One‐, Two‐, and Three‐Dimensional Coordination Polymers Built from Large Mo36‐Polyoxometalate Anionic Units and Lanthanide Cations

Abstract

AbstractThe Mo36‐polyoxometalate [Mo36O108(NO)4(H2O)16]12– reacts with Ln3+ to give crystalline solids with 1D, 2D, and 3D polymeric frameworks, depending on the size of Ln3+ and the reaction conditions. Reaction of LaCl3 with (NH4)12[Mo36O108(NO)4(H2O)16] gives (H3O)2[{La(H2O)5}2{La(H2O)6}{La(H2O)5Cl}{Mo36(NO)4O108(H2O)16}]Cl·21H2O (1), inwhose structure the La3+ cations and the polyoxometalate anions are united in a 3D framework, whereas NdCl3 and SmCl3 give [{Ln(H2O)6}4{Ln(H2O)4}{Mo36(NO)4O108(H2O)16}]Cl3·nH2O [Ln = Nd, n = 24 (2); Ln = Sm, n = 21 (3)], which have 2D frameworks. Under different conditions, large Ln3+ ions (La–Nd) give the one‐dimensional coordination polymers [{Ln(H2O)6}2{Ln(H2O)7}2{Mo36(NO)4O108(H2O)16}]·nH2O [Ln = La, n = 29 (4); Ln = Ce, n = 41 (5), Ln = Pr; n = 40 (6), Ln = Nd, n = 36 (7)], whereas reaction with Gd(NO3)3 gives [{Gd(H2O)5}4{Mo36(NO)4O108(H2O)16}]·34H2O (8), which has a unique 2D layered structure. Smaller Ln3+ ions (Tb–Lu) give isostructural 1D chain coordination polymers (H3O)3[{Ln(H2O)6}2{Ln(H2O)4}{Mo36(NO)4O108(H2O)16}]·nH2O [Ln = Tb, n = 42 (9); Ln = Dy, n = 43 (10), Ln = Ho, n = 46 (11), Ln = Er, n = 50 (12); Ln = Yb, n = 56 (13); Ln = Lu, n = 31 (14)]. The first coordination polymer based on [Mo36O112(H2O)16]8–, namely (H3O)2[{Nd(H2O)5}2{Mo36O112(H2O)16}]·40H2O (15), was prepared from MoO42–, NH2OH, and Nd3+. It has a 2D layered structure. All these compounds are obtained in moderate to high yields (35–93 %), and were characterized by elemental analysis, IR spectroscopy, and single‐crystal X‐ray structural analysis. Direct coordination of Ln3+ to the oxygen atoms of terminal cis‐MoO22+ groups is responsible for the formation of these polymeric frameworks. The coordination numbers of Ln3+ change from 9 (La–Sm) to 8 (Gd–Lu). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)