Selective Activation of Chalcogen Bonding: An Efficient Structuring Tool toward Crystal Engineering Strategies

Abstract

Metrics & MoreArticle Recommendations * sı Supporting Information CONSPECTUS: Among the noncovalent interactions available in the toolbox of crystal engineering, chalcogen bonding (ChB) has recently entered the growing family of σ-hole interactions, following the strong developments based on the halogen bonding (XB) interaction over the last 30 years. The monovalent character of halogens provides halogen bonding directionality and strength. Combined with the extensive organic chemistry of Br and I derivatives, it has led to many applications of XB, in solution (organocatalysis, anion recognition and transport), in the solid state (cocrystals, conducting materials, fluorescent materials, topochemical reactions, ...), in soft matter (liquid crystals, gels,•••), and in biochemistry. The recognition of the presence of two σ-holes on divalent chalcogens and the ability to activate them, as in XB, with electron-withdrawing groups (EWG) has fueled more recent interest in chalcogen bonding. However, despite being identified for many years, ChB still struggles to make a mark due to (i) the underdeveloped synthetic chemistry of heavier Se and Te; (ii) the limited stability of organic chalcogenides, especially tellurides; and (iii) the poor predictability of ChB associated with the presence of two σ-holes. It therefore invites a great deal of attention of molecular chemists to design and develop selected ChB donors, for the scrutiny of fundamentals of ChB and their successful use in different applications. This Account aims to summarize our own contributions in this direction that extend from fundamental studies focused on addressing the lack of directionality/predictability in ChB to a systematic demonstration of its potential, specifically in crystal engineering, and particularly toward anionic networks on the one hand, topochemical reactions on the other hand.In this Account, we share our recent results aimed at recovering with ChB the same degree of strength and predictability found with XB, by focusing on divalent Se and Te systems with two different substituents, one of them with an EWG, to strongly unbalance both σ-holes. For that purpose, we explored this dissymmetrization concept within three chemical families, selenocyanates R−SeCN, alkynyl derivatives R−C�C−(Se/Te)Me, and o-carborane derivatives. Such compounds were systematically engaged in cocrystals with either halides or neutral bipyridines as ChB acceptors, revealing their strong potential to chelate halides as well as their ability to organize reactive molecules such as alkenes and butadiynes toward [2+2] cycloadditions and polydiacetylene formation, respectively. This selective activation concept is not limited to ChB but can be effectively used on all other σ-hole interactions (pnictogen bond, tetrel bond, etc.) where one needs to control the directionality of the interaction.■ KEY REFERENCES• Huynh, H.-T.; Jeannin, O.; Fourmigué, M. Organic selenocyanates as strong and directional chalcogen bond donors for crystal engineering. Chem. Commun. 2017, 53, 84...

Te⋯I secondary-bonding interactions in crystals containing tellurium(ii), tellurium(iv) and iodide atoms: supramolecular aggregation patterns, nature of the non-covalent interactions and energy considerations

“…44) contacts in solution, and the gas-phase (Te⋯N). 45 With such persistence, it is not surprising that chalcogen-bonding finds applications 46 beyond the solid-state 47 such as in coordination chemistry, 48 catalysis, 49,50 molecular recognition 51 and materials science. 52 While less numerous, chalcogen-bonding has many parallels with the ubiquitous halogen-bonding.…”

Unveiling the Nature and Strength of Selenium-Centered Chalcogen Bonds in Binary Complexes of SeO2 with Oxygen-/Sulfur-Containing Lewis Bases: Insights from Theoretical Calculations

“…Chalcogen bonds have been defined as the attractive NCIs between an electrophilic region related to a covalent-bonded group VI atom (O, S, Se, Te) and a nucleophilic region within the same or another molecular entity [ 29 ]. In recent years, ChBs have garnered considerable attention from theoreticians and experimentalists owing to their important contributions to crystal engineering [ 30 , 31 ], molecular recognition [ 17 , 32 ], organocatalysis [ 33 , 34 ], drug design [ 6 , 35 ], materials science [ 36 , 37 ], and biological systems [ 13 , 38 , 39 ]. ChBs belong not only to a subclass of σ–hole interactions but also to a subclass of π–hole interactions [ 40 , 41 ].…”

Anion⋯anion self-assembly under the control of σ- and π-hole bonds

“…The chalcogen bond (ChB), a bonding interaction wherein the electrophile is a group 16 element, 42 is the second most impacting σ/π-hole interaction. 43,44 Similar to the HaB, the present understanding of this interaction has developed through a rather patchy course. The contributions focussing on the charge-transfer 33,35,36 and geometric 37,45 viewpoints were important in constructing the present-day ChB concept, but the topic boomed and was clearly defined 42 only after modelling based on the electrostatic standpoint was proposed.…”