Typical radical traps (galvinoxyl, TEMPO, DPPH) react with palladium hydrides, sometimes at rates competitive with those of palladium hydride catalyzed reactions that follow an insertion mechanism (for example, alkene isomerization). Thus, positive results for radical reaction tests can be misleading. The complexes with more polarizable (neutral complexes rather than cationic) and more accessible hydrides, and the less sterically protected radical traps, react faster.

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Vinylic addition polynorbornenes bearing functional groups can be obtained in a versatile way by nucleophilic substitution of a halogen in new vinylic haloalkyl polynorbornenes. The latter are obtained by vinylic homo and copolymerization of norbornene and haloalkyl norbornenes catalyzed by [Ni(C 6 F 5 ) 2 (SbPh 3 ) 2 ]. This method circumvents the problem of catalyst deactivation encountered in classical copolymerizations with polar monomers. The content of substituted monomer in the copolymers is in the range 26-59%, depending on the monomer ratio in the feed. Nucleophilic substitution reactions afford polymers with ester, cyano, phenylthio, or azido groups in the same wide range of composition. Click chemistry on the azido polynorbornenes give polynorbornenes with pendant triazole groups.

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New functionalized polynorbornenes have been obtained in good yields by vinylic copolymerization of norbornene with a (norbornenyl)SnBu(2)Cl monomer, catalyzed by [Ni(C(6)F(5))(2)(SbPh(3))(2)]. Subsequent functionalization produces a wide variety of polymers with different --SnBu(2)R groups (R=aryl, vinyl, alkynyl). The polymers can be used as R-transfer reagents in Stille couplings, thereby providing easy workup and separation of the polymeric tin byproducts from the coupling products. Tin contents of around 0.05 wt % are found in the Stille products. The stannylated polymers can be recycled and reused with good efficiency.

The behavior of palladium C-bound enolates [Pd(CH2C(O)CR3)Cl(PPh3)2] (R = H, 1; R = Me, 2) and [Pd(CH2C(O)CR3)(PPh3)2(NCMe)](BF4) (R = H, 5; R = Me, 6) has been studied. Dimeric species with bridging enolate moieties are formed in solution when a coordination site on the metal is made available, either with Pd2{μ-κ2-C,O-CH2C(O)CR3}2 or with mixed Pd2{μ-κ2-C,O-CH2C(O)CR3}(μ-X) (X = Cl, OH) bridges. It is proposed that π back-donation is important to stabilize oxygen bonding. Complexes 1 and 2 undergo exchange between free and coordinated phosphine in solution. Kinetic experiments support an intramolecular associative mechanism which could involve an oxoallyl-like transition state. The reactivity of the complexes has been explored. Some reactions typical of Pd-alkyls have been observed such as insertion of CO to give CR3C(O)CH2COOH. Electrophilic attack on oxygen is very important:  the hydrolysis of the enolate complexes has been studied and also the reaction with ClSiMe3 to give silyl enol ethers.

The polymerization of methyl acrylate by pentafluorophenyl complexes [Pd 2 (µ-X) 2 (C 6 F 5 ) 2 L 2 ] (L ) tetrahydrothiophene (tht), X ) Cl, 2; L ) tht, X ) Br, 3; L ) AsPh 3 , X ) Br, 4) gives atactic polymers in good yields. Mechanistic studies reveal that the polymerization of methyl acrylate starts by insertion of methyl acrylate in the Pd-aryl bond of the precatalyst to give the alkyl complexes trans- 6). These complexes can be isolated, and the X-ray crystal structure of 5 has been determined. Complexes 5 and 6 decompose mainly by β-H elimination but also by homolytic cleavage of the Pd-C bond in the light. In the presence of methyl acrylate, insertion of MA in hydrido-Pd species produces the alkyl complex trans-[Pd 2 (µ-Cl) 2 {CH(CO 2 Me)CH 3 } 2 (tht) 2 ] (9). Then a radical polymerization is initiated by small amounts of the radicals generated from these complexes (5, 6, or 9). Formation of 9 is the regeneration pathway of radicals after a termination reaction has occurred by recombination of the growing radical with palladium and β-H elimination. The success of the polymerization requires a slow but steady supply of radicals by slow decomposition of alkyl complexes (5 and 6) or by slow generation of Pd-H species that provide new alkyl complexes (9), as well as an efficient recycling of the Pd-H generated in the termination step to 9.