1,3-Cyclopentadiene iridium complex

CgHu, Cyclooctene, iridium complex, 21 102 C10H4, Benzene, l-isopropyl-4-methyl-, ruthenium complex, 21 75 CioHit, 1,3-Cyclopentadiene, 1,2,3,4,5-penta-methyl-, 21 181... 

The hydrogen atom of the central cyclopentadiene ring can be displaced by potassium with t-BuOK to form the K(CgoMe5) complex in which the potassium atom can then be displaced to form iridium complexes such as Ir(ri5-C6oMe5)(CO)2 [Matsuo, Iwashita and Nakamura Organometallics 24 89 2005], and with rhodium to form Rh(ri5-C6oMe5)(CO)2 [Sawamuia, Kuninobu and Nakamura Chem Soc 122 12407 2000], structures which are supported by X-ray structure analyses. The same cyclopentadiene can complex with Fe and cyclopentadiene (Cp) to form a hybrid of buckyferrocene Fe(C6oMe5)Cp [Sawamura et al. J Am Chem Soc 124 9354 2002, Nakamura Pure Appl Chem 75 427 2003],... 

C10H15N, Benzenemethanamine, N,N,4-trimethyl-, lithium complex, 26 152 C10H15P, Phosphine, diethylphenyl-, nickel complex, 28 101 platinum complex, 28 135 CioHigAsi, Arsine, 1,2-phenylenebis(dimethyl-, gold complex, 26 89 nickel complex, 28 103 CioHie, 1,3-Cyclopentadiene, 1,2,3,4,5-pen-tamethyl-, 28 317 chromium complex, 27 69 cobalt complexes, 28 273, 275 iridium complex, 27 19 samarium complex, 27 155 titanium complex, 27 62 ytterbium complex, 27 148 CioH,gBrN04S, Bicyclo[2.2.1]heptane-7-methanesulfonate, 3-bromo-1,7-di-methyl-2-oxo-, U.IRHENDO, ANTPi]-, ammonium, 26 24... 

Several cationic cyclopentadienylrhodium and iridium complexes 175 with attached chiral ligands behave like Lewis acids and have found their way as catalysts for Diels-Alder reaction. The complexes with chiral iminopyridine 175a,b [113], chiral oxazoline 175d,e [114], and chiral phosphine ligands 175c [115] were studied in the cycloaddition of cyclopentadiene with methacrolein into 176 (Scheme 78). Some typical examples are given in Table 34. 

The dichlororuthenium arene dimers are conveniently prepared by refluxing ethanolic ruthenium trichloride in the appropriate cyclohexadiene [19]. The di-chloro(pentamethylcyclopentadienyl) rhodium dimer is prepared by refluxing Dewar benzene and rhodium trichloride, whilst the dichloro(pentamethylcyclo-pentadienyl)iridium dimer is prepared by reaction of the cyclopentadiene with iridium trichloride [20]. Alternatively, the complexes can be purchased from most precious-metal suppliers. It should be noted that these ruthenium, rhodium and iridium arenes are all fine, dusty, solids and are potential respiratory sensitizers. Hence, the materials should be handled with great care, especially when weighing or charging operations are being carried out. Appropriate protective clothing and air extraction facilities should be used at all times. 

As mentioned earlier, ruthenium cymene, rhodium and iridium pentamethyl-cyclopentadiene are good metal complexes, to start with, in a screen. It is diffi-... 

Iridium(I), stabilized by the ir-cyclopentadienyl anion, forms a stable, diamagnetic complex [Ir(C6H6)(C6Ht)] with cyclopentadiene (91) by the reaction ... 

The well-known rhodium (136) and iridium 137) peroxo complexes (PhgPlaRhCKOa) (40), [(PhgPlaRhCKOalJa (41), and (Ph3P)2(C0)IrCl(02) (42) have been investigated for their reactivity with acetylacetone, acacH 138). Only the former complex, 40, exhibited any reactivity (in the presence of two equivalents of triphenylphosphine), yielding the hydroperoxo complex (43), (see Scheme 8). Complex 43 reacts with PPhg to form triphenylphosphine oxide, but does not react with any active methylene compounds (methyl acetoacetate, diethyl malonate, or acetone) save for cyclopentadiene. In the last instance, a poorly characterized, unstable system tentatively formulated as 44 may have been formed. In refluxing benzene, 43 did react with excess acacH to form the bis(acac) complex 45. 

To date, the only soluble catalysts reported to have significant activity in mediating exchange between atmospheric (isotopic) hydrogen and substrates in solution are organometallic complexes of iridium. They can be considered as consisting of three classes iridium phosphine complexes, iridium dionate complexes, and iridium cyclopentadiene complexes. 

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