Darstellung und Immobilisierung von neuartigen Rutheniumcarbenkomplexen

Rutheniumkomplexe mit nukleophilen heterozyklischen Carbenliganden (NHC's) zählen zu den am häufigsten verwendeten Katalysatoren für die Olefinmetathese. Im Rahmen der vorliegenden Arbeit wurden Ruthenium-Komplexe mit OH-funktionalisierter Seitenkette dargestellt und eine vorher unbekannte trans-cis-Isomerisierung dieser Verbindungen untersucht. Ferner gelang eine effiziente Immobilisierung dieser Verbindungen über den NHC-Liganden auf verschiedensten Trägermaterialien wie z. B. Kieselgel

Traitement auditif d'enveloppes temporelles complexes

PARIS5-BU Saints-Pères (751062109) / SudocBOULOGNE-BU Psych. Henri Pieron (920125201) / SudocSudocFranceF

Monolithic Disk-Supported Metathesis Catalysts for Use in Combinatorial Chemistry

Two metathesis catalysts, RuCl₂(PCy₃)(NHC)(CHPh) (1) [NHC=1-(2,4,5-trimethylphenyl)-3-(6-hydroxyhexyl)-imidazol-2-ylidene] and Mo(N-2,6-i-Pr₂-C₆H₃)(CHCMe₂Ph)(BIPHEN) (2) [BIPHEN=(R)-3,3′-di-t-butyl-5,5′,6,6′-tetramethyl-2,2′-biphenolate) have been immobilized on polymeric, monolithic discs using a “grafting from” protocol. Monolithic discs were prepared via ring-opening metathesis polymerization (ROMP) from norborn-2-ene (NBE), tris(norborn-5-ene-2-ylmethyleneoxy)methylsilane [(NBE-CH₂O)₃-SiCH₃], 2-propanol, toluene and RuCl₂(PCy₃)₂(CHPh). Catalyst loadings of 0.55 and 0.7 wt %, respectively, were obtained. Monolithic disc-immobilized 1 was used in various metathesis-based reactions including ring-closing metathesis (RCM), ring-opening cross metathesis and enyne metathesis. Using 0.23–0.59 mol % of supported 1, turnover numbers (TONs) up to 330 were achieved. Monolithic disc-immobilized 2 was used in various enantioselective RCM and desymmetrization reactions. Using 9–13 mol % of supported catalyst, excellent yields up to 100% and high enantiomeric excess (ee≤88%) were observed. In both cases, metal leaching was low (≤3 and ≤2%, respectively). In addition, 1 catalyzed the cyclopolymerization of diethyl dipropargylmalonate (DEDPM) to yield poly(ene)s consisting of 5-membered rings, i.e., cyclopent-1-ene-1-vinylene units. The polymerization proceeded via non-stoichiometric initiation yielding polymers with unimodal molecular weight distribution. Using a catalyst to monomer ratio of 1 : 170, molecular weights of M_w=16,400 and M_n=11,700 g/mol, PDI=1.40 were obtained