Chlorotrinitromethane and its exceptionally short carbon–chlorine bond

Abstract

Compounds that deviate from the normal range of bonding can help to assess the strengths and weaknesses of the models currently used to describe chemical bonds. Furthermore, computer simulations of molecules require experimental data to describe accurately the energies and forces between interacting molecules. Compounds that contain the trinitromethyl group, with three nitro groups bonded to one carbon atom, show remarkable inter- and intramolecular effects. In this paper, we report the structural features of chlorotrinitromethane in the solid state and present the first reliable solid-state geometry parameters of an α-halogen derivative of the trinitromethyl pseudohalogen. We found several intriguing geometrical features in terms of intra- and intermolecular interactions, as well as an exceptionally short carbon-chlorine bond (1.694(1) Å). Using a combined crystallographic and computational approach, we show that these effects can be described in terms of the computed electrostatic potential of the molecular surface.

Structure and structural transition of chiral domains in oligo(p-phenylenevinylene) assembly investigated by scanning tunneling microscopy

“…Halogen bonding also plays significant roles in a wide variety of biochemical phenomena such as protein-ligand complexation (30,31). The significance of halogen bonding has been increasingly understood from the effort of both theoretical chemistry and crystal engineering (32)(33)(34). Through a series of STM experiments we have investigated the cocrystallization of OPV3-CHO with alkyl bromides and studied the possible roles of halogen bonding.…”

Charge competition in halogenated hydrocarbons

“…The most striking r-hole effects occur for compounds with a highly polarizable atom connected to a strong electron-withdrawing group [23,24,26]. In the halomethanes, this can be illustrated by the series CF 3 AF, CF 3 ACl, and CF 3 ABr.…”

“…These nonuniform potential surfaces can be understood using the ''r-hole'' theory of Clark et al [24,25] wherein highly electron-withdrawing substituents drain electron density from sp-hybridized orbitals in polarizable atoms. An interesting and extreme example of this phenomenon is chlorotrinitromethane, ClC(NO 2 ) 3 [26], which exhibits especially long CAN bonds (1.538-1.544 Å , compared with the more customary 1.47 Å ) and an especially short CACl bond (1.712 Å ) in electron diffraction (1.694 Å from X-ray diffraction [27]). The ESP surface of this compound reveals a strong positive region on the isodensity surface of the chlorine atom, and its unusual features can be rationalized in terms of natural bond orbital analysis and r-hole theory.…”

The unique role of the nitro group in intramolecular interactions: chloronitromethanes

“…Figure 1 shows that the oxygens and the nitrogens are in three distinct planes, with the one containing the nitrogens being between the other two. This propeller-like structure is found for the C(NO 2 ) 3 group in other XC(NO 2 ) 3 molecules as well [7,9,13,14], and has been attributed to intramolecular N-O electrostatic interactions involving the oxygens in the lowest plane (farthest from X) [7,8,14].…”