Copper complexes of thiazolo[5,4-d]thiazole-based porous polymers: Efficient catalytic synthesis of 2-arylquinolines and 2-arylbenzothiazoles

Two porous polymers, i.e., MeTzTzP and OMeTzTzP, were constructed based on a thiazolo[5,4-d]thiazole moiety by polycondensation between dithiooxamide and rigid trialdehyde building blocks that inherently feature concave shapes, i.e., TMA and TOMeA, under solvothermal conditions. The polymer resulting from TMA, i.e., MeTzTzP, having marginally higher BET surface area (563 m2 g−1) than the one derived from TOMeA, i.e., OMeTzTzP, (533 m2 g−1) was treated with CuCl2 and Cu(OAc)2, providing access to porous metalated polymers, i.e., CuA@MeTzTzP and CuB@MeTzTzP, respectively. Powder X-ray diffraction analysis of MeTZTzP points to the formation of an ordered 2D covalent organic framework (COF), which upon metalation with CuCl2 and Cu(OAc)2 yield the Cu-MOFs. Applicability of the latter as heterogeneous catalysts is demonstrated for expedient synthesis of 2-arylquinolines and 2-arylbenzothiazoles, respectively. CuA@MeTzTzP and CuB@MeTzTzP are shown to exhibit very good stability, permitting recyclability up to 5–6 catalytic cycles.