Influence of fluorine substituents on the electronic properties of selenium-N-heterocyclic carbene compounds

• Main Authors: Shah Jamil, Mohamad Shazwan, Endot, Nor Azam
• Format: Article
• Language: English
• Published: MDPI AG 2020
• Subjects: QD Chemistry
• Online Access: http://eprints.utm.my/id/eprint/90668/1/MohamadShazwanShah2020_InfluenceofFluorineSubstituentsontheElectronic.pdf; http://eprints.utm.my/id/eprint/90668/; http://dx.doi.org/10.3390/molecules25215161
• Institution: Universiti Teknologi Malaysia

N-heterocyclic carbenes (NHCs) are common ancillary ligands in organometallic compounds that are used to alter the electronic and steric properties of a metal centre. To date, various NHCs have been synthesised with different electronic properties, which can be done by modifying the backbone or changing the nitrogen substituents group. This study describes a systematic modification of NHCs by the inclusion of fluorine substituents and examines the use of selenium-NHC compounds to measure the π-accepting ability of these fluorinated NHC ligands. Evaluation of the 77Se NMR chemical shifts of the selenium adducts reveals that fluorinated NHCs have higher chemical shifts than the non-fluorinated counterparts, IMes and IPh. Higher 77Se NMR chemical shifts values indicate a stronger π-accepting ability of the NHC ligands. The findings of this study suggest that the presence of fluorine atoms has increased the π-accepting ability of the corresponding NHC ligands. This work supports the advantage of the 77Se NMR chemical shifts of selenium-NHC compounds for assessing the influence of fluorine substituents on NHC ligands.