Faculty of Science, Department of Chemistry, University of Zagreb, Horvatovac 102a, HR-10000, Zagreb, Croatia.
Published: January 2019
AI Article Synopsis
Article Abstract
The formation of non-covalent directional interactions, such as hydrogen or halogen bonds, is a central concept of materials design, which hinges on using small compact atoms of the 2nd period, notably nitrogen and oxygen, as acceptors. Heavier atoms are much less prominent in that context, and mostly limited to sulfur. Here, we report the experimental observation and theoretical study of halogen bonds to phosphorus, arsenic and antimony in the solid state. Combining 1,3,5-trifluoro-2,4,6-triiodobenzene with triphenylphosphine, -arsine, and -stibine provides cocrystals based on I···P, I···As and I···Sb halogen bonds. The demonstration that increasingly metallic pnictogens form halogen bonds sufficiently strong to enable cocrystal formation is an advance in supramolecular chemistry which opens up opportunities in materials science, as shown by colossal thermal expansion of the cocrystal involving I···Sb halogen bonds.
Chloride ions play vital roles in a variety of biological and environmental processes, making their accurate and efficient detection critical for both research and practical applications. In this perspective, we explore the recent advancements in the development of metal complex-based probes for chloride ion detection, with a focus on complexes involving transition and lanthanide metals. These probes offer remarkable selectivity and sensitivity, achieved through diverse mechanisms such as metal coordination, hydrogen bonding, electrostatic interactions, and halogen or chalcogen bonding.
Two-dimensional (2D) chiral hybrid perovskites A2PbI4 (A: chiral organic ion) enable chirality controlled optoelectronic and spin-based properties. A+ organic sublattice induces chirality into the semiconducting [PbI4]2- inorganic sublattice through non-covalent interactions at organic-inorganic interface. Often, the A+ cations in the lattice have different orientations, leading to asymmetry in the non-covalent interactions.
Reaction of 2-amino-5-iodo-pyridine (5IAP) with concentrated HBr at room temperature yielded 2-amino-5-iodo-pyridinium bromide, CHIN ·Br or (5IAPH)Br. The complex formed pale-yellow crystals, which exhibit significant hydrogen bonding between the amino and pyridinium N-H donors and bromide ion acceptors. Halogen bonding is also observed.
One of the goals in synthetic chemistry is to obtain compounds featuring unusual valence states that are stable under ambient conditions. At present, stabilizing unusual Pt(III) states is considered difficult, except through direct Pt-Pt bonding such as that in platinum-blues or organometallization using bulky ligands. Pt(III) stabilization is also very difficult in halogen-bridged metal complex chains (MX-Chains).
While charge-transfer complexes involving halogen-bonding interactions have emerged as an alternative strategy for the photogeneration of carbon radicals, examples using (fluoro)alkyl bromides are limited. This report describes a dual catalytic approach for radical generation from α-bromodifluoroesters and amides under visible-light irradiation. Mechanistic studies suggest that the reaction proceeds through bromide displacement using a catalytic iodide salt, generating a C-I bond that can be engaged by our halogen-bonding photocatalysis platform.
