Homo‐ and Heterovalent Polynuclear Cerium and Cerium/Manganese Aggregates

Reactions of Ce III (NO 3 ) 3 ⋅6 H 2 O or (NH 4 ) 2 [Ce IV (NO 3 ) 6 ] with Mn‐containing starting materials result in seven novel polynuclear Ce or Ce/Mn complexes with pivalato ( t BuCO $\rm{{_{2}^{-}}}$ ) and, in most cases, auxiliary N,O‐ or N,O,O‐donor ligands. With nuclearities ranging from 6–14, the compounds present aesthetically pleasing structures. Complexes [Ce IV 6 ( μ 3 ‐O) 4 ( μ 3 ‐OH) 4 ( μ ‐O 2 C t Bu) 12 ] ( 1 ), [Ce IV 6 Mn III 4 ( μ 4 ‐O) 4 ( μ 3 ‐O) 4 (O 2 C t Bu) 12 (ea) 4 (OAc) 4 ]⋅4 H 2 O⋅4 MeCN (ea − =2‐aminoethanolato; 2 ), [Ce IV 6 Mn III 8 ( μ 4 ‐O) 4 ( μ 3 ‐O) 8 (pye) 4 (O 2 C t Bu) 18 ] 2 [Ce IV 6 ( μ 3 ‐O) 4 ( μ 3 ‐OH) 4 (O 2 C t Bu) 10 (NO 3 ) 4 ] [Ce III (NO 3 ) 5 (H 2 O)]⋅21 MeCN (pye − =pyridine‐2‐ethanolato; 3 ), and [Ce IV 6 Ce III 2 Mn III 2 ( μ 4 ‐O) 4 ( μ 3 ‐O) 4 ( t bdea) 2 (O 2 C t Bu) 12 (NO 3 ) 2 (OAc) 2 ]⋅4 CH 2 Cl 2 ( t bdea 2− =2,2′‐( tert ‐butylimino]bis[ethanolato]; 4 ) all contain structures based on an octahedral {Ce IV 6 ( μ 3 ‐O) 8 } core, in which many of the O‐atoms are either protonated to give ( μ 3 ‐OH) − hydroxo ligands or coordinate to further metal centers (Mn III or Ce III ) to give interstitial ( μ 4 ‐O) 2− oxo bridges. The decanuclear complex [Ce IV 8 Ce III Mn III ( μ 4 ‐O) 3 ( μ 3 ‐O) 3 ( μ 3 ‐OH) 2 ( μ ‐OH)(bdea) 4 (O 2 C t Bu) 9.5 (NO 3 ) 3.5 (OAc) 2 ]⋅1.5 MeCN (bdea 2− =2,2′‐(butylimino]bis[ethanolato]; 5 ) contains a rather compact Ce IV 7 core with the Ce III and Mn III centers well‐separated from each other on the periphery. The aggregate in [Ce IV 4 Mn IV 2 ( μ 3 ‐O) 4 (bdea) 2 (O 2 C t Bu) 10 (NO 3 ) 2 ]⋅4 MeCN ( 6 ) is based on a quasi‐planar {Mn IV 2 Ce IV 4 ( μ 3 ‐O) 4 } core made up of four edge‐sharing {Mn IV Ce IV 2 ( μ 3 ‐O)} or {Ce IV 3 ( μ 3 ‐O)} triangles. The structure of [Ce IV 3 Mn IV 4 Mn III ( μ 4 ‐O) 2 ( μ 3 ‐O) 7 (O 2 C t Bu) 12 (NO 3 )(furan)]⋅6 H 2 O ( 7 ⋅6 H 2 O) can be considered as {Mn IV 2 Ce IV 2 O 4 } and distorted {Mn IV 2 Mn III Ce IV O 4 } cubane units linked through a central ( μ 4 ‐O) bridge. The Ce 6 Mn 8 equals the highest nuclearity yet reported for a heterometallic Ce/Mn aggregate. In contrast to most of the previously reported heterometallic Ce/Mn systems, which contain only Ce IV and either Mn IV or Mn III , some of the aggregates presented here show mixed valency, either Mn IV /Mn III (see 7 ) or Ce IV /Ce III (see 4 and 5 ). Interestingly, some of the compounds, including the heterovalent Ce IV /Ce III 4 , could be obtained from either Ce III (NO 3 ) 3 ⋅6 H 2 O or (NH 4 ) 2 [Ce IV (NO 3 ) 6 ] as starting material.