Chalcogen bonding in crystalline diselenides and selenocyanates: From molecules of pharmaceutical interest to conducting materials

Abstract

Organic diselenides are nowadays investigated for pharmaceutical applications, as well as in material science in molecular (semi)conductors. In both application's domains, their interactions with Lewis bases, in solution or in the solid state, has been shown to play a crucial role in their biological activity or in their electronic structure. The current comprehensive survey of reported crystal structures of organic diselenides demonstrates the recurrent setting of intermolecular as well as intramolecular chalcogen bonding interactions (ChB) between the selenium atoms acting as ChB donors and Lewis bases. These interactions take place along the two covalent bonds of the selenium atom. In diselenides, stronger interactions are found in the prolongation of the Se−Se bond than in the prolongation of the C−Se bond. Charge activation of ChB is demonstrated in dicationic diselenides or in cation radical salts of 1,2-diselenole derivatives. This survey is extended to the structures of organic selenocyanates whose crystal structures reflect also the presence of two σ-holes, with a much stronger one in the prolongation of the NC−Se bond. Such ChB interactions of selenocyanates with polytopic Lewis bases or with halide anions open novel strategies in crystal engineering and anion recognition strategies.

Zero-, one-, two- and three-dimensional supramolecular architectures sustained by Se…O chalcogen bonding: A crystallographic survey

“…It is stressed that the focus of the present review is upon the role of intermolecular Se … O contacts and upon the supramolecular aggregation patterns they sustain. In general terms, chalcogen interactions find very practical applications in a range of contexts beyond biology and medicine [16] , [17] , [18] , such as in molecular/anion recognition [19] , [20] , [21] , [22] , catalysts [23] , [24] and materials science [25] , [26] . With this level of activity, it is not surprising there are several authoritative reviews of chalcogen bonding [27] , [28] , [29] , [30] , including reviews of different physiochemical procedures for their detection in phases other than in crystals [31] , [32] , [33] , the primary importance of X-ray crystallographic investigations notwithstanding.…”

Strongσ‐Hole Activation on Icosahedral Carborane Derivatives for a Directional Halide Recognition

“…This comparison further highlights that the s-hole activation through carborane reveals as trength comparable or superior to well-established halogen bond donors. Te13 .154 (8) 177.3 (6) Te53 .143 (8) 170.6(5) Te23 .087 (8) 175.7 (6) Te63 .112 (7) 178.1(5) Te33 .064 (8) 170.9(5) Te73 .120 (7) 173.1(4) Te43 .155 (10) 171.4 (5) Te83 .139 (9) 169.1(5)…”

“…Increasing demand in materials with higher complexity and more elaborate functions is driving research in the field of crystal engineering in conjunction with supramolecular chemistry [1] . Indeed, σ ‐hole interactions have been emerged during the last two decades as an appealing chemical tool to control intermolecular interactions, with their implications in crystal engineering, catalysis, functional materials, and biochemistry [2–8] . By far the most studied one is halogen bonding (XB), [2] which is defined as a net attractive interaction between an electrophilic region ( σ ‐hole) associated with a halogen atom in a molecular entity and a nucleophile.…”

Noble Gas Bonding Interactions Involving Xenon Oxides and Fluorides

“…These interactions can be divided into σ–hole [ 21 , 22 , 23 , 24 ] and π–hole interactions [ 25 , 26 , 27 , 28 , 29 ] and are nowadays entered into the toolkit supramolecular chemists. Actually, tetrel (Tt) [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ], pnictogen (Pn) [ 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ], and chalcogen (Ch) [ 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 ] bonding interactions (see Figure 1 ) have been studied by many theoretical works and are progressively used experimentally in relevant fields such as supramolecular catalysis, polymers, transmembrane ion transport and, especially, crystal engineering [ 15 , …”