Search results for "Gee"

Interactions of α2β1 integrin and its ligands, type I collagen and echovirus 1

2015

Reactivity of 4-Aminopyridine with Halogens and Interhalogens : Weak Interactions Supported Networks of 4-Aminopyridine and 4-Aminopyridinium

2019

The reaction of 4-aminopyridine (4-AP) with ICl in a 1:1 molar ratio in CH2Cl2 produced the expected charge-transfer complex [4-NH2-1λ4-C5H4N-1-ICl] (1·ICl) and the ionic species [(4-NH2-1λ4-C5H4N)2-1μ-I+][Cl–] (2·Cl–) in a 2:1 relation, as indicated by 1H NMR spectroscopy in solution. In contrast, only the ionic compound [(4-NH2-1λ4-C5H4N)2-1μ-I+][IBr2–] (2·IBr2–) was observed in the analogous reaction with IBr. The reaction between 4-AP and I2 in a 1:1 molar ratio also afforded two components, one of which was identified as the congeneric cation in [(4-NH2-1λ4-C5H4N)2-1μ-I+][I7–] (2·I7–) that contains a polyiodide anion as a result of transformation in a 1:2 molar ratio between the starti…

Halogen Bonds in Square Planar 2,5-Dihalopyridine-Copper(II) Bromide Complexes

2018

Halogen bonding in self-complementary 1:2 metal–ligand complexes obtained from copper(II) bromide (CuBr2) and seven 2,5-dihalopyridines were analyzed using single-crystal X-ray diffraction. All presented discrete complexes form 1D polymeric chains connected with C–X···Br–Cu halogen bonds (XB). In (2-chloro-5-X-pyridine)2·CuBr2 (X = Cl, Br, and I) only the C5-halogen and in (2-bromo-5-X-pyridine)2·CuBr2 (X = Cl, Br, and I) both C2- and C5-halogens form C–X···Br–Cu halogen bonds with the X acting as the XB donor and copper-coordinated bromide as the XB acceptor. The electron-withdrawing C2-chloride in (2-chloro-5-X-pyridine)2·CuBr2 complexes has only a minor effect on the C5–X5···Br–Cu XBs, a…

Thiourea Based Tritopic Halogen Bonding Acceptors

2023

Series of thiourea based tritopic receptor molecules were synthesized to be used as building blocks for halogen-bonded assemblies. Here 16 new receptor molecules were synthesized from two different 2,4,6-trialkyl-1,3,5-tris(bromomethyl)benzene starting materials via tris(isothiocyanatomethyl)benzene intermediates. The alkyl substituents in the benzene ring showed to be important for isothiocyanate group formation instead of competing thiocyanate group. The synthesis route allowed us to synthesize the isothiocyanate intermediates and further the receptor molecules without typically used and highly toxic thiophosgene. Synthesized receptor molecules were used to study their halogen bond accept…

Missing a lot of this world : formal education and political competition in Iraq through a Yezidi lens

2017

This thesis examines Yezidi perceptions of access to formal education for Yezidi children and youth from the Sinjar region of Iraq, a primary homeland of the Yezidi people and an officially disputed territory between the Kurdistan Regional Government (KRG) and the federal government of Iraq in Baghdad, between the periods of 2003–2014 and 2014 onwards. These two time frames are selected and differentiated to reflect two major events in the recent history of Sinjar – the downfall of Saddam Hussein’s regime in 2003 and subsequent de facto control of Sinjar by the KRG, and the seizing of the area by the Islamic State (IS) group and subsequent displacement of the majority of the Yezidi communit…

Carbonyl hypoiodites from pivalic and trimesic acid and their silver(I) intermediates

2022

The first tris(O–I–N) carbonyl hypoiodites have been synthesised based on trimesic acid and pyridine or 4-methylpyridine, with their structures definitively confirmed by single crystal X-ray diffraction (SCXRD). The more soluble carbonyl hypoiodites based on pivalic acid have also been studied via NMR, SCXRD, and computational analyses, enabling the study of the direct silver(I) precursor and intermediates of the resulting carbonyl hypoiodites generated using a range of substituted pyridines. peerReviewed

Halogen-Bonded [N–I–N]− Complexes with Symmetric or Asymmetric Three-Center–Four-Electron Bonds

2023

A series of LH[Z–I–Z] halogen(I) complexes, where Z = saccharinato or phthalimido anions and LH = pyridinium, pyrazinium, tetrabutyl (TBA)- or tetramethylammonium (TMA) cations, were prepared, structurally characterized, and discussed as complexes consisting of a [N–I–N]− anion with a three-center–four-electron (3c-4e) halogen bond, and a hydrogen-bonding (pyridinium or pyrazinium) or inert (TBA or TMA) cation. The symmetric [N–I–N]− anion, reminiscent of the triiodide [I–I–I]− anion, is found to be structurally equivalent to its cationic analogue [N–I–N]+ with N–I bond lengths of 2.26 Å. In contrast to the homoleptic [N–I–N]+ complexes, asymmetry of the N–I bond lengths (2.21 and 2.28 Å) w…

Macrocyclic complexes based on [N⋯I⋯N]+ halogen bonds

2021

New 1–2 nm macrocyclic iodine(I) complexes prepared VIA a simple ligand exchange reaction manifest rigid 0.5–1 nm cavities that bind the hexafluorophosphate anion in the gas phase. The size of the cavities and the electrostatic interactions with the iodine(I) cations influence the anion binding properties of these macrocyclic complexes. peerReviewed

Ligand exchange among iodine(I) complexes

2022

A detailed investigation of ligand exchange between iodine(I) ions in [N⋯I⋯N]+ halogen-bonded complexes is presented. Ligand exchange reactions were conducted to successfully confirm whether iodine(I) complex formation, via the classical [N⋯Ag⋯N]+ to [N⋯I⋯N]+ cation exchange reaction from their analogous Ag+ complexes, could be determined solely by using 1H NMR spectroscopy. In instances where the formation of the iodine(I) complex was unclear or in low yield by the traditional cation exchange reaction, a ligand exchange reaction was used to form the desired iodine(I) complexes in a quantitative manner. Mixing two homoleptic [N⋯I⋯N]+ iodine(I) complexes in 1 : 1 ratio was found to undergo a…

Halogen-Bonded Mono-, Di-, and Tritopic N-Alkyl-3-iodopyridinium Salts

2023

Halogen bonding interactions of 15 crystalline 3-iodopyridinium systems were investigated. These systems were derived from four N-alkylated 3-iodopyridinium salts prepared in this study. The experimental results in the solid state show that halogen bonding acts as a secondary intermolecular force in these charged systems but sustains the high directionality of interaction in the presence of other intermolecular forces. Halogen bonds donated by polytopic 3-iodopyridinium cations are also sufficient to enclose guest molecules inside the formed supramolecular cavities. The experimental data were supplemented by computational gas-phase and solid-state studies for selected halogen-bonded systems…