The curious case of mesityl azide and its reactivity with bpyNiEt2.

A DFT analysis of the reaction of bpyNiEt2 with ArN3 was performed for para-tolyl-azide (Ar = pTol), 3,5-dimethyl-phenyl-azide (Ar = mXy) and ortho-tolyl-azide (Ar = oTol), and mesityl-azide (MesN3). Of particular interest were the different products obtained for the latter (ethylene, butane, azomesitylene, mesityl-ethylamine, etc.) versus the other reagents, i.

Impact of d-orbital occupation on metal-carbon bond functionalization.

Metal-carbon bond functionalization leading to C-O bond formation is a promising component reaction that can ultimately form the basis for production of methanol from natural gas. Two primary pathways have been considered: (1) an organometallic Baeyer-Villiger (OMBV) pathway, and (2) a two-step, redox oxy-insertion. A series of first-row transition metal-methyl complexes was modeled for these two pathways to elucidate any trend therein.

Versatile reactivity of Pd-catalysts: mechanistic features of the mono-N-protected amino acid ligand and cesium-halide base in Pd-catalyzed C-H bond functionalization.

The widely used C-H functionalization strategies and some complexities in the Pd-catalyzed chemical transformations were analyzed. It was emphasized that in the course of catalysis various Pd-intermediates (including nano-scale Pd-clusters) could act as active catalysts. However, both identification of these catalytically active species and determination of factors controlling the overall catalytic process require more comprehensive and multi-disciplinary approaches.

Understanding the reactivity of Pd(0)/PR3-catalyzed intermolecular C(sp(3))-H bond arylation.

Mechanistic details pertaining to the Pd(0)/PCy3-catalyzed intermolecular arylation of a terminal β-C(sp(3))-H bond aryl amide substrate (SM = EtCONH-Ar, where Ar = C6H5, C6F5 and CONH-Ar is a directing group (DG)) in the presence of CsF base were elucidated. Key mechanistic features of this reaction are (1) oxidative addition of the aryl halide PhI to Pd(0)/PCy3, (2) deprotonation of SM by CsF to form DG' = [EtCON-Ar]Cs(+) for subsequent coordination to intermediate I-Pd(II)(PCy3)Ph (the substantially lower pKa of the EtCONHC6F5 in comparison to EtCONHC6H5 is instrumental for the presence of a larger population of the reactive deprotonated amides for Ar = C6F5), (3) "Cs2-I-F" cluster formation upon external (the second) CsF molecule approach to the active site of the I-Pd(II)(PCy3)Ph(DG') intermediate, (4) "Cs2-I-F cluster" assisted β-C(sp(3))-H bond activation via a concerted metalation-deprotonation (CMD) mechanism, and (5) reprotonation of the amide directing group to facilitate the C(sp(3))-Ph reductive elimination. The energy barriers, ΔG(‡) (ΔG(‡disp), associated with the "Cs2-I-F cluster" mediated β-C(sp(3))-H bond activation transition state are 6.

Computational Hammett analysis of redox based oxy-insertion by Pt(II) complexes.

A computational Hammett analysis of oxy-insertion into platinum-aryl bonds is performed. Modeled transformations involve the two-step conversion of [((X)bpy)Pt(R)(OY)](+) (R = p- or m-X-C(6)H(4); Y = 4- or 3-X-pyridine; (X)bpy = 4,4'- or 5,5'-X-bpy; X = NO(2), H, OMe, NMe(2)) proceeding through a Pt-oxo intermediate to form aryloxide [((X)bpy)Pt(OR)(Y)](+), which contrasts a one-step non-redox (Baeyer-Villiger) oxy-insertion. A structural connection is proposed between redox and non-redox transition states, linked to, among other parameters, oxidant identity.

Flavin-catalyzed insertion of oxygen into rhenium-methyl bonds.

Flavins and related molecules catalyze organic Baeyer-Villiger reactions. Combined experimental and DFT studies indicate that these molecules also catalyze the insertion of oxygen into metal-carbon bonds through a Baeyer-Villiger-like transition state.

Cooperativity between low-valent iron and potassium promoters in dinitrogen fixation.

A density functional theory (DFT) study was performed to understand the role of cooperativity between iron-β-diketiminate fragments and potassium promoters in N(2) activation. Sequential addition of iron fragments to N(2) reveals that a minimum of three Fe centers interact with N(2) in order to break the triple bond. The potassium promoter stabilizes the N(3-) ligand formed upon N(2) scission, thus making the activated iron nitride complex more energetically accessible.

Carbon-oxygen bond formation via organometallic Baeyer-Villiger transformations: a computational study on the impact of metal identity.

Metal-mediated formation of C-O bonds is an important transformation that can occur by a variety of mechanisms. Recent studies suggest that oxygen-atom insertion into metal-hydrocarbyl bonds in a reaction that resembles the Baeyer-Villiger transformation is a viable process. In an effort to identify promising new systems, this study is designed to assess the impact of metal identity on such O-atom insertions for the reaction [(bpy)(x)M(Me)(OOH)](n) → [(bpy)(x)M(OMe)(OH)](n) (x = 1 or 2; bpy = 2,2'-bipyridyl; n is varied to maintain the d-electron count at d(6) or d(8)).

Selectivity and mechanism of hydrogen atom transfer by an isolable imidoiron(III) complex.

In the literature, iron-oxo complexes have been isolated and their hydrogen atom transfer (HAT) reactions have been studied in detail. Iron-imido complexes have been isolated more recently, and the community needs experimental evaluations of the mechanism of HAT from late-metal imido species. We report a mechanistic study of HAT by an isolable iron(III) imido complex, L(Me)FeNAd (L(Me) = bulky β-diketiminate ligand, 2,4-bis(2,6-diisopropylphenylimido)pentyl; Ad = 1-adamantyl).