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Efficient NNN‐pincer type bis(imino)pyridine ligand based zinc(II) catalyzed intermolecular amidation of benzylic hydrocarbons with sulfonamides has been developed. The zinc complexes were synthesized by the reaction of bis(imino)pyridine ligand with zinc(II) precursors such as Zn(OAc)2 ⋅ 2H2Oand ZnBr2. The structure of the bis(imino)pyridine‐Zn(OAc)2 complex was characterized by single crystal X‐ray diffraction. The zinc(II)‐bis(imino)pyridine complexes were utilized as catalysts for the intermolecular amidation of benzylic C(sp3)−H bond in the presence of N‐bromosuccinimide (NBS) as an oxidant. A broad range of substrates delivered the products in moderate to good yields. This protocol provides the synthesis of various amides viaC−H activation. [ABSTRACT FROM AUTHOR]

Two new zinc(II) complexes, [2,6‐bis(methylphenyliminomethyl)pyridine]ZnBr2 (2 a) and [2,6‐bis(triflouromethylphenyliminomethyl)pyridine]ZnBr2 (2 b) were synthesized by the reactions of corresponding 2,6‐bis(imino)pyridine based [NNN]‐pincer ligand and anhydrous ZnBr2 in acetonitrile as a solvent. The catalytic properties of zinc(II) complexes were examined in azide‐alkyne cycloaddition reactions in water. The zinc(II) complexes were characterized by UV‐Vis, 1H NMR, IR, elemental analysis and mass spectroscopy. The zinc complex [2,6‐bis(triflouromethylphenyliminomethyl)pyridine]ZnBr2 was characterized by X‐ray crystallography. The zinc(II) complexes efficiently catalyzed the azide‐alkyne cycloaddition reaction for the synthesis of 1,2,3‐triazoles (mixture of 1,4‐ and 1,5‐disubstituted 1,2,3‐triazoles) in water with good to excellent yields. [ABSTRACT FROM AUTHOR]

Thetris(alkyne) copper complex [(cyclooctyne)3Cu][SbF6] has been synthesized using cyclooctyne and in situ generatedCuSbF6. Tris(alkyne) silver complexes [(cyclooctyne)3Ag]+involving weakly coordinating counterionssuch as [SbF6]−and [PF6]−have also been isolated in good yield using cyclooctyneand commercially available AgSbF6and AgPF6.These coinage metal tris(alkyne) adducts have trigonal-planar metalsites. The alkyne carbon atoms and the metal site form distorted spoke-wheel(rather than upright trigonal-prismatic) structures in the solid state.In [(cyclooctyne)3Cu][SbF6], these distortionsresult in a propeller-like arrangement of alkynes. A cationic gold(I)complex having two alkynes has been prepared by a reaction of equimolaramounts of Au(cyclooctyne)2Cl and AgSbF6indichloromethane. The gold atom of [(cyclooctyne)2Au]+coordinates to the cyclooctynes in a linear fashion, whilethe carbon atoms of the alkyne groups form a tetrahedron around gold(I).Optimized geometries of cationic [(cyclooctyne)3M]+, [(cyclooctyne)2M]+, and [(cyclooctyne)M]+and neutral [(cyclooctyne)2MCl] and [(cyclooctyne)MCl]adducts (M = Cu, Ag, Au) using density functional theory (DFT) atthe BP86/def2-TZVPP level of theory and a detailed analysis of metal–alkynebonding interactions are also presented. [ABSTRACT FROM AUTHOR]

N-heterocyclic carbene ligand SIDipp (SIDipp = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) and trimesitylphosphine ligand have been used in the synthesis of gold(I) cyanide, t-butylisocyanide, and cyclooctyne complexes (SIDipp)Au(CN) (3), (Mes(3)P)Au(CN) (4), [(Mes(3)P)(2)Au][Au(CN)(2)] (5), [(SIDipp)Au(CN(t)Bu)][SbF(6)] ([6][SbF(6)]), [(SIDipp)Au(cyclooctyne)][SbF(6)] ([8][SbF(6)]), and [(Mes(3)P)Au(cyclooctyne)][SbF(6)] ([9][SbF(6)]). A detailed computational study has been carried out on these and the related gold(I) carbonyl adducts [(SIDipp)Au(CO)][SbF(6)] ([1][SbF(6)]), [(Mes(3)P)Au(CO)][SbF(6)] ([2][SbF(6)]), and [(Mes(3)P)Au(CN(t)Bu)](+) ([7](+)). X-ray crystal structures of 3, 5, [6][SbF(6)], [8][SbF(6)], and [9][SbF(6)] revealed that they feature linear gold sites. Experimental and computational data show that the changes in π-acid ligand on (SIDipp)Au(+) from CO, CN(-), CN(t)Bu, cyclooctyne as in [1](+), 3, [6](+), and [8](+) did not lead to large changes in the Au-C(carbene) bond distances. A similar phenomenon was also observed in Au-P distance in complexes [2](+), 4, [7](+), and [9](+) bearing trimesitylphosphine. Computational data show that the Au-L bonds of "naked" [Au-L](+) or SIDipp and Mes(3)P supported [Au-L](+) (L = CO, CN(-), CN(t)Bu to cyclooctyne) have higher electrostatic character than covalent character. The Au←L σ-donation and Au→L π-back-donation contribute to the orbital term with the former being the dominant component, but the latter is not negligible. In the Au-CO adducts [1](+)and [2](+), the cationic gold center causes the polarization of the C-O σ and π orbitals toward the carbon end making the coefficients at the two atoms more equal which is mainly responsible for the large blue shift in the CO stretching frequency. The SIDipp and Mes(3)P supported gold(I) complexes of cyanide and isocyanide also exhibit a significant blue shift in υ(CN) compared to that of the free ligands. Calculated results for Au(CO)Cl and Au(CF(3))CO suggest that the experimentally observed blue shift in ν(CO) of these compounds may at least partly be caused by intermolecular forces.