# Photothermal Catalysis: Using light to thermally generate reactive intermediates with temporal and spatial control

> **NIH NIH R35** · PRINCETON UNIVERSITY · 2024 · $410,000

## Abstract

Project Summary
 Photon-driven processes have emerged as a powerful tool for achieving challenging bond cleavage and
bond formation. Photocatalysis offers the benefit of temporal and spatial control with low energy light, which has
been widely advantageous for efficiently building molecular complexity from simple starting materials. The
judicious choice of photocatalysts enables the precision of reactivity that is rarely achieved with other forms of
catalysis and heating. An underused area of photocatalysis is photothermal conversion. Irradiation of specific
nanoparticles or dyes with visible light creates intense thermal gradients in a photothermal conversion process.
In contrast to bulk heating, where the temperature remains uniform across a reaction medium, substrates would
only experience thermal energy within a few nanometers of excitation under temporal heating. Consequently,
this process would use irradiation to drive chemical processes at high temperatures with temporal and spatial
control. Spatial control enables the selective formation of highly reactive species without competing bimolecular
side reactions.
 The proposed research comprises three fundamental projects exploring the use of photothermal catalysis
to enable the synthesis of complex molecules using visible light irradiation. First, high-temperature thermal
rearrangements will be achieved using carbon-based nanoparticles and visible light irradiation under mild
conditions. This strategy will enable the synthesis of complex products without thermal decomposition generally
associated with bulk thermolysis. Additionally, the identification of various photothermal agents and synthetic
elaborations will generate more efficient catalysts. In the second project, photothermal heating will generate
carbon-centered radicals through C–C bond homolysis. Intercepting these highly reactive intermediates will forge
new C–C bonds in ring expansion reactions, in intramolecular cyclizations. Specific photothermal agent design
will enable intermolecular ring expansions to build molecular complexity. In a third project, the C–C bond
homolysis reactions identified in project two will be used in dynamic kinetic resolutions for atom economical
synthesis of enantioenriched pharmaceutical compounds. Emulsions will confine thermal gradients to within
micelles enabling the coupling of thermal epimerization reactions with highly selective enzymatic reactions.
Combined, these three projects will develop an understanding of photothermal catalysis and the effect of light
and intensity on generation of thermal gradients. A thorough understanding of how these thermal gradients can
be leveraged for high temperature reactions with the spatial and temporal control of visible light will enable new
synthetic bond disconnections previously unrealized.

## Key facts

- **NIH application ID:** 10915530
- **Project number:** 5R35GM150839-02
- **Recipient organization:** PRINCETON UNIVERSITY
- **Principal Investigator:** Erin Stache
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $410,000
- **Award type:** 5
- **Project period:** 2023-09-01 → 2028-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10915530

## Citation

> US National Institutes of Health, RePORTER application 10915530, Photothermal Catalysis: Using light to thermally generate reactive intermediates with temporal and spatial control (5R35GM150839-02). Retrieved via AI Analytics 2026-05-27 from https://api.ai-analytics.org/grant/nih/10915530. Licensed CC0.

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