By utilizing Dy(hfac)3(H2O)2 to
react with enantiomerically pure tridentate N,N,N-pincer ligands, namely (−)/(+)-2,6-bis(4′,5′-pinene-2′-pyridyl)pyridine
(L
R
and L
S
), respectively, homochiral DyIII enantiomeric pairs formulated
as Dy(hfac)3L
R
/Dy(hfac)3L
S
(R
-1/S
-1) (hfac– = hexafluoroacetylacetonate)
were achieved and structurally characterized. Meanwhile, their magnetic,
photoluminescent (PL), and chiroptical properties were probed. The
PL test results indicate that the precursor Dy(hfac)3(H2O)2 only shows very weak emission, while R
-1 exhibits characteristic DyIII f–f transition emission bands at room temperature. Furthermore,
the nonlinear optical responses of Dy(hfac)3(H2O)2, L
R
/L
S
, and R
-1/S
-1 were investigated in detail based on crystalline samples.
The results reveal that L
R
and L
S
present the coexistence of second- and third-harmonic
generation (SHG and THG) responses with more intense signals for SHG
responses; and Dy(hfac)3(H2O)2 merely
displays weak THG responses, while R
-1 and S
-1 also only exhibit THG responses.
However, the THG intensities of R
-1 and S
-1 are more than six times larger than that
of Dy(hfac)3(H2O)2 under the identical
measurement conditions. These results demonstrate that introducing
homochiral N,N,N-pincer ligands to replace two H2O molecules of Dy(hfac)3(H2O)2 results in significant improvements of both PL performances and
THG responses of resultant R
-1/S
-1 enantiomers. R
-1 and S
-1 integrate PL, THG, and chiral
optical activity in one molecule, suggesting their multifunctional
merits. In particular, a convenient method is introduced to simultaneously
test THG and SHG responses of molecular materials based on crystalline
samples in this work.