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The novel molybdenum oxo-imido bis-(aryloxide) complexes are prepared by the salt elimination reactions of [Mo(N'Bu)(O)[CI.sub.2](DME)] with the lithium aryloxide of from the cycloaddition reactions of tert-butyl isocyanate with the appropriate molybdenum dioxo bis(aryloxide) complex. The geometry around the metal in complexes is described as a distorted trigonal bipyramid, with the imido and pyridine ligands occupying axial positions and the oxo and aryloxide ligands in the equatorial plane.

N-Ylide complexes of Ir have been generated by C(sp3)H activation of α-pyridinium or α-imidazolium esters in reactions with [Cp*IrCl2]2 and NaOAc. These reactions are rare examples of C(sp3)H activation without a covalent directing group, which-even more unusually-occur α to a carbonyl group. For the reaction of the α-imidazolium ester [ 3H]Cl, the site selectivity of CH activation could be controlled by the choice of metal and ligand: with [Cp*IrCl2]2 and NaOAc, C(sp3)H activation gave the N-ylide complex 4; in contrast, with Ag2O followed by [Cp*IrCl2]2, C(sp2)H activation gave the N-heterocyclic carbene complex 5. DFT calculations revealed that the N-ylide complex 4 was the kinetic product of an ambiphilic CH activation. Examination of the computed transition state for the reaction to give 4 indicated that unlike in related reactions, the acetate ligand appears to play the dominant role in CH bond cleavage. [ABSTRACT FROM AUTHOR]

Treatment of the sterically bulky 2-(3-biphenyl-2-ol)-6-iminepyridine, 2-(3-C12H8-2-OH)-6-(CH N(2,4,6-i-Pr3C6H2))C5H3N (HL1 tripp), with Pd(OAc)2 or (MeCN)2PdCl2 results in deprotonation of HL1 tripp to afford the discrete square planar O,Npy,N-pincer complexes, [(L1 tripp)Pd(OAc)] (1) and [(L1 tripp)PdCl] (2) respectively, in good yield; conversion of 1 directly to 2 using aqueous sodium chloride or to [(L1 tripp)PdI] (3) using aqueous sodium iodide has been demonstrated. Selective reduction of the imino unit in HL1 tripp with LiAlH4 proceeds smoothly to yield the 2-(3-biphenyl-2-ol)-6-methylaminepyridine, 2-(3-C12H8-2-OH)-6-(CH2-NH(2,4,6-i-Pr3C6H2))C5H3N (HL2 tripp), which on reaction with Pd(OAc)2 at low temperature gives [(L2 tripp)Pd(OAc)] (4) as the sole product. Complex 4 exists as a dimeric species in the solid state in which two square planar monomers are linked together by two intermolecular NHamine⋯Oacetate interactions resulting in a Pd⋯Pd separation of 6.255Å. The corresponding chloride complex, [(L2 tripp)PdCl] (5), formed by reaction of 4 with aqueous sodium chloride, also exists as a dimeric assembly in the solid state but in this case the presence of two intermolecular NHamine⋯Ophenolate interactions has the effect of compressing the palladium–palladium separation to 3.2580(11)Å. Single crystal X-ray diffraction studies have been performed on 1, 2·CH2Cl2, 2·C6H6, 3, 4 and 5. [ABSTRACT FROM AUTHOR]

With a view to applications in bifunctional catalysis, a modular cross-coupling strategy has been used to prepare amine bis(imidazolium) salts (3aand 3b) and an amine mono(imidazolium) salt (6) as precursors to chelating amido-NHC ligands. Treating the pro-ligands 3with 3 equivalents of the bulky base KHMDS and Pd(OAc)2or PtCl2(COD) gave the four amido bis(N-heterocyclic carbene) pincer complexes [CNC-R]M-I [M = Pd (7) or Pt (8); R = i-Pr (a) or n-Bu (b)], including the first examples of platinum complexes of a CNC ligand. The reaction of 7awith AgOTf in pyridine gave the cationic complex {[CNC-i-Pr]Pd-py}OTf (9a). Heating a mixture of amine mono(imidazolium) salt 6with PdCl2or K2PtCl4, K2CO3and KI in pyridine at 100 °C gave the complexes [C,NH]MI2py [M = Pd (10) or Pt (11)], in which the amine arm of the NHC ligand is not deprotonated and does not coordinate to the metal. For a solution of 10in 1,4-dioxane, deprotonation of the amine occurred in a biphasic reaction with aqueous KOH at 40 °C, giving the dimeric amido complex {[C,N]Pd(μ-OH)}2(12). The more inert Pt analogue 11was unreactive under the same conditions. Solid-state structures of the complexes 7a, 7b, 9a, 10, 11and 12have been determined by single crystal X-ray diffraction. [ABSTRACT FROM AUTHOR]

The previously reported complexes [Mo(NtBu)(O)(2,6-Me2C6H3O)2(py)] (1) and [Mo(NtBu)(O)(2,6-iPr2C6H3O)2(py)] (2) have been shown to contain a nucleophilic oxo ligand. The reaction of 2 and tert-butylacetyl chloride gave the novel complex [Mo(NtBu)(2,6-iPr2C6H3O)2(O2CCH2 tBu)Cl] (3) in 63% yield as the product of nucleophilic acyl substitution. Complex 1 undergoes a clean reaction with triflic anhydride to give the novel complex [{Mo(NtBu)(2,6-Me2C6H3O)2}(μ-O)(μ-OTf)2] (4) in 75% yield. Complex 4 appears to be formed from nucleophilic attack of the oxo ligand on triflic anhydride, followed by nucleophilic attack of a second oxo moiety on the cationic intermediate. The solid-state structures of 3 and 4 have been determined by X-ray crystallography. These are rare examples of nucleophilic oxo ligands bound to a d0 transition metal centre. [ABSTRACT FROM AUTHOR]

The previously reported complexes [Mo(NtBu)(O)(2,6-Me2C6H3O)2(py)] (1) and [Mo(NtBu)(O)(2,6-iPr2C6H3O)2(py)] (2) have been shown to contain a nucleophilic oxo ligand. The reaction of 2and tert-butylacetyl chloride gave the novel complex [Mo(NtBu)(2,6-iPr2C6H3O)2(O2CCH2tBu)Cl] (3) in 63% yield as the product of nucleophilic acyl substitution. Complex 1undergoes a clean reaction with triflic anhydride to give the novel complex [{Mo(NtBu)(2,6-Me2C6H3O)2}(μ-O)(μ-OTf)2] (4) in 75% yield. Complex 4appears to be formed from nucleophilic attack of the oxo ligand on triflic anhydride, followed by nucleophilic attack of a second oxo moiety on the cationic intermediate. The solid-state structures of 3and 4have been determined by X-ray crystallography. These are rare examples of nucleophilic oxo ligands bound to a d0transition metal centre. [ABSTRACT FROM AUTHOR]

N-Ylide complexes of Ir have been generated by C(sp(3))-H activation of α-pyridinium or α-imidazolium esters in reactions with [Cp*IrCl2]2 and NaOAc. These reactions are rare examples of C(sp(3))-H activation without a covalent directing group, which-even more unusually-occur α to a carbonyl group. For the reaction of the α-imidazolium ester [3H]Cl, the site selectivity of C-H activation could be controlled by the choice of metal and ligand: with [Cp*IrCl2]2 and NaOAc, C(sp(3))-H activation gave the N-ylide complex 4; in contrast, with Ag2O followed by [Cp*IrCl2]2, C(sp(2))-H activation gave the N-heterocyclic carbene complex 5. DFT calculations revealed that the N-ylide complex 4 was the kinetic product of an ambiphilic C-H activation. Examination of the computed transition state for the reaction to give 4 indicated that unlike in related reactions, the acetate ligand appears to play the dominant role in C-H bond cleavage., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In the title complex, [PdI(2)(C(24)H(31)N(3))(2)]·2C(6)H(6), the Pd(2+) ion is located on an inversion centre in a slightly distorted square-planar geometry. The angle between the I(2)C(2) square plane and the mean plane of the N-heterocyclic carbene ring is 79.8 (2)°, with I-Pd-C-N torsion angles of -81.1 (6) and -78.2 (5)°. The Pd-carbene and Pd-I distances are 2.016 (6) and 2.5971 (10) Å, respectively.

The purpose of this study was to investigate clinical, economic, and patient-reported outcomes related to topical cyclosporin A for the treatment of dry eye. The medical records of 181 patients with dry eye were reviewed (mean age, 67.6 yr; 72% women) for up to two years (average follow-up, 1.34 yr) before and after treatment with cyclosporin A 0.05% ophthalmic solution administered topically twice daily. Corneal staining, average discomfort scores, and patient satisfaction markedly improved, whereas the number of prescriptions for ancillary medications and dry eye-related visits to the ophthalmologist declined significantly during the treatment period. In a naturalistic clinical setting, topical cyclosporin A therapy improved the signs and symptoms of dry eye disease, resulting in high patient satisfaction, fewer patients with chronic dry eye visiting the ophthalmologist, and less ancillary drug use.