Planar chiral derivatives of 1,1′-diphosphaferrocene with potential application in nonlinear optics

Planar chiral “push–pull” derivatives of 1,1′-diphosphaferrocene were obtained in the Knoevenagel reaction starting from racemic or optically resolved 2-formyl-3,3′,4,4′-tetramethyl-1,1′-diphosphaferrocene. Their second-order non-linear optical (NLO) properties were studied by powder tests and the EFISHG technique at 1.907 μm.