Cyclometalated complexes derived from calix[4]arene bisphosphites and their catalytic applications in cross-coupling reactions

摘要: Abstract Palladium and platinum dichloride complexes of a series symmetrically unsymmetrically substituted 25,26;27,28-dibridged p-tert-butyl-calix[4]arene bisphosphites in which two proximal phenolic oxygen atoms p-tert-butyl- or p-H-calix[4]arene are connected to P(OR) (R = substituted phenyl) moiety have been synthesized. The palladium calix[4]arene bearing sterically bulky aryl substituents undergo cyclometalation by C–C C–H bond scission. An example cycloplatinated complex is also reported. characterized by NMR spectroscopic single crystal X-ray diffraction studies. During crystallization the palladium dichloride bisphosphite dichloromethane, insertion occurs into Pd–P give P,O-coordinated complex. framework these their metal adopt distorted cone conformation; conformation more flattened than free bisphosphites. Some cyclometalated proved be active catalysts for Heck Suzuki cross-coupling reactions but, on an average, yields only modest.