Structural and spectroscopic characterization of iridium trihydride complexes: Evidence for proton-proton exchange coupling

Journal Article · Wed Jan 31 00:00:00 EST 1990 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00159a001· OSTI ID:6837063

Heinekey, D M; Millar, J M; Payne, N G; Zilm, K W ^[1]; Koetzle, T F ^[2]

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1. Yale Univ., New Haven, CT (USA)
2. Brookhaven National Lab., Upton, NY (USA)

Protonation of the neutral iridium dihydrides {eta}-C{sub 5}H{sub 5}Ir(L)H{sub 2} with HBF{sub 4} {times} Et{sub 2}O affords cationic trihydride complexes of the form (({eta}-C{sub 5}H{sub 5})Ir(L)H{sub 3})BF{sub 4} (L = various phosphine and phosphite ligands). The {sup 1}H NMR spectra of the cations in the hydride region at low temperature display AB{sub 2}X spin systems (X = {sup 31}P), which are simplified to AB{sub 2} spin systems in the {sup 1}H({sup 31}P) spectra. The values for J{sub A-B} derived by computer fitting of the observed spectra are extremely large, ranging from 61 to 1,565 Hz. In general, J{sub A-B} is inversely proportional to the basicity of the ligand L. The J{sub A-B} values are strongly temperature dependent, increasing rapidly over the temperature range 150-200 K. Coupling constants have not been evaluated at temperatures higher than 200 K due to the onset of A/B site exchange, which causes line broadening and eventual coalescence of the two resonances. In derivatives partially labeled with deuterium in the hydride ligands, no H-D coupling was resolved. In a tritiated derivative, {sup 3}H NMR was used to detect J{sub H-T}, which was substantially reduced from the expected value. a neutron diffraction study of ({eta}-C{sub 5}H{sub 5})Ir(PMe{sub 3})H{sub 3}BF{sub 4} (21) has been carried out. Compound 21 crystallizes in the space group P2{sub 1}2{sub 1}2{sub 1} (Z = 4) with a = 8.840 (2) {angstrom}, b = 9.971 (1) {angstrom}, c = 14.278 (2) {angstrom} c = 14.278 (2) {angstrom}, and V = 1,258.5 (5) {angstrom}{sup 3} (130 K).

• DOE Contract Number: AC02-76CH00016
• OSTI ID: 6837063
• Journal Information: Journal of the American Chemical Society; (USA), Vol. 112:3; ISSN 0002-7863
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
IRIDIUM HYDRIDES
NMR SPECTRA
PROTON-PROTON INTERACTIONS
CATALYSTS
CRYSTAL STRUCTURE
DATA ANALYSIS
EXPERIMENTAL DATA
HYDROGEN
MEASURING INSTRUMENTS
MEASURING METHODS
NEUTRON DIFFRACTION
ORGANOMETALLIC COMPOUNDS
BARYON-BARYON INTERACTIONS
COHERENT SCATTERING
DATA
DIFFRACTION
ELEMENTS
HADRON-HADRON INTERACTIONS
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
INTERACTIONS
IRIDIUM COMPOUNDS
NONMETALS
NUCLEON-NUCLEON INTERACTIONS
NUMERICAL DATA
ORGANIC COMPOUNDS
PARTICLE INTERACTIONS
PROTON-NUCLEON INTERACTIONS
REFRACTORY METAL COMPOUNDS
SCATTERING
SPECTRA
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
& Refractories- Physical Properties
400201 - Chemical & Physicochemical Properties