Design and Synthesis of water-soluble P,N-Ligands for coordination to Ruthenium centers: Applications in Aqueous atom transfer radical addition and aqueous nitrile hydration
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Authors
Schollnick, Hailey Elise
Issue Date
2025
Type
Dissertation
Language
en_US
Keywords
aqueous catalysis , Organometallic chemistry , PN-ligands
Alternative Title
Abstract
This dissertation investigates the ability of the phosphine, 1,3,5-triaza-7- phosphaadamantane (PTA) and derivatives to serve as either a monodentate phosphine ligands or bidentate P,N-ligands coordinated to metal catalysts. “Upper-rim” modified PTA derivatives were coordinated to an η5 -cyclopentadienyl ruthenium center. These complexes were synthesized and characterized by 1H, 13C{1H}, 31P{1H} NMR spectroscopy, 2D- NMR (HSQC, HMBC, and COSY), and ESI-MS. All complexes bearing η5 -cyclopentadienyl moiety were evaluated as catalysts for aqueous atom transfer radical addition at 60 °C. These complexes promoted aqueous ATRA in good conversions and moderate TOFs. [CpRu(CH3CN)2 (PTACHPhNH(p C6H4OMe)]PF6 showed a TOF of 12.5 h-1 in acetonitrile in 6 h with a 75% conversion. PTA derivatives were synthesized utilizing tetrafluoroboric acid to offer a less coordinating anion and achieve a P,N-ligand capable of binding through both the phosphorous and nitrogen at the same time. The P(CH2NH3BF4 )3 derivative was coordinated to different η6 -arene derivatives. These complexes were characterized by 1H, 13C{1H}, 31P{1H} NMR spectroscopy, 2D- NMR (HSQC, HMBC, and COSY), and ESI-MS. The η6 -arene ruthenium complexes and the free ligand (P(CH2NH3BF4 )3 ) with RuCl3 were evaluated for aqueous nitrile hydration at 100 °C at 1 mol % catalyst. Both the in-situ and pre-made catalysts were active for nitrile hydration. (η6–C6H5CH3 )RuCl2P(CH2NH3BF4 )3 showed a TOF of 2.75 h-1 over 24 h.