Designing Modular Lattice Systems with Chiral Space Groups

Herein, a novel mechano-responsive luminescent (MRL) material based on crystal-to-crystal phase transitions between crystals of a chiral and those of a centrosymmetric space group, accompanied by a change of emission properties, is described. Initially, a gold complex containing a biphenyl moiety, which exhibits an achiral structure in solution, afforded an orange-emitting amorphous phase together with a viscous isotropic oil after evaporation of the solvent. Upon pricking, the orange-emitting oil spontaneously crystallized either in a centrosymmetric or in a chiral space group while simultaneously changing the emission properties. Remarkably, grinding the chiral crystals induced a solid-state phase transition to the achiral crystals under concomitant changes of the emission properties.

The molten reaction of 2-naphthol, 4-(aminomethyl)pyridine, and 4-pyridinecarboxaldehyde at about 180 degrees C yields trans-2,3-dihydro-2,3-di(4'-pyridyl)benzo[e]indole (1) which possesses two chiral centers, rather than an expected Betti-type reaction product with only one chiral carbon center. The same reactions, using 3-pyridinecarboxaldehyde, 4-cyanobenzaldehyde, or 3- cyanobenzaldehyde instead of 4-pyridinecarboxaldehyde produce the related compounds trans-2,3-dihydro-2-(4'-pyridyl)-3-(3"-pyridyl)benzo[e]indole (2), trans-2,3-dihydro-2-(4'-pyridyl)-3-(4"-cyanophenyl)benzo[e]indole (3), and trans-2,3-dihydro-2-(4'-pyridyl)-3-(3"-cyanophenyl)benzo[e]indole (4), respectively. This reaction proceeds with a high degree of stereoselectivity with a trans/cis ratio of about 98:2 at elevated temperature. Compounds 1, 2, and 4 crystallize in a noncentrosymmetric space group (Pca2(1), Pca2(1), and Cc), while compound 3 has a chiral space group (P2(1)). These successfully acentric packing arrangements are probably due to the molecule bearing both two chiral centers and potential hydrogen-bonding groups. Furthermore, the reaction of racemic 6-hydroxy-2'-methyl-2-naphthaleneacetic acid with ethyl-2-cyano-1-(4'-pyridyl)acrylic acetate in the presence of piperidine gives 1-pyridyl-2-ethoxycarbonyl-3-amino-1H-naphtho[2,1-b]pyran-2'-methylacetic acid (5), which likewise crystallizes in a chiral space group. All of compounds are second harmonic generation (SHG) active, and have a very strong SHG response approximately about 8.0, 5.0, 12.0, 6.0, and 1.4 (for 1-5 compounds) times that of urea. Ferroelectric property measurements indicate that compounds 1, 2, 4, and 5 may display ferroelectric behavior.

[Zn(FZ)2Cl2] (1) (FZ = Voriconazole, (2R,3S)-2-(2,4-difluorophenyl)-3(5-fluoropyrimidin-4-yl)-1-(1H-1,2,4-triazol-1-yl)butan-2-ol), has been obtained through the reaction of zinc chloride and FZ and has been characterized by FT-IR, UV–vis and fluorescence spectra, elemental analysis (EA), single crystal X-ray diffraction, powder X-ray diffraction and thermogravimetric analysis (TGA). FZ was also characterized by FT-IR, UV–vis spectra, single crystal X-ray diffraction and TGA. FZ crystallizes in the chiral space group P21 and 1 crystallizes in chiral space group P1 with a mononuclear structure. In 1, there are three kinds of hydrogen bonding interactions and weak stacking interactions which generate a 3-D architecture. The primary antimicrobial results show that 1 exhibits potent activity against Aspergillus (Aspergillus niger, Aspergillus terreus, Aspergillus fumigatus and Aspergillus flavus) and Candida species (Candida albicans, Candida krusei, Candida glabrata and Cryptococcus neoformans), higher than that of free FZ. Fluorescence spectra of 1 and FZ have been discussed.

A Gold Quartet Framework with Reversible Anisotropic Structural Transformation Accompanied by Luminescence Response

Supramolecular assembly based on a series of meso-tetrakis( p-methoxyphenyl)porphrin complexes

Two chiral three-dimensional (3-D) coordination polymers, [Cd4(μ3-HPhIDC)2(μ4-HPhIDC)2(H2O)] (1) and two achiral 3-D coordination polymers, [Mn1.5(μ3-PhIDC)(H2O)3] (2) and [Mn(μ3-HPhIDC)(H2O)]2} (3), have been synthesized by hydro(solvo)thermal reaction, employing 2-phenyl-1H-imidazole-4,5-dicarboxylic acid (H3PhIDC) as organic ligand, and characterized by single-crystal X-ray diffraction, elemental analyses, and IR spectra. Polymer 1 crystallizes in the orthorhombic chiral space group P2(1)2(1)2(1) and exhibits a 3-D framework, in which two-dimensional (2-D) layers are composed of right-handed helices along the b-axis and are further pillared by μ4-HPhIDC2− linkages. Polymer 2 crystallizes in trigonal chiral space group R3̅ and presents a novel 3-D structure, which is generated from 2-D honeycomb-like layers, containing similar right-handed helical chains along the a or b axes, respectively. Polymer 3 also has a 3-D architecture and is composed of novel 2-D stairlike layers in the bc plane. The theoretical prediction of the phenyl substituent effect of the H3PhIDC ligand has first been presented.

Inclusion complexes of 9,10-dihydro-9,10-etheno-anthracene-11,12-bis(diphenylphosphine oxide) (1) as host are synthesized using a variety of guest solvent molecules and the photochemistry of the host molecule is studied in solution and in the crystalline complexes. The crystal structures of four complexes are determined and correlated with their photochemical reactivity. In each case only one dibenzosemibullvalene photoproduct is obtained in the photolysis. Since three of the complexes studied crystallize in the chiral space group P212121, irradiation of single crystals produces a chiral photoproduct in >90% enantiomeric excess. Determination of the absolute configurations of reactants and products allows elucidation of the key structural features that control the enantiospecific solid-state photorearrangements.

The title salt, [(C6H11)2NH2][(C6H5O)2P(O)(O)], crystallizes in the chiral space group P212121, composed of achiral cation and anion components. The strong charge-assisted N–H…O hydrogen bonds build a linear assembly along the a axis, including a non-centrosymmetric C22(6) chain graph-set motif. The intra and intermolecular C–H…O interactions as well as the C–H…π-electron ring interactions also exist in the crystal structure. Fingerprint plots are used for a detailed investigation of intermolecular interactions participating in the crystal packing. The spectroscopic features (IR, 1H NMR, 13C{1H} NMR, 31P{1H} NMR, and mass) are studied.

Using 4-pyridyl-1,2,4-triazole (pytrz) as ligand and a variety of copper(II) salts, nine copper(II) coordination polymers, {[Cu(pytrz)(OH)]X}n (X = Cl−, (1); Br−, (2); (NO3−)·H2O, (3); BF4−, (4); CF3SO3−, (5)), {[Cu(pytrz)2](BF4)2·2H2O}n (6), {[Cu3(pytrz)2(OH)2(NO2)2(H2O)2](NO3)2·H2O}n (7), {[Cu3(pytrz)2(OH)2(H2O)2](SO4)2·10H2O}n (8), and {[Cu4(pytrz)4(OH)2(H2O)2](SiF6)3·11.5H2O}n (9), were prepared and their crystal structures were determined via single-crystal X-ray diffraction. Complexes 1−3 crystallize in a chiral space group P212121 and exhibits a three-dimensional (3D) chiral framework constructed by left-handed (CuO)n helixes (L). Complex 4 consists of (CuO)n helixes with the opposite chirality (R) and have the analogous cationic framework as 1. The structure of 5 is constructed through (CuO)n zigzag chains and represents the same (327583)(372) topology as 1−4. Complex 6 exhibits a novel two-dimensional (2D) Kagome topology with bidentate pytrz. The structures of complexes 7 and 8 are based on trin...

Organic-inorganic hybrid chiral small-molecule materials combine the inherent properties of both components; however, studies integrating chirality with rare-earth double-perovskite materials are limited. In this work, we synthesized two enantiomers of three-dimensional (3D) hybrid rare-earth double-perovskites, [R-3-HDMP]2CsEu(NO3)6 (1) and [S-3-HDMP]2CsEu(NO3)6 (2), by reacting R-3-HDMP and S-3-HDMP (where 3-HDMP = 3-hydroxy-N,N-dimethylpyrrole) with CsNO3 and Eu(NO3)3 in a 2:1:1 ratio within an acidic solution. Both R-3-HDMPI and S-3-HDMPI crystallize in the chiral space group P212121 at room temperature, exhibiting a transition from SHG-on to SHG-off (SHG = second harmonic generation) upon heating and cooling. The temperature-dependent X-ray single-crystal diffraction analysis carried out on compound 1 and compound 2, before and after the phase transition, disclosed the transformation of their space groups from noncentrosymmetric to centrosymmetric. Additionally, the incorporation of rare-earth elements as hybrid B-site cations imparts exceptional fluorescence properties to the compounds. These materials effectively merge the unique characteristics of chiral molecules with the exceptional luminescence of double-perovskite structures, paving the way for innovative optical devices and advanced information processing technologies.

The achiral compound 2-(2-naphthylthio or 2-quinolinethio)-3-methylcyclohexen-1-one was found to crystallize in the chiral space group P212121. In one crystal, only one-handedness was found. In particular, although 2-(2-naphthylthio)-3-methylcyclohexen-1-one showed conformational polymorphism, both polymorphs were chiral crystals.

Using the achiral 1,4-naphthalenedicarboxylic acid (H2L) ligand and corresponding cadmium(II) salts, under hydrothermal conditions, a novel 3D chiral inorganic-organic hybrid complex with the formula [Cd(μ6-L)(DMF)]n has been isolated and characterized by single-crystal X-ray diffraction, FT-IR, TGA, and luminescent analysis. The crystal crystallizes in the chiral space group P212121, a = 6.7180(10) Å, b = 13.507(2) Å, c = 15.229(2) Å, Z = 4, the flack parameter is near zero (–0.02(4)). Two kinds of 1D infinite right-handed Cd-O-Cd helical chains can be observed, which are further interlinked into 1D infinite Cd-O-Cd linkage in a unique arrangement way. Solid-state luminescent spectrum of 1 also has been investigated indicating the strong emission band centered at 494 nm upon excitation at 370 nm. The result also represents a good example of the construction of those chiral inorganic-organic hybrid frameworks containing infinite M-O-M linkage using the achiral precursor. Supplementary materials are available for this article. Go to the publisher's online edition of Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry to view the supplemental file.

Two 3,6-diiodocarbazole derivatives were prepared from the iodination of the corresponding phenylcarbazole. 3,6-Diiodo-9-phenylcarbazole crystallises in the chiral space group P21 and shows good second-harmonic generation effects. Thermogravimetric analysis of the two compounds shows high thermal stabilities, in which the decomposition temperature for 1 and 2 are 273 and 308 °C, respectively.

Nine compounds based on o-carboxylphenoxyacetate acid (H2OCPA) ligand: [Cu(OCPA)(4,4′-bipy)0.5]n (1), {[Cu2(OCPA)2(4,4′-bipy)2(H2O)]·H2O}n (2), [Co2(OCPA)2(4,4′-bipy)(H2O)4] (3), {[Co(OCPA)(4,4′-bipy)0.5(H2O)]·H2O}n (4), {[Co(OCPA)(4,4′-bipy)1.5]·0.5H2O}n (5), [Ni2(OCPA)2(4,4′-bipy)(H2O)4] (6), {[Ni(OCPA)(4,4′-bipy)1.5]·2H2O}n (7), {[Zn(OCPA)(4,4′-bipy)0.5(H2O)]·H2O}n (8), and [Mn(OCPA)(H2O)]n (9) (4,4′-bipy = 4,4′-bipyridine) were synthesized by hydrothermal methods. The results of structural analyses reveal that the giant structural divergence of the compounds with same metal ions mainly originated from the different amounts of 4,4′-bipy used in syntheses. For Cu-containing compounds, the structural divergences are from one-dimensional (1D) chain 1 to two-dimensional (2D) network 2; for Co, through binuclear 3 to 1D ladder-like 4, and to another different 1D ladder-like chain 5; for Ni, from binuclear 6 to 1D chain 7. But for Zn and Mn, 1D chain 8 and 2D network 9 are obtained with the presence of excess 4,4′-bipy. Compound 9 crystallizes in chiral space group P21 with a second harmonic generation (SHG) efficiency of 0.8 times that of urea. The magnetic studies show that compounds 1 and 9 have antiferromagnetic coupling between the adjacent metallic ions. Compound 4 is a weak ferromagnet based on antiferromagnetic interaction and spin canting. Both the bifurcation temperature of the field-cooled (FC) and zero-field-cooled (ZFC) and the peaks of the real χM′ and the imaginary χM″ parts of alternating current (AC) magnetic susceptibilities are observed at 2.2 K, indicated that the critical temperature Tc is 2.2 K. A very little hysteresis loop is observed with a small coercive field of 20 Oe.

Spontaneous resolution in a new chiral purely organic crystal containing homochiral helical chains: Synthesis, crystal structure, and phosphorescence