We report on self-assembly of guanosines with aromatic esters at their 5'-position. Depending on the basicity of the 5'-ester either discrete octamers G8·K(+)I(-) or hexadecamers G16·3K(+)3I(-) are formed. The thermodynamic and kinetic stabilities of the G-quadruplex can be controlled by interlayer hydrogen-bonding and by dispersion interactions on the assembly's periphery.

We describe at emplating/covalent capture strategy that enables photochemical formation of 8cyclobutanes in one noncovalent assembly.T his process was characterized by experiment and quantum mechanical/molecular mechanics (ONIOM) calculations.Thus,KIand 16 units of 5'-cinnamate guanosine form aG -quadruplex where C = C p bonds in neighboring G 4 -quartets are separated by 3.3 ,e nabling [2+ +2] photocycloaddition in solution. This reaction is highyielding (> 90 %), regio-and diastereoselective.S ince all components are in dynamic equilibrium this photocycloaddition is catalytic in K + .

We describe a templating/covalent capture strategy that enables photochemical formation of 8 cyclobutanes in one noncovalent assembly. This process was characterized by experiment and quantum mechanical/molecular mechanics (ONIOM) calculations. Thus, KI and 16 units of 5′‐cinnamate guanosine form a G‐quadruplex where C=C π bonds in neighboring G4‐quartets are separated by 3.3 Å, enabling [2+2] photocycloaddition in solution. This reaction is high‐yielding (>90 %), regio‐ and diastereoselective. Since all components are in dynamic equilibrium this photocycloaddition is catalytic in K+.