# Methyl Viologen Lead Iodide for Photocatalytic Reductive Coupling of Aromatic Carbonyls via Proton-Coupled Electron Transfer

## TL;DR

A new photocatalyst made from methyl viologen lead iodide efficiently performs chemical reactions in protic solvents without breaking down.

## Contribution

A stable, easily prepared photocatalyst (MVPb2I6) enables reductive coupling of aromatic carbonyls under visible light.

## Key findings

- MVPb2I6 efficiently catalyzes reductive coupling of aromatic aldehydes and ketones in protic solvents.
- MVPb2I6 retains structural integrity after photoreduction, indicating high robustness.
- Incorporating quaternary pyridinium cations improves OIMH stability for photocatalytic reactions.

## Abstract

Organic–inorganic metal halides (OIMHs) have emerged
as
promising photocatalysts for organic transformations due to their
excellent optoelectronic properties. However, their instability, particularly
under protic conditions, has limited their broader applications. Here,
we report that a facilely prepared methyl viologen lead iodide (MVPb2I6) powder can efficiently catalyze the visible-light-driven
reductive coupling of aromatic aldehydes and ketones in protic solvents.
Remarkably, MVPb2I6 retains its structural integrity
after photoreduction, highlighting its robustness. These results suggest
that incorporating quaternary pyridinium cations into the OIMHs can
enhance their stability and expand their applicability in photocatalytic
organic synthesis.