Electronic Structures of Homodinuclear Platinum(II), Palladium(II) and Gold(I) Complexes Featuring Janus-type Benzoxazolin-2-ylidene Linkers
Main Article Content
Abstract
Electronic structures of a series of three homodinuclear platinum(II), palladium(II) and gold(I) complexes featuring Janus-type benzoxazolin-2-ylidene bridges and N,N-diisopropyl benzimidazolin-2-ylidene auxiliary ligands have been investigated. The gas-phase molecular structures of all compounds were first optimized using B3PW91 functional and SDD/6-31G(d) combination of basis sets. The nature of their frontier orbitals were then examined. The higher energy occupied molecular orbitals are predominantly d orbital of the metal in combination with p orbital of N,N-diisopropyl benzimidazolin-2-ylidene. On the other hand, the lower energy unoccupied molecular orbitals are p orbitals of the benzoxazolin-2-ylidene. TD-DFT calculations reveal that all the complexes require high energy ultraviolet photon for excitation and photoexcitations form excited state with decreased electron density on metal centers.
Keywords:
N-heterocyclic carbene, electronic structures, benzoxazolin-2-ylidene, platinum(II), palladium(II), gold(I) complex.
References
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[12] A. Biffis, P. Centomo, A. D. Zotto, M. Zecca, Pd Metal Catalysts for Cross-Couplings and Related Reactions in the 21st Century: A Critical Review, Chem. Rev. 118 (2018) 2249-2295. http://doi.org/10.1021/acs.chemrev.7b00443.
[13] T. Strassner, Phosphorescent Platinum(II) Complexes with C^C* Cyclometalated NHC Ligands, Acc. Chem. Res. 49 (2016), 2680-1689. http://doi.org/ 10.1021/acs.accounts.6b00240.
[14] J. P. Perdew, J. A. Chevary, S. H. Vosko, K. A. Jackson, M. R. Pederson, D. J. Singh, C. Fiolhais, Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation, Phys. Rev. B 46 (1992) 6671-6687. https://doi.org/10.1103/PhysRevB.46.6671.
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[17] P. Schwerdtfeger, M. Dolg, W. H. Eugen Schwarz, A. B. Graham, P. D. W. Boyd. Relativistic effects in gold chemistry. I. Diatomic gold compounds. J. Chem. Phys. 91 (1989) 1762-1774. https://doi.org/10.1063/1.4
57082.
[18] M. Bouché, G. Dahm, A. Maisse-François, T. Achard, S. Bellemin-Laponnaz, Selective Formation of cis-N-Heterocyclic Carbene-PtII-Pnictogen Complexes and in vitro Evaluation of Their Cytotoxic Activities toward Cancer Cells, Eur. J. Inorg. Chem. (2016) 2828-2836. https://doi.org/ 10.1002/ejic.201600296.
[19] V. H. Nguyen, B. M. El Ali, H. V. Huynh, Stereoelectronic Flexibility of Ammonium-Functionalized Triazole-Derived Carbenes: Palladation and Catalytic Activities in Water, Organometallics, 37 (2018) 2358-2367. https://doi.org/10.1021/acs.organomet.8b00347.