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The Photochemistry of the (Cycloalkene)(hydro)(trispyrazolylborato)iridium Complexes [Ir( η 4 ‐cod)(Tp Me2 )] and [Ir( η 2 ‐coe)H 2 (Tp Me2 )]: the Formation of [IrH 4 (Tp Me2 )] and [Ir(CO)H 2 (Tp Me2 )]
Author(s) -
Ferrari Arlen,
Merlin Massimo,
Sostero Silvana,
Traverso Orazio,
Rüegger Heinz,
Venanzi Luigi M.
Publication year - 1998
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/(sici)1522-2675(19981111)81:11<2127::aid-hlca2127>3.0.co;2-h
Subject(s) - chemistry , photodissociation , iridium , photochemistry , cycloalkene , organic chemistry , catalysis
Photolysis of [Ir( η 2 ‐coe)H 2 (Tp Me2 )] ( 1 ; Tp Me2 =hydrotris(3,5‐dimethylpyrazolyl)borato, coe=( Z )‐cyclooctene) in CH 3 OH gives a mixture of [IrH 4 (Tp Me2 )] ( 4 ) and [Ir(CO)H 2 (Tp Me2 )] ( 5 ) in a ca . 1 : 1 ratio. Mass‐spectral analysis of the distillate of the reaction mixture at the end of the photolysis shows the presence of coe. When pure CD 3 OD is used as solvent, the deuteride complexes [IrD 4 (Tp Me2 )] ((D 4 )‐ 4 ) and [Ir(CO)D 2 (Tp Me2 )] ((D 2 )‐ 5 ) are obtained. Also the photolysis of [Ir( η 4 ‐cod)(Tp Me2 )] ( 3 ) (cod=cycloocta‐1,5‐diene) gives 4 and 5 . A key feature of this photoreaction is the intramolecular dehydrogenation of cod with formation of cycloocta‐1,3,5‐triene, detected by mass spectroscopy at the end of the photolysis. Labeling experiments using CD 3 OD show that the hydrides in 4 originate from MeOH. When 13 CH 3 OH is used as solvent, [Ir( 13 CO)H 2 (Tp Me2 )] is formed demonstrating that CH 3 OH is the source of the CO ligand. The observation that the photolysis of both 1 and 3 give the same product mixture is attributed to the formation of a common intermediate, i.e. , the coordinatively unsaturated 16e − species {IrH 2 (Tp Me2 )}.