Homo‐ and Heterovalent Polynuclear Cerium and Cerium/Manganese Aggregates |
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| Authors: | Valeriu Mereacre Ayuk?M Ako Muhammad?Nadeem Akhtar Anja Lindemann Christopher?E Anson Annie?K Powell |
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| Institution: | Institut für Anorganische Chemie der Universit?t Karlsruhe, Karlsruhe Institute of Technology, Engessserstrasse?15, Geb.?30.45, D‐76131 Karlsruhe, (phone: +49‐721‐6082135) |
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| Abstract: | Reactions of CeIII(NO3)3?6 H2O or (NH4)2CeIV(NO3)6] with Mn‐containing starting materials result in seven novel polynuclear Ce or Ce/Mn complexes with pivalato (tBuCO ) 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 CeIV6(μ3‐O)4(μ3‐OH)4(μ‐O2CtBu)12] ( 1 ), CeIV6MnIII4(μ4‐O)4(μ3‐O)4(O2CtBu)12(ea)4(OAc)4]?4 H2O?4 MeCN (ea?=2‐aminoethanolato; 2 ), CeIV6MnIII8(μ4‐O)4(μ3‐O)8(pye)4(O2CtBu)18]2CeIV6(μ3‐O)4(μ3‐OH)4(O2CtBu)10(NO3)4] CeIII(NO3)5(H2O)]?21 MeCN (pye?=pyridine‐2‐ethanolato; 3 ), and CeIV6CeIII2MnIII2(μ4‐O)4(μ3‐O)4(tbdea)2(O2CtBu)12(NO3)2(OAc)2]?4 CH2Cl2 (tbdea2?=2,2′‐(tert‐butylimino]bisethanolato]; 4 ) all contain structures based on an octahedral {CeIV6(μ3‐O)8} core, in which many of the O‐atoms are either protonated to give (μ3‐OH)? hydroxo ligands or coordinate to further metal centers (MnIII or CeIII) to give interstitial (μ4‐O)2? oxo bridges. The decanuclear complex CeIV8CeIIIMnIII(μ4‐O)3(μ3‐O)3(μ3‐OH)2(μ‐OH)(bdea)4(O2CtBu)9.5(NO3)3.5(OAc)2]?1.5 MeCN (bdea2?=2,2′‐(butylimino]bisethanolato]; 5 ) contains a rather compact CeIV7 core with the CeIII and MnIII centers well‐separated from each other on the periphery. The aggregate in CeIV4MnIV2(μ3‐O)4(bdea)2(O2CtBu)10(NO3)2]?4 MeCN ( 6 ) is based on a quasi‐planar {MnIV2CeIV4(μ3‐O)4} core made up of four edge‐sharing {MnIVCeIV2(μ3‐O)} or {CeIV3(μ3‐O)} triangles. The structure of CeIV3MnIV4MnIII(μ4‐O)2(μ3‐O)7(O2CtBu)12(NO3)(furan)]?6 H2O ( 7 ?6 H2O) can be considered as {MnIV2CeIV2O4} and distorted {MnIV2MnIIICeIVO4} cubane units linked through a central (μ4‐O) bridge. The Ce6Mn8 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 CeIV and either MnIV or MnIII, some of the aggregates presented here show mixed valency, either MnIV/MnIII (see 7 ) or CeIV/CeIII (see 4 and 5 ). Interestingly, some of the compounds, including the heterovalent CeIV/CeIII 4 , could be obtained from either CeIII(NO3)3?6 H2O or (NH4)2CeIV(NO3)6] as starting material. |
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| Keywords: | Cerium aggregates Manganese aggregates Heterometallic complexes |
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