Heat capacities and enthalpies of formation of BaGd2O4were determined by high‐temperature differential scanning calorimetry and high‐temperature oxide melt solution calorimetry, respectively. Thermodynamic stability of BaLn2O4compounds increases with decreasing Ln3+ionic radius. Previously reported data on BaNd2O4and BaSm2O4corroborate this trend. Missing data for compounds in BaO–Ln2O3(Ln = La, Pr, Eu, Er) systems were estimated from established relations, thermodynamic assessment was performed, and binary phase diagrams were calculated.
Synthesis and reduction of [(C 5 H 4 SiMe 3 ) 2 Ln(μ-OR)] 2 (Ln = La, Ce) complexes: structural effects of bridging alkoxides
Alcoholysis of (C5H4SiMe)3Ln results in bimetallic complexes with unexpected decreases in Ln⋯Ln distances as bridging alkoxides become bulkier. These complexes were characterized by DOSY NMR, CV, DPV, and a LaIIspecies was observed by EPR.
more » « less- PAR ID:
- 10557280
- Publisher / Repository:
- Royal Society of Chemistry
- Date Published:
- Journal Name:
- Dalton Transactions
- ISSN:
- 1477-9226
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Lanthanide triflates have been used to incorporate NdIIIand SmIIIions into the 2.2.2‐cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3complexes (Ln=Nd, Sm; OTf=SO3CF3) react with crypt in THF to form the THF‐soluble complexes [LnIII(crypt)(OTf)2][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII‐in‐crypt complexes using KC8in THF forms the neutral LnII‐in‐crypt triflate complexes [LnII(crypt)(OTf)2]. DFT calculations on [NdII(crypt)]2+], the first NdIIcryptand complex, assign a 4f4electron configuration to this ion.
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Abstract Lanthanide triflates have been used to incorporate NdIIIand SmIIIions into the 2.2.2‐cryptand ligand (crypt) to explore their reductive chemistry. The Ln(OTf)3complexes (Ln=Nd, Sm; OTf=SO3CF3) react with crypt in THF to form the THF‐soluble complexes [LnIII(crypt)(OTf)2][OTf] with two triflates bound to the metal encapsulated in the crypt. Reduction of these LnIII‐in‐crypt complexes using KC8in THF forms the neutral LnII‐in‐crypt triflate complexes [LnII(crypt)(OTf)2]. DFT calculations on [NdII(crypt)]2+], the first NdIIcryptand complex, assign a 4f4electron configuration to this ion.
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The reduction potentials (reported vs. Fc + /Fc) for a series of Cp′ 3 Ln complexes (Cp′ = C 5 H 4 SiMe 3 , Ln = lanthanide) were determined via electrochemistry in THF with [ n Bu 4 N][BPh 4 ] as the supporting electrolyte. The Ln( iii )/Ln( ii ) reduction potentials for Ln = Eu, Yb, Sm, and Tm (−1.07 to −2.83 V) follow the expected trend for stability of 4f 7 , 4f 14 , 4f 6 , and 4f 13 Ln( ii ) ions, respectively. The reduction potentials for Ln = Pr, Nd, Gd, Tb, Dy, Ho, Er, and Lu, that form 4f n 5d 1 Ln( ii ) ions ( n = 2–14), fall in a narrow range of −2.95 V to −3.14 V. Only cathodic events were observed for La and Ce at −3.36 V and −3.43 V, respectively. The reduction potentials of the Ln( ii ) compounds [K(2.2.2-cryptand)][Cp′ 3 Ln] (Ln = Pr, Sm, Eu) match those of the Cp′ 3 Ln complexes. The reduction potentials of nine (C 5 Me 4 H) 3 Ln complexes were also studied and found to be 0.05–0.24 V more negative than those of the Cp′ 3 Ln compounds.more » « less
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/D4DT02137A
