Crystal structure, supramolecular self-assembly and interaction with DNA of a mixed ligand manganese(II) complex

Abstract

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...

Linear Optical Absorption, Emission Properties and Ultrafast Carrier Dynamics of Aqua‐chloro‐bis(1,10‐phenanthroline)manganese(II) 4‐formylbenzoate Trihydrate

“…As is well known, emission spectra of complexes originate from their central metal ions and ligands. However, both the emission peaks, which are obtained here, are similar to the emission peak of the Mn (II) complex that has been studied previously [38] . The emission peaks of this study are result of medium‐strong π*→π, weak π*→n and σ*→n electronic transitions owing to C−O, C−H, O−H, Mn−N bonds, benzene rings and carboxyl groups.…”

“…The figure is showing that the complex is an ultraviolet spectral region absorber below 300 nm wavelength. In addition, Figure 8 fully reflects the linear absorption spectra of the Mn (II)‐phenanthroline complex, [38] and similar to that of the oxalic acid which is a member of the carboxylic acid family [39] . The medium‐strong π→π * , weak n→π * and n→σ * transitions contribute to the UV spectral absorption region because of C⋅⋅⋅O, C⋅⋅⋅H, O⋅⋅⋅H, Mn⋅⋅⋅N bonds, benzene rings and carboxyl groups.…”

“…However, both the emission peaks, which are obtained here, are similar to the emission peak of the Mn (II) complex that has been studied previously. [38] The emission peaks of this study are result of medium-strong π*!π, weak π*!n and σ*!n electronic transitions owing to CÀ O, CÀ H, OÀ H, MnÀ N bonds, benzene rings and carboxyl groups. The fluorescence property of the Mn(II) complexes had been carried out for the investigating of the DNA binding.…”

“…The emission peaks of this study are result of medium‐strong π*→π, weak π*→n and σ*→n electronic transitions owing to C−O, C−H, O−H, Mn−N bonds, benzene rings and carboxyl groups. The fluorescence property of the Mn(II) complexes had been carried out for the investigating of the DNA binding [38,41] . The complexes with fluorescence properties can be used in application area such as: detection of the nitroaromatic explosives, biosensor in immunology, optical and chemical sensors, DNA analysis by fluorescence quenching detection, security printing, data recording and storage image acquisition without lens and filter, and laser applications [38,41–45] …”

“…[38,41] The complexes with fluorescence properties can be used in application area such as: detection of the nitroaromatic explosives, biosensor in immunology, optical and chemical sensors, DNA analysis by fluorescence quenching detection, security printing, data recording and storage image acquisition without lens and filter, and laser applications. [38,[41][42][43][44][45] In order to investigate charge carrier dynamics and excited state lifetime of the complex the transient pump-probe experiments were carried out. Ultrafast transient absorption spectra of the complex with photo excitation at 365 nm wavelength in DMSO is given in Figure 10.…”