C-H oxidative addition and reductive elimination reactions in a dinuclear iridium complex

Journal Article · Wed Dec 07 04:00:00 EST 1988 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00233a020· OSTI ID:5117359

McGhee, W D; Hollander, F J; Bergman, R G ^[1]

---

1. Lawrence Berkeley Lab., CA (USA)

Thermolysis of the hydridoallyliridium complex ({eta}{sup 5}-C{sub 5}Me{sub 5})({eta}{sup 3}-C{sub 3}H{sub 5})(H)Ir at relatively high concentrations of starting material in benzene leads to the dinuclear benzene C-H oxidative addition product ({eta}{sup 5}-C{sub 5}Me{sub 5})(C{sub 6}H{sub 5})Ir({eta}{sup 1},{eta}{sup 3}-C{sub 3}H{sub 4})({mu}-H)-Ir({eta}{sup 5}-C{sub 5}Me{sub 5}) (1). Heating this material causes reductive elimination of benzene from the dinuclear complex 1 in a clean first-order process. The lack of dependence of the rate of this process on the concentration of entering ligand demonstrates than an intermediate is formed in the reductive elimination; this species is proposed to be the coordinatively unsaturated dinuclear complex ({eta}{sup 5}-C{sub 5}Me{sub 5})Ir({eta}{sup 1},{eta}{sup 3}-C{sub 3}H{sub 4})Ir({eta}{sup 5}-C{sub 5}Me{sub 5}) (13). Transient intermediate 13 reacts with dative ligands such as phosphines, ethylene, and tert-butyl isocyanide to give direct trapping products ({eta}{sup 5}-C{sub 5}Me{sub 5})(L)Ir({eta}{sup 1},{eta}{sup 3}-C{sub 3}H{sub 4})Ir({eta}{sup 5}-C{sub 5}Me{sub 5}) (2-6), formed by coordination of the ligand to one of the iridium centers. Reaction of 13 with reagents having activated X-H bonds, such as benzene-d{sub 6}, H{sub 2}, and acetonitrile, leads to intermolecular oxidative addition products having structures analogous to that of 1. Comparative inter- and intramolecular kinetic isotope effect studies have provided evidence that in the reversible reaction of 13 with benzene, an additional {eta}{sup 2}-arene intermediate is not required to explain the results. Thermolysis of 2 and 4, the PMe{sub 3{sup {minus}}} and ethylene-trapped products of 13, leads to three new dinuclear complexes (7, 8, and 9). These materials are formed by intramolecular insertion into the dative ligand C-H bonds, followed by rearrangement. 30 refs., 6 figs., 2 tabs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5117359
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 110:25; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400202 -- Isotope Effects
Isotope Exchange
& Isotope Separation
ALKANES
AROMATICS
CHEMICAL REACTIONS
COMPLEXES
DATA
DEUTERIUM
ELEMENTS
EXPERIMENTAL DATA
HYDROCARBONS
HYDROGEN
HYDROGEN ISOTOPES
INFORMATION
IRIDIUM COMPLEXES
ISOTOPE APPLICATIONS
ISOTOPE EFFECTS
ISOTOPES
LABELLED COMPOUNDS
LIGHT NUCLEI
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANOMETALLIC COMPOUNDS
STABLE ISOTOPES
TRACER TECHNIQUES
TRANSITION ELEMENT COMPLEXES