A comprehensive review of synthesis, characterization, single-crystal X-ray diffraction, and applications of transition metal complexes with tricyanomethane anions

This review article showcases unrevealed N/O and N-donor Schiff bases (SBs) transition metal complexes with tricyanomethane anions (TCM), [C(CN)₃]^-, primarily focuses on their design, synthetic update, structural characterization, and applications. The increasing scientific focus on TCM complexes, owing to their diverse bridging attraction with metal ions (Mⁿ⁺) and numerous applications, underscores the importance of this review. Only those metal complexes with available X-ray crystal structures are considered for this review article. X-ray crystal structures were obtained from the Cambridge Crystallographic Data Centre (CCDC) and the Cambridge Structural Database (CSD). Elemental (CHN), conventional spectroscopy, SCXRD (single-crystal X-ray diffraction), TGA, PXRD, Fluorescence, and magnetic moment characterize the metal complexes. TCM complexes are growing in research interest due to their fascinating X-ray crystal structure and supramolecular chemistry originating from TCM's bridging propensity. Therefore, the review emphasizes the potential uses in multidimensional areas, including Photoluminescence/Fluorescence, thermal, and temperature variable magnetic moment. The review also searches for less explored research areas of applications covering complexes' biological aspects such as antibacterial, fungal, antifungal photodynamic therapy (APDT) and cytotoxicity, as well as high-profile DFT-based investigation. Meanwhile, the review examines the X-ray crystallographic in-depth novel supramolecular features unveiled in the literature. This article will inspire next-generation researchers to divulge the TCM complex's broad chemistry after tuning the spacer's active role in coordination chemistry.