Castellano Research Group

Last week, our very own Dr. Sarah Arteta formally graduated as one of the Fall 2025 graduates! Congratulations to Dr. Arteta! 🎉🎓

Congratulations to Adrienne Faulkner for defending her preliminary thesis, "A Computational Study on Heteroleptic Cu(I) Photosensitizers"! 🎉

Spin-Vibronic Effect in Photoinduced Electron Transfer The spin-vibronic effect (SVE) accelerates quantum-mechanically forbidden electronic transitions, but experimental manifestations of this phenomenon remain limited. In this contribution, the role of SVE in photoinduced electron transfer (PET) dynamics is probed by coherent vibrational wavepacket (CVWP) motions in Pt(II) dimer-naphthalene diimide donor–acceptor complexes. Metal–metal-to-ligand charge-transfer (MMLCT) excitation of the donor triggers ballistic PET, driving the molecule away from equilibrium. The SVE then directs the PET trajectory from the 1MMLCT excited state to an intermediate ligand-centered triplet state, modulating the CVWP dynamics along the reaction coordinates. Herzberg–Teller type oscillations indicate that the Pt–Pt stretching vibration, arising from the formation of the excited triplet intermediate, serves as the reaction coordinate for charge separation. Our experimental findings advance the understanding of the interplay between electronic, vibrational, and spin degrees of freedom in ultrafast photoactivated processes.

"Spin-Vibronic Effect in Photoinduced Electron Transfer"
An investigation of Pt(II) dimer systems that undergo metal-metal-to-ligand charge-transfer. Sarah Kromer and Nicolas Durand collaborated with the Chen group at Argonne National Labs!
Read more about it here: pubs.acs.org/doi/10.1021/...

Programmable Light-Driven Color Tuning of Perovskite Quantum Dots Precise, sustainable, and scalable bandgap tuning of metal halide perovskite (MHP) nanocrystals (NCs) is critical for their integration into advanced optoelectronic and photocatalytic systems. Photoin...

"Programmable Light-Driven Color Tuning of Perovskite Quantum Dots"
A study on tuning the bandgap of metal halide perovskite nanocrystals. This work was a collaboration with the Abolhasani group here at NC State!

Read more about it here: doi.org/10.1021/acsc...

This past weekend was the North Carolina Photochemistry Symposium! Our group had the chance to show off what we've been up to, and our member @azkaarshad.bsky.social gave a talk to those in attendance as well!

Plasmon-enhanced ultralow-threshold solid-state triplet fusion upconversion - Nature Photonics Performance of solid-state triplet fusion upconversion films is enhanced by surface plasmons, intensity threshold is reduced by a factor of 17 and external quantum efficiency is enhanced by a factor o...

Check out our most recent publication detailing "Plasmon-enhanced ultralow-threshold solid-state triplet fusion upconversion"

Read more here!
doi.org/10.1038/s415...

This past week we got to host Exploris school to show off some cool experiments to excited students! This year we had a new station featuring TLC experiments with leaves! Huge thanks to the Abolhasani lab for showing of their AI powered liquid handling robot that plays tic tac toe!

Congratulations to Dr. Emily Brown for defending her thesis “UV and Visible Light Photoactivation of Parahydrogen Induced Hyperpolerization and Signal Amplification by Reversible Exchange”. She will be moving on to a fellowship at the Lawerence Berkeley National Laboratory! @eebrown.bsky.social 🎉

A Rhenium Bis- tetramethylphenanthroline Catalyst for CO2 Reduction to Formate Catalytic CO2 reduction reactions featuring high selectivity toward formate are relatively rare. In some homogeneous molecular CO2-reducing electrocatalysis, using triethylamine (TEA) and isopropanol ...

Check out “A Rhenium Bis- tetramethylphenanthroline Catalyst for CO2 Reduction to Formate”. By our group members Dr. Reem Alameh, Dr. Sarah Arteta, Dr. Nicolas Durand, and Dr. Hala Atallah

Great work everyone! Read more here:
doi.org/10.1021/acs....

⚡️Check out “Characterizing Ultrafast Intersystem Crossing Pathways in Molecular Pt Dimers Using Time-Resolved Wide-Angle X-ray Scattering” a recent publication featuring work from our member Sarah Kromer.

Read more here:
doi.org/10.1021/acs....

Congrats to Dr. Sarah Arteta for successfully defending her thesis “Mechanistic Investigation of Transition Metal Complexes for Symbiotic Copper Photocatalysis and Electochemical Formate Generation” ! 🎊🎉

Direct Evidence for Buffer-Enhanced Proton-Coupled Electron Transfer Generation of a High-Valent Metal-Oxo Complex The oxidation of metal-aquo and -hydroxo complexes to generate the high-valent metal-oxo species used in oxidative catalysis is often kinetically slow due to sluggish proton transfer between ligated −H2O/–OH in the proton-coupled electron transfer (PCET) chemistry. In this research, a ruthenium water oxidation catalyst anchored to a conductive tin-doped indium oxide (ITO) thin film, abbreviated ITO|RuII–OH2, was characterized by spectroscopic and electrochemical methods in acetate or phosphate buffers. The deprotonated intermediate, RuII–OH, was observed spectroscopically in the PCET half-reaction ITO(e–)|RuIII–OH + H+ → ITO|RuII–OH2 indicating an underlying stepwise ET-PT mechanism. In contrast, at elevated buffer concentrations, this intermediate was absent, and a 2–4 order of magnitude increase in the proton transfer rate constant was observed. Kinetic data for this PCET reaction measured as a function of the driving force provided the reorganization energy λ = 1.05 eV and was assigned to a concerted electron–proton transfer (EPT) mechanism. In addition, the standard heterogeneous rate constants for two PCET equilibria, RuIII–OH + H+ + e– ⇌ RuII–OH2 and RuIV = O + H+ + e– ⇌ RuIII–OH were enhanced by these same buffers. Collectively, the data show that the added buffers can enhance the kinetics and thermodynamics for PCET reactions relevant to oxidative catalysis.

Check out “Direct Evidence for Buffer-Enhanced Proton-Coupled Electron Transfer Generation of a High-Valent Metal-Oxo Complex” a collaboration with the Meyers group at UNC with our staff scientist Dr. Evgeny Danilov.

Read about it here: doi.org/10.1021/acs....

Immobilizing a Lehn-Type Catalyst with Nitrocyclocondensation Chemistries: CO2 Reduction on Silicon Hybrid Photoelectrodes We present the first examples of installing a redox reporter and CO2 reduction (CO2R) catalyst onto freshly HF-etched Si (photo)electrodes using a solution-phase nitrocyclocondensation (NCC) reaction....

“Immobilizing a Lehn-Type Catalyst with Nitrocyclocondensation Chemistries: CO2 Reduction on Silicon Hybrid Photoelectrodes” featuring work from our group members Nicolas Durand and @abonfig3.bsky.social, in collaboration with our friends at UNC. Check it out here:

doi.org/10.1021/acsa...

🎉 Congratulations to Dr Austin Pyrch for the successful defense of his Thesis “Probing 1st Row Transition Metal Complexes for Radical Generation and Photoredox Applications”

We’re happy to announce that our very own Professor Phill Castellano was awarded NCSU’s Outstanding Research award and has thus been inducted into the universities Research Leadership Academy. Hats off! 🎉

Congratulations to Dr. Reem Alameh for defending her thesis! 🥳 Reem is graduating after presenting her work on the Spectroscopic and Electrocatalytic Investigation of Rhenium (I) Complexes. Reem was a beloved member of the lab and we wish her good luck in her future endeavors.

@ralameh.bsky.social

🎉 Our very own @alextbarth.bsky.social was selected as one of the 2025 CAS future leaders! 🎉
This program is awarded to 35 graduate students and or post docs across 12 countries.

Read more here:

www.cas.org/press-releas...

Our very own @alextbarth.bsky.social from @castellanogroup.bsky.social @ncstatechem.bsky.social is also on the list of 35!

Emily Brown just had her work on “Photo-ejected ligands hyperpolarized by parahydrogen in reversible exchange”. published in ChemComm!

Read more about it here:

DOI: 10.1039/d4cc06807f

🎉 Congrats to @ralameh.bsky.social for her publication in ChemPhysChem! 🎉“Photophysical and Time-resolved Infrared Properties of Long Lived Rhenium (I) 4,5-Diazafluorene Tricarbonyl Chromophores”

Read more about it here: doi.org/10.1002/cphc.202500008

We are excited to announce a recent publication in Matter featuring molecules designed and synthesized by former group members Dr. Hala Atallah and Dr. Nicolas Durand! Read about it here: doi.org/10.1016/j.ma...

Some of the group went out ice skating recently! Loads of fun and hopefully proof we don’t spend all of our time in lab. :)

Congrats to Azka Arshad for presenting her seminar on “Homolecular Triplet-Triplet Annihilation in Metalloporphyrin Photosensitixers”

Hats off 🎉

Happy Fluorescence Friday! Check out these beautiful Pt(II) complexes phosphorescing under UV light!

Congrats to Conor McCormick for presenting his second year seminar talk on Tuning Rhenium Photosensitizers via Ligand Substitution. 🎉

Check out our most recently published article in JPC, reporting triplet extinction coefficients and annihilation rate constants for commonly used metalloporphyrin photosensitizers, a critical advancement in understanding this fundamental photochemical process.

pubs.acs.org/doi/full/10....

We had a blast hosting The Exploris School for two days of showing cool chemistry to excited students! Huge thanks to The Sustainable Dye Chemistry lab for the cool dye experiments, and the Abolhasani lab for showing off an awesome AI powered robotic arm that could play tic tac toe with pipettes!