J. Appl. Cryst.の発刊に際して

This critical review describes how halocarbons can function as effective binding sites of anions via halogen bonding, the noncovalent interaction whereby halogen atoms accept electron density. The focus is on the binding and coordination of oxyanions, by far the most numerous class of anions in organic chemistry. It is shown how a large variety of inorganic and organic oxyanions can form discrete adducts and 1D, 2D, or 3D supramolecular networks with chloro-, bromo-, and iodocarbons. Specific examples are discussed in order to identify new supramolecular synthons based on halogen bonding and to outline some general principles for the design of effective and selective receptors based on this interaction. The interaction allows for several other anions to self-assemble with halocarbons and mention is also given to the halogen bonding-based coordination of halides, polycyano- and polyoxometallates (72 references).

Halogen bonding: a general route in anion recognition and coordination

The high-power broadband terahertz (THz) generator is an essential tool for a wide range of THz applications. Here, we present a novel highly efficient electro-optic quinolinium single crystal for THz wave generation. For obtaining intense and broadband THz waves by optical-to-THz frequency conversion, a quinolinium crystal was developed to fulfill all the requirements, which are in general extremely difficult to maintain simultaneously in a single medium, such as a large macroscopic electro-optic response and excellent crystal characteristics including a large crystal size with desired facets, good environmental stability, high optical quality, wide transparency range, and controllable crystal thickness. Compared to the benchmark inorganic and organic crystals, the new quinolinium crystal possesses excellent crystal properties and THz generation characteristics with broader THz spectral coverage and higher THz conversion efficiency at the technologically important pump wavelength of 800 nm. Therefore, the quinolinium crystal offers great potential for efficient and gap-free broadband THz wave generation.

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High-power Broadband Organic THz Generator

A novel highly efficient ionic electro-optic quinolinium single crystals for THz wave applications is reported. Acentric quinolinium derivatives, HMQ-T (2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium 4-methylbenzenesulfonate) and HMQ-MBS (2-(4-hydroxy-3-methoxystyryl)-1-methylquinolinium 4-methoxybenzenesulfonate) exhibit high order parameters cos3θp = 0.92 and cos3θp = 1.0, respectively, as well as a large macroscopic optical nonlinearity, which is in the range of the benchmark stilbazolium DAST (N,N-dimethylamino-N’-methylstilbazolium 4-methylbenzenesulfonate) and phenolic polyene OH1 (2-(3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile) crystals. As-grown unpolished bulk HMQ-T crystals with a side length of about 6 mm and thickness of 0.56 mm exhibit 3.1 times higher THz generation efficiency than 0.37 mm thick OH1 crystals and about 8.4 times higher than 1 mm thick inorganic standard ZnTe crystals at the near-infrared fundamental wavelength of 836 nm. Therefore, HMQ crystals with high order parameter obviously have a very high potential for high power THz-wave generation and its applications.

Highly Efficient Organic THz Generator Pumped at Near-Infrared: Quinolinium Single Crystals

Halogen bonding is often described as being driven predominantly by electrostatics, and thus adducts between anionic halogen bond (XB) donors (halogen-based Lewis acids) and anions seem counterintuitive. Such "anti-electrostatic" XBs have been predicted theoretically but for organic XB donors, there are currently no experimental examples except for a few cases of self-association. Reported herein is the synthesis of two negatively charged organoiodine derivatives that form anti-electrostatic XBs with anions. Even though the electrostatic potential is universally negative across the surface of both compounds, DFT calculations indicate kinetic stabilization of their halide complexes in the gas phase and particularly in solution. Experimentally, self-association of the anionic XB donors was observed in solid-state structures, resulting in dimers, trimers, and infinite chains. In addition, co-crystals with halides were obtained, representing the first cases of halogen bonding between an organic anionic XB donor and a different anion. The bond lengths of all observed interactions are 14-21 % shorter than the sum of the van der Waals radii.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/anie.202003083

"Anti-Electrostatic" Halogen Bonding.

In the title compound, C19H18NO2+. C7H7SO3−, the cation is almost planar and the benzene ring of the anion makes dihedral angles of 59.17 (9) and 60.59 (10)° with the mean planes through the quinolinium and benzene ring of the cation, respectively. The cations and anions are packed as alternate layers along the b axis. These layers are inter­connected through O—H⋯O and C—H⋯O inter­actions to form a three-dimensional network. The structure is stabilized by these inter­actions and C—H⋯π inter­actions.

2‐[(E)‐2‐(3‐Hydr­oxy‐4‐methoxy­phen­yl)ethen­yl]‐1‐methyl­quinolinium 4‐methyl­benzene­sulfonate

The structure of the title compound, C19H18NO2+·C7H7O4S-, was determined by a single crystal X-ray diffraction technique. The compound crystallizes in monoclinic space group Pc with a = 10.9895(1), b = 7.1363(1), c = 15.6341(2)A, β = 110.300(1)°, Z = 2, V = 1149.94(2)A3 and Dx = 1.385 g cm-3. In the crystal packing, the cations and anions are individually linked into alternate layers parallel to the bc plane by weak C-H…O interactions; these ionic layers are interconnected through an intermolecular O-H…O hydrogen bond and weak intermolecular C-H…O interactions, forming a three-dimensional network. The molecular packing is stabilized by an O-H…O hydrogen bond and weak C-H…O interactions. The second harmonic generation (SHG) efficiency of the compound is about 0.45-times that of urea.

Crystal and Molecular Structures of 2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylquinolinium 4-methoxybenzenesulfonate

(NLO) properties usually consist of a frame with a delocalized π system, and end-capped with either a donor or an acceptor substituent or both. The most important requirement for these materials to exhibit second-order NLO properties is for the molecules to be oriented in a non-centrosymmetric environment.1 Benzenesulfonate is frequently used to cocrystallize with cations to form compounds which are expected to have NLO properties.2 Our continuing research on non-linear optical materials3,4 has led us to synthesize the title compound x27 ANALYTICAL SCIENCES 2007, VOL. 23

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Synthesis, Characterization and Crystal Structure of 2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylquinolinium 4-chlorobenzenesulfonate

The title compound, C15H16NO2+·C6H4ClO3S−, is isomorphous with the 4-bromo­benzene­sulfonate derivative. The cation is almost planar and the benzene ring of the anion makes dihedral angles of 82.79 (1) and 76.39 (1)° with the mean planes through the benzene ring of the cation and the pyridinium ring, respectively. The cations and anions are packed as alternate layers parallel to the ac plane. These layers are inter­connected through O—H⋯O, C—H⋯O and C—H⋯π inter­actions to form a three-dimensional network.

4‐(4′‐Hydroxy‐3′‐methoxy­styr­yl)‐1‐methyl­pyridinium 4‐chloro­benzene­sulfonate

In the title compound, C15H16NO2+·C6H4BrSO3−, the cation is almost planar. The benzene ring of the anion makes dihedral angles of 82.00 (8) and 74.96 (8)° with the mean planes through the benzene ring of the cation and the pyridinium ring, respectively. In the solid state, the cations and anions are packed as alternate layers parallel to the ac plane. These layers are interconnected through O—H⋯O, C—H⋯O and C—H⋯π interactions to form a three-dimensional network.

Boonwasana Jindawong

Papers

2‐[(E)‐2‐(3‐Hydroxy‐4‐methoxyphenyl)ethenyl]‐1‐methylquinolinium 4‐methylbenzenesulfonate

Crystal and Molecular Structures of 2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylquinolinium 4-methoxybenzenesulfonate

Synthesis, Characterization and Crystal Structure of 2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylquinolinium 4-chlorobenzenesulfonate

4‐(4′‐Hydroxy‐3′‐methoxystyryl)‐1‐methylpyridinium 4‐chlorobenzenesulfonate

4-(4′-Hydroxy-3′-methoxystyryl)-1-methylpyridinium 4-chlorobenzenesulfonate

Boonwasana Jindawong

Papers

2‐[(E)‐2‐(3‐Hydr­oxy‐4‐methoxy­phen­yl)ethen­yl]‐1‐methyl­quinolinium 4‐methyl­benzene­sulfonate

Crystal and Molecular Structures of 2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylquinolinium 4-methoxybenzenesulfonate

Synthesis, Characterization and Crystal Structure of 2-[(E)-2-(4-Hydroxy-3-methoxyphenyl)ethenyl]-1-methylquinolinium 4-chlorobenzenesulfonate

4‐(4′‐Hydroxy‐3′‐methoxy­styr­yl)‐1‐methyl­pyridinium 4‐chloro­benzene­sulfonate

4-(4′-Hydroxy-3′-methoxystyryl)-1-methylpyridinium 4-chlorobenzenesulfonate

2‐[(E)‐2‐(3‐Hydroxy‐4‐methoxyphenyl)ethenyl]‐1‐methylquinolinium 4‐methylbenzenesulfonate

4‐(4′‐Hydroxy‐3′‐methoxystyryl)‐1‐methylpyridinium 4‐chlorobenzenesulfonate