上海科技大学知识管理系统

Birefringent materials are vital materials to modulate the polarization
of light, and play a key role in plorization devices such as linear optical
devices, optical communication devices, and fiber optic sensors. It is
still a challenge to design excellent birefringent materials. Herein, we
report an organic–inorganic hybrid oxalate birefringent material,
(CN4H7)SbC2O4F2(H2O)0.5, by introducing organic delocalized
p-conjugated [CN4H7]+ and [C2O4]2 groups, and stereochemical
active inorganic SbO4F2 polyhedra. (CN4H7)SbC2O4F2(H2O)0.5 exhibits
a large birefringence (Dn = 0.126@546 nm) that is almost equal to that
of the well-known birefringent material a-BaB2O4. Theoretical calculations reveal that the distinguished birefringence should stem from
the synergistic arrangement of p-conjugated [CN4H7]+ and [C2O4]2
planar groups, and highly distorted SbO4F2 polyhedra with a stereochemically active lone pair. The synergistic effect of p-conjugated
systems and the lone pair electrons greatly boosts the birefringence,
which is helpful for the development of high-performance birefringent
materials.