Novel Zinc β-Diketonates with Donor–Acceptor Ligands: Synthesis and Comprehensive Structural, Thermal, and Photophysical Characterization

We report the synthesis, structural characterization, and ultrafast photophysical in-vestigation of a novel series of homoleptic and heteroleptic Zn(II) β-diketonates de-rived from donor–acceptor ligands. Single-crystal X-ray diffraction revealed that all complexes adopt monomeric octahedral geometries, with ancillary nitrogen-based ligands inducing variable distortions. UV–Vis absorption and femtosecond transient absorption spectroscopy established that the chelated β-diketonate ring constitutes the primary optically active chromophore, while Zn coordination markedly alters excit-ed-state dynamics. In contrast to the free ligand, which undergoes rapid internal con-version, Zn binding stabilizes the triplet state, generating a long-lived and chemically reactive species. Thermal and mass spectrometric analyses confirmed their stability and decomposition pathways, supporting their potential use as precursors for la-ser-induced three-dimensional ZnO growth. Such features underline the relevance of these complexes in photonic and electronic applications where controlled nanostruc-ture development is required. Overall, these findings provide fundamental insights into structure–photophysics relationships in Zn β-diketonates. They demonstrate how tailored ligand environments can be exploited to tune excited-state properties, offering a rational framework for the design of functional precursors suitable for nonlinear photolysis and advanced nanomaterial synthesis.