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The use of hydrazones as a new type of submonomer in peptoid synthesis is described, giving access to peptoid monomers that are structure-inducing. A wide range of hydrazones were found to readily react with α-bromoamides in routine solid phase peptoid submonomer synthesis. Conditions to promote a one-pot cleavage of the peptoid from the resin and reduction to the corresponding N -alkylamino side chains were also identified, and both the N -imino- and N -alkylamino glycine residues were found to favor the trans -amide bond geometry by NMR, X-ray crystallography, and computational analyses. 

A pathway for the catalytic hydrosilylation of carbonyl substrates with M(C 6 F 5 ) 3 (M = B, Al and Ga) was calculated by DFT (B3PW91-D3) and it was shown that in the case of the Al reagent, the carbonyl substrate binds irreversibly and inhibits catalysis by generating a stable carbonyl adduct. In contrast, the reduced electrophilicity of B(C 6 F 5 ) 3 disfavors the binding of the carbonyl substrate and increases the concentration of an activated silane adduct which is the species responsible for catalytic turnover. A similar mechanism was found for both cationic and neutral Re( iii ) species. Further, it was shown by tuning the electrophilicity of the rhenium catalysts, conditions can be found that would enable the catalytic hydrosilylation of ketone and nitrile substrates that were unreactive in previously reported systems. Thus the mechanisms proposed in this work, lay the foundation for the design of new catalytic systems. 

A method for the preparation of nitridorhenium( v ) complexes of the form (SSS)Re(N)(L) (where SSS = 2-mercaptoethylsulfide and L = PPh 3 and t -BuNC) has been described. These complexes react with Lewis acids allowing for the isolation of adducts. The lack of a significant steric profile on the SSS ligand combined with enhanced nucleophilicity of the nitrido group does not allow for the effective formation of frustrated Lewis pairs with these complexes and as a result these species are poor catalysts for the hydrogenation of unactivated olefins. 

Cp*Ir( iii ) complexes have been shown to be effective for the halogenation of N , N -diisopropylbenzamides with N -halosuccinimide as a suitable halogen source. The optimized conditions for the iodination reaction consist of 0.5 mol% [Cp*IrCl 2 ] 2 in 1,2-dichloroethane at 60 °C for 1 h to form a variety of iodinated benzamides in high yields. Increasing the catalyst loading to 6 mol% and the time to 4 h enabled the bromination reaction of the same substrates. Reactivity was not observed for the chlorination of these substrates. A variety of functional groups on the para -position of the benzamide were well tolerated. Kinetic studies showed the reaction dependence is first order in iridium, positive order in benzamide, and zero order in N -iodosuccinimide. A KIE of 2.5 was obtained from an independent H/D kinetic isotope effect study. Computational studies (DFT-BP3PW91) indicate that a CMD mechanism is more likely than an oxidative addition pathway for the C–H bond activation step. The calculated functionalization step involves an Ir( v ) species that is the result of oxidative addition of acetate hypoiodite that is generated in situ from N -iodosuccinimide and acetic acid. 

The synthesis of (PNP)Re(N)X (PNP = [2-P(CHMe 2 ) 2 -4-MeC 6 H 3 ] 2 N, X = Cl and Me) complexes is described. The methylnitridorhenium complex 3 was found to react differently with CO and isocyanides, leading to the isolation of a Re( v ) acyl complex 4 and an isocyanide adduct 6 . Two parallel pathways were observed for the reaction of 3 with CO: (1) CO inserts into the Re–Me bond to afford 4 , and (2) 3 isomerizes by distortion of the aryl backbone of the PNP ligand to afford the isomer 3′ . This is followed by the reaction of 3′ with CO to afford the tricarbonyl complex 5 , which was fully characterized. The contrasting reaction of 3 with 2,6-dimethylphenyl isocyanide lends further support for the proposed isomerization pathway. DFT (M06) calculations suggest that insertion of CNR into the Re–Me bond (27.2 kcal mol −1 ) is inaccessible at room temperature. Instead the substrate adds to the metal center via the most accessible face i.e. syn to the rhenium–nitrido bond, to afford 6 . The addition of CO to isomer 3′ is proposed to proceed with a similar mechanism to 2,6-dimethylphenyl isocyanide.