6533b859fe1ef96bd12b77f7

RESEARCH PRODUCT

Strong N−X⋅⋅⋅O−N Halogen Bonds: A Comprehensive Study on N‐Halosaccharin Pyridine N ‐Oxide Complexes

J. Mikko RautiainenKari RissanenRakesh PuttreddyToni Mäkelä

subject

Halogen bond010405 organic chemistryPyridine-N-oxideGeneral MedicineGeneral ChemistryCrystal structure010402 general chemistry01 natural sciencesCatalysis0104 chemical sciencesCrystallographychemistry.chemical_compoundchemistryHalogenPyridineAcetoneElectrostatic model

description

A study of the strong N-X⋅⋅⋅- O-N+ (X=I, Br) halogen bonding interactions reports 2×27 donor×acceptor complexes of N-halosaccharins and pyridine N-oxides (PyNO). DFT calculations were used to investigate the X⋅⋅⋅O halogen bond (XB) interaction energies in 54 complexes. A simplified computationally fast electrostatic model was developed for predicting the X⋅⋅⋅O XBs. The XB interaction energies vary from -47.5 to -120.3 kJ mol-1 ; the strongest N-I⋅⋅⋅- O-N+ XBs approaching those of 3-center-4-electron [N-I-N]+ halogen-bonded systems (ca. 160 kJ mol-1 ). 1 H NMR association constants (KXB ) determined in CDCl3 and [D6 ]acetone vary from 2.0×100 to >108  m-1 and correlate well with the calculated donor×acceptor complexation enthalpies found between -38.4 and -77.5 kJ mol-1 . In X-ray crystal structures, the N-iodosaccharin-PyNO complexes manifest short interaction ratios (RXB ) between 0.65-0.67 for the N-I⋅⋅⋅- O-N+ halogen bond.

yearjournalcountryeditionlanguage
2019-11-07Angewandte Chemie International Edition
https://doi.org/10.1002/anie.201909759