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Title: Influence of Substituents in the Benzene Ring on the Halogen Bond of Iodobenzene with Ammonia
Abstract

The effects on the C−I⋅⋅N halogen bond between iodobenzene and NH3of placing various substituents on the phenyl ring are monitored by quantum calculations. Substituents R=N(CH3)2, NH2, CH3, OCH3, COCH3, Cl, F, COH, CN, and NO2were each placed ortho, meta, and para to the I. The depth of the σ‐hole on I is deepened as R becomes more electron‐withdrawing which is reflected in a strengthening of the halogen bond, which varied between 3.3 and 5.5 kcal mol−1. In most cases, the ortho placement yields the largest perturbation, followed by meta and then para, but this trend is not universal. Parallel to these substituent effects is a progressive lengthening of the covalent C−I bond. Formation of the halogen bond reduces the NMR chemical shielding of all three nuclei directly involved in the C−I⋅⋅N interaction. The deshielding of the electron donor N is most closely correlated with the strength of the bond, as is the coupling constant between I and N, so both have potential use as spectroscopic measures of halogen bond strength.

 
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Award ID(s):
1954310
NSF-PAR ID:
10364026
Author(s) / Creator(s):
 ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
ChemPhysChem
Volume:
23
Issue:
6
ISSN:
1439-4235
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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