Cyclo iridium

In contrast, 1,5-cyclo-octadiene remains coordinated during the catalytic cycle of hydrogenation of phenylacetylene to styrene, catalyzed by the related iridium complex [Ir(C0D)( Pr2PCH2CH20Me)]BF4. This complex, which contains an ether-phosphine-chelated ligand, catalyzes the selective hydrogenation reaction via a dihydrido-cyclo-octadiene intermediate. The reaction is first order in each of catalyst, phenylacetylene and hydrogen [11] the proposed catalytic cycle is shown in Scheme 2.3. 

Soluble and stable iridium nanoparticles (3.0 0.4nm diameter) have been prepared by reduction of the polyoxoanion-supported lr(l) complex (n-Bu4N)sNa3 [(C0D)lr(P2WisNb3062)] (COD = 1,5-cyclo-octadiene) with molecular hydrogen in... 

An interesting additional experiment to follow the iridium nanoparticles formation was demonstrated by Watzky and Finke ]30], who used a direct method of monitoring by gas-hquid chromatography (GLC) the evolution of cyclo-octane... 

No complex was obtained on treatment of iridium (III) chloride with ethylene (67, 97, 138) or cyclo-octa-1,5-diene (45), but the ethylene complex [IrCl2(C2H4)] was reported to be formed by the action of ethanol on iridium chloride (67,138). No further examination of this complex has been reported. 

The ligands triphos or/ and np in presence of compounds of iron, cobalt, nickel, rhodium, iridium and palladium, by reaction with THF solutions of white phosphorus, P, or yellow arsenic, As, form mononuclear or dinuclear sandwich complexes containing the cyclo-triphosphorus or cyclo-triarsenic units which behave as 3n-electrons rings. 

F4BIr02P2C]tH]t, Iridium(III), diaquadihy-dridobis(triphenylphosphine)-, tetra-fluoroborate( 1 - ), 26 124 F4BIr02P2C42H44, Iridium(III), bis(ace-tone)dihydridobis(triphenylphos-phine)-, tetrafluoroborate(l -), 26 123 F4BIrP2C35H3i Iridium(l + ), (T) -l,5-cyclo-octadiene)[ 1,3-propanediylbis-(diphenylphosphine)]-, tetrafluorobor-ate(l-), 27 23... 

N,BCIF4lrP2C Hj, Iridium(III), chloro-(dinitrogen)hydrido(tetrafluoroborate-(1 - ))-bis(triphenylphosphine)-, 26 119 N,Br2RuC77H22, Ruthenium(II), bis-(benzonitrile)dibromo( iv -1,5-cyclo-octadiene)-, 26 71... 

FS,C,oH 2,2 -Bi-l,3-dithiolo[4,5-6][l,4]-dithiinylidene fluorosulfate, 26 393 O3F3SCH, Methanesulfonic acid, trifluoro-, iridium, manganese and rhenium complexes, 26 114, 115, 120 platinum complex, 26 126 OsFeC H, Iron, acetyldicarbonyl(r) -cyclo-pentadienyl)-, 26 239... 

In contrast, the reaction of [Cp Fe(q5-P5)] with [ Cp Ir(CO) 2] transforms the planar P5 ligand into a folded cyclo-P5 envelope (77), which, after addition of a second iridium complex, is definitely cleaved to a P5 chain (78) (Scheme 12) [98]. 

Third, n-allyl complexes are formed by palladium and cobalt analogous complexes of nickel and platinum are less stable, while ruthenium, rhodium, and iridium are not yet known to form them. In catalytic reactions the deuteration of cyclic paraffins over palladium has provided definite evidence for the existence of rr-bonded multiply unsaturated intermediates, while 7r-allylic species probably participate in the hydrogenation of 1,3-butadiene over palladium and cobalt, and of 1,2-cyclo-decadiene and 1,2-cyclononadiene over palladium. Here negative evidence is valuable platinum, for example does not form 7T-allylic complexes readily and the hydrogenation of 1,3-butadiene using platinum does not require the postulate that 7r-allylic intermediates are involved. Since both fields here are fairly well studied it is unlikely that this use of negative evidence will lead to contradiction in the light of future work. 

Fi2Fe2N2P2S2Ci8H26, Iron(2 +), bis(acetoni-trile)bis(r 5-cyclopentadienyl)bis-p.-(ethane-thiolato)di-, bis(hexafluorophosphate), 21 39 Fl2Fe4P2SJC2oH2o, Iton(2 + ), tetrakis(r 5-cyclo-pentadienyl)-p.3-(disuUur)tri-p.3-thio-tetra-, bis(hexafluorophosphate), 21 44 F12IrN4OP4C4oH36, Iridium(IIl), tris(acetoni-dile)nitrosylbis(triphenylphosphine)-, bis-[hexafluotophosphate], 21 104 F,2N4P2PdC12H3o, Palladium(II), [M V -bis[2-(dimethylamino)ethyl)-N J -dimethyl-1,2-ethanediamine]-, bis(hexafluorophosphate), 21 133... 

A few model reactions known from the literature also support the idea of an oxametalla-cyclobutane intermediate such as the formation of the irida(III)oxetane 10 modeling the metal-mediated transfer of oxygen to a coordinated olefin (step B). This reaction is explained by autoxidation of the iridium(I)-cyclo-octadiene complex 9 via the plausible dinuclear oxoiridium(III) intermediate. [15]... 

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