Objective: The aim of this study was to evaluate the cure efficiency and biocompatibility of a novel iron-based coordination complex used as a photoinitiator in comparison to conventional ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L) and camphorquinone (CQ) as photoinitiators in dental 3D-printed resins. Materials and Methods: Experimental dental resin formulations were prepared by blending 1:1 ratio of Bis-GMA and TEGDMA, to which 0.2 wt% of either the iron-based coordination complex or CQ were added, along with 0.2 wt% EDAB and 0.4 wt% IOD, and the TPO-L. The degree of conversion (DC) was measured using Fourier transform infrared spectroscopy (FTIR). Biocompatibility was assessed by evaluating the viability of L929 fibroblast-like cells using the MTT assay 24 h post-exposure. Statistical analyses included a two-way ANOVA followed by Tukey’s test for post hoc comparisons, with significance at p < 0.05. Results: The degree of conversion for the iron-based coordination complex (84.54% ± 1.69%) was significantly higher than that for the TPO-L (78.77% ± 1.25%) and CQ-based resins (73.21% ± 0.47%) (p < 0.001). The iron-based coordination complex and TPO-L resins exhibited significantly higher conversion than CQ-based resins (p < 0.001). Regarding biocompatibility, the cell viability test revealed that the iron-based coordination complex demonstrated the highest cell viability at 86.5% ± 10.24%, followed by TPO-L with 80.03% ± 11.07%. CQ showed the lowest cell viability of 51.29% ± 8.44% (p < 0.05). Tukey’s test confirmed significant differences between CQ and other photointiators (p < 0.05), while no significant difference was found between TPO-L and the iron-based coordination complex. Conclusions: This study introduces a novel iron-based coordination complex photoinitiator that demonstrates enhanced cure efficiency and comparable biocompatibility to TPO-L, while significantly reducing the cytotoxicity associated with CQ. Its longer absorption wavelength supports deeper layer curing, making it a promising alternative for dental 3D printing, particularly in bioactive scaffold applications requiring minimized cytotoxicity.

The whole molecule of the title compound, C₂₂H₂₈N₂, (I), is generated by inversion symmetry. The molecule is rather similar to that of 2,3-bis[(2-tert-butylphenyl)imino]butane, (II), a diimine ligand comprising similar structural features [Ferreiraet al.(2006).Acta Cryst.E62, o4282–o4284]. Both ligands crystallize with the –N=C(R)—C(R)=N– group around an inversion centre, in atransconfiguration. Comparing the two structures, it may be noted that the independent planar groups in both molecules [the central link, –N=C(R)—C(R)=N–, and the terminal aromatic ring] subtend an angle of 69.6 (1)° in (II) and 49.4 (2)° in (I). Ferreira and co-workers proposed that such angle deviation may be ascribed to the presence of two non-classical intramolecular hydrogen bonds and steric factors. In fact, in (I), similar non-classical hydrogen bonds are observed, and the larger angular deviation in (II) may be assigned to the presence of methyl groups in the diimino fragment, which can cause steric hindrance due to the presence of bulkytert-butyl substituents in the aromatic rings. The C=N bond lengths are similar in both compounds and agree with comonly accepted values.

Atualmente, o câncer é considerado como um problema de saúde pública mundial. Por conta disso, busca-se por novos medicamentos antitumorais que apresentem sistemas com alta citotoxidade a células cancerosas e baixos efeitos colaterais. Diversos compostos de coordenação têm sido alvo de inúmeras pesquisas com objetivo de sua aplicação como medicamentos antitumorais. No entanto, alguns desses ainda apresentam alguns efeitos colaterais. Em virtude disso, houve o desenvolvimento de uma classe de polímeros descoberta no século XX chamada de metalopolímeros. Esta classe se destaca por causa de uma combinação única de componentes orgânicos e inorgânicos em um sistema macromolecular, sendo excelentes candidatos para a administração de fármacos, pois tentam resolver algumas desvantagens dos medicamentos convencionais como a alta toxicidade e baixa especificidade a partir de um sistema de liberação de fármacos que pode liberar o medicamento dentro das células cancerosas.