The design of highly electron-active and stable heterogeneous catalysts for the ambient nitrogen reduction reaction is challenging due to the inertness of the N₂ molecule. Here, we report the synthesis of a zinc-based coordination polymer that features bridging dinitrogen anionic ligands, {[Zn(L)(N₂)_0.5(TCNQ–TCNQ)_0.5]·(TCNQ)_0.5}_n (L is tetra(isoquinolin-6-yl)tetrathiafulvalene and TCNQ is tetracyanoquinodimethane), and show that it is an efficient photocatalyst for nitrogen fixation under an ambient atmosphere. It exhibits an ammonia conversion rate of 140 μmol g⁻¹ h⁻¹ and functions well also with unpurified air as the feeding gas. Experimental and theoretical studies show that the active [Zn²⁺–(N≡N)⁻–Zn²⁺] sites can promote the formation of NH₃ and the detachment of the NH₃ formed creates unsaturated [Zn²⁺···Zn⁺] intermediates, which in turn can be refilled by external N₂ sequestration and fast intermolecular electron migration. The [Zn²⁺···Zn⁺] intermediates stabilized by the sandwiched cage-like donor–acceptor–donor framework can sustain continuous catalytic cycles. This work presents an example of a molecular active site embedded within a coordination polymer for nitrogen fixation under mild conditions.

由于 N ₂分子的惰性，设计用于环境氮还原反应的高电子活性和稳定的多相催化剂具有挑战性。在这里，我们报告了一种锌基配位聚合物的合成，该聚合物具有桥联二氮阴离子配体 {[Zn(L)(N ₂ ) _0.5 (TCNQ–TCNQ) _0.5 ]·(TCNQ) _0.5 } _n（L 是四（ isoquinolin-6-yl)tetrathiafulvalene and TCNQ is tetracyanoquinodimethane), 表明它是一种在环境大气下有效的固氮光催化剂。它的氨转化率为 140 μmol g ^-1 h ^-1并且以未净化的空气作为进料气体也能很好地发挥作用。实验和理论研究表明，活性[Zn ²⁺ -(N≡N) ^- -Zn ²⁺ ]位点可以促进NH 3 的形成，形成的NH _3的脱离产生不饱和的[Zn ²⁺ ···Zn ⁺ ] 中间体，其又可以通过外部 N ₂封存和快速分子间电子迁移重新填充。[Zn ²⁺ ···Zn ⁺] 由夹层笼状供体-受体-供体框架稳定的中间体可以维持连续的催化循环。这项工作展示了一个嵌入配位聚合物中的分子活性位点的例子，用于在温和条件下固氮。