Host–guest complexes of conformationally flexible C-hexyl-2-bromoresorcinarene and aromatic N-oxides: solid-state, solution and computational studies (original) (raw)
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Cumhuriyet Science Journal, 2018
The chemical properties of recently synthesized 6-bromo-5-nitroquinoline-1-oxide under a mild reaction condition by regioselective nitration of 6-bromoquinoline-1-oxide at C5 on going our research were investigated as theoretical. The crystal structure of 6-bromo-5-nitroquinoline-1-oxide, C 9 H 5 BrN 2 O 3 , was determined by X-ray analysis. Crystallized in Pmc2 1 in the orthorhombic space group with a = 13.6694 (13) Å, b = 9.6036 (10) Å, c = 14.1177 (16) Å, Z = 8, D x = 1.929 mg/m 3. In this study, theoretical calculations were performed using the GaussView 4.1 molecular imaging program and the Gaussian03W packet program. In the ground state, stable structures of the wholes molecule in the gaseous phase are investigated based on Density Functional Theory (DFT). Molecularly optimized geometries, dipole moments, charge density, thermodynamic properties (heat capacity, enthalpy, entropy), chemical shift values (1 H NMR and 13 C NMR), energies, molecular electrostatic potentials and frontier orbitals (HOMO and LUMO) B3LYP/6-311G(d,p) base set. Thus, the results obtained by the X-ray diffraction method are supported by theoretical foundations. Finally, the distribution of interactions between molecules in the crystal structure of 6-bromo-5-nitroquinoline-1-oxide (3) was investigated by analysis using Hirshfeld surface production and two-dimensional fingerprinting.
CrystEngComm, 2012
The synthesis and characterization of new bromine substituted pyridine and benzyl functionalized tetramethoxy resorcinarene tetrapodands are described and their solid state structural properties and interactions were studied by single crystal X-ray crystallography. Three different crystal structures were obtained for the pyridine derivative and one for the benzyl derivative, which revealed that the interactions of the bromine substituent have explicitly an effect on the crystal packing of the resorcinarene molecules. One of the structures obtained had very interesting halogen-halogen interaction with the same geometry as is generally found for compounds used in nonlinear optical studies.
New Journal of Chemistry, 2010
The reactions of bis(3-pyridylcarboxamido)alkanes (amides, 1) and bis(3-pyridyl)alkanediamides (reverse amides, 2) with Cu(SCN) 2 in the presence of various guests afforded 22 crystalline complexes containing 1D and 2D coordination networks with or without guest inclusion. In these complexes, the ratio of metal to ligand is either 1 : 1 or 1 : 2, despite carrying out all the reactions by taking metal and ligand in 1 : 2 ratio. The recognition of coordination networks via amide-to-amide hydrogen bonds in the form of b-sheet was observed in the complexes containing metal to ligand ratio (1 : 2). Various guest molecules such as DMF, nitrobenzene, benzonitrile, 1,4-dihalobenzenes, phenanthrene, biphenyl, anthracene, 9-anthraldehyde and pyrene were found to include in these networks depending on the lengths of the spacers in 1 or 2. The ligands 1 or 2 with shorter spacers such as -(CH 2 ) 2 -and -(CH 2 ) 4 -have shown no consistency or preference to any particular network geometry. However the ligands with longer spacers such as -(CH 2 ) 6 -, -(CH 2 ) 8 -or phenyl have exhibited consistency in network geometries. The iso-structurality between the coordination polymers of amides and reverse amides was observed for ligands with longer spacers such as -(CH 2 ) 6 -and -(C 6 H 4 )-. The spacer -(CH 2 ) n -found to exhibit different conformations for accommodating the guests of different sizes and shapes. The guest occupied volume in these crystal lattices varies from 27% to 60%.
Structural studies of supramolecular host-guest systems
2015
This research work details a systematic study of the structure and function of supramolecular host-guest systems. Host-guest inclusion complexes were formed between β-Cyclodextrin (β-CD) and its copolymers (as hosts), with several types of guest molecules both in aqueous solution and the solid state. The research is divided into two themes; (1) structural characterization and dynamic properties of the inclusion compounds of -CD with various guest systems in aqueous solution and the solid phase, and (2) heterogeneous adsorption and structural studies of β-CD based copolymers with various guest systems in aqueous solutions. The guest systems include alkyl and perfluoroalkyl carboxylates, perfluoroalkyl sulfonate, and pnitrophenol (PNP) at variable experimental conditions. In the first theme (chapters 2-5), perfluorinated compounds (PFCs), namely; perfluorooctanoic acid (PFOA), perfluorobutyric acid (PFBA), and sodium perfluorooctanoate (SPFO) represent the guest molecules. The host-guest complexes in the solid state were prepared using dissolution and slow cool methods at variable host/guest mole ratios (i.e., 1:1 and 2:1). The complexes were further characterized using 19 F/ 13 C DP/MAS and CP/MAS solid-state NMR spectroscopy. The solution state complexes were prepared in D 2 O for structural characterization using 1 H/ 19 F NMR spectroscopy. The NMR studies were complemented using FT-IR, thermal analyses (DSC, and TGA), and powder X-ray diffraction (PXRD). Evidence for the formation of host-guest inclusion compounds (ICs) was provided using CP/MAS solids NMR spectroscopy and complexation-induced chemical shift (CIS) values of 1 H/ 19 F nuclei in aqueous solution. The β-CD/PFC ICs displayed variable guest geometry and hydration states as determined by the hostguest stoichiometry and the conformation of the guest. PFOA and SPFO form 1:1 and 2:1 ICs with β-CD, wherein the guest adopts a range of gauche and trans conformations, respectively. v 1:1 host-guest complexes were concluded for short perfluorocarbon chains (i.e., PFBA) where the gauche conformation of the PFC guest in the bound state was favoured. The phase purity of the β-CD/PFC ICs was assessed using DSC and 19 F DP/MAS NMR spectroscopy at ambient and variable temperature (VT) conditions. The complexes prepared by the slow cool method were found to be of relatively high phase purity when compared to complexes prepared by the dissolution method. However, a simple modified dissolution method was developed to afford complexes with greater phase purity. The phase purity of the complexes was further assessed using deconvolution analyses of the 19 F DP/MAS NMR resonance line shapes. 1 H/ 13 C/ 19 F NMR relaxation (T 1 /T 2 /T 1ρ) data of the phase pure β-CD/PFC ICs in the solid state revealed variable host and guest dynamics that were governed by dipolar coupling, Hbonding, and combinations of host-guest motional dynamics that involve peripheral and hydrate water within the cavity of β-CD. Coupling constants of the simulated 19 F spectra and deconvolution analyses of selected 19 F nuclei were used to supplement the 19 F NMR relaxation results. In general, two types of motional dynamics of the guest were concluded; (i) 120° rotational jumps of the fluoromethyl (CF 3) group at the termini of the PFC chain, and (ii) axial (libration) motion of the entire PFC chain. The rotational and axial dynamics of the guest in the complexes differ in their distribution and magnitude, in accordance with the host-guest stoichiometry and the geometry of the guest within the host. In the second theme (chapters 6-8), β-CD based copolymers were used as host materials. The structural characterization of a soluble poly-CD material (known as HDI-1) revealed that the solution behaviour of such polymeric hosts are sensitive to the presence of guest compounds such as p-nitrophenol (PNP) (i.e. chemo-responsive), as well as temperature variations (i.e. thermo-responsive). The host-guest chemistry of the soluble poly-CD material, as studied by 2-D vi solution NMR and induced circular dichroism (ICD) spectroscopy, indicates that PNP was bound within the cavity sites of β-CD and the interstitial domains of the copolymer (cf. Scheme 1.6 and chapter 6). The observed responsive nature of such polymeric host materials to temperature variation and chemical potential resembles behaviour characteristic of 'smart materials'. Herein, 'smart materials' refer to systems which are responsive to external stimuli (e.g. temperature and chemical). The adsorption properties of the soluble (HDI-1) and insoluble (HDI-3 and-6) poly-CD adsorbents with octyl and perfluorooctyl carboxylate and sulfonate anions were estimated using the Sips and BET models. The hydrocarbon (HC) and fluorocarbon (FC) anions form monolayer and multilayer structures at the surface of the polymeric adsorbents, respectively. The formation of layered structures was controlled by the relative hydrophobicity of the alkyl/perfluoroalkyl chains and their mutual miscibility with the adsorbent surface. Other factors include the inductive effects of the alkyl/perfluoroalkyl head groups and their interactions with aqueous solvent or dipolar domains of the adsorbent surface. The adsorbed species at the liquid-solid interface were characterized using FT-IR spectroscopy, thermal analyses, and contact angle. vii
Dalton Trans., 2015
We have synthesized two palladacyclopentadienyl derivatives bearing bidentate ligands heteroditopic 8-(diphenylphosphino)quinoline or 8-(diphenylphosphino)-2-methylquinoline. We have reacted the palladacyclopentadienyl complexes with Br 2 and I 2 to gain clues on the formation mechanism of the corresponding σ-butadienyl derivatives. We were able to obtain the pure σ-butadienyl derivative only in the case of Br 2 reacting with the palladacyclopentadienyl complex bearing the unsubstituted quinoline. However, an equilibrium mixture of the σ-butadienyl and a novel zwitterionic species was obtained when the same complex reacts with I 2 . Furthermore, we have obtained exclusively an unprecedented zwitterionic complex when I 2 reacts with the palladacyclopentadienyl complex bearing the substituted quinoline and a different ratio of an equilibrium mixture of σ-butadienyl and the zwitterionic species when the latter derivative reacts with Br 2 . The solid state structures of one σ-butadienyl complex and of the two novel zwitterionic derivatives were determined and an interpretation of the observed reactivity based on kinetic data and a computational study has been suggested. † Electronic supplementary information (ESI) available: Further details of the structure determination, final coordinates, bond distances and bond angles and ORTEP representations for 2a, 4b and 5b, NMR spectra, schematic computational outcomes. CCDC 1053523-1053525. For ESI and crystallographic data in CIF or other electronic format see
Journal of Molecular Structure, 2011
pÁÁÁp XÁÁÁp interactions abstract The compound [3,5-dibromo-2-amino-4,6-dimethylpyridinium] 2 CuCl 4 , (1), was prepared from acidic hydrochloric acetonitrilic medium containing CuCl 2 and 3,5-dibromo-2-amino-4,6-dimethylpyridinium bromide while [3,5-dibromo-2-amino-4,6-dimethylpyridinium] 2 CuBr 4 , (2), from acidic HBr/Br 2 ethanolic medium containing 4,6-dimethylpyridine and CuBr 2 . The ring got dibrominated at 3 and 5 positions in situ. Single-crystal X-ray diffraction proved the compounds to be isomorphous in P À 1. A systematic study of the crystallographic parameters in dibrominated and nonbrominated 2-amino-4,6-dimethylpyridine salts will explain the role of nonclassical noncovalent interaction between aryl bromine and ionic metal bromide in the control of structure.
The Journal of Organic Chemistry, 1993
that for CI-CI so that our measurements with their large uncertainties provide no experimental evidence on the point. Some supporting evidence is available in the results of X-ray diffraction investigation of [4.4.2]propella-3,8-diene-l1,1 2-dione,I5 a molecule with a CBD subunit, and trans-3,4-di-tert-butylcyclobutane-1,2-dione" The first of these has distances of 1.551 (3) A, 1.534 (3) A, and 1.572 (3) A for the bonds corresponding to C&, C1-C4, and C -C4 in CBD; the second has distances of 1.560 A, 1.527 (2) A, and 1.560 (3) A. Thus the CI-C1 type distance is in each case longer than normal and the CI-C4 type smaller than its neighbors.
Journal of The Chemical Society-dalton Transactions, 1997
2-Aminopyridinium (2-amino-5-bromopyridine)tribromocuprate() 1 and bis(2-aminopyridinium) tetrabromocuprate() 2 have been prepared from acetonitrile solutions containing CuBr 2 , HBr and 2-aminopyridine in 1 : 2 : 2 and 1 : 2 : 1 molar ratio, respectively. The mother-liquor of 1 was photoirradiated with a superhigh-pressure mercury lamp and the organic base underwent partial electrophilic para bromination of the substituted pyridine ring. The compounds have been characterised by elemental analysis, IR, UV/VIS and ESR spectroscopies, thermal analysis, variable-temperature magnetic susceptibility measurements and single-crystal X-ray diffraction. The crystal structure of 1 consists of infinite zigzag chains of [C 5 H 7 N 2 ] + cations and distorted [CuBr 3 (C 5 H 5 BrN 2 )] Ϫ tetrahedral anions running along the b axis and held together by means of N᎐H ؒ ؒ ؒ Br hydrogen contacts and non-covalent interactions between the π systems of the pyridine rings. In 2 organic cations and flattened [CuBr 4 ] 2Ϫ anions form two-dimensional N᎐H ؒ ؒ ؒ Br hydrogen-bonded sheets which are connected by electrostatic interactions, van der Waals forces and face-to-face stacking interactions between the π systems of the aromatic cations. Magnetic susceptibility measurements of powdered samples showed that both compounds exhibit weak antiferromagnetic exchange interactions [J = Ϫ1.20 (1), Ϫ2.43 cm Ϫ1 (2)]. Thermal decomposition of both compounds yielded copper() oxide and metallic Cu as stable final residues in synthetic air and dinitrogen atmospheres, respectively.