Combining Cyclic Triimidazo Triazine Core With Ethynyl-N-Methyl-Pyridinium Groups for Targeting G-Quadruplex Structures Chiara Platella, Stefano Di Ciolo, Andrea Criscuolo, Daniele Malpicci, Rosa Gaglione, et al. Archiv Der Pharmazie, 2025 The synthesis and characterization of a mini‐library of cyclic triimidazo triazine (TT) derivatives functionalized with one, two, or three ethynyl‐N‐methyl‐pyridinium moieties are reported here. These compounds were designed with the aim of targeting cancer‐related DNA G‐quadruplex structures. The newly synthesized compounds were tested for their ability to bind G‐quadruplexes from both telomeric and oncogene promoter sequences using an affinity chromatography‐based assay, spectroscopic and electrophoretic techniques, as well as molecular docking analysis. The obtained results demonstrated the effective capacity of the investigated compounds to specifically recognize the selected G‐quadruplex models, with their TT cores targeting the outer G‐quartets and their positively charged N‐methyl‐pyridinium groups interacting with the top edge of G‐quadruplex grooves. Notably, the trisubstituted cyclic triimidazole compounds showed higher stabilizing properties than the related disubstituted derivatives, which in turn were stronger binders than their monosubstituted analogs. However, the mono‐ and disubstituted derivatives showed higher G‐quadruplex versus duplex recognition selectivity compared with the trisubstituted ones. Altogether, the biophysical experiments, also in agreement with the biological assays, underlined the advantage of introducing an alkyne linker between the triimidazole core and the methylpyridinium group, proving to be beneficial to increase both the stabilizing effects on the G‐quadruplexes and the anticancer activity compared with the analogs of the same family lacking the alkyne linker.
Excitation Dependent Multiemissive Behaviour of Triimidazole Carboxylic Acid anti-Kasha Luminophore and its Mononuclear Metal Complexes Daniele Malpicci, Alessandra Forni, Elena Lucenti, Daniele Marinotto, Daniele Maver, et al. European Journal of Inorganic Chemistry, 2024 Materials based on small molecules characterized by multi‐component short and long‐lived emissive behaviour are extremely desirable for various applications. The derivative of cyclic triimidazole (TT) functionalized with a carboxylic group, namely TT‐COOH, is isolated, investigated and used as coordinative ligand to obtain a series of isomorphous mononuclear complexes of general formula [M(TT‐COO)2(H2O)2] (M=Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)). Crystals of TT‐COOH display aggregation induced enhanced emission (AIEE) comprising dual fluorescence and dual phosphorescence of molecular origin together with an aggregation induced long lived, low energy phosphorescence. Emissive features are retained in crystals of the Zn(II) and Cd(II) complexes, where the metal plays the role of an external heavy atom perturber, but strongly quenched in the others. The mechanisms involved in the photophysics of TT‐COOH and its metal complexes have been disclosed thanks to combined structural, spectroscopic and computational investigations which reveal the presence of anti‐Kasha emissions.
Layered Ag(I), Cd(II) and Cu(I) Luminescent Coordination Polymers Assembled Through a Tri-Pyridyl Cyclic Triimidazole Ligand Daniele Malpicci, Delia Blasi, Alessandra Forni, Elena Lucenti, Daniele Marinotto, et al. European Journal of Inorganic Chemistry, 2024 The versatility of a nitrogen rich pyridinic derivative of the cyclic triimidazole scaffold with C3 symmetry is here exploited to obtain three luminescent coordination polymers (CPs). By reaction of 3,7,11‐tri(pyridin‐4‐yl)triimidazo[1,2‐a:1′,2′‐c:1′′,2′′‐e][1,3,5]triazine, (4 py)3TT, with Ag(I), Cd(II) and Cu(I) salts, [Ag{(4‐py)3TT}(SO3CF3)]n ⋅ nCH2Cl2, [Cd{(4‐py)3TT}(NO3)2(EtOH)]n and [(Cu2I2)3{(4‐py)3TT}4]n ⋅ xn(H2O,EtOH) are obtained. The trigonal symmetry of (4 py)3TT results in 2D structures with hcb topology in [Ag{(4‐py)3TT}(SO3CF3)]n ⋅ nCH2Cl2 and [Cd{(4‐py)3TT}(NO3)2(EtOH)] and a rare 3,4‐connected (3,4‐c) topology in [(Cu2I2)3{(4‐py)3TT}4]n ⋅ xn(H2O,EtOH). The multifaceted emissive behaviour of the CPs and the free ligand has been investigated and interpreted through spectroscopic, structural and computational studies. The fluorescence and the high energy phosphorescence of [Ag{(4‐py)3TT}(SO3CF3)]n ⋅ nCH2Cl2, [Cd{(4‐py)3TT}(NO3)2(EtOH)]n and (4 py)3TT itself are correlated to singlet and triplet excited states of molecular origin while their low energy phosphorescence derives from supramolecular entities associated with strong π–π interactions with little metal contribution as it is the case for the single phosphorescence observed for [(Cu2I2)3{(4‐py)3TT}4]n ⋅ xn(H2O,EtOH). In agreement, unusually long lifetimes in the ms regime are measured for crystals of all compounds.
