# Functional Synthetic Models of Cu-dependent Monooxygenases

> **NIH NIH R35** · CARNEGIE-MELLON UNIVERSITY · 2020 · $229,499

## Abstract

Project Summary:
In this research project, we develop synthetic inorganic copper complexes to understand the fundamental
aspects of structure and function in Cu-dependent monooxygenase enzymes. These metalloenzymes contain
1 or 2 Cu ions in their active center and they couple the reduction of O2 with the oxidation of substrates via
formation of transient Cun/O2 species. We are particularly interested in studying the reactivity of mononuclear
Cu/O2 intermediates since they have been proposed as active oxidants in the hydroxylation of strong C-H
bonds in enzymes such as particulate methane monooxygenases (pMMOs) and lytic polysaccharide
monooxygenases (LPMOs). Many questions concerning the identity of the active Cu/O2 species remain
unanswered, including: i) oxidation state of Cu (CuI vs. CuII vs. CuIII); ii) reduction/protonation state of O2
(O2Ÿ−,(H)O22−, (H)O2−) and the pKa and redox potentials associated with these Cu/O2 species; iii) mechanism
by which the Cu/O2 intermediates carry out C-H hydroxylations (e.g. O-O cleavage mechanism before or after
C-H oxidation?; generation of high-valent Cu-oxyl species before substrate hydroxylation?). In this research
proposal, we tackle this problem using two different approaches:
1) We utilize ligand scaffolds (L) that contain C-H substrates covalently attached to their structure (substrate-
ligands) that permit us to generate and characterize LCu/O2 species and evaluate their reactivity towards
intramolecular C-H hydroxylation. Substrate-ligand modifications will permit us to: i) evaluate the ability of the
Cu/O2 species to oxidize sp3 C-H bonds and sp2 C-H bonds; ii) control the stereo-electronic properties of the
Cu complexes by the use of different ligand donors (i.e. N2, N3, N4) that will lead to the generation of
mononuclear and dinuclear LCu/O2 species, and analyze their reactivity towards intramolecular C-H
hydroxylation including characterization of reaction intermediates, kinetics and computations; iii) utilize this
approach (Cu-directed hydroxylations) to develop synthetic protocols to promote challenging organic
transformations such as enantioselective C-H hydroxylations and one-pot synthesis of 1,3-oxazines.
2) We synthesize mononuclear Cu complexes bearing redox-active ligands with tunable H-bonds that stabilize
Cu-hydroxo and Cu-oxyl cores. These unusual Cu complexes are able to reach multiple oxidation states via
oxidation of the metal and/or ligand scaffold. These high-valent CuO(H) cores will be characterized by various
spectroscopic methods and their ability to perform biorelevant intermolecular 2e− C-H hydroxylations will be
examined systematically using the Bordwell equation (i.e. species with higher redox potential and higher pKa
should be capable of oxidizing stronger C-H bonds), kinetic experiments and analysis of the reactions products
derived from hydroxylation (e.g. organic product(s) and oxidation/protonation state of the final Cu complexes).
Overall, these studies will contri...

## Key facts

- **NIH application ID:** 10402075
- **Project number:** 7R35GM137914-02
- **Recipient organization:** CARNEGIE-MELLON UNIVERSITY
- **Principal Investigator:** Isaac Garcia-Bosch
- **Activity code:** R35 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $229,499
- **Award type:** 7
- **Project period:** 2020-09-01 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10402075

## Citation

> US National Institutes of Health, RePORTER application 10402075, Functional Synthetic Models of Cu-dependent Monooxygenases (7R35GM137914-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10402075. Licensed CC0.

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