Organic Selenocyanates as Halide Receptors: From Chelation to One-Dimensional Systems

Asia Marie S. Riel, Huu Tri Huynh, Olivier Jeannin, Orion Berryman, Marc Fourmigué

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

Organic selenocyanates were recently identified as strong chalcogen bond donors. They also play an important role in biochemistry. Here, we show that 1,2-bis(selenocyanatomethyl)benzene (1) and 1,2,4,5-tetrakis(selenocyanatomethyl)-benzene (2) crystallize from dimethylformamide (DMF) to afford solvates where two ortho-SeCN moieties act as a chelate toward the carbonyl oxygen atom of DMF through strong Se⋯O chalcogen bonds. This result led us to explore their ability to also chelate halide anions (Cl - , Br - ) in solution as well as in the solid state, an important issue in view of applications in crystal engineering or organocatalysis. NMR titration experiments provide an association constant between 1 and Cl - of 148 M -1 . We also observed the recurrent formation of cocrystal salts from the association of the ChB donors 1 and 2 with the onium salts Ph 4 PCl, Ph 4 PBr, and Bu 4 NCl. We demonstrate that not only μ 2 -halide but also μ 4 -halide structures can be stabilized though ChB interactions, leading to the formation of complex polymeric anionic networks. Continuous shape measure calculations of these μ 4 -halide structures demonstrate that seesaw symmetry best describes the μ 4 -Br - bromide structures, while the smaller chloride anions tend to favor a close-to-tetrahedral μ 4 -Cl - organization, which is also confirmed by density functional theory calculations. Electrostatic surface potential calculations further demonstrate the efficiency of this chelating ortho-bis(selenocyanatomethyl) motif in 1 and 2, with V s,max values reaching 50 kcal mol -1 , to be compared with the simplest benzyl selenocyanate (36.4 kcal mol -1 ) or the reference halogen bond donor F 5 C 6 -I (35.7 kcal mol -1 ) in the same conditions.

Original languageEnglish
Pages (from-to)1418-1425
Number of pages8
JournalCrystal Growth and Design
Volume19
Issue number2
DOIs
StatePublished - Feb 6 2019

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