Cl Intermolecular Interactions Research Articles

Spin-Crossover Anticooperativity Induced by Weak Intermolecular Interactions.

As a rule, rational design of cooperative spin-crossover (SCO) molecular switches is largely based on consideration of sizes and structures of individual building blocks, whereas a meticulous analysis of crystal packing, including the weakest intermolecular interactions, is often assumed to play a secondary role or is even fully neglected. By investigating cobalt(II) clathrochelates, which do not change the molecular volume upon SCO, we showed that even weak (1.2 kcal/mol) π···Cl intermolecular interactions can cause a pronounced anticooperativity of SCO, being more gradual in the solid state than in solution. Our results clearly demonstrate that the "chemical pressure" concept is not as general as it is thought to be, and the successful design of molecular switches requires in-depth analysis of intermolecular interactions, however weak they seem.

Two new metastable forms of 6-chloroquinolin-2(1H)-one: Crystal structure, Hirshfeld surfaces and spectroscopic studies

Two new metastable crystalline forms of 6-chloroquinolin-2(1H)-one (forms II and III), which were induced by two kinds of 3D inorganic anions (ClO4- and BF4-), have been prepared and characterized in this work. We performed single-crystal diffraction, X-ray powder diffraction (XRPD), Hirshfeld surfaces, solid-state vibrational spectroscopy (IR) and thermal analysis (DSC, TGA) to these two new forms as well as the original one (form I). Form I featured with 1D chain, while form II and III featured with dimeric unit with stronger π⋯π and hydrogen bonds interactions. The 3D inorganic anions force the self-assemble behavior of 6-chloroquinolin-2(1H)-one molecules from 1D chain structure (form I) to dimeric unit (forms II and III) due to their large steric hindrance, and different anions induced different orientations for dimeric unit. These transformations lead to the increase of N–H⋯O, π⋯π, and Cl–Cl intermolecular interactions, which lead to blue shift of IR spectra in 1700–1500cm−1 region as well as luminescence peaks, while red shift of IR spectra in 650–550cm−1 region.

Structural reinvestigation of the photoluminescent complex [NdCl2(H2O)6]Cl

The structure of the photoluminescent compound hexaaquadichloridoneodymium(III) chloride has been redetermined from single-crystal X-ray diffraction data at 100 K, with the aim of providing an accurate structural model for the bulk crystalline material. The crystal structure may be described as a network of [NdCl2(H2O)6](+) cations with distorted square-antiprism geometry around the Nd(III) centre. The Nd(III) cation and the nonbonded Cl(-) anion are both located on twofold symmetry axes. The crystal packing consists of three different neodymium pairs linked by a three-dimensional network of O-H···Cl intermolecular interactions. The pair distribution function (PDF) calculated from the experimentally determined structure is used for the discussion of the local structure.

Structures of a co-crystal of tautomers of (E)-N-7-chloro-4-(2-methoxycinnamolyhydrazinyl)quinoline and a single tautomer of the 4-methoxy analogue

Abstract A crystal structure determination confirmed that the product from 7-chloroquinilin-4-ylhydrazine and 4-methoxycinnanamic acid had been isolated from MeOCH2CH2OH solution as [(E)-N′-7-chloro-4-(4-methoxycinnamolyhydrazinyl)quinoline, 1. In contrast, recrystallization of the 2-MeO derivative, 2, from the same solvent, produced a 1 : 1 co-crystalline mixture of two tautomers, namely (E)-N′-7-chloro-4-(2-methoxycinnaämolyhydrazinyl)quinoline and 7-chloro-4(1 H)quinolinone 3-(2-methoxycinnamoyl)hydrazone, molecules A and B, respectively. Molecules 1 and 2A have “L”-shapes and, in general, have very similar conformations, which differ from that of 2B, mainly arising from the rotation about the (O)C—N(N) bond within the linker unit between the quinolone and methoxyphenyl rings. In both 1 and 2, the 3-dimensional supramolecular arrangements involve strong N—H…N, N—H…O, C—H…O and C—H…π hydrogen bonds, while additionally in 2, there are π…π, C—Cl…π and C—H…Cl intermolecular interactions.

The perchlorotriphenylmethyl (PTM) radical

In spite of the considerable understanding and development of perchlorotriphenylmethyl (PTM) radical derivatives, the preparation of crystals of the pure unsubstituted PTM radical, C19Cl15, suitable for single-crystal X-ray diffraction has remained a challenge since its discovery, and only two studies dealing with the crystal structure of the unsubstituted PTM radical have been published. In one study, the radical forms clathrates with aromatic solvents [Veciana, Carilla, Miravitlles & Molins (1987). J. Chem. Soc. Chem. Commun. pp. 812-814], and in the other the structure was determined ab initio from powder X-ray diffraction data [Rius, Miravitlles, Molins, Crespo & Veciana (1990). Mol. Cryst. Liq. Cryst. 187, 155-163]. We report here the preparation of PTM crystals for single-crystal X-ray diffraction and their resolution. The structure, which shows monoclinic symmetry (C2/c), revealed a nonsymmetric molecular propeller conformation (D3 symmetry) caused by the steric strain between the ortho-Cl atoms, which protect the central C atom (sp(2)-hybridization and major spin density) and give high chemical and thermal persistence to the PTM. The supramolecular structure of PTM shows short Cl...Cl intermolecular interactions and can be described in terms of layers formed by rows of molecules positioned in a head-to-tail manner along the c axis.

Investigation of H-bonding and halogen-bonding effects in dichloroacetic acid: DFT calculations of NQR parameters and QTAIM analysis

A theoretical study was performed to examine hydrogen and halogen bonds properties in gas phase and crystalline dichloroacetic acid (DCAA). The specific pattern of O-H∙∙∙O, C-H∙∙∙O, HCl, Cl∙∙∙O and Cl∙∙∙Cl interactions in DCAA dimers is described within the quantum theory of atoms in molecules (QTAIM) formalism. Based on QTAIM results, a partial covalent character is attributed to the O-H∙∙∙O hydrogen bonds in DCAA, whereas all the C-H∙∙∙O, Cl···O and Cl∙∙∙Cl intermolecular interactions are weak and basically electrostatic in nature. MP2/6-311++G** calculations indicate that the interaction energies for DCAA dimers lie in the range between -0.40 and -14.58kcalmol(-1). One of the most important results of this study is that, according to energy decomposition analyses, halogen bonds are largely dependent on both electrostatic and dispersion interactions. For those nuclei participating in the hydrogen-bonding and halogen-bonding interactions, nuclear quadrupole coupling constants exhibit significant changes on going from the isolated molecule model to the crystalline DCAA. Of course, the magnitude of these changes at each nucleus depends directly on its amount of contribution to the interactions.

Crystal structure of bis[2-((E)-(p-tolylimino) methyl)-6-bromo-4-chlorophenol]copper(II)

A new complex CuL2 1 [HL = 2-((E)-(p-tolylimino) methyl)-6-bromo-4-chlorophenol] is obtained and characterized using the single crystal X-ray diffraction analysis. The crystal belongs to the monoclinic system, P21/c space group, with a = 13.3203(13) A, b = 12.3052(11) A, c = 17.8664(17) A, β = 105.3420(10)°, V = 2824.1(5) A3, Z = 4, Dc = 1.672 g/cm3, R1 = 0.0686. The geometry around copper(II) is intermediate between square planar and tetrahedral. The units of the complex are linked via weak intermolecular Br…Br contracts, leading to the formation of one-dimension (1D) chains along the b axis; the multipoint Cu…Cl intermolecular interactions extend the 1D chain into a 2D layer.

Crystal structure of indium(III) Schiff base complex

The title compound [In(C22H30N4O4)]Cl (I) bis[(N-salicylidene-N′-(2-hydroxyethyl)ethyleneediamine) indium(III) chloride is prepared, and its crystal structure is determined by single crystal X-ray diffraction at room temperature. The complex crystallizes in the monoclinic space group P21/n, a = 9.9704(6) A, b = 24.9554(15) A, c = 10.5707(6) A, β = 116.46(2)°, V = 2354.6(2), Z = 4. The X-ray analysis reveals that the InIII ion is surrounded by four nitrogen and two oxygen atoms from two ligands leading to a distorted octahedral geometry. The molecule has the form of tongs at a junction point with the metal. Five membered rings adopt envelope conformation. In the crystal structure, the molecules are linked via N-H...Cl, O-H...O, O-H...Cl, and C-H...Cl intermolecular interactions. The structure is further stabilized by C-H...π (arene) interactions.

Nature of Cl···Cl Intermolecular Interactions via Experimental and Theoretical Charge Density Analysis: Correlation of Polar Flattening Effects with Geometry

The experimental charge density distribution in three compounds, 2-chloro-3-quinolinyl methanol, 2-chloro-3-hydroxypyridine, and 2-chloro-3-chloromethyl-8-methylquinoline, has been obtained using high-resolution X-ray diffraction data collected at 100 K based on the aspherical multipole modeling of electron density. These compounds represent type I (cis), type I (trans), and type II geometries, respectively, as defined for short Cl···Cl interactions. The experimental results are compared with the theoretical charge densities using theoretical structure factors obtained from a periodic quantum calculation at the B3LYP/6-31G** level. The topological features derived from the Bader's theory of atoms in molecules (AIM) approach unequivocally suggest that both cis and trans type I geometries show decreased repulsion, whereas type II geometry is attractive based on the nature of polar flattening of the electron density around the Cl atom.

Analysis of Cl…Cl and C-H…Cl intermolecular interactions involving chlorine in substituted 2-chloroquinoline derivatives

Six crystal structures of substituted 2-chloroquinoline derivatives have been analysed to evaluate the role of Cl atom as a self recognizing unit resulting in the formation of Cl…Cl and C-H…Cl interactions to generate supramolecular assembly in the solid state. The features of Type I and Type II geometries associated with Cl…Cl interactions have been analysed to show directional preferences leading to differences in the packing motifs in these crystal structures. C-H…Cl interactions are generated exclusively in structures depicting Type II Cl…Cl interaction have been observed in these structures.

5-Pyridine 4-yl-3H-(1,3,4) Oxadiazole-2 Thione Hydrochloride Monohydrate, (I), and 4 [5-Ethylsulfanyl)-(1,3,4) Thiadiazole-2-yl]-Pyridinium Perchlorate, (II)

The title compounds C7H8ClN3O2S, (I), and C9H10ClN3O4S2, (II), both crystallize in monoclinic space group P21 /c with unit cell parameters (I) a = 7.9402(7), b = 10.6312(9), c = 11.7626(10), A, β = 99.271(5)°, Z = 4 and (II) a = 5.1439(2), b = 9.0636(4), c = 27.1814 (7), A, β = 95.116(2)°, Z = 4. In (I) the molecule consists of a 5-pyridine-4-yl group bonded to the carbon atom at the 5 position of (1, 3, 4) oxadiazole-2 thione hydrochloride monohydrate. The angle between the mean planes of the oxadiazole and pyridine rings is 9.6(6)°. Crystal packing in (I) is stabilized by strong N–H···O hydrogen bonds in concert with a solvent water molecule and weak O–H···Cl, O–H···S, N–H···Cl intermolecular interactions. The crystal structure of compound (II) consists of 4 [5-ethylsulfanyl)-(1, 3, 4) thiadiazole-2-yl]-pyridinium perchlorate, (C9H10N3S2)+(ClO4)−, cation–anion pairs, containing strong intermolecular N–H···O hydrogen bonds and weak C–H···O and N–H···O intermolecular interactions operating between the ionic species that form a cooperative hydrogen-bonded, infinite chain O–H···O–H···O–H network which generates a sheet motif structure in the unit cell. It is also supported by weak intermolecular Cg···Cg π–π and Cl–O···Cg π-ring interactions which gives additional support to molecular packing stability in the unit cell. Geometry optimized MOPAC AM1 computational calculations on each compound provides support to the structural features in their respective crystal structures. The crystal structures of 5-Pyridine 4-yl-3H-(1,3,4) oxadiazole-2 thione hydrochloride monohydrate, C7H8ClN3O2S, (I), and 4 [5-Ethylsulfanyl)-(1,3,4) thiadiazole-2-yl]-pyridinium perchlorate, C9H10ClN3O4S2, (II) are investigated. Both molecules crystallize in the monoclinic space group P21 /c. Crystal packing in (I) is stabilized by strong N–H···O hydrogen bonds in concert with a solvent water molecule and weak O–H···Cl, O–H···S, N–H···Cl intermolecular interactions. The crystal structure of compound (II) consists of cation–anion pairs, (C9H10N3S2)+(ClO4)−, containing strong intermolecular N–H···O hydrogen bonds and weak C–H···O and N–H···O intermolecular interactions operating between the ionic species which form a cooperative hydrogen-bonded, infinite chain O–H···O–H···O–H network which generates a sheet motif structure in the unit cell. The geometric and packing parameters of both structures are described and compared to a MOPAC AM1 computational calculation.

Crystal Structure and Magnetic Characteristics of a New 3‐Methylisoquinolinium Tetrachloridoferrate(III)

AbstractThe crystal structure of a new 3‐methylisoquinolinium[3‐Me(IsoQH)] salt, [3‐Me(IsoQH)][FeCl4], was determined. The iron cation is tetracoordinated by chlorine anions, and it adopts a slightly distorted tetrahedral coordination. In the crystal structure, there are π···π stacking interactions between the 3‐methylisoquinolinium cations in an ABAB infinite arrangement, N–H···Cl hydrogen bonds, and C–H···Cl intermolecular interactions. Magnetic measurements of a powdered sample were carried out. A negative Weiss constant as well as the intermolecular exchange parameter for [3‐Me(IsoQH)][FeCl4] indicate the occurrence of antiferromagnetic interactions transmitted in the crystal lattice.

Synthesis and Characterization of a New Mebendazole Salt: Mebendazole Hydrochloride

Mebendazole hydrochloride [(5-benzoyl-1H-benzimidazole-2-yl)-carbamic acid methyl ester hydrochloride, MBZ.HCl], a new stable salt of mebendazole (MBZ), has been synthesized and characterized. It can easily be obtained from recrystallization of forms A, B, or C of MBZ in diverse solvents with the addition of hydrochloric acid solution. Crystallographic data reveals that the particular conformation adopted by the carbamic group contributes to the stability of the network. The crystal packing is stabilized by the presence of three N-H...Cl intermolecular interactions that form chains along the b axis. The XRD analyses of the three crystalline habits found in the crystallization process (square-based pyramids, pseudohexagonal plates, and prismatic) show equivalent diffraction patterns. The vibrational behavior is consistent with crystal structure. The most important functional groups show shifts to lower or higher frequencies in relation to the MBZ polymorphs. The thermal study on MBZ.HCl indicates that the compound is stable up to 160 degrees C approximately. Decomposition occurs in four steps. In the first step the HCl group is eliminated, and after that the remaining MBZ polymorph A decomposes in three steps, as happens with polymorphs B and C. (

A conserved core in the SufE sulfur-acceptor protein mediates interdomain interactions in variety of redox protein complexes

Dichloromethane, CH2Cl2, has been crystallized in a diamondanvil cell and its structure determined by X-rays at 1.33GPa/293K, and at 1.63GPa/293K. The structures are orthorhombic, space-group Pbcn, and isostructural with the low temperature structure [1]. The Cl Cl intermolecular interactions have been considered as the primary reason for the layer structure of the dichloromethane crystal. The intermolecular distances and molecular geometry of low temperature and high-pressure structures are compared in the Table below. CH2Cl2 at T: 153 K 293 K 293 K P: 0.1 MPa 1.33 GPa 1.63 GPa Ref. [1] This work This work C–H 0.99(13) A 1.01 (9) A 1.13 (12) A C–Cl 1.768(13) A 1.765 (4) A 1.769 (5) A Cl Cl 2.932(4) A 3.360 (3) A 3.324 (5) A Cl–C–Cl 112(1) 111.6(3) 111.4 (4) H–C–H 112(7) 99 (9) 102 (10)

Syntheses and crystal structures of diorganotin (IV) moieties with 3-hydroxy-2-pyridinecarboxylic acid

A series of new organotin (IV) complexes with 3-hydroxy-2-pyridinecarboxylic acid (3-OH-2-picH) of two types: R 2SnCl(3-OH-2-pic) ( I) (R = Me 1, n-Bu 2, Ph 3, PhCH 2 4) and R 2 Sn(3-OH-2-pic) 2 ( II) (R = Me 5, n-Bu 6, Ph 7, PhCH 2 8)have been synthesized by reactions of diorganotin (IV) dichloride with 3-hydroxy-2-pyridinecarboxylic acid in the presence of sodium ethoxide. All complexes are characterized by elemental analyses, IR spectra and NMR spectra analyses. Among them, complexes 1, 5, 6 and 7 are also characterized by X-ray crystallography diffraction analyses. Complex 1 is a 1D polymeric chain with six-coordinate tin atoms and the packing of complex 1 is stabilized by the C–H⋯Cl intermolecular weak interactions, thus a 2D network of 1 is formed. Complex 5 is also a 1D polymeric chain with seven-coordinate tin atoms. Complex 6 is a zigzag polymeric chain linked by Sn⋯O intermolecular weak interactions. Complex 7 is a monomeric complex with distorted octahedral geometry.

In-situ pressure crystallization and X-ray diffraction study of 1,1,2,2-tetrachloroethane at 0.5 GPa

Abstract 1,1,2,2-Tetrachloroethane, C2H2Cl4 (denoted TCE, m.p. 230 K) has been in-situ pressure crystallized in a Merrill-Bassett diamond-anvil cell, and its structure has been determined at 0.5 GPa and 295 K from the single-crystal X-ray diffraction data. TCE crystallizes in the monoclinic space group P21 /c with the molecules located at the inversion centers. The molecules are in the s-trans conformation, while they assume the gauche conformation in the crystal obtained by cooling. This implies that a phase transition may exist between the low-temperature and high-pressure phases of TCE. In the high-pressure phase the HC–CH moiety of the C2H2Cl4 molecule is disordered in two sites, one related to the other by the non-crystallographic mirror plane approximately through the four Cl atoms of one molecule. The refined occupancy factors for the disordered sites are 0.77 and 0.23. The role played by the Cl…Cl intermolecular interactions for the disorder, and the phase transition between TCE phases built of s-trans (high-pressure) and gauche (low-temperature) molecules have been discussed.

High-pressurein-situcrystallization, structure and phase transitions in 1,2-dichloroethane

AbstractThe single crystal of 1,2-dichloroethane, C2H4Cl2wasin-situcrystallized in a Merrill-Bassett diamond-anvil cell, and its structure determined at 0.7 GPa and 280 K. The crystals are monoclinic, space groupP21/c. The C2H4Cl2molecules in thes-transconformation are located at the inversion centers. The —H2C—CH2—ethylene group is disordered in two sites, with equal occupancies, one rotated by 180° to the other about the Cl⋯Cl axis of the molecule. The crystal cohesion forces have been attributed mainly to Cl⋯Cl intermolecular interactions, and their role in the mechanism of the phase transition at 177 K has been analysed. It was found that the order-disorder phase transition in the structure of 1,2-dichloroethane is associated with the breaking of the Cl⋯Cl intermolecular interactions in the disordered phase. The crystal amorphization under non-homogeneous strain and subsequent transition to a new pressure-induced polymorph at 1.5 GPa has been observed.

Syntheses, characterizations, and crystal structures of organotin(IV) chloride complexes with 4,4′‐bipyridine

AbstractThe organotin(IV) chlorides RnSnCl4−n (n = 3, R = Ph, PhCH2, n−Bu; and n =2, R = n−Bu, Ph, PhCH2) react with 4,4′‐bipyridine (4′4‐bpy) to give [(Ph3SnCl)2(4,4′‐bpy)1.5(C6H6)0.5] (1), [(PhCH2)3‐ SnCl]2 (4,4′‐bpy) (2), [(n−Bu)3SnCl]2(4,4′‐bpy) (3), [(n−Bu)2SnCl2(4,4′‐bpy)] (4), [Ph2SnCl2(4,4′‐bpy)] (5), and [(PhCH2)2SnCl2(4,4′‐bpy)] (6). The new complexes have been characterized by elemental analyses, IR, 1H, 13C, 119Sn NMR spectroscopy. The structures of (1), (2), (4), and (6) have been determined by X‐ray crystallography. Crystal structures of (1) and (2) show that the coordination number of tin is five. In complex (1), two different molecules exist: one is a binuclear molecule bridged by 4,4′‐bpy and another is a mononuclear one, only one N of 4,4′‐bpy coordinate to tin. Complex (2) contains an infinite 1‐D polymeric binuclear chain by weak Sn…Cl intermolecular interactions with neighboring molecules. In the complexes (4) and (6), the tin is six‐coordinate, and the 4,4′‐bpy moieties bridge adjacent dialkyltin(IV)dichloride molecules to form a linear chain. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:338–346, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20016

Macrocyclic, Dinuclear Zinc(II)‐Directed Self‐Assembly with Pyridine, 2,2′‐Bipyridine and 2‐Methylquinoline: μ2‐OH Bridging Bi‐Macrocyclic Complexes and Hydrogen‐Bond‐Supported Donor‐Acceptor Complexes

AbstractTwo macrocyclic dinuclear zinc(II) complexes (1a and 1b) have been self‐assembled in the presence of pyridine and 2,2′‐bipyridine, respectively, to form μ2‐OH‐bridged bimacrocycles with a Zn4O4 cavity through coordination bonding. The X‐ray structural analysis reveals that both compounds {2a: [Zn4La2(OH)2]2(ClO4)2; 2b: [Zn4Lb2(OH)2]2(ClO4)2} have an open‐mouthed sandwich‐like structure with π−π interactions between parts of two phenyl rings to strengthen two hydroxyl groups connecting the metal atoms in the same direction of the macrocycle. Furthermore, nonclassical C−H···Cl intermolecular interactions have been observed in the crystal of 2b. In addition, the reaction of 1a with quinoline derivatives has yielded novel hydrogen‐bond‐supported donoracceptor complexes {3a: [Zn2La(H2O)2(C10H9N)2](ClO4)2}. The crystallographic study of the complex containing 2‐methylquinoline indicates that two 2‐methylquinoline molecules are linked to two coordinating water molecules above and below the macrocyclic framework through O−H···N hydrogen bonds. The 2‐methylquinoline plane interacts in a face‐to‐face fashion with the phenyl ring of adjacent macrocyclic frameworks, forming an ordered arrangement where one macrocycle and two 2‐methylquinolines are arrayed alternately with almost the same separation. The interplanar distance mentioned before is ca. 3.6 Å. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

2-trichloromethylthio-1H-isoindole-1,3(2H)-dione (Folpet).

The title compound (C9H4Cl3NO2S), commonly known as Folpet, belongs to a group of phthalimides which function as fungicides or can be used in the laboratory as sulfurizing agents. The phthalimide moiety is slightly folded with a dihedral angle of 3.5 (4)°. The molecule participates in C—H⋯O and Cl⋯Cl intermolecular interactions.