Syntheses, structures and properties of a series of inorganic–organic hybrid copper–lanthanide heterometal comprising germanotungstates with mixed ligands.

The hydrothermal reaction of K 8 Na 2 [A-α-GeW 9 O 34 ]·25H 2 O, Cu(CH 3 COO) 2 ·H 2 O, Ln(NO 3 )·6H 2 O and ethylenediamine (en) has led to a series of inorganic–organic hybrid copper–lanthanide heterometal comprising germanotungstates (GTs) [Cu(en) 2 (H 2 O)] 6 [Ln(H 2 O)(CH 3 COO)(α-GeW 11 O 39 )] 2 ·8H 2 O [Ln = Nd 3+ ( 1 ), Sm 3+ ( 2 ), Eu 3+ ( 3 ), Gd 3+ ( 4 ), Dy 3+ ( 5 ), Ho 3+ ( 6 )], which have been characterized by elemental analyses, IR spectra, thermogravimetric (TG) analyses and single-crystal X-ray diffraction. Their common feature of 1 – 6 is that they all comprise a CH 3 COO-bridging mono-Ln substituted dimeric GT fragment [Ln(H 2 O)(CH 3 COO)(α-GeW 11 O 39 )] 2 12− with six supporting [Cu(en) 2 (H 2 O)] 2+ complex cations. To the best of our knowledge, such monovacant Keggin-type GTs containing both Cu–Ln heterometal centers and mixed en and acetate ligands are very rare. The luminescence properties and the lifetime decay behavior of the solid sample of 3 have been intensively investigated at room temperature. [ABSTRACT FROM AUTHOR]