# Ligand effects on reactivity of hydride-decorated and reduced multi-iron compounds

> **NIH NIH R01** · UNIVERSITY OF FLORIDA · 2021 · $276,893

## Abstract

Title: Ligand effects on reactivity of hydride-decorated and reduced multi-iron compounds
Abstract
 Metal cluster cofactors provide substrates with many potential orientations to bind and subsequently
undergo chemical transformations. This is particularly true for cluster cofactors that activate small
molecule substrates. The focus of this proposal is on the chemistry of the iron-molybdenum cofactor in
the molybdenum-dependent nitrogenases, which catalyzes the eight electron and eight proton reduction of
dinitrogen and two protons to generate two equivalents of ammonia and one of dihydrogen. The current
mechanism proposed for the conversion of N2 to NH3 by this enzyme uses concepts that are common to
numerous other metal cofactors, such as the protonation of bridging sulfide donors, the use of metal
hydrides to store reducing equivalents, and the potential to coordinate the hydrides and dinitrogen in
either terminal or bridging modes. How the iron-molybdenum cofactor binds hydride donors and
dinitrogen, as well as intermediates during the catalytic reaction, are fundamental aspects of the
mechanism but remain unclear. This is the knowledge gap that this proposal addresses. This proposal will
accomplish this goal by using synthetic clusters in which substrates (hydrides and dinitrogen) can bind in
either bridging or terminal coordination modes, which mirrors the coordinative flexibility possible for
these substrates on the iron-molybdenum cofactor. As part of this inquiry, this proposal will dissect how
number, identity, and connectivity of bridging ligands modulate substrate coordination. The results
generated in this proposal have broader implications for biochemical reactions, and specifically, shed
light on the principles that govern biological catalysis of multi-electron multi-proton redox reactions (e.g.,
water oxidation in photosynthesis, dioxygen reduction in respiration).

## Key facts

- **NIH application ID:** 10093066
- **Project number:** 5R01GM123241-05
- **Recipient organization:** UNIVERSITY OF FLORIDA
- **Principal Investigator:** Leslie Justin Murray
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $276,893
- **Award type:** 5
- **Project period:** 2017-04-01 → 2023-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10093066

## Citation

> US National Institutes of Health, RePORTER application 10093066, Ligand effects on reactivity of hydride-decorated and reduced multi-iron compounds (5R01GM123241-05). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10093066. Licensed CC0.

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