Abstract
Hydrogen Bonds with Cyanide Ions? The Structures of 1,3‐Diisopropyl‐4,5‐dimethylimidazolium Cyanide and 1‐Isopropyl‐3,4,5‐trimethylimidazolium Cyanide1,3‐Diisopropyl‐4,5‐dimethylimidazolium cyanide (2a) and 1‐isopropyl‐3,4,5‐trimethylimidazolium cyanide (2b) are obtained from the reaction of the corresponding 2,3‐dihydrodimethylimidazol‐2‐ylidenes (1) and hydrogen cyanide in excellent yield. Their crystal structure analyses reveal the presence of ion pairs linked by hydrogen bonds. The crystal structure analysis of 2a reveals a near colinear orientation of the C(1)‐H bond axis and the cyanide ion while in 2b this orientation is perpendicular. In both cases, the interionic distances are in the expected range for hydrogen bonds. Ab‐initio calculations of the total energy of the salts 2 indicate small differences in energy between the colinear and perpendicular orientation of the ions as well as between the colinear C‐H···C‐N and C‐H···N‐C orientations. The comparison of calculated and measured 13C and 15N NMR chemical shifts does not allow the distinction between the possible orientations.

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