Unconventional cooperative lone pair–π, anion–π and π+–π+ interactions appear in the studied complexes. The energies associated with these assemblies have been computed using density functional theory (DFT) calculations and rationalized by molecular electrostatic potential surface analysis. The protonated adenine ring presents an extended π‐acidic surface adequate for the interaction with electron–rich atoms (O/Cl) or moieties (phenyl ring). However, in another complex, establishes unexpected π+–π+ interactions with an adjacent diprotonated adenine ring promoted by the [Cd3(μ–L)2(μ–Cl)4Cl6]4− anions.
Synthesis, X-ray Characterization and Density Functional Theory Studies of N6-benzyl-N6-methyladenine-M(II) Complexes (M=Zn, Cd): The Prominent Role of π-π, C-H···π and Anion-π Interactions
Roser Pons, Cristina Ibánez, Ana B. Buades, Antonio Franconetti, Àngel García-Raso, Juan J. Fiol, Angel Terrón, Elies Molins, Antonio Frontera
Applied Organometallic Chemistry 33, e4906, 2019
Figure: (a) Molecular Electrostatic Potential (MEP) surface (0.002 a.u.) of the zwiterionic complex [Zn(HL)Cl3]·H2O being L= N6-benzyl-N6-methyladenine. MEP values at selected points of the surface are indicated. (b) Lp–π and anion–π assembly. (c) Lp–π complex where only water is considered.