Novel phosphonated bicyclic frameworks from Diels–Alder reaction as chelating agents of di- and trivalent metal cations

The synthesis of novel [4+2] cycloadducts by Diels–Alder (DA) reaction between diethyl 1-phosphono-1,3-butadiene and cyclic CC and NN dienophiles, such as maleimide and 1,2,4-triazole-3,5-dione derivatives, is described. These phosphonated bicyclic frameworks feature a cage shape enabling metal chelation. Indeed, stable complexes were formed in solution with M2+ and M3+ metal cations, as evidenced by HRMS in the ESI mode (electrospray ionization). L1:M (one ligand–one metal) and L2:M (two ligands–one metal) complexes were identified depending on the nature of the cation.

描述了1 - 膦酰基-1,3 - 丁二烯二乙酯与环状碳 - 碳和氮 - 氮亲双烯体（如马来酰亚胺和1,2,4 - 三唑 - 3,5 - 二酮衍生物）之间通过狄尔斯 - 阿尔德（DA）反应合成新型[4 + 2]环加成物。这些膦酸化的双环骨架具有笼状结构，能够实现金属螯合。实际上，在溶液中与二价和三价金属阳离子形成了稳定的配合物，这通过电喷雾电离（ESI）模式下的高分辨质谱（HRMS）得以证明。根据阳离子的性质，确定了L1:M（一个配体 - 一个金属）和L2:M（两个配体 - 一个金属）配合物。