Chemical Implications of Incompatible Ligand versus Metal Coordination Geometry Preferences

摘要: Binding an electron deficient pincer ligand which strongly dictates planar, mer stereochemistry, to a metal prefers tetrahedral structure, e.g., d10 CuCl, is explored for possible intramolecular redox chemistry. Experiment shows that the 2,2′-bis-tetrazinyl pyridine, btzp, forms complex (btzp)CuCl chloride-bridged polymer in solid state, hence with 20 valence electrons around copper. DFT calculations show even monomer has nonplanar copper tetrazinyl nitrogen lone pairs somewhat misdirected away from copper, long Cu/N bonds, singlet ground state; 13.9 kcal/mol less stable triplet, whose electronic structure one state Cu(I) been transferred π* orbital. Outer sphere transfer yields (btzp)Cu where added gone into pincer, leave ligand-centered radical, characterized by EPR, chemical reactivity, and X-ray photoelectron spectroscopy.