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Unsaturated Ruthenium Hydrides as Reactive Intermediates: An Experimental Investigation and Theoretical Model Study of (dtbpm‐ κ 2 P )Ru(H)Cl, (dtbpe‐ κ 2 P )Ru(H)Cl and Their Dinuclear Dynamic Precursor Complexes
Author(s) -
Volland Martin A. O.,
Hofmann Peter
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20011114)84:11<3456::aid-hlca3456>3.0.co;2-p
Subject(s) - chemistry , isomerization , ruthenium , metathesis , valence (chemistry) , catalysis , olefin metathesis , medicinal chemistry , stereochemistry , organic chemistry , polymerization , polymer
A detailed spectroscopic and quantum‐chemical structure investigation of the dinuclear, 16‐valence‐electron complexes [( t Bu 2 P(CH 2 ) n P t Bu 2 ‐ κ 2 P )RuH] 2 ( μ 2 ‐Cl) 2 ( n =1, 2), stabilized by the bulky, electron‐rich chelating ligands bis[di( t ‐butyl)phosphano]methane ( t Bu 2 PCH 2 P t Bu 2 , dtbpm) and 1,2‐bis[di( t ‐butyl)phosphano]ethane ( t Bu 2 PCH 2 CH 2 P t Bu 2 , dtbpe) is reported. VT‐NMR Spectroscopy of [(dtbpm‐ κ 2 P )RuH] 2 ( μ 2 ‐Cl) 2 , an important precursor of olefin metathesis catalysts, and of its homologue [(dtbpe‐ κ 2 P )RuH] 2 ( μ 2 ‐Cl) 2 reveals facile interconversion of dinuclear cis ‐ and trans ‐dihydride isomers for both systems. Crossover experiments provide evidence for the existence of short‐lived, mononuclear intermediates (dtbpm‐ κ 2 P )Ru(H)Cl and (dtbpe‐ κ 2 P )Ru(H)Cl in solution. Mechanistic features of the cis‐trans isomerization process as well as structural and electronic properties of model systems for the dinuclear complexes and mononuclear intermediates were treated theoretically by DFT calculations.