Heterocluster‐Assembled Crystalline Hydrophobic Complexes with Delayed Fluorescence

Abstract Metal–organic frameworks (MOFs) with metal─sulfur bonds exhibit unique electrical, redox, and optical properties. However, their development has been hindered by rapid nucleation during crystallization. To address this challenge, amine‐based modulators to retard nucleation through competitive coordination with ligands, enabling the synthesis of a series of Cu‐S cluster‐based MOFs with diverse network topologies: Cu‐BDT‐hcb ( 1 ), Cu‐TBT‐acs ( 2 ), Cu‐TBT‐pcu ( 3 ), Cu‐TBT‐sql ( 4 ), Cu‐TBT‐dia ( 5 ), and Cu‐TBT‐hcb ( 6 ), are utilized. Using donor‐acceptor (D‐A) ligands ( o/p ‐mercaptobenzoic acid— o/p MBA), [Sn 4 ]‐based MOFs: Sn‐ o DTBA‐cds ( 7 ) and Sn‐ p DTBA‐pcu ( 8 ), are fabricated. During synthesis, sulfhydryl groups underwent reductive coupling to generate novel dicarboxylate ligands with disulfide (S–S) linkages. Notably, the first bimetallic heterocluster MOF, SnCu‐ m MBA‐dia ( 9 ), incorporating both a metal‐oxygen cluster [Sn 4 O 2 (carboxylate) 4 ] and a metal‐sulfur cluster [Cu 8 (thiolate) 8 ] is developed. This framework, constructed using m ‐mercaptobenzoic acid ( m MBA) as a D–A bifunctional ligand, exhibits spatially separated HOMO and LUMO, minimizing the singlet–triplet energy gap to promote thermally activated delayed fluorescence (TADF). Compound 9 also demonstrates exceptional hydrolytic stability due to steric shielding by hydrophobic organotin moieties. This work pioneers a modulator‐assisted strategy for heterocluster MOF construction, offering a paradigm for designing stable luminescent materials with tailored optoelectronic functionalities.