π-Stacking induced complexes with Z-shape motifs featuring a complementary approach between electron-rich arene diamines and electron-deficient aromatic N-heterocycles

Abstract

Based on ligands of N,N′-bis((diphenylphosphino)methyl)benzene-1,4-diamine (L1) and N,N′-bis((diphenylphosphino)methyl)naphthalene-1,5-diamine (L2), six complexes of {[Ag(L1)0.5(phen)](BF4)·(H2O)0.5}2 (1), {[Cu(L1)0.5(phen)(CH3CN)](ClO4)·(H2O)0.5}2 (2), {[Cu(L1)0.5(4,4′-bipyridine)(CH3CN)](ClO4)·(CH3COCH3)}n (3), {[Ag(L2)0.5(phen)(NO3)]}2 (4), {[Cu(L2)(2,2′-bipyridine)](BF4)·(CH3CH2OCH2CH3)}n (5) and {[Ag(L2)0.5(4,4′-bipyridine)](CF3SO3)·(DMF)}n (6) are isolated. Single crystal X-ray diffraction analyses show that all of these complexes contain three-layer π-stacking Z-shape motifs in which an electron-rich π plane of arene diamine is sandwiched between two electron-deficient aromatic N-heterocycles. The complementarity in shape and electron between electron-rich and electron-deficient π rings directs the formation of these complexes, and the flexible organophosphine ligands adopt a trans coordination mode to meet the need of electron complementarity between π-systems. π–π Stacking interactions are discussed in detail in this report. As an extension of these studies, the intermolecular interactions are also roughly discussed.