Herringbone Motif Research Articles

Organic–inorganic hybrid coordination polymers based on tetratopic pyridyl-bridging ligand: Syntheses, structures, and luminescent properties

Employing the symmetrical ligand 1,2,3,4-tetra-(4-pyridyl)-butane (TPB) as bridges, two novel Zn(II) coordination polymers were obtained and characterized by single crystal X-ray diffraction: [Zn(TPB) 0.5(NCS) 2] ( 1) and [Zn(TPB)(N 3) 2] ( 2). Polymer 1 features a 2D network with herringbone structural motif constructed by TPB, while polymer 2 shows a dense 3D network connected by TPB and μ 1,3-N 3- bridges. In the former, the TPB ligand acts as a four-connector, while in the latter it acts as four-connector and linear bridge. Both 1 and 2 exhibit strong fluorescent emissions in the solid state, which may be of significance in the field of photoactive materials.

N,N-Diethyl-N′-[(E)-4-pyridylmethylene]benzene-1,4-diamine: a combined X-ray and density functional theory study

The crystal structure of the title compound, C16H19N3, comprises neutral molecules of a dipolar Schiff base chromophore. A density functional theory (DFT) optimized structure at the B3LYP/6-31G(d) level is compared with the molecular structure in the solid state. The compound crystallizes in the noncentrosymmetric space group Pna2(1) with a herring-bone packing motif and is therefore a potential candidate for nonlinear optical effects in the bulk.

Structurally tailored thiophene-based hybrid materials for thin-film and single-crystal transistors: Synthesis, photophysics and carrier-transport properties

The structures, optical properties, thin-film and single-crystal field-effect transistor performance of three thiophene-based hybrid materials, 5-(9-butyl-3-carbazolyl)terthiophene ( BCTT), 2,5-bis(9-butyl-3-carbazolyl)thiophene ( BBCT) and 2-(9-butyl-3-carbazolyl)-5-(2-dibenzothienyl)thiophene ( BCDT), are reported. The structural modifications at one side of thiophene have significant effects on the intermolecular interaction, morphology and carrier-transport properties. The adjacent molecules in the solid state of BCTT adopt H aggregation, while compounds BBCT and BCDT both exhibit the formation of J aggregation. In BCTT, the crystal structure features a herringbone motif. The hole mobility for the single-crystal field-effect transistor based on BCTT reaches 0.094 cm 2 V −1 s −1, which is much higher than those of BBCT and BCDT. This study reveals that the enhanced rigidity in the molecules of BBCT and BCDT is not favorable to carrier transport.

Supramolecular architectures of simple aminoanthraquinones: Revised structure of 1-aminoanthraquinone

The solid-state supramolecular architectures of 1-aminoanthraquinone and 1,5-diaminoanthraquinone were determined by single-crystal X-ray structural analysis. In this paper, revised model − in space group P2 1/ c − is given for the crystal structure of 1-aminanthraquinone. 1-Aminoantaquinone molecules are joined together in infinite chains by N H⋯O hydrogen bonds and stacked by face-to-face π−π and C H⋯π interactions thus creating layers and the characteristic herring-bone motif. In the structure of 1,5-diaminoanthraquinone the molecules are connected via N H⋯O hydrogen bonds in the 2D networks of (4,4) topology. These molecular networks are further stacked by face-to-face π−π and carbonyl−carbonyl interactions. The supramolecular organizations of these two compounds are compared with other simple aminoanthraquinones (with at least one non-substituted amino group) thus providing more insights into the basic principles of the solid-state assembling for this class of molecules.

The Role of π-Stacking in the Composition of Phloroglucinol and Phenazine Cocrystals

Cocrystallization of phloroglucinol (PHG) and phenazine (Phen) afforded cocrystals of 1:1.5, 1:1.75, and 1:2 PHG·Phen stoichiometry upon grinding the two components in different starting ratios and then using suitable solvents for single crystal growth. The phenol···pyridine O−H···N synthon directs 1:1.5 bimolecular organization of PHG and Phen molecules in a π-stacked motif (cocrystal 1). Additional phenazine molecules insert in the π-stacks to give a higher proportion of the aromatic species in cocrystals 2 and 3 (1:1.75 and 1:2). A hydrate cocrystal of 1:2:1 composition (4) was also obtained. The π-stack dimer motif of phenazine templated by the 1,3-(OH)2 moiety of phloroglucinol at about van der Waals distance in these crystal structures is postulated to promote the crystallization of the β-phenazine polymorph having a sandwich herringbone motif. These results suggest a role for cocrystal formers as hydrogen bond additives that favor and stabilize specific motifs for the crystallization of new polymorphs.

The Supramolecular Architecture of Arene Complexes of Bis(polyfluorophenyl)mercurials

AbstractThe 1:1 (arene)mercury complexes [HgR2(arene)] [R = C6F4‐o‐NO2, C6F4‐m‐NO2, C6F4‐o‐H, C6F5; arene = TMB (1,2,4,5‐tetramethylbenzene), PMB (1,2,3,4,5‐pentamethylbenzene)] are readily formed when mixtures of the mercurial and arene are crystallised from CH2Cl2 or CH2Cl2/hexane. Analogous 1:1 complexes are also formed from Hg(C6F5)2 and PhMe, whereas novel 1:2 complexes [HgR2(arene)2] result from Hg(C6F4‐o‐NO2)2 and PhMe or TMO (1,2,4‐trimethoxybenzene) and from Hg(C6F5)2 and TMO. In the crystalline state, the 1:1 [HgR2(arene)] complexes exist as canted columns of alternating planar HgR2 and arene layers linked by weak (Hg···C 3.2–3.5 Å) η1 or η2 π‐arene–mercury interactions. For the TMB (R = C6F4‐o‐NO2, C6F4‐o‐H, C6F5) and PhMe (R = C6F5) complexes, the packing of neighbouring columns shows aligned, alternating fluoroarene and arene ring planes resulting in a 2D brick‐wall motif with potential supramolecular components (fluoroarene–fluoroarene and fluoroarene–arene stacking). For the TMB complex with R = C6F4‐m‐NO2 the 2D array is distorted into a herringbone motif by weak C–H···O interactions. The 1:2 complex [Hg(C6F4‐o‐NO2)2(PhMe)2] has an analogous mercury environment to the 1:1 complexes, and the packing shows a distinct layer structure of alternating rows of PhMe and HgR2 with two PhMe units per HgR2 unit but with no inter‐stack interactions. The TMO complexes have long Hg···O contacts (3.2 Å) rather than Hg···C and similarly show a layered structure, but in this case, with a single column of alternating HgR2 and pairs of TMO. Theoretical calculations for the 1:2 [HgR2(TMB)2] complexes (R = C6F4‐o‐NO2, C6F4‐m‐NO2) are consistent with the findings from the observed crystal structures. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

8-Bromonaphthalen-1-amine

The title compound, C10H8BrN, was obtained by slow addition of sodium azide to 8-bromo-1-naphthoic acid, followed by addition of aqueous ammonia. The crude product was crystallized from petroleum ether to give pink crystals. Compared to other 1,8-disubstituted naphthalene compounds, this compound exhibits less strain between the 1 and 8 substituents. Additionally, the NH protons form both intra- and inter­molecular hydrogen bonds. The naphthalene units are arranged in a herring-bone stacking motif.

Dibenzyl penta-thio-dicarbonate.

In the title compound, C16H14S5, the non-bonded intra­molecular distances between the non-terminal S atoms are 2.808 (16) and 2.784 (16) Å, shorter than the typical distance of 2.9 Å. One phenyl ring participates in an offset π-π inter­action with another phenyl ring related by a centre of inversion; the inter­planar distance is 3.41 (2) Å. The crystal structure also exhibits edge-to-face C—H⋯π stacking of the phenyl rings, thus forming a herring-bone packing motif.

Synthesis of Oligo(thienylfuran)s with Thiophene Rings at Both Ends and Their Structural, Electronic, and Field‐Effect Properties

Oligo(thienylfuran)s with thiophene rings at both ends (SOSOSOS, DE-SOSOS, DH-SOSOS, DE-SOSOSOS, and DH-SOSOSOS; S and O denote thiophene and furan rings, respectively, DE and DH denote diethyl- and dihexyl-substituted, respectively) were newly synthesized by repetitive Stille coupling reactions. The UV/Vis maximum absorptions of the oligomers, SO, SOSO, SOSOS, SOSOSO, and SOSOSOS, exhibited a clear bathochromic shift with increasing number of heterocycles. The value of the oxidation peak potential (E(pa)1) determined by cyclic voltammetry decreased with an increase in the number of heterocycles by 0.06-0.08 V per heterocycle. The crystal-packing structures of DE-SOSOS and DH-SOSOS determined by X-ray crystallography have a herringbone motif and are denser than the reported structures of pentacene and alpha-sexithiophene. The morphologies of thin films prepared by vacuum deposition and spin coating were investigated by atomic force microscopy and X-ray diffraction. Among these films, those of DE-SOSOS and DH-SOSOS exhibited highly ordered arrangements. The devices based on vacuum-deposited and spin-coated films of DE-SOSOS and DH-SOSOS displayed the highest FET mobilities of 10(-2)-10(-3) cm2 V(-1) s(-1) among the oligomers reported in this study.

Structure and magnetic properties of a copper malonate/dipyridylamine layered coordination polymer with both syn–anti and anti–anti copper carboxylate chains

The novel 2-D copper metal–organic layered coordination polymer {[Cu 2(malonate) 2(dpa)(H 2O) 2] · H 2O} ( 1, dpa = 4,4′-dipyridylamine) has been prepared and characterized by single-crystal X-ray diffraction, IR and thermogravimetric analysis. The structure of compound 1 consists of alternating syn– anti and anti–anti copper malonate 1-D chains linked into a (6,3) herringbone layer motif through tethering dpa ligands. Variable temperature magnetic studies indicate weak ferromagnetic coupling through the 1-D copper malonate chains with J = 0.64(1) cm −1 and g = 2.033(4).

5-Fluoro-3-hydroxy-3-(nitromethyl)-1H-indol-2(3H)-one

The title compound, C9H7FN2O4, was isolated during a manual crystallization screen on 5-fluoroisatin (5-fluoroindoline-2,3-dione). Hydrogen-bonded ribbons of the oxindole are formed through pairs of N-H center dot center dot center dot O and O-H center dot center dot center dot O interactions. These ribbons then pack parallel to (09 (2) over bar) and (091) such that a herring-bone motif is established.

1,2,4-Triiodobenzene

In the crystal structure of the title compound, C6H3I3, the mol­ecules are planar and the packing displays a herringbone motif. Mol­ecules are held together by long weak non-bonding I⋯I inter­actions.

2,3-Diiodonaphthalene

In the crystal structure of the title compound, C10H6I2, the mol­ecules are planar and packed in a herring-bone motif. The mol­ecules are held together by weak I⋯I inter­molecular inter­actions.

Exploration of the high-pressure behaviour of polycyclic aromatic hydrocarbons: naphthalene, phenanthrene and pyrene

The structural response of three members of the family of polycyclic aromatic hydrocarbons (PAHs) to high-pressure recrystallization from dichloromethane solutions is presented. Recrystallization of naphthalene in the 0.2-0.6 GPa pressure range does not result in the formation of a new polymorph. Furthermore, direct compression of a single crystal to 2.1 GPa does not result in a phase transition. A density decrease of 18.2% over the 0.0-2.1 GPa pressure range is observed and the principal effect of pressure is to ;tighten' the herringbone structural motif and decrease the size of void regions. A new polymorph of pyrene, form III, has been crystallized at 0.3 and at 0.5 GPa. Structural investigation of this new polymorph by means of topological analysis and comparison of Hirshfeld surfaces and fingerprint plots shows that intermolecular interactions are substantially different from those found in the ambient-pressure structures, and do not fit a previously established packing model for PAHs. Similar discrepancies are found for the high-pressure polymorph of phenanthrene, which is here re-investigated in greater detail. The structures of these high-pressure polymorphs are dominated by pi...pi stacking with a limited contribution from C-H...pi (peripheral) interactions. It is perhaps not surprising that high-pressure polymorphs deviate from a model that has been devised for ambient-pressure structures, and this may be a direct consequence of the ability of pressure to modify and combine intermolecular interactions in ways that are not usually found at ambient pressure. This is achieved by modifying the relative orientations of molecules and by encouraging the formation of denser structures in which molecules pack together more efficiently.

Triphenylene Analogues with B2N2C2 Cores: Synthesis, Structure, Redox Behavior, and Photophysical Properties

A series of alkyl (1-3), aryl (6), and benzo-annulated (4, 5) heteroaromatic triphenylene analogues with B(2)N(2)C(2) cores have been synthesized via chelation of pyridazine derivatives using difunctional Lewis acidic diborabiphenyl precursors. In contrast to triphenylene, NICS(1) calculations on 1 suggested high aromaticities for the central (-11.3 ppm) and outer borabenzene rings (-7.7 ppm), along with nonaromatic behavior for the pyridazine ring (-0.7 ppm). Crystal structure analyses supported this analysis. When the a- and c-faces of the pyridazine moiety were free of substitution (1, 3), planar structures resulted, but upon substitution, a twisted B(2)N(2)C(2) core was observed due to steric repulsion of neighboring hydrogen atoms (e.g., 5). The increase of steric bulk from H (1) to (i)Pr (3) in the planar species was found to result in a dimeric, head-to-tail herringbone packing motif, held together by close intermolecular B...N interactions of 3.39 Angstrom. One-electron reduction by Cp(2)Co was found to afford the radical anions of 3 and 5, which were characterized by broad, featureless singlets in the EPR spectra; [3](.)(-)[Cp(2)Co](+) was characterized by X-ray crystallography. While the planar structures (1-4) were observed to possess weak fluorescence (Phi(F) = 0.02-0.08) with either yellow-orange (ca. 555 nm) or green emission (521 nm), the twisted structures (5, 6) were found to be nonfluorescent.

Ring Fusion Effects on the Solid-State Properties of α-Oligothiophenes

The solid-state properties of a series of fused-ring oligothiophenes were studied by UV−visible absorption spectroscopy and single crystal X-ray diffraction. Although the degree of ring fusion has little effect on the solution absorption spectra, the solid-state spectra are dramatically different. Three thieno[3,2-b]thiophene-containing oligomers display spectral blue shifts when comparing the solid state to solution because they adopt a herringbone packing motif that leads to H aggregation. The solid-state structure of a dithieno[3,2-b:2‘,3‘-d]thiophene-based oligomer contains both herringbone and slipped π−π interactions, and the overlap of transitions from these different interaction modes results in a broad absorption spectrum in the solid state. The fully fused pentathienoacene adopts a π-stacked packing motif and displays a small blue shift in the solid-state spectrum compared to solution. Time-dependent density functional theory calculations of the electronic transitions of isolated molecules and i...

1-Bromopyrene

1-Bromopyrene, C16H9Br, is a planar, fused aromatic organic compound. The molecule is approximately planar with an r.m.s. deviation of 0.0243 Å for the ring C atoms and 0.0261 Å for all non-H atoms. A herringbone packing motif based on π-π interactions is observed, with a perpendicular distance between adjacent stacked molecules of 3.519 Å.

Structural and vibrational characterization of the organic semiconductor tetracene as a function of pressure and temperature

Neutron powder diffraction and inelastic neutron scattering measurements were performed on crystalline tetracene, a molecular semiconductor of triclinic crystal structure that adopts a herringbone layered motif, as a function of pressure up to 358 MPa. In combination with theoretical and simulated computations, these measurements permit detailed characterization of the structural and vibrational changes of tetracene as a function of pressure. Powder diffraction at 295 K reveals anisotropic modification of the crystal structure with increasing pressure. Particularly, the unit cell parameters associated with the two-dimensional herringbone layers of the solid state structure displayed continuous change at all measured pressures, whereas perpendicular to the herringbone layers the structure remains relatively unchanged. The measured compressibilities along the [1 0 0], [0 1 0], and [0 0 1] crystal axes are −3.8 × 10 −4, −1.9 × 10 −4, and −3.4 × 10 −4 Å/MPa, respectively. Inelastic neutron scattering spectra were collected at several pressures in the 25–75 and 0–25 meV energy ranges using a filter analyzer and a Fermi chopper time-of-flight spectrometer, respectively. Assignment of the spectral peaks to specific intramolecular vibrational modes has been accomplished using ab initio density functional theory calculations and the low energy lattice phonon modes were interpreted from the results of molecular dynamics simulations at 1 atm and 358 MPa. Anisotropic behavior parallel to that observed in the structural measurements is also apparent in both the intramolecular and lattice phonon vibrational dynamics. Intramolecular vibrations having atomic displacements entirely within the plane of the molecule’s aromatic ring remain unchanged with increasing pressure while vibrations with atomic displacements perpendicular to the molecular plane shift to higher energy. The lattice phonons display a similar anisotropy with increasing pressure. Phonon modes propagated within the herringbone layer are significantly shifted to higher energy with increasing pressure relative to the modes with displacements primarily perpendicular to the layers. Overall, both the planar internal geometry and the layered arrangement of the tetracene molecules significantly influence the observed structural and vibrational behavior with increasing pressure.

Organization of Acenes with a Cruciform Assembly Motif

This study explores the assembly in the crystalline state of a class of pentacenes that are substituted along their long edges with aromatic rings forming rigid, cruciform molecules. The crystals were grown from the gas phase, and their structures were compared with DFT-optimized geometries. Both crystallographic and computed structures show that a planar acene core is the exception rather than the rule. In the assembly of these molecules, the phenyl groups block the herringbone motif and further guide the arrangement of the acene core into higher order structures. The packing for the phenyl-substituted derivatives is dictated by close contacts between the C-H's of the pendant aromatic rings and the carbons at the fusions in the acene backbone. Using thiophene substituents instead of phenyls creates cofacially stacked acenes. In thin films, the thiophene-substituted derivative forms devices with good electrical properties: relatively high mobility, high ON/OFF ratios, and low threshold voltage for device activation. An unusual result is obtained for the decaphenyl pentacene when devices are fabricated on its crystalline surface. Although its acene cores are well isolated from each other, this material still exhibits good electrical properties.

Crystal structures and packing motifs of 2,3-diphenylquinoxaline and 2,3-diphenylbenzo[g]quinoxaline

White plates of 2,3-diphenylquinoxaline crystallize in the monoclinic space group P21/n with Z = 4 and a = 6.0325(3) A, b = 10.9516(6) A, c = 22.5985(13) A, and β = 95.107(2)°. The phenyl rings in 2,3-diphenylquinoxaline form torsion angles of 36.88(5)° and 53.32(4)° with the plane defined by the quinoxaline moiety. Yellow plates of 2,3-diphenylbenzo[g]quinoxaline crystallize in the monoclinic space group C2/c with Z = 8 and a = 25.0621(16) A, b = 7.7190(5) A, c = 21.2225(14) A, and β = 123.674(2)°. The phenyl rings in 2,3-diphenylbenzo[g]quinoxaline form torsion angles of 46.89(3)° and 43.42(3)° with the plane defined by the benzo[g]quinoxaline moiety. Packing in 2,3-diphenylquinoxaline can best be described as following the herringbone motif; whereas the packing in 2,3-diphenylbenzo[g]quinoxaline crystals can also be described as herringbone—albeit a herringbone pattern made up of head-to-tail oriented neighbors.