scholarly journals Tuning colour in multi-component complexes: Molecular disorder as a design tool

2014 ◽  
Vol 70 (a1) ◽  
pp. C1007-C1007
Author(s):  
Charlotte Jones ◽  
Chick Wilson ◽  
Lynne Thomas
Keyword(s):  
Single Crystal ◽  
Crystal Engineering ◽  
Crystal Packing ◽  
Colour Change ◽  
Molecular Complexes ◽  
Design Tool ◽  
Layered Crystal ◽  
Molecular Rearrangement ◽  
Organic Systems ◽  
Inorganic Systems

The key aim of multi-component crystallisation is modification of the physicochemical properties for a specific task.[1] Tuning colour using molecular components is a relatively unexplored area, which is surprising given the possible advantages in pigment development. In crystalline materials, the optical characteristics are not solely dependent on the molecules but also on the crystal packing;[2] it follows that the optical properties could be modified using crystal engineering techniques. We have systematically investigated co-crystallising haloanilines with dinitrobenzoic acids to build an understanding of the intermolecular interactions. Molecular disorder of one or more of the components tends to lead to layered crystal structures that include stacking interactions and therefore strong colour, indicating that molecular disorder is desirable. Defects in inorganic systems are routinely exploited as a route to enhancing or introducing physical properties but similar effects in organic systems are yet to be properly exploited. We will discuss the methods by which disorder can be designed into molecular complexes, and the local ordering effects which give rise to strong diffuse scattering. Additionally we have identified a pair of thermochromic molecular complexes, 2-iodoaniline/2-bromoaniline 3,4-dinitrobenzoic acid, where disorder appears to be crucial in lending the materials their properties. Both complexes undergo a temperature-induced colour change from red to yellow corresponding to a significant molecular rearrangement. The thermochromic transition is a single-crystal to single-crystal effect; the role of molecular disorder as a facilitator for the molecular rearrangement, maintaining the crystal integrity, will be discussed. Despite the complexes being isostructural, only the bromoaniline complex shows reversible thermochromic behaviour; subtleties in the manifestation of this disorder can explain the differences in the reversibility of the transition.

Utilizing proton transfer to produce molecular salts in bromanilic acid substituted-pyridine molecular complexes – predictable synthons?

2013 ◽  
Vol 69 (11) ◽  
pp. 1279-1288 ◽  
Author(s):  
Lynne H. Thomas ◽  
Martin S. Adam ◽  
Andrew O'Neill ◽  
Chick C. Wilson
Keyword(s):  
Proton Transfer ◽  
Crystal Engineering ◽  
Crystal Packing ◽  
Molecular Complexes ◽  
Design Tool ◽  
Acid Molecule ◽  
Protonation State ◽  
Molecular Salts ◽  
Potential Strategy ◽  
A Charge

Controlled introduction of proton transfer into the design of a series of molecular complexes is described, delivering the systematic production of ionic molecular complexes (molecular salts). The controlled production of molecular salts has relevance as a potential strategy in the design of pharmaceutical materials. In nine molecular complexes consisting of bromanilic acid with the N-heterocyclic compounds 2-, 3- and 4-picoline [bis(2/3/4-methylpyridinium) 2,5-dibromo-3,6-dioxocyclohexa-1,4-diene-1,4-diolate, 2C6H8N+·C6Br2O42−], 2,3-, 2,4-, 2,5- and 3,5-lutidine [2,3/2,4/2,5/3,5-dimethylpyridinium 2,5-dibromo-4-hydroxy-3,6-dioxocyclohexa-1,4-dien-1-olate, C7H10N+·C6HBr2O4−], and 3-bromo-4-methylpyridine [3-bromo-4-methylpyridinium 2,5-dibromo-4-hydroxy-3,6-dioxocyclohexa-1,4-dien-1-olate, C6H7BrN+·C6HBr2O4−] and 2-bromo-3-methylpyridine [2-bromo-3-methylpyridine–2,5-dibromo-3,6-dihydroxycyclohexa-2,5-diene-1,4-dione (1/1), C6H6BrN·C6H2Br2O4], proton transfer occurs readily between the bromanilic acid molecule and the N heteroatom of the pyridine ring, in all cases producing a charge-assisted bifurcated N—H...O hydrogen bond. This reinforces the value of this motif as a design tool in the crystal engineering of such complexes. The protonation state (and stoichiometry) significantly affect the supramolecular synthons obtained, but 1:2 stoichiometries reliably give rise to PBP synthons and 1:1 stoichiometries to PBBP synthons (where P indicates a methylpyridine co-molecule and B a bromanilic acid molecule). The influence of halogen interactions on the wider crystal packing is also discussed, with C—H...Br and Br...O interactions the most prevalent; only one Br...Br interaction is found.

scholarly journals "Organic Fluorine" and its Importance in Crystal Engineering

2014 ◽  
Vol 70 (a1) ◽  
pp. C669-C669
Author(s):  
Angshuman Roy Choudhury ◽  
Gurpreet Kaur ◽  
Maheswararao Karanam ◽  
Sandhya Patel
Keyword(s):  
Crystal Engineering ◽  
Crystal Packing ◽  
Weak Interactions ◽  
Crystal Lattices ◽  
Organic Systems ◽  
Organic Solid ◽  
Group A ◽  
Number Of Publications ◽  
Organic Fluorine

The phrase "Organic fluorine" [1] was introduced by Dunitz and Taylor in 1997 to identify the C–F bonds in organic systems. Different research groups have used the phrase to glorify or deny the influence of C–F bond in crystal lattices. Once Dunitz stated that "Organic Fluorine: Odd Man Out" and Howard et al. questioned the role of "Organic fluorine" in crystal engineering. While some researchers have refuted the role of "organic fluorine" in crystal packing; the others indicated the importance of the interactions involving the same group. A number of publications have shown the importance of "Organic fluorine" in influencing crystal packing. We have been interested in the area of weak interactions in organic solid state chemistry since 1999 [2]; especially interactions involving "Organic fluorine". The study is being conducted following a systematic approach and is still in progress. We have looked at the structures of a number if tetrahydroisoquinoline derivatives, a number of differently substituted imines, phenyleacetanilydes, benzanilides and azobenzenes [3] etc. in order to elucidate the influence of "Organic fluorine" in crystal engineering both in the presence and in the absence of strong hydrogen bonding functional groups present within the molecule. A short summary of our observations will be highlighted in the presentation.

Arene–perfluoroarene interactions in crystal engineering. Part 14. 1:1 Complexes of octafluoronaphthalene with fluorene and 9,10-dihydrophenanthrene

2006 ◽  
Vol 84 (2) ◽  
pp. 238-242 ◽  
Author(s):  
Jonathan C Collings ◽  
Andrei S Batsanov ◽  
Judith AK Howard ◽  
Todd B Marder
Keyword(s):  
Single Crystal ◽  
Key Words ◽  
Crystal Engineering ◽  
Molecular Complexes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Face To Face ◽  
Π Stacking

The 1:1 molecular complexes of octafluoronaphthalene (OFN) with fluorene (1) and with 9,10-dihydrophenanthrene (2) were prepared by cocrystallization of the components and characterized by single-crystal X-ray diffraction. The structure of 1 can be described as a mixed-stack or a laminar checkerboard motif of alternating OFN and fluorene molecules, whilst slanted mixed-stack, herringbone, and face-to-face heteromolecular dimer motifs can all be recognised in 2.Key words: single crystal, X-ray structure, π stacking, fluoroarene.

scholarly journals Zn(II) Heteroleptic Halide Complexes with 2-Halopyridines: Features of Halogen Bonding in Solid State

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3393
Author(s):  
Mikhail A. Vershinin ◽  
Marianna I. Rakhmanova ◽  
Alexander S. Novikov ◽  
Maxim N. Sokolov ◽  
Sergey A. Adonin
Keyword(s):  
Solid State ◽  
Quantum Yield ◽  
Crystal Packing ◽  
Halogen Bonding ◽  
Molecular Complexes ◽  
Substituted Pyridines ◽  
Halide Complexes

Reactions between Zn(II) dihalides and 2-halogen-substituted pyridines 2-XPy result in a series of heteroleptic molecular complexes [(2-XPy)2ZnY2] (Y = Cl, X = Cl (1), Br (2), I (3); Y = Br, X = Cl (4), Br (5), I (6), Y = I, X = Cl (7), Br (8), and I (9)). Moreover, 1–7 are isostructural (triclinic), while 8 and 9 are monoclinic. In all cases, halogen bonding plays an important role in formation of crystal packing. Moreover, 1–9 demonstrate luminescence in asolid state; for the best emitting complexes, quantum yield (QY) exceeds 21%.

Structural diversity of salts of terpyridine derivatives with europium(III) located in both, cation and anion, in comparison to molecular complexes

2020 ◽  
Vol 235 (8-9) ◽  
pp. 353-363
Author(s):  
Alexander E. Sedykh ◽  
Robin Bissert ◽  
Dirk G. Kurth ◽  
Klaus Müller-Buschbaum
Keyword(s):  
Thermal Properties ◽  
Crystal Packing ◽  
Side Reaction ◽  
Molecular Complexes ◽  
Structural Diversity ◽  
Organic Ligands ◽  
Ionic Complexes ◽  
Structural Variability ◽  
Dimeric Complexes ◽  
The Common

AbstractThree salts of the common composition [EuCl2(X-tpy)2][EuCl4(X-tpy)]·nMeCN were obtained from EuCl3·6H2O and the respective organic ligands (X-tpy = 4′-phenyl-2,2′:6′,2″-terpyridine ptpy, 4′-(pyridin-4-yl)-2,2′:6′,2″-terpyridine 4-pytpy, and 4′-(pyridin-3-yl)-2,2′:6′,2″-terpyridine 3-pytpy). These ionic complexes are examples of salts, in which both cation and anion contain Eu3+ with the same organic ligands and chlorine atoms coordinated. As side reaction, acetonitrile transforms into acetamide resulting in the crystallization of the complex [EuCl3(ptpy)(acetamide)] (4). Salts [EuCl2(ptpy)2][EuCl4(ptpy)]·2.34MeCN (1), [EuCl2(4-pytpy)2][EuCl4(4-pytpy)]·0.11MeCN (2), and [EuCl2(3-pytpy)2][EuCl4(3-pytpy)]·MeCN (3) crystallize in different structures (varying in space group and crystal packing) due to variation of the rear atom of the ligand to a coordinative site. Additionally, we show and compare structural variability through the dimeric complexes [Eu2Cl6(ptpy)2(N,N′-spacer)]·N,N′-spacer (5, 6, 7) obtained from [EuCl3(ptpy)(py)] by exchanging the end-on ligand pyridine with several bipyridines (4,4′-bipyridine bipy, 1,2-bis(4-pyridyl)ethane bpa, and 1,2-bis(2-pyridyl)ethylene bpe). In addition, photophysical (photoluminescence) and thermal properties are presented.

Organic crystal engineering with piperazine-2,5-diones. 2. Crystal packing of weakly dipolar piperazinediones derived from 2-amino-4-bromo-7-methoxyindan-2-carboxylic acid

Tetrahedron ◽  
1999 ◽  
Vol 55 (50) ◽  
pp. 14301-14322 ◽  
Author(s):  
Lawrence J. Williams ◽  
B. Jagadish ◽  
Michael G. Lansdown ◽  
Michael D. Carducci ◽  
Eugene A. Mash
Keyword(s):  
Carboxylic Acid ◽  
Crystal Engineering ◽  
Crystal Packing ◽  
Organic Crystal

scholarly journals Accurate H-atom parameters for the two polymorphs of L-histidine at 5, 105 and 295 K

2021 ◽  
Vol 77 (5) ◽  
pp. 785-800
Author(s):  
Giulia Novelli ◽  
Charles J. McMonagle ◽  
Florian Kleemiss ◽  
Michael Probert ◽  
Horst Puschmann ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Single Crystal ◽  
Diffraction Data ◽  
Crystal Packing ◽  
Basis Sets ◽  
X Ray Diffraction ◽  
X Ray ◽  
Refinement Method ◽  
Primary Amino ◽  
Precision And Accuracy

The crystal structure of the monoclinic polymorph of the primary amino acid L-histidine has been determined for the first time by single-crystal neutron diffraction, while that of the orthorhombic polymorph has been reinvestigated with an untwinned crystal, improving the experimental precision and accuracy. For each polymorph, neutron diffraction data were collected at 5, 105 and 295 K. Single-crystal X-ray diffraction experiments were also performed at the same temperatures. The two polymorphs, whose crystal packing is interpreted by intermolecular interaction energies calculated using the Pixel method, show differences in the energy and geometry of the hydrogen bond formed along the c direction. Taking advantage of the X-ray diffraction data collected at 5 K, the precision and accuracy of the new Hirshfeld atom refinement method implemented in NoSpherA2 were probed choosing various settings of the functionals and basis sets, together with the use of explicit clusters of molecules and enhanced rigid-body restraints for H atoms. Equivalent atomic coordinates and anisotropic displacement parameters were compared and found to agree well with those obtained from the corresponding neutron structural models.

scholarly journals Single-crystal-to-single-crystal transformations triggered by dehydration in polyoxometalate-based compounds

2018 ◽  
Vol 74 (11) ◽  
pp. 1222-1242 ◽  
Author(s):  
Santiago Reinoso ◽  
Beñat Artetxe ◽  
Juan M. Gutiérrez-Zorrilla
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Crystal Engineering ◽  
Structural Response ◽  
Transformation Process ◽  
External Stimulus ◽  
Stimuli Responsive ◽  
Feature Article ◽  
Crystal Transformation ◽  
Solvent Molecules

Single-crystal-to-single-crystal transformations are solid-state phase transitions between different crystalline states in which the crystal integrity and the long-range structural order are retained through the whole transformation process. Such a phenomenon constitutes the structural response that some compounds afford when being exposed to a given external stimulus (temperature, pressure, light, etc.) and, therefore, its study has become a relevant focus of interest within crystal engineering because it allows for monitoring how certain properties (colour, magnetism, luminescence, porosity) of the stimuli-responsive material are modified as the structure evolves into the activated form. A range of organic, inorganic and hybrid systems have been found to undergo such phase transitions, but these examples only include a small number of compounds that incorporate polyoxometalate anions, among which the removal of guest solvent molecules (dehydration) stands out as the most common external stimulus able to induce the occurrence of a single-crystal-to-single-crystal transformation. This feature article compiles the examples of dehydration-triggered single-crystal-to-single-crystal transformation studies that have been reported to date for polyoxometalate-based compounds and reviews some of their most relevant structural aspects.

Study on Novel Structure of Praseodymium Complex, C5H13O11Pr

2013 ◽  
Vol 834-836 ◽  
pp. 515-518
Author(s):  
Hai Xing Liu ◽  
Qing Liu ◽  
Ting Ting Huang ◽  
Yang Xu ◽  
Lin Tong Wang ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Single Crystal ◽  
Hydrothermal Reaction ◽  
Crystal Packing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Novel Structure ◽  
Praseodymium Complex

A novel praseodymium complex C5H13O11Pr has been synthesized from hydrothermal reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Pr1 atom is nine coordinated by nine O atoms. The crystal packing is stabilized by O-H...O hydrogen bonding interactions.

scholarly journals Regioisomeric control of layered crystallinity in solution-processable organic semiconductors

2020 ◽  
Vol 11 (46) ◽  
pp. 12493-12505
Author(s):  
Satoru Inoue ◽  
Toshiki Higashino ◽  
Shunto Arai ◽  
Reiji Kumai ◽  
Hiroyuki Matsui ◽  
...  
Keyword(s):  
Single Crystal ◽  
Organic Semiconductors ◽  
High Performance ◽  
Crystal Packing ◽  
Positional Isomers ◽  
Solution Processable

An isomorphous bilayer-type layered herringbone crystal packing is reported for a series of four positional isomers of mono-C8-BTNTs, where the single-crystal devices with the isomers exhibit high-performance TFT characteristics.

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