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Abstract Selective cleavage and subsequent functionalization of C−C single bonds present a fundamental challenge in synthetic organic chemistry. Traditionally, the activation of C−C single bonds has been achieved using stoichiometric transition-metal complexes. Recently, examples of catalytic processes were developed in which use is made of precious metals. However, the use of inexpensive and Earth-abundant group IV metals for catalytic C−C single-bond cleavage is largely underdeveloped. Herein, the zirconium-catalyzed C−C single-bond cleavage and subsequent hydroboration reactions is realized using Cp2ZrCl2 as a catalytic system. A series of structures of various γ-boronated amines are readily obtained, which are otherwise difficult to obtain. Mechanistic studies disclose the formation of a N–ZrIV species, and then a β-carbon elimination route is responsible for C–C single bond activation. Besides zirconium, hafnium exhibits a similar performance for this transformation.

Despite their higher abundance, 3d metal-based catalysts are less investigated than their precious metal counterparts. Here, the authors report a cobalt-triphos complex as molecularly-defined non-noble metal catalyst for the reductive amination of carbonyl compounds with gaseous ammonia and hydrogen.

Catalytic transformations involving main group compounds is much less developed than carbon chemistry. Here, the authors report the use of catalytic or stoichiometric tBuOK in presence of a hydrogen acceptor for efficient P–P and P–heteroatom coupling reactions.

Identifying active sites and designing rationally heterogeneous catalysts are not inherently straightforward due to their complexity. Here, the authors reveal the nature of active sites for efficient C–H bond activation in C1-C4 alkanes over bare ZrO2 and provide fundamentals for controlling their concentration.

Synthesis of molecularly defined single-active site catalytic materials is the key to bridging the gap between homogeneous and heterogeneous catalysis. Here, the authors develop such catalysts for selective oxidation of heterocyclic compounds to quinoline and indole via the oxidative polymerization of pyrrole derivatives.

Green Friedel–Crafts acylation reactions belong to the most desired transformations in organic chemistry. The resulting ketones constitute important intermediates, building blocks, and functional molecules in organic synthesis as well as for the chemical industry. Over the past 60 years, advances in this topic have focused on how to make this reaction more economically and environmentally friendly by using green acylating conditions, such as stoichiometric acylations and catalytic homogeneous and heterogeneous acylations. However, currently well-established methodologies for their synthesis either produce significant amounts of waste or proceed under harsh conditions, limiting applications. Here, we present a new protocol for the straightforward and selective introduction of acyl groups into (hetero)­arenes without directing groups by using available olefins with inexpensive CO. In the presence of commercial palladium catalysts, inter- and intramolecular carbonylative C–H functionalizations take place with good regio- and chemoselectivity. Compared to classical Friedel–Crafts chemistry, this novel methodology proceeds under mild reaction conditions. The general applicability of this methodology is demonstrated by the direct carbonylation of industrial feedstocks (ethylene and diisobutene) as well as of natural products (eugenol and safrole). Furthermore, synthetic applications to drug molecules are showcased.

Density functional theory is used for studying the structure and stability of a set of [(CF).sub.60] isomers. The relative energy per CF unit of the most stable isomer to graphite fluoride [(CF).sub.n] is 3.7 kcal/mol, which is smaller than that of [C.sub.60] fullerene per carbon to graphite.

Density functional theory calculations are performed to examine 12-electron reduced [alpha],[beta],[gamma],[delta] and [elipson] Keggin-like [[(Mo[O.sub.4])[Mo.sub.12][O.sub.12][S.sub.12][(OH).sub.12]].sup.2-] polyoxothiometalates (POTMs). Energy decomposition analysis shows that the enhanced stabilities of [gamma], [delta], and [elipson] isomers originate the favorable arrangements of their [Mo.sub.12][O.sub.12][S.sub.12][(OH).sub.12] shell, in which the edge-sharing [[Mo.sup.v.sub.2][([mu]-S).sub.2][O.sub.2]] fragment plays a fundamental role in stabilizing the overall structure.

A study is conducted to probe the incorporation processes of [Mn.sup.2+] and [Co.sup.2+] into the framework of aluminophosphate molecular sieve AlP[O.sub.4]-5, at the onset of crystallization. The DFT computation results indicate that much higher transformation energy of [[Mn[(OP[(OH).sub.3]).sub.4]].sup.2+] than that of [[Co-[(OP[(OH).sub.3]).sub.4]].sup.2+] was responsible for the diversity of the incorporation behaviors.

A study computed the adsorption and dissociation of thiophene on the MoP(001), [gamma]-Mo2N(100), and Ni2P(001) surfaces by using the density functional theory method. Results reveal that thiophene adsorbs dissociatively on MoP(001), while nondissociatively on [gamma]-Mo2N(100) and Ni2(001).

Density functional theory (DFT) is used to study the CO adsorption on the Fe3O4(111) surfaces, which are considered as active catalysts in water-gas shift reaction. The results have shown that the adsorbed CO can migrate from the on-top site to the bridge site or 3-fold site and the oxidation of CO through surface oxygen atoms is feasible.

Density functional theory calculation was carried out for hydrogen adsorption on the (001), (110), and (100) surfaces of Fe(sub 5)C(sub 2) and found that the most stable hydrogen species is C(sub S)H at 1/3 and 2/3 monolayer (ML) on (001). On the metallic Fe(Sub 5)C(sub 2)(100) surface which lacks surface carbon atoms on the surface monolayer, dissociated hydrogen is found at 1/2 ML, while both dissociated hydrogen and activated H(sub 2) are found at 1 ML.

The structure and energy of aluminum nitride cages (AIN) (sub n) (n=2 -41) investigated theoretically is described. The qualitative results obtained were validated on the basis of ab initio and density functional calculations and compared with those of the structural related (BN) (sub n) cages from density functional tight-binding results.

The structure and stability of the (B12N12)n (n = 1, 2) cages are calculated at the B3LYP level of density functional theory. The most stable B24N24 structure deduced from the two B12N12 (Th) cages is found to have an unexpected tube form.

Research has been conducted on the 10-azatriquinacene and its hydrogenation products. The computation results of the formation and hydrogenation enthalpies, proton affinities and vertical ionization potentials are described.

Research has been conducted on the heterofullerenes and their hexaanions and a dimer. The use of the ab initio calculations in investigating these aromatic compounds is discussed.

Research has been conducted on the oxocarbon dianions cyclic delocalization. Results indicate that they are moderately or doubly aromatic.

Research is presented describing the synthesis of stable neutral silaaromatic compounds, 2-silanaphthalenes, which were found to have almost as much aromatic character as naphthalene.

The development of the general palladium-catalyzed carbonylative vinylation of aryl halides with olefins in the presence of CO is described. Aryl halides and olefins are used for preparing versatile building blocks and the generality and functional group tolerance of the protocol is shown.

A study was conducted to examine the reactivity of variously substituted alkynylsilanes toward selected group 4 metallocene complexes. DFT calculations supported the proposed reaction mechanism leading to various metallocene products and alkyne, though the alkynylsilanes [R.sup.1][C.sub.2]Si[R.sup.2.sub.2]H (R1 = SiMe3, R2 = Me) could not form any product types could be utilized to synthesize the P[Me.sub.3]-stabilized hafnocene alkyne complexes.

Spin-polarized density functional theory calculations are performed to explore the carbon pathways and hydrogenation mechanism for C[H.sub.4] formation on [Fe.sub.2]C(011), [Fe.sub.5][C.sub.2](010), [Fe.sub.3]C(001), and [Fe.sub.4]C(100). The calculated reaction energies and effective barriers revealed the C[H.sub.4] formation to be more favorable on [Fe.sub.5][C.sub.2](010) and [Fe.sub.2]C(011), while [Fe.sub.4]C(100) and [Fe.sub.3]C(001) are inactive toward C[H.sub.4] formation.

Indole aziridines and their hydroxyl derivatives are used for preparing a small library of novel functionalized bisindoles. The density functional theory calculations have shown that the mechanism has proceeded through a charge stabilized azabutadiene motif that has reacted at the benzylic position to rebuild the aromatic ring system.

An electronic structures and the alpha/beta relative stability of Keggin-typed [[X[W.sub.12][O.sub.40]].sup.n-] anions with transition metal as heteroatom (X= [Cr.sup.VI], [V.sup.V], [Ti.sup.IV], [Fe.sup.III], [Co.sup.III], [Ni.sup.III], [Co.sup.II] and [Zn.sup.II]) are investigated using density functional theory calculations. The structural parameters from experiment are reproduced by computation and the conventional trend of the higher stability of alpha over the beta isomer is confirmed by the studies.

The structures and energies of [Mo.sub.27][S.sub.x][C.sub.y] cluster models are computed by density functional theory (DFT) in order to understand the carburization processes of Mo[S.sub.x] catalysts. The results have shown that the model cluster, [Mo.sub.27][S.sub.24][C.sub.30], with a fully carbonized S edge and [S.sub.1] bulky sulfur, is the most favored full carburization.

NO probe molecule adsorption on the stoichiometric (Mo16S32) and nonstoichometric (Mo16S34 and Mo16S29) clusters is investigated using density functional theory (DFT) method. The calculated adsorption energies indicate that the stoichiometric cluster has stronger NO affinity than the nonstoichiometric surfaces.

Density functional theory studies are carried on the CO adsorption on both hexagonal and triangular clusters and the structures have determined adsorption properties. Hexagonal clusters have preferred monocarbonyl adsorption over dicarbonyl adsorption on the stoichiometric and nonstoichiometric Mo sites at low coverage and dicarbonyl adsorptions have existed at high CO coverage.

Density functional theory (DFT) calculations are used to investigate C[O.sub.2] reforming of C[H.sub.4] on Ni(111). The computed energy barriers of the most favorable elementary reaction have identified the C[H.sub.4] activation into C[H.sub.3] and H as the rate-determining step of C[O.sub.2] reforming of C[H.sub.4] on Ni(111).

Density functional theory computations are carried out to study the structure and stability of MoS(sub x) clusters with the change of sulfur coverage at both Mo and S edges. The interaction between Mo and S edges under the variation of sulfur coverage is analyzed with the change of Mo(sub 27)S(sub x) clusters and the stability of triangular MoS(sub x) clusters are discussed.

A systematic density functional theory (DFT) of hydrogen adsorption on Fe(111) at various coverages is presented. The coverage effects on the adsorption configrations and adsorption energies are addressed.

A systematic density functional study on the structure and stability of triangular molybdenum sulfide [MoS(sub x)] models is carried out. It is found that CO adsorption at the corner site represents the most stable conformation.

Density functional theory calculations are carried out on the CO/H2 coadsorption on the (001), (110), and (100) surfaces of Fe5C2 for the understanding of the Fischer-Tropsch synthesis (FTS) mechanism. The stable surface species changes with the variation of the H2 and CO coverage.

The structure of the acid sites in the channels and intersections of H-, Li-, and Na--ZSM-5 and their interactions with pyridine molecule is computed with the help of three corresponding models containing 22 tetrahedral sites. The structures indicate that the zeolite lattice framework surrounding the adsorption site has important contributions to the adsorption energy of the pyridine molecule.

The way benzannelation affects the degree of aromatic character in mobius annulenes is described. Computations on other mobius systems show that benzannelation clearly reduces the degree of bond-length equalization.

CO adsorption on four MoSx clusters is investigated by using density functional method. It is found that CO prefers adsorption on the coordinatively unsaturated (1010) surface.

The structures and energies of isolobal (CH)n and (BCO)n polyhedral species are computed at the B3LYP density functional theory level. Unlike the (CH)n cages, the most stable (BCO)n polyhedra (n greater than equal to 10) prefer structures with the largest numbers of three-membered rings.

Density functional theory calculations are carried out to study CO adsorption on the (001), (100), and (110) surfaces of Fe5C2, which are considered as active catalysts in Fischer-Tropsch synthesis. Study indicates that CO prefers to adsorb at three 3--fold sites (three iron atoms) on the three surfaces at low coverage with maximum adsorption energies of -2.10, -2.21 and -2.34 eV, respectively.

The vertical ionization potentials and the energy as well as the nucleus independent chemical shift (NICS) at the cage center are computed for the first four most stable isomers. The structure and stability of 27C(sub 48) fullerene is computed at B3LYP.

Aqueous M(super 3+)/M(super 2+) redox potentials for nine of the ten fourth-period transition metals, M, were calculated with the use of density-functional theory methodology in combination with the continuum solvation model. For the ions studied, the average absolute difference from experimental values is 0.29 V, with four out of nine potentials reproduced with better than 0.1 V accuracy.

The homolytic dissociation enthalpies of various bonds were computed by using five density functional methods. The quality of these methods is comprehensively evaluated on the basis of the available experimental bond dissociation enthalpies, and it was found that MPW1P86 had the best agreement.

Research has been conducted on chiral silylphospholane. The results of highly stereoselective synthesis of this compound, which can be used as a building block under base-free conditions, are described.

Research has been conducted on oligomeric polycyclic neutral oxocarbons. The compounds have been identified as stable via the use of density functional theory calculations, and the details are reported.

The structures and electronic configurations and C-O stretch frequencies and bond dissociation charges of [Co(CO)n](super m) (m=0, 1+,1-) were investigated with the B3LYP density functional method. It was found that these complexes preferred less symmetrical structures as the most stable states and marginal structural deformations had large energetic consequence.

Commercially available Ru-MACHOTM-BH is an active catalyst for the hydrogenation of several functional groups and for the dehydrogenation of alcohols. Herein, we report on the new application of this catalyst to the base-free transfer hydrogenation of carbonyl compounds. Ru-MACHOTM-BH proved to be highly active and selective in this transformation, even with α,β-unsaturated carbonyl compounds as substrates. The corresponding aliphatic, aromatic and allylic alcohols were obtained in excellent yields with catalyst loadings as low as 0.1–0.5 mol % at mild temperatures after very short reaction times. This protocol tolerates iPrOH and EtOH as hydrogen sources. Additionally, scale up to multi-gram amounts was performed without any loss of activity or selectivity. An outer-sphere mechanism has been proposed and the computed kinetics and thermodynamics of crotonaldehyde and 1-phenyl-but-2-en-one are in perfect agreement with the experiment. [ABSTRACT FROM AUTHOR]

Isolobal CH --> boron carbonyl (BCO) substitution favors delocalized, neutral bishomoaromatic systems substantially. BCO substitution can result in low-lying triplet and open-shell singlet states as in semibullvalene by the computed diatropic nucleus-independent chemical shifts (NICS) at the Cope rearrangement centers.