Supramolecular Architecture in an Oxovanadium(V)-Schiff Base Complex:  Synthesis, Ab initio Structure Determination from X-ray Powder Diffraction, DNA Binding and Cleavage Activity

Abstract

The synthesis, spectroscopic characterization, X-ray powder structure determination, and thermal behavior of a binuclear bis(µ-oxo)-bridged vanadium(V) complex, [(VO 2 L) 2 ], L ) N,N′-dimethylenediamine(o-hydroxyl acetophenon), along with its DNA binding ability and photoinduced DNA cleavage activity, have been described. The compound crystallizes in a monoclinic system with a ) 7.679(3) Å, b ) 12.020(5) Å, c ) 13.882(6) Å, β ) 90.799(4)°, space group P2 1 /c, and Z ) 2. The crystal structure has been solved from laboratory X-ray powder diffraction data using the direct space approach and refined by the Rietveld method. The dimeric complex consists of two edge-sharing vanadium octahedra with each metal center coordinated to one oxo-, one phenolate-, and two bridging-oxygen ligands, and two nitrogen donor atoms. The molecular structure reveals a two-dimensional grid of R 4 4 (24) rings in the (011) plane, which on combination with one-dimensional polymeric chains along the [100] direction, forms a novel three-dimensional supramolecular framework. Thermogravimetric analysis of the complex indicates multiple overlapping decomposition steps in the temperature range 180-800 °C with the end product being V 2 O 5 . The complex binds to double-stranded DNA giving a K app value of 1.56 × 10 7 M -1 and displays DNA cleavage activity on UV (300 nm) irradiation via a mechanistic pathway involving formation of singlet oxygen as the reactive species.

Crystal structure of (N,N′-bis(2-(((2,6-diisopropylphenyl)imino)methyl)phenyl)benzene-1,2-diamido-κ4 O,O′,O′′,O′′′)oxidovanadium(IV), C44H48N4OV

“…Investigations into vanadium complexes are motivated by their wide range of properties useful for various applications, including pharmaceutics, catalysts and physiology [1][2][3][4][5][6]. The title compound is a very important organic intermediate in the applications of medicines [7].…”

Synthesis, Crystal Structure, and Biological Property of a Dinuclear Oxovanadium(V) Complex Derived From 2-[(2-Ethylaminoethylimino)methyl]-6-methylphenol

“…The VÀ ÀO and V-N coordinate bond lengths in the complex are comparable to the corresponding values observed in other similar oxovanadium(V) complexes with Schiff bases. [14][15][16][17] There exist two NÀ ÀHÀ ÀO hydrogen bonds between the two [VO 2 L] units, which may contribute to the formation of dimeric structure. Crystal structure of the complex is stabilized by hydrogen bonds, as shown in Figure 2.…”

Di-μ-oxido-bis[(2-ethoxy-6-{[2-(2-hydroxyethylamino)ethylimino]methyl}phenolato-κ3N,N′,O1)oxidovanadium(V)]

“…For background to vanadium complexes with Schiff base ligands, see: Kwiatkowski et al (2006); Mondal et al (2007); Rayati et al (2007Rayati et al ( , 2008; Mikuriya & Matsunami (2005).…”

“…Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1998); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL. Kwiatkowski et al, 2006;Mondal et al, 2007;Rayati et al, 2008;Rayati et al, 2007;Mikuriya & Matsunami, 2005). In this paper, the crystal structure of the title compound, (I), is reported.…”