Trinodal Dual-SBU Cobalt(II)–Organic Framework for Microwave-Assisted Domino Synthesis of Indenopyrrole-3-Carboxamides

The inclusion of unique secondary building units (SBUs) into a unified metal–organic framework (MOF) offers a compelling approach to develop advanced heterogeneous catalysts with excellent characteristic features. Herein, we develop a new cobalt(II)-based metal–organic framework, (CoNDB-1), featuring a trinodal architecture with dual paddlewheel SBUs. CoNDB-1 was synthesized solvothermally under environmentally friendly conditions, employing an ethanol–water solvent system. Single-crystal X-ray diffraction analysis revealed that the framework comprises two [Co2(NDC)2(bpy)2] structural building units (SBUs), where NDC = 2,6-naphthalenedicarboxylic acid and bpy = 4,4′-bipyridyl. We designate these chemically identical yet crystallographically different units as Co1–Co2 and Co3–Co3′. Topological analysis classified the structure as a trinodal (2-, 4-, 6-connected) framework, showcasing a distinctive 3-fold (2 + 1) interpenetrated network. CoNDB-1 efficiently catalyzes the domino multicomponent synthesis of new indenopyrrole-3-carboxamides under microwave irradiation. The reaction completes within 10 min and affords high yields (85–97%), signifying a notable enhancement in speed and efficacy. The strategy exhibits a broad substrate scope, excellent yields, operational simplicity, and catalyst recyclability (up to 5 cycles), underscoring its potential for sustainable synthesis.