A series of rigid–flexible-ligand functionalized dodeca-nuclear lanthanide–tungsten heterometal cluster incorporated ring-shaped selenotungstates [H2N(CH3)2]16Na2[Ln4(H2O)6(HPDCA)2(HFMA)2W8O21][B-α-SeW9O33]4·29H2O [Ln = Ce3+ (1), Pr3+ (2), Nd3+ (3); H2PDCA = 2,3-pyrazine dicarboxylic acid, H2FMA = fumaric acid]...