Electronic Structural Characterization of Porphyrnoids and Charge Transfer Complexes

Ligand field and charge transfer transitions are critical to a variety of photochemical and electrochemical transformations. Using fundamental insight from a number of advanced spectroscopic and theoretical techniques (i.e. EAS/spectroelectrochemistry, EXAFS/XANES, MCD, TDDFT/CASSCF), we aim to identify key electronic transitions and structural properties that contribute to various modes of reactivity. We are presently interested in Lewis acid effects on mono-/multimetallic cyanide complexes and metalloporphyrinoids for applications in photo-/electrocatalysis and redox flow batteries. 

(Left Diagram) Orbital splitting with intermediate spin-orbit coupling and simultaneous deconvolution of (a) UV-vis-NIR and (b) MCD spectra for Lewis acid derivatized hexacyanoosmate and transition assignments.

(Above) Effects of Lewis basic alkylimidazolium ionic liquids on the Soret band transitions in manganese tris(pentafluorophenyl)corrole (Mn(tpfc)). 

Representative Publications:

  • Muldowney, B. E.; Grace, H. M.; McNicholas, B. J.✷, Nemykin, V. N.✷ Elucidation of Triplet-Multiplet and Charge Transfer Excited States in Copper and Vanadyl Phthalocyanines Using Combined Experimental (Magneto)optical Spectroscopy and Time-Dependent Density Functional Theory Calculations. Journal of Porphyrins and Phthalocyanines. 2025, https://www.worldscientific.com/doi/10.1142/S1088424625500038

  • McNicholas, B. J.✷; Nie, C.; Jose, A.; Oyala, P. H.; Takase, M. K.; Henling, L. M.; Barth, A. T.; Amaolo, A. A.; Hadt, R. G.; Solomon, E. I.; Grubbs, R. H.; Winkler, J. R.; Gray, H. B.✷; Despagnet-Ayoub, E.✷ Boronated Cyanometallates. Inorg. Chem. 2023, 62, 2959–2981. https://pubs.acs.org/doi/10.1021/acs.inorgchem.2c03066

  • McNicholas, B. J.; Grubbs, R. H.; Winkler, J. R.; Gray, H. B.✷; Despagnet-Ayoub, E.✷ Tuning the Formal Potential of Ferrocyanide over a 2.1 V Range. Chem. Sci. 2019, 10, 3623-3626. https://pubs.rsc.org/en/content/articlelanding/2019/sc/c8sc04972f

  • McNicholas, B. J.; Blumenfeld, C. M.; Kramer, W. W.; Grubbs, R. H.✷; Gray, H. B.✷ Electrochemistry in Ionic Liquids: Case Study of a Manganese Corrole Complex. Russ. J. Electrochem. 2017, 53, 1189-1193. https://link.springer.com/article/10.1134/S1023193517100068