Synthesis, structure, and reactivity of (C(5)Me(4)R))3Ln complexes for the evaluation of sterically induced reduction.

摘要

The research in this dissertation explores the synthesis and reactivity of new sterically crowded lanthanide complexes for evaluating a new type of reduction chemistry that appears to derive from this steric crowding. To test the validity and generality of this proposed sterically induced reduction (SIR), four sets of complexes were synthesized: the first diamagnetic (C ₅Me₅)₃Ln complex, (C₅Me₅) ₃La; a series of diamagnetic complexes with larger ligands, (C ₅Me₄R)₃La (R = Et, iPr, SiMe ₃); the first (C₅Me₅)₃Ln complexes more crowded than (C₅Me₅)₃Sm, (C₅Me ₅)₃M (M = Gd, Y); and a series of fluorenide complexes (C ₅Me₅)₂Ln-R [R = C₁₃H₉, C ₁₄H₁₁, C₁₆H₁₇Si], which have reactivity that mimics the (C₅Me₅)₃Ln chemistry. These complexes allowed a more comprehensive study of SIR and revealed that (C ₅Me₅)₃M complexes also have C-H activation reactivity.; The synthesis of precursors to (C₅Me₄R)₃Ln (R = Me, Et, iPr, SiMe₃) complexes, namely the allyl (C₅Me₄R)₂Ln(C₃H₅) and tetraphenylborate [(C₅Me₄R)₂Ln][BPh ₄] complexes, are described in chapter 1.; The conversion of these [(C₅Me₄R)₂Ln][BPh ₄] complexes to (C₅Me₄R)₃Ln (Ln = La, Nd, R = Me, Et, iPr, SiMe₃) complexes with the appropriate cyclopentadienide salt is described in chapter 2.; The synthesis of the first two (C₅Me₅)₃M complexes more crowded than (C₅Me₅)₃Sm is described in chapter 3. (C₅Me₅)₃Gd, is made using [(C₅Me₅)₂Gd][BPh₄] and KC ₅Me₅. (C₅Me₅)₃Y, is made from [(C₅Me₅)₂YH]₂ with two equivalents of tetramethylfulvene in cyclohexane. The solid state features are discussed and compared with all of the known (C₅Me₅)₃Ln complexes.; Reactivity data on the (C₅Me₄R)₃Ln (Ln = La - Y, R = Me, Et, iPr, SiMe₃) complexes is presented in chapter 4. The reactivity data is divided into two sections, the insertion chemistry and reduction chemistry.; The 5th chapter of this dissertation describes the synthesis and solid state features of a new type of lanthanide complex with fluoremde ligands, (C₅Me₅)₂La-R [R = C₁₃H₉, C₁₄H₁₁, C₁₆H₁₇Si]. A possible reaction pathway for the reaction of (C₅Me₅)₂La-C ₁₄H₁₁ and Ph₃P=Se to generate [(C₅Me ₅)₂La]₂(Se₂) and (C₁₄H ₁₁)₂ is presented.; The sixth chapter reports the structural features of a common oxide bimetallic decomposition product found in this area.; The seventh chapter describes the synthesis of divalent lanthanocene complexes using the C₅H₃(SiMe₃)₂ − ligand.