Zinc Complex Enables Imine Bond Formation in Water
Researchers in Italy report a method that forms highly stable imine bonds in water using a zinc-based complex.
Updated on Nov. 5, 2026 in Chemistry
Italian researchers developed a way to form imine bonds in water, addressing the bonds' low stability in aqueous conditions. The method uses a zinc complex that binds and pre-organises the aldehyde precursor, yielding highly stable imines within two hours.
Why it matters
Imine bonds are dynamic covalent bonds used across materials, supramolecules, and sensors, but water produced during formation typically drives hydrolysis, making aqueous synthesis difficult. A method that works in water could broaden where these bonds can be applied.
The study reports stable imine formation within two hours at neutral pH and micromolar concentrations, with pyridine-containing precursors shortening reaction times from days to hours. Performance at higher concentrations and with other substrate classes remains unreported.
The players
University of Padova
A public research university in Padua, Italy, one of the oldest universities in the world and the affiliation of lead researcher Leonard Prins.
University of Sydney
A public research university in Sydney, Australia, the affiliation of chemist Kate Jolliffe, who commented on the work without being involved in it.
The details
The team used amine precursors functionalised with 1,4,7-triazacyclononane (TACN)·Zn(ii), which bind and pre-organise the aldehyde to activate it for nucleophilic attack while stabilising the resulting imine through coordination. The reaction was extended to simple amines and pyridine-based aldehydes and also formed imine bonds in Escherichia coli cell lysate.
Timeline
Highly stable imines form within two hours using the zinc-complex method.
The Big Picture
Imine chemistry is a cornerstone of dynamic covalent chemistry, where reversible bonds enable self-healing materials and adaptive supramolecular assemblies. Extending imine formation into water opens this toolkit to biological and aqueous environments where the bonds previously hydrolysed too readily to be useful.
Imine bonds underpin self-healing materials and chemical sensors, so a water-compatible route could make these applications easier to develop for biological and environmental uses. Commercialization timelines are not addressed in the source study.
The takeaway
Chemistry that works in water is often harder than chemistry in organic solvents, so methods like this one that succeed in aqueous conditions are worth watching. Readers following materials science can track how dynamic covalent bonds move from lab benches toward applied uses.
Further reading
Explore more Chemistry coverage for context on bond formation and reaction chemistry.
Source note: This article includes information reported by Chemistry World.
