Boron hydrides have been an object of intensive theoretical and experimental investigation for many decades due to their unusual and somewhat unique bonding patterns. Despite boron being a neighboring element to carbon, boron hydrides almost always form non-classical structures with multi-center bonds. However, we expect indium to form its interesting molecules with non-classical patterns, though such molecules still need to be extensively studied theoretically. In this work, we investigated indium hydrides of In2Hx (x = 0–4,6) and In3Hy (y = 0–5) series via DFT and ab initio quantum chemistry methods, performing a global minimum search, chemical bonding analysis, and studies of their thermodynamical stability. We found that the bonding pattern of indium hydrides differs from the classical structures composed of 1c-2e lone pairs and 2c-2e bonds and the bonding pattern of earlier investigated boron hydrides of the BnHn+2 series. The studied stoichiometries are characterized by multi-center bonds, aromaticity, and the tendency for indium to preserve the 1c-2e lone pair.

Recently fabricated 2D biphenylene network is an astonishing solid‐state material, which possesses unique metal‐like conductive properties. At the same time, two‐dimensional boron nitride network (2D‐BN)—an isoelectronic and structural analogue of biphenylene network, is an insulator with a wide direct bandgap. This study investigates the relationship between the electronic properties and chemical bonding patterns for these species. It is shown that the insulating 2D‐BN network possesses a strong localization of electron density on the nitrogen atoms. In turn, for a carbon‐containing sheet, we found a highly delocalized electron density and an appreciable overlap of pz orbitals of neighboring C6 rings, which might be a reason for the conductive properties of the material.

The study of the mechanism of the Noyori−Ikariya asymmetric transfer hydrogenation of ketones spans nearly three decades of investigations. Whereas the early part of the catalytic cycle being the hydride transfer is now well-understood, the later part being the proton transfer is still ambiguous. Specifically, the source of the proton can be the N−H functionality of the catalyst and/or the O−H functionality of the reagent/solvent, leading to two conceptually different catalytic cycles or even their combination. For three popular reagents/solvents typically used in the method, namely, propan-2-ol, 5:2 HCO 2 H−NEt 3 , and water, either the source of the proton is presently unknown or the evidence is presented partially by only one approach�experimental or computational. The present work eliminates this ambiguity by means of various molecular dynamics simulation methods such as ab initio, quantum mechanics/ molecular mechanics, and path integral to include quantum tunneling effects. Here, we show that for the archetypal (S)-RuH[(R,R)-Tsdpen](mesitylene) catalyst complex, the source of the proton in propan-2-ol is the catalyst's N−H functionality, whereas in more acidic water, binary 5:2 HCO 2 H−NEt 3 , or neat formic acid, the source of the proton is the reagent/solvent. Thus, depending on the nature of the reagent/solvent, the catalyst's ligand can be either chemically non-innocent or chemically innocent in the Noyori−Ikariya reaction, which opens opportunities for outer-sphere homogeneous catalyst design.

A remarkable distinction between boron and carbon hydrides lies in their extremely different bonding patterns and chemical reactivity, resulting in diverse areas of application. Particularly, carbon, characterized by classical two‐center – two‐electron bonds, gives rise to organic chemistry. In contrast, boron forms numerous exotic and non‐intuitive compounds collectively called non‐classical structures. It is reasonable to anticipate that other elements of Group 13 exhibit their own unusual bonding patterns; however, our knowledge of the hydride chemistry for other elements in Group 13 is much more limited, especially for the heaviest stable element, thallium. In this work, we performed a conformational analysis of Tl2Hx and Tl3Hy (x=0–6, y=0–5) series via Coalescence Kick global minimum search algorithm, DFT, and ab initio quantum chemistry methods; we investigated the bonding pattern using the AdNDP algorithm, thermodynamic stability, and stability toward electron detachment. All found global minimum structures are classified as non‐classical structures featuring at least one multi‐center bond.