Double Sb‐N Coordination Enables Record‐High Birefringence in UV‐Transparent Crystals

Abstract Achieving high birefringence in ultraviolet (UV)‐transparent crystals has remained a significant challenge due to the absence of systematic design methodologies. Herein, we present a novel organic–inorganic coordination strategy that combines π‐conjugated organic ligands ([C 12 H 8 N 2 ]) with inorganic Sb‐based polyhedra featuring stereochemically active lone pairs. This approach facilitates the formation of the first coplanar double Sb‐N coordination framework, enabling the synthesis of two new birefringent hybrid crystals: (C 12 H 8 N 2 )SbF 2 (H 2 PO 3 ) (PNSP) and (C 12 H 8 N 2 )SbF 3 (PNSF). Notably, PNSF demonstrates an unprecedented birefringence of 0.79 at 546 nm, exceeding all known…

• NN
  National Natural Science Foundation of China

  Awards: 22122106, 22071158, 22305166, 22375139