The windmill-shaped hexanuclear copper(II) cluster {(H2O)2Cu2(G SRC="/images/entities/mgr.gif">3-(Ade)4[Cu(oda)(H2O)]4}·6H2O (1-o) has beensynthesized in aqueous medium by in situ core-controlled expansion of the neutral building block Cu2(ges/entities/mgr.gif">2-N3,N9-Ade)4(H2O)2 (2) with Cu(oda)(H2O) (3-o) (Ade = adeninato(1-) and oda = oxydiacetato(2-) ligands). Crystal datafor 2-b (2·5H2O): triclinic, space group Pges/entities/onemacr.gif">; a = 9.374(1), b = 9.440(1), c = 10.326(1) Å; ges/gifchars/alpha.gif" BORDER=0> = 78.72(1), ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> =76.77(1), ges/gifchars/gamma.gif" BORDER=0 > = 63.51(1)ges/entities/deg.gif">; final R1 = 0.059; T = 100(2) K. Crystal data for 1-o: monoclinic, space group P21/n; a= 15.203(2), b = 10.245(1), c = 19.094(2) Å; ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 101.61(1)ges/entities/deg.gif">; final R1 = 0.049; T = 293(2) K. The X-shapedhexanuclear molecule consists of a central core (2) and four terminal arms (3-o) linked together by bridging ges/entities/mgr.gif">3-N3,N7,N9-Ade ligands. There are three crystallographic independent metal atoms (two terminals, one central). AllCu(II) atoms exhibit a 4 + 1 coordination, of which one is an aqua apical ligand. The basal coordination setscomplete the CuN4 + O or CuO3N + O chromophores for the central or terminal metal atoms, respectively. Thermalstability and spectral and magnetic properties were also studied. Analogous compounds to 1-o with tridentate ortripodal tetradentate ligands L2-, instead of oda, have also been synthesized.