Provider: - Institution: - Data provided by Europeana Collections- U okviru ovog rada pripravljena su ukupno 73 nova liganda derivata trifenilfosfina s aminokiselinama, kraćim peptidima i/ili ...aminima. Ligandi su podijeljeni u tri skupine (A, B i C) obzirom na supstituciju fenilnog prstena fosfina i dentatnost, a njihovi in situ pripravljeni kompleksi s Rh(I) ispitani su kao homogeni katalizatori u reakcijama enantioselektivnog hidrogeniranja dvaju modelnih supstrata, metil-2-acetamidoprop-2-enoata (S1) i metil-(Z)-2-acetamido-3-fenilprop-2-enoata (S2). Kiralna informacija aminokiselina udaljena je od prokiralnog metala, a prenosi se "posrednom indukcijom" putem vodikovih veza. Postignuti maksimalni enantiomerni višak (ee) iznosi ee(R) = 68%, ee(S) = 84% i ee(R) = 81% upotrebom monodentatnih A, B, odnosno bidentatnih C liganda. Pripravljeni su Pd(II) i Pt(II) kompleksi s A i B u svrhu ispitivanja interakcija među ligandima. Priređeni ligandi i njihovi metalni kompleksi okarakterizirani su različitim analitičkim metodama (1H, 13C, 31P NMR, COSY, NOESY, ESI-MS, MALDI-TOF HRMS, CD i difrakcija X-zraka na jediničnom kristalu), a stereokemija produkata reakcije hidrogeniranja objašnjena je stereokemijskom analizom i DFT izračunima.- Within this thesis, a total of 73 new ligands based on triphenylphosphine derivatives with aminoacids, short peptides and/or amines, were synthesized. The ligands were divided into three categories (A, B, and C) by the phosphine phenyl ring substitution and denticity. Their in situ prepared Rh(I) complexes were tested as catalysts in the enantioselective hydrogenation of model substrates, methyl-2-acetamidoprop-2-enoate (S1) and methyl-(Z)-2-acetamido-3-phenylprop-2-enoate (S2). Chiral information from distant amino acids is transmitted to the prochiral metal through "backdoor induction" via hydrogen bonding. The obtained maximal enantiomeric excess (ee) is ee(R) = 68 %, ee(S) = 84 % and ee(R) = 81 % using monodentate A, B, and bidentate C ligands, respectively. Pd(II) and Pt(II) complexes of A and B were synthesized as model compounds for examination of ligand interactions. The ligands and their metal complexes were characterized with different analytical methods (1H, 13C, 31P NMR, COSY, NOESY, ESI-MS, MALDI-TOF HRMS, CD, and single crystal X-ray diffraction). The stereochemistry of the hydrogenation products was explained using stereochemical analysis and DFT calculations.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
Se realizó la síntesis de los complejos (RhCl(n4-1,5-COD)(2-ampy)) y (RhCl(PPh3)2(2-ampy)2), (donde COD es ciclaoctadieno, 2-ampy es 2-ominopiridino y PPh3 trifenilfosfino). El compuesto (RhCl(PPh ...3)2(2-ampy)2) presento un doblete a 29.4 ppm, con una constante de acoplamiento Rh-P de 86 Hz, indicando que las fosfinas se encuentran en posición trans. Los compuestos fueron activos en Ja hidroformilación de eugenol e isoeugenol, en donde la selectividad y actividad catalítica depende de varios factores tales como, los impedimentos estéricos en el ligante, los factores electrónicos y la temperatura de reacción. El complejo con los ligantes fosfina presento una menor actividad catalítica pero una mayor selectividad hacia aldehídos lineales.
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