The ethylene adducts of copper(I) tris(pyrazolyl)borates, [HB(3,5-(CF 3 ) 2 Pz) 3 ]Cu(C 2 H 4 ), ),5-(C 6 H 5 )Pz) 3 ]Cu(C 2 H 4 ), and [HB(3-(CF 3 )Pz) 3 ]Cu(C 2 H 4 ), have been prepared by reacting the corresponding sodium derivative with CF 3 SO 3 Cu in the presence of ethylene. They were characterized both in the solid state and in solution using 1 H, 13 C, and 19 F NMR and IR spectroscopy and by X-ray crystallography. Solid samples of these nonionic copper complexes featuring fluorinated tris(pyrazolyl)borate ligands display notably high stability toward air oxidation and ethylene loss. The 1 H NMR chemical shifts of the copper(I)-bonded ethylene protons appear in the 4.8-5.2 ppm region. The 13 C signal of copper-coordinated ethylene shows an upfield shift of about 35 ppm, whereas the 1 J C-H shows a minor change (an increase of about 2-5 Hz) compared to the values for free ethylene. X-ray structural data show the presence of pseudo-tetrahedral copper ions and η 2 -bonded ethylene units and relatively unperturbed ethylene C-C distances. The copper adducts [HB(3,5-(CF 3 ) 2 Pz) 3 ]Cu-(C 2 H 4 ) and [HB(3-(CF 3 ),5-(C 6 H 5 )Pz) 3 ]Cu(C 2 H 4 ) are competent aziridination catalysts, readily converting a variety of olefins into the corresponding N-tosyl aziridines with N-tosyl phenyliodinane.

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2003 Halogenated carboxylic acids and esters Halogenated carboxylic acids and esters P 0260 Activation of Alkyl Halides via a Silver-Catalyzed Carbene Insertion Process. -A new silver complex catalyzes the formation of aliphatic carbon-halogen bond activation products under mild conditions. The presence of β-hydrogen atoms on the alkyl halide leads to net hydrogen halide addition to the carbene with concomitant formation of an alkene. -(DIAS*, H. V. R.; BROWNING, R. G.; POLACH, S. A.; DIYABALANAGE, H. V. K.; LOVELY*, C. J.; J. Am. Chem. Soc. 125 (2003) 31, 9270-9271; Dep. Chem. Biochem., Univ. Tex., Arlington, TX 76019, USA; Eng.) -S. Adam 45-064

Diazoalkane compounds are excellent starting materials for the preparation of a variety of organic compounds. 1,2 Transition metal ions play an important role as catalysts in most of these reactions. [2][3][4][5] For example, a large number of copper and rhodium reagents, including those featuring poly(pyrazolyl)borate ligands, [6][7][8] are used widely for cyclopropanation and cyclopropenation reactions involving diazo compounds. 2 Silver(I) compounds are among the best catalysts for effecting the Wolff rearrangement of diazoketones to ketenes. 2,9 Diazoalkane reagents are also useful for the synthesis of metal carbene complexes. 3 Metal adducts containing diazoalkane ligands have also attracted significant interest. 1,3,5,[10][11][12][13] They are considered as models for key intermediates in reactions involving diazoalkanes and metal ions. 2,3,5,14,15 In this paper, we describe the use of a highly fluorinated tris(pyrazolyl)borate ligand [HB(3,5-(CF 3 ) 2 Pz) 3 ] -(where Pz ) pyrazolyl) 16 to isolate one such species involving silver(I) and dimethyl diazomalonate. 2,9 The treatment of [HB(3,5-(CF 3 ) 2 Pz) 3 ]Ag(THF) 17,18 with N 2 C(CO 2 -CH 3 ) 2 19 in hexane resulted in the formation of [HB(3, ) 2 -Pz) 3 ]Ag[OC(OCH 3 )] 2 CN 2 (1) as a colorless, air-stable solid in 89% yield. 20 It is thermally stable up to ca. 90 °C. NMR spectroscopic data are consistent with the formation of a 1:1 adduct. The IR spectrum of [HB(3,5-(CF 3 ) 2 Pz) 3 ]Ag[OC(OCH 3 )] 2 -CN 2 exhibited a strong absorption band at 2162 cm -1 , corresponding to the N-N stretching mode of the coordinated N 2 C(CO 2 CH 3 ) 2 . Interestingly, this ν NN value is higher than that reported for the free ligand (2137 cm -1 ). 21 The ν CdO band of the silver adduct appears at a value (1736 cm -1 ) lower than the ν CdO of the free ligand (1764 cm -1 ). A manganese(I) adduct containing