An iodine promoted phosphonation of benzoxazoles and benzothiazoles with trialkyl phosphites was described. This reaction undergoes three steps: an addition procedure, followed by a radical oxidation, and an elimination reaction, provides an efficient method to access 2-phosphated products with a broad scope of substrates.

The reaction of manganese(II) halide MnCl2·4H2O and tris(2-aminoethyl)amine N(CH2CH2NH2)3 in the concentrated acid HCl at 65 °C resulted in the formation of an inorganic–organic hybrid complex: [(C6H22N4)2(H3O)(MnCl6)(MnCl5)(Cl)2]·3H2O (1) and a known byproduct [(C6H22N4)Cl4]·H2O. The analogue reactions between MnBr2·4H2O and N(CH2CH2NH2)3 in HBr acid gave a pure complex [(C6H22N4)2Br5](MnBr5) (2). Crystal structures revealed that Mn centers in 1 adopted trigonal bipyramidal and octahedral two geometries, while in 2 showed only trigonal bipyramidal geometry. Luminescent investigation exhibited complex 1 gave pink luminescence and complex 2 emitted yellow light in solid states, which were both directly originated from the coordinated geometries of Mn2+ ion.Two organic–inorganic hybrids obtained by reactions of MnX2 and tris(2-aminoethyl)amine in halide acids (HX, X = Cl, Br) gave pink and yellow emission when excited by 440 nm light.Download high-res image (63KB)Download full-size image

•Two products were obtained with the same reactants but different molar ratios.•The title two organic-inorganic hybrid compounds have different crystal structure.•The fluorescent spectra of the two organic-inorganic hybrid compounds were different.Two inorganic–organic hybrid compounds [(C7H18N2)6Pb7I26] (1) and [(C7H18N2)Pb2I6] (2) have been synthesized by reactions of 2-(2-aminoethyl)-1-methylpyrrolidine and lead iodide with 1: 1 and 1: 2 M ratios in concentrated HI aqueous. The single-crystal X-ray diffraction revealed that the inorganic component in compound 1 can be viewed as a wave-like 2D sheet built up from alternatively perovskite and non-perovskite structure types connected with corner-, edge- sharing octahedral [PbI6]; and that in complex 2 is a zigzag chain constructed with edge- sharing octahedral [PbI6]. In addition, both complexes showed fluorescent properties with complex 1 emitted green light at 545 nm and complex 2 emitted blue light at 467 nm.Reactions of 2-(2-aminoethyl)-1-methylpyrrolidine with lead iodide with 1:1 and 1:2 M ratios in concentrated HI aqueous led to a 2D wave-like sheet (1) and a 1D zigzag chain (2), both showed fluorescent properties.Download high-res image (309KB)Download full-size image

An organic–inorganic hybrid molecule [(PyCH2NH3)6][Pb5I22]·3H2O (1) with a 2D inorganic layer was produced by reaction of 2-aminomethyl-pyridine with PbI2 in a concentrated HI aqueous solution. Compound 1 exhibited solid thermochromism showing a reversible color change from orange at room temperature to red at 80 °C, which was caused by the structural changes.

An organic–inorganic hybrid molecule [(PyCH2NH3)6][Pb5I22]·3H2O (1) with a 2D inorganic layer was produced by reaction of 2-aminomethyl-pyridine with PbI2 in a concentrated HI aqueous solution. Compound 1 exhibited solid thermochromism showing a reversible color change from orange at room temperature to red at 80 °C, which was caused by the structural changes.

Reactions of two free N-heterocyclic carbenes (NHCs) 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) and 1,3-dimesitylimidazol-2-yliden (IMes) with group VB transition metals MCl5 at low temperature gave a mono-NHC complex [(IPr)TaCl5] (1) and two bis-NHCs [(IMes)2MCl4][MCl6] (M = Ta, 2; =Nb, 3). Crystallographic studies revealed that the substitution effect plays an important role in the construction of these two different types of NHC complexes. Although mono-NHC complex 1 has been theoretically analyzed by F. Marchetti, complexes 2 and 3 represented the first examples of the structurally characterized bis-NHCs Ta(V) and Nb(V) complexes. In addition, complexes 1–3 showed catalytic efficiency in the cycloaddition between CO2 and propylene oxide to synthesize cyclic carbonates under mild conditions.

A simple and practical protodecarboxylation of o-nitrobenzoic acids as well as heteroaromatic carboxylic acids with various substituents via using CuI/Et3N has been established. This transformation provides a viable and low-cost approach to generating previously unavailable substituted arenes from readily accessible aryl carboxylic acids as the starting materials.

•Two tantalum complexes [(IMes:CO2)TaCl5] and [(IPr:CO2)2TaCl3][TaCl6]2 with high oxidation were obtained.•The crystal structures of the obtained tantalum complexes were discussed.•The catalytic properties of two complexes on the cycloaddition between CO2 and propylene oxide were investigated.Carboxylation of two free N-heterocyclic carbenes (NHCs) 1,3-dimesitylimidazol-2-yliden (IMes) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr) with CO2 led to two adducts [IMes:CO2] and [IPr:CO2], which were further reacted with TaCl5 to afford the finial metal complexes [(IMes:CO2)TaCl5] (1) and [(IPr:CO2)2TaCl3][TaCl6]2 (2), respectively. NMR spectroscopy, elemental analysis and single crystal X-ray diffraction proved that the carboxylate groups were retained in complexes 1 and 2. Crystallography revealed that the metal centers in complexes 1 and 2 adopted the distorted octahedral and pentagonal bipyramidal geometries, respectively, in which complex 1 was constructed with one [IMes:CO2] adducts, while complex 2 with two [IPr:CO2] adducts. In addition, the catalytic properties of complexes 1–2 on the cycloaddition between CO2 and propylene oxide to synthesize cyclic carbonate at the mild condition were investigated.Two imidazolylidene carboxylates [IMes:CO2] and [IPr:CO2], which were obtained by combination of CO2 with N-heterocyclic carbenes, were reacted with VB group metal TaCl5 to give a monomeric complex [(IMes:CO2)TaCl5] (1) and a dimeric complex [(IPr:CO2)2TaCl3][TaCl6]2 (2) with high oxidation of metal.

A streamlined Pd-catalyzed direct oxidative arylation of the pentafluorobenzene C–H bond with readily available (diacetoxyiodo)arenes has been described. Under the optimized conditions, three (diacetoxyiodo)arene derivatives were found to undergo coupling with pentafluorobenzene to furnish the substituted (pentafluorophenyl)benzenes in moderate to good yields.

Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (−I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.

A copper-mediated tandem reaction of β-ketoesters/ketones with tertiary amines was achieved, which provides a simple and efficient approach to the synthesis of 2,3-dihydrofuran derivatives. In this tandem reaction, the tertiary amine not only offers the methylene moiety but also serves as the base.

A novel waste-free Cu-catalyzed decarboxylative homocoupling of ortho-nitrobenzoic acids has been developed, and diverse substituents on the phenyl core of ortho-nitrobenzoic acid are compatible with the transformation. This method provides a practical alternative to synthesize valuable 2,2′-dinitrosubstituted biaryls from cheap and readily available ortho-nitrobenzoic acids.

•Discussing effects of reaction conditions on Cu(II)-catalyzed oxidation of phenols.•Revealing free phenoxy radicals is relatively inert to O2.•Dissociating ArO–Cu(II)–OO to phenoxy radical is difficult to phenol oxidation.•Tuning Cu(II)–trihistidinyl redox potential to promote phenol oxygenation by CuAOs.Cu(II)-mediated autoxidations of 4-tert-butylphenol under various conditions was studied, the data confirmed imidazole is the best ligand to promote phenol oxygenation. The same reaction of 2,4-di-tert-butylphenol proceeded much more quickly to lead nearly exclusively to oxidative coupling rather than oxygenation under high pressure O2. These results suggested that Cu(II)-catalyzed phenol autoxidation by activating O2 and phenol in terms of a phenoxy radical (ArO)–Cu(II)–superoxide ternary complex, whereas selectivity between oxygenation and coupling depends mainly on the electronic structure of ArO. It is appeared that CuAOs could achieve stoichiometric tyrosine monooxygenation by modulating the redox potential of Cu(II) and stabilizing the ternary complex through protein conformational adjustment.Cu(II)-catalyzed autoxidation of alkyl substituted phenols has been studied to gain insight into the mechanism of tyrosine phenol oxygenation step in TPQ biogenesis of CAOs. The results suggest that the difficulty of Cu(II)-catalyzed phenol oxygenation is not the inability of Cu(II) to activate phenol and O2, but is the high tendency of the ternary complex ArO–Cu(II)–OO to dissociate into free phenoxy radicals. The conclusion is further supported by the great ease of Cu(II)-catalyzed oxygenation of hydroquinone, catechols and resorcinols.

A Pd-catalyzed direct arylation of electron-deficient polyfluoroarenes with readily available aryliodine(III) diacetates was developed with moderate to good yields. The process exhibited good functional tolerance with respect to methyl, methoxy, bromo, chloro, trifluoromethyl, cyano, and aldehyde groups. Mechanistic studies revealed this coupling involved in situ generation of aryl iodide from heating-promoted decomposition of aryliodine(III) diacetate, followed by coupling with polyfluoroarenes substrates to afford the desired products.

A novel route was developed for the C3-formation of indoles using iodine as the catalyst. This transformation involves the cleavage of the C–N bond of tertiary amines by the Cross-Dehydrogenative Coupling reaction (CDC), and is well tolerated by a range of 1H-indoles under aerobic conditions. Moreover, this method can be applied to gram-scale synthesis.

A new 3D pillared framework has been obtained through self-assembly of 4,4′-biphenyldicarboxylic acid (4,4′-H2BPDC) and Pb(NO3)2 under solvothermal reaction and characterized by TGA, IR spectroscopy, element analyses, and X-ray single crystal diffraction. The X-ray structure analysis reveals that the oxygen atoms of the carboxylate groups link the Pb(II) to form metal-carboxylate layers, and 4,4′-BPDC ligands act as pillars to connect adjacent layers into a novel 3D pillared framework, where the BPDC displayed a rare μ6 coordination mode of each BPDC linking with six Pb(II) ions. Furthermore, the highly thermally stable compound 1 exhibits blue photoluminescence at room temperature in the solid state.A novel metal-organic polymer 1, [Pb(BPDC)] possesses parallel 2D infinite Pb-carboxylate layers bridged by carboxylate oxygen atoms. The 2D layers are further linked by the rigid 4,4′-BPDC ligands into a 3D pillared framework.

A copper-mediated tandem reaction of β-ketoesters/ketones with tertiary amines was achieved, which provides a simple and efficient approach to the synthesis of 2,3-dihydrofuran derivatives. In this tandem reaction, the tertiary amine not only offers the methylene moiety but also serves as the base.