Fluoride Anion Complexation by a Triptycene‐Based Distiborane: Taking Advantage of a Weak but Observable C−H⋅⋅⋅F Interaction

Abstract

Fluoride anion complexation impacts a number of areas ranging from sensing to nucleophilic fluorination chemistry. Described here is a new bidentate Lewis acid consisting of two stiborane units connected by a 1,8-triptycenediyl backbone. This neutral derivative captures fluoride with an unprecedented affinity for a neutral, water-compatible Lewis acid. Structural, spectroscopic and computational studies demonstrate that fluoride anion binding is assisted by the formation of a C-H⋅⋅⋅F hydrogen bond which involves a methine group of the 1,8-triptycenediyl backbone.

Naked‐Eye Heterogeneous Sensing of Fluoride Ions by Co‐Polymeric Nanosponge Systems Comprising Aromatic‐Imide‐Functionalized Nanocellulose and Branched Polyethyleneimine

“…Hence, recognition and sensing of fluoride anions in solution is highly topical, as documented by the large and increasing number of works that can be found in the literature. [14] On the contrary, solid-state systems working under heterogeneous conditions remain quite rare. [15] In 2015, we have developed a properly functionalized CNS capable to selectively recognize fluoride anions by a color change, visible by the naked-eye, when dipped into DMSO.…”

Guest Binding via N−H⋅⋅⋅π Bonding and Kinetic Entrapment by an Inorganic Macrocycle

“…[1][2][3][4][5][6][7][8][9] Directly comparable inorganic counterparts (based on main-group elements other than carbon) have received far less attention, partly due to the presence of weaker and normally more polar bonds,w hich makes the development of systematic strategies to geometrically complex molecules amajor synthetic challenge. [17][18][19] Key advantages of inorganic anion receptors over organic counterparts are their inherently more polar nature and the ease by which their proton acidities can be modulated. [12][13][14][15][16] So far, however,i norganic anion receptors have largely been based on Lewis acidic centers rather than hydrogen bonding.…”

“…[12][13][14][15][16] So far, however,i norganic anion receptors have largely been based on Lewis acidic centers rather than hydrogen bonding. [17][18][19] Key advantages of inorganic anion receptors over organic counterparts are their inherently more polar nature and the ease by which their proton acidities can be modulated.Thehigh bond energy of PÀNs ingle bonds and their low polarity underpin the stability of adiverse range of previously reported phosphazane compounds,and provide agood foundation for the development of anew range of robust inorganic macrocycles. [20][21][22][23][24][25][26][27][28][29] Of particular interest is the pentameric host macrocycle 1 (Figure 1), toroidal shape,l arge void volume, endo-cyclic N-H functionalities,a nd exo-cyclic t Bu groups of which make it ahighly unusual, sterically hindered H-bonding host.…”

Pushing the Lewis Acidity Boundaries of Boron Compounds With Non‐Planar Triarylboranes Derived from Triptycenes

“…The phosphonium‐borate 14 b (and analogue 14 e , Scheme ) smoothly underwent selective phenyl protodeboronation with HBF 4 to yield the fluoroborates 17 – 18 (Scheme ). Their 19 F NMR spectrum showed a resonance at −235 ppm consistent with a F−BAr 3 − bond but low shifted by 45 ppm from the F−B resonance in F−B(C 6 F 5 ) 3 − . Their formation supported a mechanistic scenario involving the transient formation of the highly Lewis acidic cationic boratriptycenes 15 – 16 which abstracted a fluoride from BF 4 − .…”