Coordination complexes exhibiting anion...pi interactions: synthesis, structure, and theoretical studies.
The polydentate ligand 2,4,6-tris(dipyridin-2-ylamino)-1,3,5-triazine (dpyatriz) in combination with the Cu(ClO 4) 2/CuX 2 salt mixtures (X (-) = Cl (-), Br (-), or N 3 (-)) leads to the formation of molecular coordination aggregates with formulas [Cu 3Cl 3(dpyatriz) 2](ClO 4) 3 ( 2), [Cu 3Br 3(dpyatriz) 2](ClO 4) 3 ( 3), and [Cu 4(N 3) 4(dpyatriz) 2(DMF) 4(ClO 4) 2](ClO 4) 2 ( 4). These complexes consist of two dpyatriz ligands bridged via coordination to Cu (II) and disposed either face-to-face in an eclipsed manner ( 2 and 3) or parallel and mutually shifted in one direction. The copper ions complete their coordination positions with Cl (-) ( 2), Br (-) ( 3), or N 3 (-), ClO 4 (-), and N, N-dimethylformamide (DMF) ( 4) ligands. All complexes crystallize together with noncoordinate ClO 4 (-) groups that display anion...pi interactions with the triazine rings. These interactions have been studied by means of high level ab initio calculations and the MIPp partition scheme. These calculations have proven the ClO 4 (-)...[C 3N 3] interactions to be favorable and have revealed a synergistic effect from the combined occurrence of pi-pi stacking of triazine rings and the interaction of these moieties with perchlorate ions, as observed in the experimental systems.
Barrios
Leoní A
LA
Departament de Química Inorgànica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain.
Aromí
Guillem
G
Frontera
Antonio
A
Quiñonero
David
D
Deyà
Pere M
PM
Gamez
Patrick
P
Roubeau
Olivier
O
Shotton
Elizabeth J
EJ
Teat
Simon J
SJ
D000838:Anions / Q000737:chemistry*; D003460:Crystallization; D004583:Electrons; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D010472:Perchlorates / Q000737:chemistry*; D014227:Triazines / Q000737:chemistry*
D000838:Anions; D008024:Ligands; D010472:Perchlorates; D014227:Triazines