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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]

Smart materials and devices play an increasingly important role in improving modern life due to their richer functions, enhanced controllability, and improved biocompatibility. Herein, calcium silicate hydration (C–S–H) is integrated with layered [Co(NCS)2(pyrazine)2]n metal–organic frameworks (Co–MOF) and polymeric skeleton to fabricate the smart building material (M–C–S–H). C–S–H was anchored on the polymeric skeleton to reinforce the network structure for enhanced mechanical strength and toughness. Simultaneously, the highly porous skeleton structure enables the uniform distribution of layered Co–MOF, which could maintain its molecular form to endow the M–C–S–H with the photoresponsive color‐switching performance. The M–C–S–H as a smart building material exhibits the color change between light blue and black blue upon near‐infrared illumination on/off within a wide temperature range to achieve personalized wall and building decoration. Taking advantage of the low cost, rapid response, outstanding reversibility, and good color stability, M–C–S–H could provide lively, dynamic, and changeable decorating effects for walls and buildings. [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]

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]

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]

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]

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]

In the title mol-ecular salt (systematic name: 3-{2-[4-(6-fluoro-1,2-benzoxazol-3-yl)piperidin-1-yl]eth-yl}-9-hy-droxy-2-methyl-1,6,7,8,9,9a-hexa-hydro-pyrido[1,2-a]pyrimidin-4-one nitrate), C(23)H(29)FN(4)O(3) (+)·NO(3) (-), the piperidine ring displays a chair conformation and its N atom is protonated; the N-H bond is in an axial orientation. The ring bearing the hy-droxy group exhibits a half-chair conformation. The hy-droxy group as well as the adjacent methyl-ene group are disordered over two sets of sites in a 0.823 (5):0.177 (5) ratio. In the crystal, O-H⋯N, O-H⋯O, N-H⋯O and N-H⋯N hydrogen bonds connect the components into a three-dimensional network.

In the title compound, C(9)H(6)FNO(2), all the non-H atoms are approximately coplanar, the carb-oxy O atoms deviating by 0.0809 and -0.1279 Å from the indole plane. In the crystal, O-H⋯O hydrogen bonds link the mol-ecules into dimers which are linked via N-H⋯O hydrogen bonds and π-π inter-actions [centroid-centroid distance = 3.680 (2) Å].

The title compound, C(16)H(13)N, is essentially planar [maximum deviation from the least-squares plane = 0.081 (3) Å], with a dihedral angle of 1.65 (13)° between the planes of the indole and benzene rings. In the crystal, there are no significant inter-molecular π-π inter-actions [minimum ring centroid-centroid separation = 4.217 (5) Å].

The title compound, C(10)H(7)ClN(2), contains two approximately planar mol-ecules, A and B (r.m.s. deviations = 0.039 and 0.064 Å, respectively) in the asymmetric unit. In the crystal, N-H⋯N hydrogen bonds link the mol-ecules into C(7) chains of alternating A and B mol-ecules propagating along the a-axis direction. The crystal used for the data collection was found to be a racemic twin.

In the title compound, C(10)H(7)ClN(2), the carbonitrile group is twisted away from the plane of the indole ring system [C(cy)-C(me)-C(ar)-C(ar) = -44.7 (8)°; cy = cyanide, me = methyl-ene and ar = aromatic]. In the crystal, N-H⋯N hydrogen bonds link the mol-ecules into C(7) chains propagating in [010]. Aromatic π-π stacking inter-actions [minimum centroid-centroid separation = 3.663 (3) Å] are also observed.

In the title compound, C(9)H(6)FNO(2), the carboxyl group is twisted slightly away from the indole-ring plane [dihedral angle = 7.39 (10)°]. In the crystal, carboxyl inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R(2) (2)(8) loops and N-H⋯O hydrogen bonds connect the dimers into (10[Formula: see text]) sheets.

In the title compound, C(11)H(10)N(2)O, the O atom and the C atom of the methyl-ene group deviate only slightly [0.029 (3) and 0.055 (3) Å, respectively] from the approximately planar ring system (r.m.s. deviation = 0.013 Å). In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into zigzag chains running along the b axis.

In the title compound, C(17)H(12)N(2), the inter-planar angle between the indole mean plane [max.deviation 0.030 (1) Å] and the phenyl ring is 24.32 (7)°. In the crystal, inter-molecular N-H⋯N C hydrogen bonds form zigzag chains in the a-axis direction augmented by weak C-H⋯N C contacts.

In the title compound, C(11)H(10)N(2)O, the cyanide group is twisted away from the indole-ring plane [C(cy)-C(me)-C(ar)-C(ar) = 70.7 (2)°; cy = cyanide, me = methyl-ene, ar = aromatic], whereas the meth-oxy C atom is almost coplanar with the ring system [displacement = 0.014 (5) Å]. In the crystal, N-H⋯N hydrogen bonds link the mol-ecules into C(7) chains propagating in [100].

In the title compound, C(11)H(10)N(2), the carbonitrile group is twisted away from the indole plane [C(cy)-C(me)-C(ar)-C(ar) = 66.6 (2)°; cy = cyanide, me = methyl-ene and ar = aromatic]. In the crystal, N-H⋯N hydrogen bonds link the mol-ecules into C(7) chains propagating in the [001] direction.

In the title compound, C(9)H(6)ClNO, the Cl atom deviates by 0.142 (1) Å from the quinoline ring mean plane (r.m.s. deviation = 0.013 Å). In the crystal, N-H⋯O hydrogen bonds link the mol-ecules into [010] C(4) chains. Aromatic π-π stacking inter-actions [shortest centroid⋯centroid distance = 3.685 (3) Å] are also observed.

In the title compound, C(9)H(6)ClNO(2), the carboxyl group is twisted from the indole ring system by 9.00 (8)°. In the crystal, inversion dimers linked by pairs of O-H⋯O hydrogen bonds generate R(2) (2)(8) loops and N-H⋯O hydrogen bonds link the dimers into (001) sheets. Aromatic π-π stacking inter-actions [centroid-centroid distance = 3.7185 (12) A °] are also observed.

In the crystal structure of the title compound, C(8)H(5)NO(6), both carboxyl groups are involved in inter-molecular centrosymmetric cyclic O-H⋯O hydrogen-bonding associations, which give a zigzag chain structure extending along (2[Formula: see text]1). Weak π-π stacking inter-actions are also present [minimum ring centroid separation = 3.893 (4) Å].

In the crystal structure of the title compound, C(5)H(5)NO(3), all the non-H atoms are approximately coplanar: the carb-oxy O atoms deviating by 0.013 (2) and -0.075 (2) Å from the isoxazole ring plane. In the crystal, the molecules form inversion dimers linked by pairs of O-H⋯O hydrogen bonds and the dimers stack via π-π inter-actions [centroid-centroid distance = 3.234 (2) Å].

All non-H atoms of the title compound, C(7)H(7)NO(2), are nearly coplaner, the r.m.s. deviation being 0.0087 Å. In the crystal, the partially overlapped arrangement and the face-to-face distance of 3.466 (17) Å between parallel pyridine rings of neighboring mol-ecules indicates the existence of π-π stacking. Inter-molecular O-H⋯N hydrogen bonding and weak C-H⋯O hydrogen bonding are present in the crystal structure.

In the title compound, C(7)H(5)Br(4)NO(2), intra-molecular O-H⋯N hydrogen bonds are observed. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into dimers.

In the title compound, [CoCl(2)(C(13)H(20)N(4))]·H(2)O, the Co(II) atom lies on a mirror plane and is four-coordinated by two N atoms of the imidazole ligand and two Cl atoms in a distorted tetra-hedral arrangement. The water mol-ecule participates in the formation of hydrogen bonds, resulting in a three dimensional network involving the Cl atoms and the NH groups. The terminal C atom of the ethyl group is disordered over two sites of equal occupancy.

In the title compound, [Ni(NO(3))(C(13)H(20)N(4))(2)]NO(3), the Ni(II) ion shows a distorted octa-hedral geometry formed by four N atoms from two bis-(2-ethyl-5-methyl-1H-imidazol-4-yl)methane ligands and two O atoms from a chelating nitrate anion. Three ethyl groups in the complex cation and the O atoms of the uncoordinated nitrate anion are disordered over two sets of positions [occupancy ratios of 0.52 (3):0.48 (3) and 0.63 (3):0.37 (3), respectively]. In the crystal, inter-molecular N-H⋯O hydrogen bonds connect the complex cations into a zigzag chain along [010] and further N-H⋯O hydrogen bonds between the chains and the uncoordinated nitrate anions lead to layers parallel to (100).

In the title compound, [Cu(C(2)O(4))(C(13)H(20)N(4))(H(2)O)]·2H(2)O, the Cu(II) atom exhibits a distorted square-pyramidal geometry with the two N atoms of the imidazole ligand and the two O atoms of the oxalate ligand forming the basal plane, while the O atom of the coordinated water mol-ecule is in an apical position. The Cu(II) atom is shifted 0.232 (2) Å out of the basal plane toward the water mol-ecule. The asymmetric unit is completed by two solvent water mol-ecules. These water mol-ecules participate in the formation of an intricate three-dimensionnal network of hydrogen bonds involving the coordinated water mol-ecule and the NH groups.