Cyclopentadienyl functionality

Verdet and Stille1 employed brominated poly(phenylene oxide) intermediates in an effort to synthesize more stable catalyst supports containing (cyclopentadienyl)metal complexes. Treatment of poly(oxy-2,6-dimethyl-l,4-phenylene) with N-bromosuccinimide under photolytic conditions produced only the bromomethyl derivative if the D.F. did not exceed 0.35. Subsequent treatment of the bromomethylated polymer with sodium cyclopentadienide afforded the cyclopentadienyl functionalized polymer, 5, but the reaction was accompanied by crosslinking and it was not possible to remove the bromomethyl substituents quantitatively. 

An alternative synthesis of a thermally stable cyclopentadienyl functionalized polymer involved ring bromination of poly(oxy-2,6-diphenyl-l,4-phenylene), followed by lithiation with butyl lithium to produce an aryllithium polymer. Arylation of 2-norbornen-7-one with the metalated polymer yielded the corresponding 2-norbornen-7-ol derivative. Conversion of the 7-ol to 7-chloro followed by treatment with butyl lithium generated the benzyl anion which undergoes a retro Diels-Alder reaction with the evolution of ethylene to produce the desired aryl cyclopentadiene polymer, 6. 

Metallation of cyclopentadienyl-functionalized silica materials with tetrakis (diethylamino) titanium. 

The cyclopentadienyl-functionalized solid was added to a flask with excess tetrakis (diethylamino) titanium in toluene. The mixture was stirred under reflux for 24 hours. The resulting solid was filtered, washed with toluene, and dried under vacuum at room temperature overnight, and then stored in a drybox. 

More recently, the Diels Alder cycloaddition was used as a single-step strategy for attaching diene-capped polymers onto CNTs sidewalls through grafting to methods (see Section 3.3.1.6 for more details). Examples include attachment of furfuryl-functionalized polystyrene [35] and cyclopentadienyl-functionalized polymethyl methacrylate [36]. 

Recently, the first example of a structurally proven [allyl] -> [alkyl] exchange reaction was reported. The addition of excess trimethylaluminum to the cyclopentadienyl-functionalized yttrocene monoallyl complex [CsMe4 (SiMe2CH2CH=CI I2)]2Y(f73-C3I I5) quantitatively yielded the dimeric alumi-... 

The generation of the precursors for cyclopentadienyl-silanol-functionalized iron complexes involves the formation of the corresponding iron anion in a first step [6], 2a is obtained by reductive cleavage of the methoxysilyl-cyclopentadienyl-substituted iron dimer 1 with sodium amalgam in THF (Scheme 1). This reaction is restricted to alkoxysilyl-cyclopentadienyl-functionalized iron anions because of the limited access to the corresponding Si-H-functionalized iron dimers. 

Royo and coworkers investigated the reactivity of molybdenum (II) complexes containing cyclopentadienyl-functionalized NHCs toward olefin epoxidation... 

Figure 1.16 Hetero Diels-Alder (HDA) reaction between a thioamide-functionalized peptide (Phos-GGFPWWG) and cyclopentadienyl functional cellulose for the preparation of peptide-decorated cellulose.

CYCLOPENTADIENYL-FUNCTIONALIZED A-HETEROCYCLIC CARBENE COMPLEXES OE IRON AND NICKEL CATALYSTS EOR REDUCTIONS... 

CYCLOPENTADIENYL-FUNCTIONALIZED N-HETEROCYCLIC CARBENE COMPLEXES OF IRON AND NICKEL... 

PREPARATION OF CYCLOPENTADIENYL-FUNCTIONALIZED AT-HETEROCYCLIC CARBENE LIGANDS 135... 

Figure 10.3 Unsubstituted and substituted cyclopentadienyl-functionalized imidazolium pro-ligands.

Following this synthetic method, substituted and unsubstimted cyclopentadienyl-functionalized NHCs of Fe(II) can be prepared. These iron complexes, isolated as green crystalline solids, are very stable in the solid state and can be handled in air. 

A bidentate cyclopentadienyl-functionalized NHC complex of nickel(II) catalyses hydrosilylation of aldehydes, allowing quantitative reduction in 5 min at 25 A transient nickel hydride complex, ( Cp-NHC)NiH, is implicated as the active species. 

Cyclopentadienyl functionality (Cp) in polymers has not received as much attention in the recent literature as, for example, azides and thiols. Nevertheless, the potential for such materials to form tuneable and reversible linkages holds great promise in the design of various uniquely thermoresponsive materials. There is, however, an inherent difficulty in achieving... 

In contrast to Ru-NHC complexes, there are only a few examples of NHC-Fe catalyzed TH reactions. When a series of piano-stool NHC-Fe" complexes 104, bearing bidentate cyclopentadienyl-functionalized NHC ligands, was tested for the TH of ketones in refluxing KOH/i-PrOH, 100% conversion... 

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