Embedding Mo2O2S2-Bis(thiosemicarbazone) Complexes Into Polyurethane Matrices: Synthesis and Characterization

[Mo^V ₂O₂S₂]²⁺-based thiosemicarbazone complexes are an interesting family of molecules, which can display various biological properties. However, in order to develop applications, it is necessary to shape this type of complex, in polymer matrices for example. In this article, we report the synthesis of a series of 16 composite materials corresponding to the incorporation of [(Mo₂O₂S₂) _n (L^1–6) _n ] (n = 1, 2) bis-thiosemicarbazones complexes in a polyurethane matrix. These composites are described as [Mo^V ₂O₂S₂]²⁺–thiosemicarbazone-based polyurethanes and denoted PU-[(Mo₂O₂S₂) _n (L^1–6) _n ] (n = 1, 2). Various [(Mo₂O₂S₂) _n (L^1–6) _n ]–bis-thiosemicarbazone complexes were used including di- or tetranuclear structures with different numbers of uncoordinated amino and hydroxyl groups and alkyl substituents on the ligands L ⁱ (i = 1–6). The composite materials obtained are studied in depth by SEM–EDX, FT-IR, NMR, TGA, and DSC to understand the organization of polymer chains and complexes within the materials and to highlight certain changes in physical properties induced by the nature of the complexes. The complexes are homogeneously distributed within the polymer matrices and the embedding of these complexes seems to be mainly due to hydrogen bonding networks. Nevertheless, these H-bond networks are strong enough to provoke modification of the physical properties of the polymers in terms of thermal stability or flexibility.