A family of 2,9-di(3-R-1H-imidazolium-1-yl)-1,10-phenanthroline iodides and hexafluorophosphates (R = allyl, benzyl, mesityl, picolyl) were synthesized from 2,9-diiodophenanthroline and imidazole or N-substituted imidazoles. Simple reactions of these diimidazolium salts with copper powder at room temperature have afforded a series of multinuclear copper(I)-NHC complexes in good yields. The structures vary depending on the N substituents and counterions. [Cu4(L1)2(MeCN)4](PF6)4 (R = allyl) exhibits a zigzag Cu4 chain with two terminal [Cu(NHC)(MeCN)2] and two internal [Cu(phen)(NHC)] moieties. [Cu3(L2)2](PF6)3 (R = benzyl) contains a strictly linear Cu3 framework with two [Cu(NHC)2] units and a [Cu(phen)2] located at the center. Both complexes [Cu3(L4)2](PF6)3 (R = mesityl) and [Cu3(L5)2](PF6)3 (R = picolyl) consist of a triangular Cu3 core in which two copper(I) ions are surrounded by a phen and a NHC group and the third copper(I) is coordinated by two NHC groups. [Cu3(L3)2](PF6)3 derived from 2,9-di(3-benzyl-1H-benzimidazolium-1-yl)-1,10-phenanthroline hexafluorophosphate can undergo transannulation of the benzimidazolylidene ring giving [Cu2(L3')2](PF6)2. The decomposition process might involve solvent-induced rearrangement of the ligand and hydrolysis of carbene moieties. Treatment of 2,9-di(3-mesityl-1H-benzimidazolium-1-yl)-1,10-phenanthroline iodide with copper powder generated dinuclear complex [Cu2(L4)2][Cu2(μ-I)2I2] (R = mesityl) possessing a macrocyclic cation and [Cu2(μ-I)2I2](2-) anion. Tetranuclear complex [Cu4(L5)2(μ-I)2](CuI3) (R = picolyl) has been obtained from its diimidazolium iodide and copper powder. All Cu(I) complexes have been characterized by X-ray single diffraction analysis, elemental analysis, and NMR spectra. Their redox behavior and fluorescent properties have also been studied.
An efficientcatalytic approach to the synthesis of N,N-dialkyl-2-alkynylanilinesw as developed by using Pd-catalyzed norbornene-mediated three-component reactions of haloarenes, alkoxyamines (RO-NR 2 ), and alkynes. Thep rocedure forms one C À Nb onda nd one C À Cb onde fficiently in ao ne-pot manner from readily available starting materials.Anumber of 2-alkynylanilinesw ith ab road range of functional groups were afforded in good to excellent yields.
Rhodium-catalyzed transannulation of 1,2,3-triazoles and ring-opening reactions of epoxides is described. A number of 3,4-dihydro-2H-1,4-oxazines are obtained in moderate yields probably involving generation of α-imino rhodium(II) carbene species.
HL·(PF6) (L = 2,4-dimethyl-8-phenyl[1,2,4]triazolo[4,3-a][1,8]naphthyridin-9-ylidene) was synthesized from the
nucleophilic reaction of 7-chloro-2,4-dimethyl-1,8-naphthyridine with
phenylhydrazine and subsequent acidification, anion exchange, and
condensation with triethyl orthoformate. Its silver, copper, cobalt,
and nickel complexes [Ag2(L)2(CH3CN)2](PF6)2 (1), [CuL(CH3CN)2](PF6) (2), [CuL(phen)](PF6) (3), [CuL(dppe)](PF6) (4), [Co(L)2(CH3CN)2](PF6)2 (5), and [Ni(L)3](PF6)2 (6) have been synthesized and fully characterized
by NMR, elemental analysis, and X-ray diffraction analysis. The copper
complex 2 exhibits excellent catalytic activity in the
Cu(I)-catalyzed azide–alkyne cycloaddition reaction of 2,2,6,6-tetramethylpiperidinyl-1-oxy-tethered
alkynes in an air atmosphere at 50 °C.
A palladium-catalyzed, norbornene-mediated acylation/cyanation reaction of iodobenzene was developed by the use of acyl chlorides as acylation reagents and cuprous cyanide. The reaction gave the 2-cyanoaryl ketones efficiently by using readily available starting materials.
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