One‐, Two‐, and Three‐Dimensional Coordination Polymers Built from Large Mo 36 ‐Polyoxometalate Anionic Units and Lanthanide Cations

The Mo 36 ‐polyoxometalate [Mo 36 O 108 (NO) 4 (H 2 O) 16 ] 12– reacts with Ln 3+ to give crystalline solids with 1D, 2D, and 3D polymeric frameworks, depending on the size of Ln 3+ and the reaction conditions. Reaction of LaCl 3 with (NH 4 ) 12 [Mo 36 O 108 (NO) 4 (H 2 O) 16 ] gives (H 3 O) 2 [{La(H 2 O) 5 } 2 {La(H 2 O) 6 }{La(H 2 O) 5 Cl}{Mo 36 (NO) 4 O 108 (H 2 O) 16 }]Cl · 21H 2 O ( 1 ), inwhose structure the La 3+ cations and the polyoxometalate anions are united in a 3D framework, whereas NdCl 3 and SmCl 3 give [{Ln(H 2 O) 6 } 4 {Ln(H 2 O) 4 }{Mo 36 (NO) 4 O 108 (H 2 O) 16 }]Cl 3 · n H 2 O [Ln = Nd, n = 24 ( 2 ); Ln = Sm, n = 21 ( 3 )], which have 2D frameworks. Under different conditions, large Ln 3+ ions (La–Nd) give the one‐dimensional coordination polymers [{Ln(H 2 O) 6 } 2 {Ln(H 2 O) 7 } 2 {Mo 36 (NO) 4 O 108 (H 2 O) 16 }] · n H 2 O [Ln = La, n = 29 ( 4 ); Ln = Ce, n = 41 ( 5 ), Ln = Pr; n = 40 ( 6 ), Ln = Nd, n = 36 ( 7 )], whereas reaction with Gd(NO 3 ) 3 gives [{Gd(H 2 O) 5 } 4 {Mo 36 (NO) 4 O 108 (H 2 O) 16 }] · 34H 2 O ( 8 ), which has a unique 2D layered structure. Smaller Ln 3+ ions (Tb–Lu) give isostructural 1D chain coordination polymers (H 3 O) 3 [{Ln(H 2 O) 6 } 2 {Ln(H 2 O) 4 }{Mo 36 (NO) 4 O 108 (H 2 O) 16 }] · n H 2 O [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 [Mo 36 O 112 (H 2 O) 16 ] 8– , namely (H 3 O) 2 [{Nd(H 2 O) 5 } 2 {Mo 36 O 112 (H 2 O) 16 }] · 40H 2 O ( 15 ), was prepared from MoO 4 2– , NH 2 OH, and Nd 3+ . 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 Ln 3+ to the oxygen atoms of terminal cis ‐MoO 2 2+ groups is responsible for the formation of these polymeric frameworks. The coordination numbers of Ln 3+ change from 9 (La–Sm) to 8 (Gd–Lu). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)