R 5-Pentamethylcyclopentadienyl

The pz-diol with M = Ni was peripherally metalated with CpiTiCh, Cp ZrC, and CpjHfC (Cp = r]5-pentamethylcyclopentadienyl) to formporphyrazines 205 (20%), 206 (45%), and 207 (21%) (Scheme 41) (10). The optical spectra of the metalocene appended catecholato pz exhibits a loss of the n-n peak (450 nm), which indicates that the lone pairs of the peripheral oxygen atoms are unavailable for charge transfer into the pz upon peripheral metalation. 

Treatment of [ C5(CH3)5 RuCl]4 with 3,5-dimethylpyrazolatopotassium, 3,5-diphenylpyrazo-lato(tetrahydrofuran)potassium, or 3,5-di-/m-butylpyrazolatopotassium in tetrahydrofuran afforded (r 5-3,5-dimethylpyrazolato)(r 5-pentamethylcyclopentadienyl)rathenium(II) (71 %), (r 5-3,5-di-tert-butylpyrazolato)(r 5-pentamethylcyclopentadienyl)ruthenium(II) (72%), or (r 5-3,5-diphenylpyrazolato)(r 5-pentamethylcyclopentadienyl)ruthenium(II) (71%), as dark green, pale yellow, or dark brown crystalline solids, respectively. 

Col2OCMH,5, Cobalt(III), carbonyldiiodo(r 5-pentamethylcyclopentadienyl)-, 23 16 CoKN20 C2H, Cobaltate(III), diammine-bis(carbonato)-, cis-, potassium,... 

Brij BSA Bu CBDTS CD CHIRAPHOS Cn COD Cp Cp CTAB DBA = seep.78 = bovine serum albumin = butyl = tetrasulfonated cyclobutane-DIOP, 37, see p. 17 = cyclodextrin = 2,3-bis(diphenylphosphino)butane = 1,4,7-trimethyl-1,4,7-triazacyclononane = 1,5-cyclooctadiene = r 5-cyclopentadienyl = ti5-CsMe5, r 5-pentamethylcyclopentadienyl = hexadecyltrimethylammonium bromide = 1,5-diphenyl-l, 4,-pentadiene-3-one (dibenzylideneacetone)... 

A method for the stabilization of the isocyano metabolites by formation of rhodium complexes has been developed. The (r 5-pentamethylcyclopentadienyl)- or (r 5-ethyltetramethylcyclopenta-dienyl)-di- i-thiocyanato rhodium complexes of the isocyanides (eg 129) normally provide stable, crystalline compounds, thus facilitating the analysis and the purification of these metabolites [139,140]. 

VJhen the title compound, trioxo(r)5-pentamethylcyclopentadienyl)-rhenium(VII) (1), was discovered in our laboratory by Serrano [1], there was much surprise about the existence and stability of this material. No one would have predicted that such a pleasant and versatile chemistry would be developed from this discovery. Some basic, synthetically useful reactions have been described in a number of... 

The structure of these typical stannylenes 1 and 2 are discussed in Chapter 4 as well as that of bis(pentamethylcyclopentadienyl)tin(II) (3) which does not aggregate either but contains two r 5-bonded cyclopentadieny] ligands29), the coordination number being difficult to establish. 

Synthesis of [r 5-3,5-Dimethyl(phenyl,ferf-butyl)pyrazolato] (ri5-pentamethylcyclopentadienyl)ruthenium(ll) 711 (3.147) [313]... 

M. J. Wax, J. M. Stryker, J. M. Buchanan, C. A. Kovac, and R. G. Bergman, Reversible C—H Insertion/Reductive Elimination in ( 5-Pentamethylcyclopentadienyl)(trimethyl-phosphine)iridium Complexes. Use in Determining Relative Metal-Carbon Bond Energies and Thermally Activating Methane, J. Am. Chem. Soc. 106, 1121-1122 (1984). 

The driving force of aromaticity can be exploited for C-C bond cleavage in prearomatic systems. Pentamethylcyclopentadienyl complexes are obtained from reactions of hexamethyl-(Dewar benzene) with RhCl3 and IrCl3 [56]. A r 4-(en-do-ethylcyclopentadienyl)molybdenum complex rearranges with breaking of the Cp-Et bond to a r 5-(cyclopentadienyl)(ethyl)molybdenum complex upon generation of a vacant coordination site on the metal [57]. 

Figure 2. ORTEP drawing of the nonhydrogen atoms for the [Th(r)5-(CH3)5-C5)2( -02C2(CHS)2)]2 molecule, la. All atoms are represented by thermal vibrational ellipsoids drawn to encompass 50% of the electron density. Atoms of a given type labelled with a prime ( ) are related to those labelled without by the crystallographic inversion center midway between the two thorium atoms. The crystallographically independent pentamethylcyclopentadienyl ligands are labelled A and B, respectively (32).

Mononuclear complexes of the type [Cp RhCl2(L)]H20 and [Ru(cymene) C12(L)] H20 have been obtained from the reaction of anellated azaphospholes (L = 2-phosphaindolizine and l,3-azaphospholo[5,l-a]isoquinoline) with [r 5-Cp RhCl2]2 (Cp = pentamethylcyclopentadienyl) and [Ru[r 6-cymene)Cl2]2 respectively. NMR studies reveal a dynamic equilibrium between covalent and ionic forms of the complexes in solution [101]. The zwitterionic pyridinodithio-phosphinates (103), obtained from the reaction of 2-phosphaindolizines with H2S/S8, have been used as chelating ligands to obtain [PdCl(L)]+ Cl" type complexes (Scheme 35) [102],... 

A RhCp complex (S,S)-6 (Cp =pentamethylcyclopentadienyl), which is iso-lobal with Ru(rj6-arene) complex (S,S)-5 (Scheme 13), effected the transfer hydrogenation of a cyclic imine substituted by an isopropyl group with an S/C of 200 in the presence of a 5 2 mixture of formic acid and triethylamine to give the R amine in 99% ee (Scheme 13) [31]. When the reaction was performed with an S/C of 1,000, the optical yield decreased to 93%. The methyl imine was reduced with a 91% optical yield. Reduction of a cyclic sulfonimide resulted in the R sul-tam in 81% ee. 

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