Two new isolated Zn-ε-Keggin clusters modified by conjugated organic ligands with decent electrocatalytic and third-order NLO properties†
Two new bifunctional isolated hybrid compounds, [ε-PMoV8MoVI4O37(OH)3Zn4][iql]4·6H2O (1) and [ε-PMoV8MoVI4O38(OH)2Zn4][bipy]3[(CH3COO)(bipy)2Zn]·2H2O (2) (where iql = isoquinoline and bipy = 2,2′-bipyridine), based on Zn-ε-Keggin were successfully synthesized by self-assembly under hydrothermal conditions. It is interesting to note that acetate in 2 acted as a linker connecting the ε-Keggin anion with the one Zn atom (Zn5) and enabled the ε-Keggin anion to coordinate with more bipy ligands, culminating with a larger isolated system, which is the first reported isolated cluster of Zn5PMo12. Meanwhile, compounds 1–2 show great electrochemical behaviors and excellent electrocatalytic activity for the degradation of NaNO2. In addition, compound 2 displays better third-order NLO performance than 1 due to the presence of more conjugated rings, with a TPA cross section (σ) of 1819 GM, which suggests that compound 2 has the potential to function as a bifunctional material with tremendous prospects.