Beyond Single-Wavelength SHG Measurements: Spectrally-Resolved SHG Studies of Tetraphosphonate Ester Coordination Polymers

Powder second-harmonic generation
(SHG) efficiencies are usually measured at single wavelengths. In
the present work, we provide a proof of concept of spectrally resolved
powder SHG measured for a newly obtained series of three non-centrosymmetric
coordination polymers (CPs). CPs are constructed from tetrahedral
linker–tetraphenylmethane-based tetraphosphonate octaethyl
ester and cobalt­(II) ions of mixed, octahedral (Oh), and tetrahedral (Td), geometries and different sets of
donors (CoO6 vs CoX3O). Isostructurality of
the obtained materials allowed for the determination of anion-dependent
tunability of SHG optical spectra and their relationship with solid-state
absorption spectra.