Four N,O-bidentate chelating ligands [L 1 = N-(4thiazolylmethyl)morpholine-N-oxide, L 2 = N-(2-pyridylmethyl)pyrrolidine-N-oxide, L 3 = N-(4-thiazolylmethyl)pyrrolidine-Noxide, and L 4 = N-(2-pyridylmethyl)morpholine-N-oxide] were designed and synthesized. The treatment of N,O-bidentate ligands with CuCl 2 in ethanol at room temperature afforded four new copper complexes-[Cu(L 1 ) 2 ]Cl 2 ([Cu(L 4 ) 2 (CH 3 OH) 2 ][CuCl 4 ] 2 (IV)-which were fully characterized by single-crystal X-ray diffraction, IR spectroscopy and elemental analyses. Most interestingly,t he single-crystal Xray diffraction analyses revealed that the N,O-bidentate ligands L 1 -L 4 can tune the corresponding geometry configu-ration of coppera toms in complexes I-IV.T he copper atoms in I and II showed four-coordinated distorted squarep lanar geometry,w hereas the central coppera tom in III adopted a distorted square pyramidal geometry.I ts hould be noted that complex IV was constructed by ad istorteds quare planar CuN 2 O 2 unit, one octahedral CuN 2 O 4 unit and two [CuCl 4 ] 2À anions. Importantly,t hese copper(II) complexes, especially complex IV,s howedh igh catalytic activity in Chan-Lam coupling reactions of primary or secondary amines with arylboronic acid under mild conditions. Substrates with many functionalg roups were tolerated and the C-N coupling products were afforded in good to excellent yields (up to 96 %y ield).[a] Dr.

An effective and practical protocol for the CuIcatalyzed Ullmann-type N-arylation of azoles/amines with aryl halides is reported. The key strategy is the employment of CH 2 linker N,O-bidentate ligands, especially N-(4-thiazolylmethyl)morpholine N-oxide, as superior supporting ligands. The highly efficient CÀ N coupling reactions between various azoles/amines and aryl halides bearing different functional groups can be achieved under CuI/N-(4-thiazolylmethyl) morpholine N-oxide catalytic system, affording a variety of Narylated products. The use of cheap copper(I) salt and readily available N,O-bidentate ligands make this procedure more attractive for synthesis of valuable functionalized nitrogencontaining heterocyclic compounds.[a] Dr. under vacuum. Purification of the crude products was performed by flash column chromatography on silica gel (ethyl acetate/ petroleum ether = 1/12) to afford the desired product 7.

Four novel N,O-bidentate ligand-tunable copper complexes were developed as a catalyst for Chan–Lam coupling reactions of arylboronic acids with 1H-imidazole derivatives under base-free conditions.

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