Stable homogeneous silver(I) catalysts for the highly efficient cycloaddition of azides onto terminal alkynes in
Meysam Kakavand1, Anna Kozakiewicz-Piekarz2, Abdollah Neshat1
1Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), 444 Prof. Sobouti Blvd., Gava Zang, Zanjan 45137-66731, Iran. a.neshat@iasbs.ac.ir.
Abstract:
To develop stable and efficient silver(I) catalysts and evaluate the role of sulfur and phosphorus donor ligands in the catalytic cycloaddition of selected organic azides and alkynes (AAC), a series of mononuclear Ag(I) and heteronuclear Ag(I)-Fe(II) complexes were synthesized. The synthesis utilized phosphine and sulfur donors from the dialkyldithiophosphate and borate families, specifically Na[S2H2B(mt)2]. These complexes are designated as [(dppf)AgSP(S)(OiPr)2] (1), [S2H2B(mt)2Ag(μ-dppf)AgS2H2B(mt)2] (2), [(dppf)Ag(μ-dppf)Ag(dppf)] (3), and [(dppe)AgS2H2B(mt)2] (5). The complexes 1-5 were characterized using a combination of 1H, 13C{1H}, and 31P{1H} NMR spectroscopy, as well as IR spectroscopy techniques. In two instances, single-crystal X-ray diffraction analysis was also employed. Complex 3 exhibited high catalytic activity and regioselectivity in the cycloaddition reaction conducted in water at 40 °C.
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