Anion-induced near-infrared (NIR) luminescent Zn2Nd and ZnNd complexes based on the pure Salen-type Schiff-base ligand

With the Zn-Schiff-base [ZnL(CH3CN)] from the pure Salen-type Schiff-base ligand H2L (H2L = N,N′-bis(salicylidene)phenylene-1,2-diamine) as the precursor, a hetero-trinuclear Zn2Nd complex [Zn2Nd(L)2(NO3)3(CH3CN)2] (1) and a hetero-binuclear ZnNd complex [ZnNd(L)2Cl(DMF)] (2) are obtained by the further reaction with Nd(NO3)3·6H2O or NdCl3·6H2O, respectively. The influence of structural differences of the two complexes on their photophysical properties shows the anionic inducement leads to the effective modulation of the NIR luminescent properties by the adjustment of the coordination sphere of the Nd3+ ions.

Graphical AbstractA hetero-trinuclear Zn2Nd complex [Zn2Nd(L)2(NO3)3(CH3CN)2] (1) and a hetero-binuclear ZnNd complex [ZnNd(L)2Cl(DMF)] (2) are obtained from the further reaction of Nd(NO3)3·6H2O or NdCl3·6H2O with the Zn-Schiff-base [ZnL(CH3CN)] precursor from the pure Salen-type Schiff-base ligand H2L (H2L = N,N′-bis(salicylidene)phenylene-1,2-diamine), respectively. The influence of structural differences of the two complexes on their photophysical properties shows the anionic inducement should be a potentially effective way to the modulation of the NIR luminescent properties by the adjustment of the coordination sphere of the Nd3+ ions.Figure optionsDownload as PowerPoint slideResearch HighlightsBased on the nuclearity of the d–f complexes of the pure Salen-type Schiff-base ligands by anion-inducement, the change of anions from NO3– to Cl– led to the formation of Zn2Nd (1) and ZnNd (2) complexes. Correlation of their molecular structures versus NIR luminescent properties showed the modulation of their NIR luminescence from anion-inducement should be relatively effective.
► Hetero-trinuclear and binuclear complexes.
► Effective modulation of NIR luminescence.
► Anion-inducement.