Tin(II)–Nitrene Radical Complexes Formed by Electron Transfer from Redox-Active Ligand to Organic Azides and Their Reactivity in C(sp3)–H Activation

A tin­(II) complex coordinated by a sterically demanding o-phenylenediamido ligand is synthesized. The ligand is redox-active to reach a tin­(II) complex with the diiminobenzosemiquinone radial anion in the oxidation by AgPF6. The tin­(II) complex reacts with a series of nosylazides (x-NO2C6H4–SO2–N3; x = o, m, or p) at −30 °C to yield the corresponding nitrene radical bound tin­(II) complexes. The nitrene radical complexes exhibit C­(sp3)–H activation and amination reactivity.

本研究合成了一种由空间位阻较大的邻苯二胺配体配位的二价锡配合物。该配体具有氧化还原活性，经六氟磷酸银（AgPF6）氧化后，可得到含有二亚胺半醌自由基阴离子的二价锡配合物。该二价锡配合物在-30 ℃下与一系列通式为x-NO2C6H4–SO2–N3的苯磺酰叠氮（x为邻、间或对位取代）反应，得到相应的氮宾自由基配位二价锡配合物。此类氮宾自由基配合物展现出碳(sp3)-氢键活化与胺化反应活性。