Coordination Chemistry of a Controlled Burst of Zn2+ in Bulk Aqueous and Nanosized Water Droplets with a Zincon Chelator

Cheryle N Beuning; Noah E Barkley; Prem N Basa; Shawn C Burdette; Nancy E Levinger; Debbie C Crans

doi:10.1021/acs.inorgchem.9b02848

Coordination Chemistry of a Controlled Burst of Zn²⁺ in Bulk Aqueous and Nanosized Water Droplets with a Zincon Chelator

Inorg Chem. 2020 Jan 6;59(1):184-188. doi: 10.1021/acs.inorgchem.9b02848. Epub 2019 Dec 6.

Authors

Cheryle N Beuning¹, Noah E Barkley¹, Prem N Basa², Shawn C Burdette², Nancy E Levinger¹, Debbie C Crans¹

Affiliations

¹ Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523-1872 , United States.
² Department of Chemistry and Biochemistry , Worcester Polytechnic Institute , Worcester , Massachusetts 01609 , United States.

PMID: 31808684
DOI: 10.1021/acs.inorgchem.9b02848

Abstract

The light-induced photolysis of [Zn(NTAdeCage)]^- generates a temporally controlled burst of Zn²⁺, which is rapidly chelated in situ by the free ligand Zincon^2-. The [Zn(Zincon)]^2- coordination progress is monitored using absorption spectroscopy in bulk aqueous buffer and reverse micelle environments. The [Zn(NTAdeCage)]^- photocage and free ligand Zincon^2- have different reverse micelle locations that affect the [Zn(Zincon)]^2- formation at the nanoscale compared to the bulk aqueous buffer. The formation of [Zn(Zincon)]^2- in a bulk aqueous buffer is more efficient despite the released Zn²⁺ and Zincon^2- being physically closer within reverse micelles. The observed reduction of complex formation is attributed to the interfacial partitioning of Zincon^2-, distinct from the Zn²⁺ photocage in the water pool, requiring diffusion for the species to meet to form [Zn(Zincon)]^2-. This work introduces a proof-of-concept methodology to experimentally measure fast chelation reactions in confined spaces and thus provides an approach to exploring cellular responses.