octahedral geometry and shows a “butterfly” coordination framework. Structural analysis demonstrated that the organic ligands play an important role in determining the resultant structure. In addition, both complexes were further characterized by thermal stability properties and Hirshfeld surface analysis. [ABSTRACT FROM AUTHOR]

An investigation into the effect of switching methoxy and hydroxyl groups on molecular salts is presented in this study. The salts HL1+·NO3− (1), L1·HL1+·ClO4− (2), L1·HL1+·H2PO4−·H2O (3), HL2+·NO3− (4), HL2+·ClO4− (5) and HL2+·H2PO4− (6) were synthesized and structurally characterized. The study was carried out by analyzing the crystal structure, properties and intermolecular interactions within each of the salts using IR and fluorescence spectra, TGA, Hirshfeld surface analyses and π…π stacking motifs. Salt 1 has a layered structure, while 4 has a distorted 3-D structure. Salt 2 possesses an edge-to-face type plane interaction, while 5 is formed with a twisted structure. It is important to note that water molecules play a key role in the 1-D chain structure of salt 3. The π…π stacking motif of salts 1–3 have a herringbone structure, while salts 3–6 exhibit a γ-structure. In addition, the competitive crystallization of the synthetic salts was investigated and found to be consistent with the measured solubility. [ABSTRACT FROM AUTHOR]

By using the ligands 4-(4-bromobenzylideneamino)-4H-1,2,4-triazole (L1) and 4-(4-iodobenzylideneamino)-4H-1,2,4-triazole (L2), four different organic salts HL1+·Cl− (1), L1·HL1+·ClO4− (2), HL2+·Cl− (3), and L2·HL2+·ClO4− (4) have been synthesized and structurally characterized through single-crystal X-ray diffraction (L1, L2, 2 and 3) and PXRD (1 and 4) measurements. The results revealed that ligands L1 and L2 themselves exhibit a polymeric 1-D chain in a zigzag structure connected by C–Br…N and C–I…N halogen-bonding contacts, respectively. L1 in salt 2 was connected into a 3-D structure through N–H…O hydrogen-bonding contacts, while the interleaved 3-D network of L2 in salt 3 was mainly connected by C–I…Cl halogen-bonding contacts. As a result, the fluorescence properties of ligands L1 and L2 were reserved in halogen-bonding connected salts 1 and 3, while there was a reduction in hydrogen-bonding connected salts 2 and 4. Thus, the relationship between emission properties and halogen-bonding contacts can be proposed. [ABSTRACT FROM AUTHOR]

Fluorescent materials have many interesting applications, but it remains difficult to control the luminescence of organic materials and in particular to retain the same luminescence in solution and in the solid state, a property of interest for various imaging applications. In this work, the influence of inorganic-anions on the crystal structure and physical–chemical properties of a series organic salts L + Cl − ( 1 ), L + ClO 4 − ( 2 ), L + NO 3 − ·H 2 O ( 3 ), 2 L + SO 4 2− ·2H 2 O ( 4 ) ( L = 4-[(4H-1,2,4-triazol-4-ylimino)methyl]phenol) has been investigated. Single crystal X-ray analyzes revealed that salt 1 formed a linear structure connected by H⋯O interactions, while salts 2 – 4 all formed 2D network structures through O⋯O interactions. The protonated L + s adopt face-to-face slipped π-stacked arrangement in salts 1 and 3 , while display monomer arrangements in 2 and 4 , the latter can be attribute to the entrapment of heavy anions in the crystal lattices. Optical-properties measurements of these four salts have shown L + arrangements dependent on solid-state properties: salt 1 and 3 show broad emission bands ( λ 1 = 478 nm, λ 2 = 487 nm) with a red shift of about 60 nm relative to its fluorescence in solvents, while 2 and 4 are similar to each other, exhibiting sharp bands ( λ 3 = 453 nm, λ 2 = 433 nm) with the higher ϕ PL values ( ϕ PL1 = 0.08, ϕ PL1 = 0.15, ϕ PL1 = 0.06, ϕ PL1 = 0.14). These results demonstrated the significant influence of inorganic-anions on the organic salts and the optical properties of organic materials could be modulated by entrapping different anions in lattice. [ABSTRACT FROM AUTHOR]

In the present study, the assembly of 6-aminonicotinic acid with inorganic acids (HBr, HNO 3 and H 3 PO 4 ) has been performed, which resulted in the molecular salts C 6 H 7 N 2 O 2 + ·Br − ( 1 ), C 6 H 7 N 2 O 2 + ·NO 3 − ( 2 ) and C 6 H 7 N 2 O 2 + ·H 2 PO 4 − ( 3 ), respectively. These three molecular salts have been characterized by single-crystal X-ray diffraction, differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and UV–Vis absorption spectroscopy (UV). The results revealed that molecular salt 1 exhibits an infinite 1-D chain structure stabilized mainly by N–H⋯Br contacts, while 2 and 3 show a 2-D network and a 3-D stereoscopic framework, respectively, which are stabilized mainly by strong N–H⋯O hydrogen bonding contacts. Hirshfeld surface analysis demonstrated the presence of H⋯H, O–H⋯N, C–H⋯π and π⋯π intermolecular interactions. In addition, the UV–Vis spectra exhibit a slight blue-shift to a shorter wavelength, which suggests the clear influence of the inorganic anions. [ABSTRACT FROM AUTHOR]

The co-crystallization of a benzimidazole derivative ( 1, CHNO, 3-[[[2-[[(4-Cyanophenyl) amino]methyl]-1-methyl-1H-benzimidazol-5-yl]carbonyl]pyridin-2-ylamino]propionic acid ethyl ester), with fumaric acid (FA) and maleic acid (MA), has been performed. The FA and MA molecules, both are connected with two molecules of CHNO, giving birth to a three-components compound ( 1·0.5FA, CHNO) and a four-components compound ( 1·MA, CHNO). Single-crystal X-ray diffractions show that the three different planar moieties (4-cyanophenyl, benzimidazol, and pyridin-2-yl) in compound CHNO display ' cis-form' conformation ( a) in the crystal of 1, while exhibiting 'intermediate-state' conformation ( b) and ' trans-form' conformation ( c) in compounds 1·0.5FA and 1·MA, respectively. Hirshfeld surfaces analysis, DFT calculations, DSC measurements, IR and Raman spectroscopy were performed, which revealed that the thermal stability of the three conformations follows the order c > b > a. [ABSTRACT FROM AUTHOR]

Four new complexes, [Co(dmbpy) 2 (dca) 2 ]·CH 3 OH ( 1 ), [Ni(dmbpy) 2 (dca) 2 ]·CH 3 OH ( 2 ), [Zn(dmbpy) 2 (dca) 2 ]·( 3 ) and [Cu(dmbpy) 2 (OH) 2 ]·5H 2 O ( 4 ) (dca = dicyanamide), derived from 4,4′-dimethyl-2,2′-bipyridine (dmbpy) have been synthesized and characterized by elemental analysis, TGA and single-crystal X-ray diffraction. Crystal structures and Hirshfeld surfaces analysis revealed that the complexes 1 – 3 were mainly supported by O H ⋯ N, C H ⋯ N and π ⋯ π intermolecular interactions, and for complex 4 , the uncoordinated water molecules play a key role in the construction of the 3D stacking motif. UV spectrum measurements demonstrate that all of the complexes show typical metal to ligand charge transfer (MLCT) absorption bands between 301 and 306 nm. Moreover, after complexation, the absorption maximum bands about intraligand π → π* transitions similarly show slightly red shift compared to dmbpy ligand, consisting with the DFT calculations. [ABSTRACT FROM AUTHOR]

Single crystals of compound L (CHN): 4-(2-benzimidazole)-1,2,4-triazole and its hydrate were obtained via slow evaporation. The structures of the crystals were characterized by IR, TGA/DSC and X-ray diffraction analysis. Molecules in crystal 1 are linked by a combination of N-H···N and C-H···N hydrogen bonds into 2D layers, and further stacked into a 3D structure by π··· π stacking interactions. Compared to crystal 1, the water molecules play a key role in the construction of the crystal structure of hydrate 2. The 2D layers were formed via O-H···N, O-H···O, N-H···N hydrogen bonds, and further stacked by O-H···O hydrogen bonds and π··· π stacking interactions in crystal 2. A detailed analysis of the intermolecular interactions and crystal packing via Hirshfeld surface analysis and fingerprint plots reveals that the structures are stabilized mainly by N···H/H···N, C···H/H···C hydrogen bonds, H···H weak interactions and π··· π stacking interactions. [ABSTRACT FROM AUTHOR]

2,3-Dimethylpyrazine and 1,2-bis(4-pyridyl)ethane are both N-containing aromatic heterocyclics with two N atoms approximately in the para position. We here report two compounds derived from these heterocyclics (compounds 1 and 2). Compounds 1 and 2 both form a 1:1 2,3-dimethylpyrazine:perchloric acid (PA) and 1,2-bis(4-pyridyl)ethane:PA cocrystal, respectively. Their crystal structures were characterized by single-crystal X-ray diffraction, which revealed that the C-H⋯O and N-H⋯O hydrogen bonding interactions were found to stabilize the crystal structure in compounds 1 and 2. However, PA plays a necessary role for the one-dimensional structure in 1 and the three-dimensional structure in 2. Hirshfeld surfaces and fingerprint plots were applied to get the same conclusion. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) MOFs nanosheets are prosperous regarding the novel peculiarity of nano-interface and broad development prospects, but the key to achieving the control and design of 2D nanomaterials' morphology is still arduous. In this work, we prepared two complexes contained pyrazine ligand, namely Ni(pyz) 2 Cl 2 and Ni(pyz) 2 Br 2 (pyz = pyrazine), which derived from a synthesis of bridged pyrazine and nickel halogen nide. 2D nanomaterials of them were obtained by using the liquid phase exfoliation method to feature a series of structure and surface morphology. We investigated the difference in physical and chemical properties between 2D MOFs nanomaterials and bulk materials, and studied the influence of different halogen interactions on the morphology of nanomaterials. The results showed that the stacking force and electronic transition have made a significant influence on the 2D nanomaterials. [Display omitted] • Ultra-thin 2D nanosheets of Ni-based MOFs have been prepared. • The correlation between halogen interactions and morphologies of 2D nanosheets has been proposed. • The influence of halogen interactions on the properties of 2D nanosheets has been demonstrated. [ABSTRACT FROM AUTHOR]