13C-NMR Study of Halogen Bonding of Haloarenes. Measurement of Solvent Effects and Theoretical Analysis.
Rainer Glaser*, Naijun Chen, Hong Wu, and Nathan Knotts
Department of Chemistry, University of Missouri-Columbia, Columbia, Missouri, 65211 (USA)
Institut für Anorganische Chemie, Universität Würzburg, Würzburg, Germany
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Figure legends with embedded web-enhanced objects
Figure 1. The crystal structure of 4-Iodoacetophenone-(4-methoxyphenylethylidene) hydrazone, the (MeO, I)-azine 7, features perfect dipole-parallel alignment within 2-d layers and near-perfect dipole-parallel alignment in the direction in which the layers are stacked. The directionality of the halogen bonding might control the stacking of the layers.
Figure 2. Crystals of (MeO, I)-azine 7 contain halogen bonded strings. The halogen bonding is characterized by d(O-I) = 313.8 pm, (C-O...I) = 126.28o, and (O...I-C) = 171.34o.
Figure SM-only. Structures of 4-iodoacetophenone imine 9 (B3LYP, MP2), 4-iodoacetophenone hydrazone 10 (B3LYP, MP2), 4-iodoacetophenone 11 (B3LYP, MP2), and 4-iodobenzene 12 (B3LYP, MP2).
Figure SM only. Structures of the azine 4 in C2- (B3LYP, MP2), Ci- (B3LYP, MP2), and C2h- symmetry (B3LYP, MP2). Animations of the imaginary vibrations of the C2h- symmetric structure computed at the MP2 level: Animation 1 and animation 2 of the i31.8 cm-1 mode; animation 1 and animation 2 of the i21.7 cm-1 mode. Animations of the imaginary vibration of the Ci- symmetric structure computed at the B3LYP level: Animation 1 and animation 2 i1.9 cm-1.
Figure 3. Structures of the iodine bonding complexes between DMSO and 4-iodoacetophenone imine 9 (B3LYP, MP2)), 4-iodoacetophenone hydrazone 10 (B3LYP, MP2), 4-iodoacetophenone 11 (B3LYP, MP2), and 4-iodobenzene 12 (B3LYP, MP2). The online version of this paper contains web-enhanced objects that allow for the 3D-display of the DMSO complex of 12 and of its six lowest vibrations with frequencies 7 cm-1 (torsion mode of the (S-O...Cipso-Cortho) dihedral angle L), 20 cm-1 (rotational mode about the S-O bond), 22 cm-1 (S-O...I angle bending W), 48 cm-1 (O...I-Cipso) angle bending G), 52 cm-1 (S-O...I) angle bending in combination with (O...Cipso-Ph) bending), and 106 cm-1 (d(O...I) stretching mode).
Figure 4. Computed structures of the doubly iodine bonded complexes between two molecules of DMSO and azine 4 in C2-symmetry (B3LYP, MP2) and Ci-symmetry (B3LYP, MP2).