Two 2D Cu–Ln heterometallic polyoxometalate aggregates constructed from bis(undecatungstophosphate)lanthanate units and copper-complex bridges

Reactions of the trivacant polyoxotungstate Na9[A-α-PW9O34]·7H2O with CuCl2·2H2O and LnCl3 (Ln = SmIII, ErIII) in the presence of 1,2-diaminopropane (dap) have led to two organic–inorganic hybrid Cu–Ln heterometallic polyoxotungstates [Cu(dap)2(H2O)][Cu(dap)2]4.5[Sm(α-PW11O39)2]·5H2O (1) and [Cu(dap)2(H2O)][Cu(dap)2]4.5[Er(α-PW11O39)2]·4H2O (2). 1 and 2 are isomorphic and display the 2D 5-connected sheet constructed from alternating bis(undecatungstophosphate)lanthanate [Ln(α-PW11O39)2]11− units and [Cu(dap)2]2+ connectors, in which the [Ln(α-PW11O39)2]11– subunits act as 5-connected nodes and adjacent 2D sheets show the –AAA– packing mode. Furthermore, their thermogravimetric analyses and magnetic susceptibilities have been investigated.