Um complexo misto de manganês(II), [Mn(sal)(phen) 2 ]ClO 4 (1) (sal = salicilaldeído, phen = 1,10-fenantrolina), foi sintetizado e caracterizado por análise elementar e difração de raio-X de monocristais. A análise dos difratogramas revelou que o complexo 1 cristaliza no grupo espacial monoclínico P2 1 /n. A unidade assimétrica do complexo é composta do cátion complexo [Mn(sal)(phen) 2 ] + e do ânion perclorato não coordenado. O manganês(II) está num ambiente de coordenação MnN 4 O 2 de geometria octaédrica bem distorcida. Quatro tipos de empilhamento p-p envolvendo ligantes fenantrolina e salicilaldeído estão envolvidos na auto-montagem supramolecular. Estas interações de empilhamento aromático cooperam com ligações de hidrogênio para a montagem de uma fascinante arquitetura supramolecular 3D com o complexo. Estudos de espectroscopia de absorção eletrônica e de titulação monitorando-se a fluorescência de 1 com DNA de timo de bezerro sugerem a ligação do complexo por intercalação com uma constante de formação igual a 7,97×10 3 L mol −1 e uma constante de supressão de Stern-Volmer de 1,34×10 4 L mol −1 .A mixed ligand manganese(II) complex, [Mn(sal)(phen) 2 ]ClO 4 (1) (sal = salicylaldehyde, phen = 1,10-phenanthroline), has been synthesized and characterized by elemental analysis and single crystal X-ray diffractometry. The structural analysis revealed that complex 1 crystallizes in the monoclinic space group P2 1 /n. The asymmetric unit of the complex is comprised of [Mn(sal)(phen) 2 ] + complex cation and uncoordinated perchlorate anion. The manganese(II) is located in a seriously distorted octahedral MnN 4 O 2 coordination environment. Four types of p-p stacking modes involving phenanthroline and salicylaldehyde ligands are involved in the supramolecular self-assembly. These aromatic stacking interactions cooperate with hydrogen bonding to assemble the complex into a fascinating 3D supramolecular architecture. Electronic absorption spectroscopy and fluorescence titration studies of the interaction between complex 1 and calf thymus DNA suggest an intercalative binding mode with a constant of 7.97×10 3 L mol −1 and a Stern-Volmer quenching constant of 1.34×10 4 L mol −1 .Keywords: manganese(II) complex, crystal structure, supramolecular self-assembly, DNA interaction, spectrum
IntroductionMuch attention has been given to rational design, synthesis and characterization of new transition metal complexes in the past decades because some of them can interact with DNA acting as probes for nucleic acid structure manipulation or exhibiting nuclease property. [1][2][3][4][5] Metal complex can bind to DNA in non-covalent way such as by electrostatic interaction, minor or major groove-bound fashion and intercalation. 6,7 Considerable efforts are yet necessary to develop novel metal complexes binding to DNA through an intercalative association because of their unique properties and applications. [8][9][10][11][12][13] A metallointercalator binds DNA through the insertion of a planar polycyclic aromatic 23 also present int...