Bioorthogonal Activation and Mitochondrial Targeting of an Iridium(III) Nitrone Complex via Cyclooctynylated Phosphonium Cations for Phototheranostics

Lawrence Cho-Cheung Lee; Edward R. H. Walter; Peter Kam-Keung Leung; Kenneth Kam-Wing  Lo; Nicholas J. Long

Bioorthogonal Activation and Mitochondrial Targeting of an Iridium(III) Nitrone Complex via Cyclooctynylated Phosphonium Cations for Phototheranostics

Lawrence Cho-Cheung Lee (Co-first Author)
, Edward R. H. Walter (Co-first Author)
, Peter Kam-Keung Leung
, Kenneth Kam-Wing Lo^*
, Nicholas J. Long^*

^*Corresponding author for this work

Department of Chemistry

Research output: Conference Papers › RGC 33 - Other conference paper

Abstract

Mitochondria are central to cellular functions and key targets in cancer therapy. In this study, we designed an iridium(III) nitrone complex (1) as a bioorthogonally activatable phototheranostic agent, and prepared a series of cyclooctynylated phosphonium cations (BCN-Phos-n) to direct the phosphorogenic nitrone complex to mitochondria via a bioorthogonal strain-promoted alkyne–nitrone cycloaddition reaction. Notably, complex 1 displayed significant emission turn-on both in solutions and in live cells upon reaction with BCN-Phos-5 and BCN-Phos-6, which carry two lipophilic methyl or methoxy groups on each phenyl ring of the triphenylphosphonium unit. The complex also exhibited increased (photo)cytotoxicity in cells pretreated with BCN-Phos-5 or BCN-Phos-6. These results show that the theranostic potential of transition metal nitrone complexes can be enhanced via the strategic structural manipulation of their bioorthogonal partners.

Original language	English
Publication status	Presented - 9 May 2026
Event	32nd Symposium on Chemistry Postgraduate Research in Hong Kong - , Hong Kong, China Duration: 9 May 2026 → 9 May 2026 https://www.cuhk.edu.hk/chem/32ndPostGradSymp/index.html

Conference

Conference	32nd Symposium on Chemistry Postgraduate Research in Hong Kong
Place	Hong Kong, China
Period	9/05/26 → 9/05/26
Internet address	https://www.cuhk.edu.hk/chem/32ndPostGradSymp/index.html

Funding

We thank “Laboratory for Synthetic Chemistry and Chemical Biology” under the Health@InnoHK Program launched by Innovation and Technology Commission, The Government of HKSAR, P. R. China for financial support.

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@conference{107157f1c80d4f5db5857bc94074d232,

title = "Bioorthogonal Activation and Mitochondrial Targeting of an Iridium(III) Nitrone Complex via Cyclooctynylated Phosphonium Cations for Phototheranostics",

abstract = "Mitochondria are central to cellular functions and key targets in cancer therapy. In this study, we designed an iridium(III) nitrone complex (1) as a bioorthogonally activatable phototheranostic agent, and prepared a series of cyclooctynylated phosphonium cations (BCN-Phos-n) to direct the phosphorogenic nitrone complex to mitochondria via a bioorthogonal strain-promoted alkyne–nitrone cycloaddition reaction. Notably, complex 1 displayed significant emission turn-on both in solutions and in live cells upon reaction with BCN-Phos-5 and BCN-Phos-6, which carry two lipophilic methyl or methoxy groups on each phenyl ring of the triphenylphosphonium unit. The complex also exhibited increased (photo)cytotoxicity in cells pretreated with BCN-Phos-5 or BCN-Phos-6. These results show that the theranostic potential of transition metal nitrone complexes can be enhanced via the strategic structural manipulation of their bioorthogonal partners.",

author = "Lee, \{Lawrence Cho-Cheung\} and Walter, \{Edward R. H.\} and Leung, \{Peter Kam-Keung\} and Lo, \{Kenneth Kam-Wing\} and Long, \{Nicholas J.\}",

year = "2026",

month = may,

day = "9",

language = "English",

note = "32nd Symposium on Chemistry Postgraduate Research in Hong Kong ; Conference date: 09-05-2026 Through 09-05-2026",

url = "https://www.cuhk.edu.hk/chem/32ndPostGradSymp/index.html",

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Bioorthogonal Activation and Mitochondrial Targeting of an Iridium(III) Nitrone Complex via Cyclooctynylated Phosphonium Cations for Phototheranostics. / Lee, Lawrence Cho-Cheung (Co-first Author); Walter, Edward R. H. (Co-first Author); Leung, Peter Kam-Keung et al.
2026. 32nd Symposium on Chemistry Postgraduate Research in Hong Kong, Hong Kong, China.

Research output: Conference Papers › RGC 33 - Other conference paper

TY - CONF

T1 - Bioorthogonal Activation and Mitochondrial Targeting of an Iridium(III) Nitrone Complex via Cyclooctynylated Phosphonium Cations for Phototheranostics

AU - Lee, Lawrence Cho-Cheung

AU - Walter, Edward R. H.

AU - Leung, Peter Kam-Keung

AU - Lo, Kenneth Kam-Wing

AU - Long, Nicholas J.

PY - 2026/5/9

Y1 - 2026/5/9

N2 - Mitochondria are central to cellular functions and key targets in cancer therapy. In this study, we designed an iridium(III) nitrone complex (1) as a bioorthogonally activatable phototheranostic agent, and prepared a series of cyclooctynylated phosphonium cations (BCN-Phos-n) to direct the phosphorogenic nitrone complex to mitochondria via a bioorthogonal strain-promoted alkyne–nitrone cycloaddition reaction. Notably, complex 1 displayed significant emission turn-on both in solutions and in live cells upon reaction with BCN-Phos-5 and BCN-Phos-6, which carry two lipophilic methyl or methoxy groups on each phenyl ring of the triphenylphosphonium unit. The complex also exhibited increased (photo)cytotoxicity in cells pretreated with BCN-Phos-5 or BCN-Phos-6. These results show that the theranostic potential of transition metal nitrone complexes can be enhanced via the strategic structural manipulation of their bioorthogonal partners.

AB - Mitochondria are central to cellular functions and key targets in cancer therapy. In this study, we designed an iridium(III) nitrone complex (1) as a bioorthogonally activatable phototheranostic agent, and prepared a series of cyclooctynylated phosphonium cations (BCN-Phos-n) to direct the phosphorogenic nitrone complex to mitochondria via a bioorthogonal strain-promoted alkyne–nitrone cycloaddition reaction. Notably, complex 1 displayed significant emission turn-on both in solutions and in live cells upon reaction with BCN-Phos-5 and BCN-Phos-6, which carry two lipophilic methyl or methoxy groups on each phenyl ring of the triphenylphosphonium unit. The complex also exhibited increased (photo)cytotoxicity in cells pretreated with BCN-Phos-5 or BCN-Phos-6. These results show that the theranostic potential of transition metal nitrone complexes can be enhanced via the strategic structural manipulation of their bioorthogonal partners.

M3 - RGC 33 - Other conference paper

T2 - 32nd Symposium on Chemistry Postgraduate Research in Hong Kong

Y2 - 9 May 2026 through 9 May 2026

ER -

Bioorthogonal Activation and Mitochondrial Targeting of an Iridium(III) Nitrone Complex via Cyclooctynylated Phosphonium Cations for Phototheranostics

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