**6. Antibacterial activity**

It is known that killing of bacteria by chelated ligand is more powerful than non-chelated ligand, therefore chelated ligand acts as potent bactericidal agents. It was observed that due to delocalization of the *π* electrons over whole ligand and partial sharing of its positive charge with donor groups reduce the polarity of a metal ion in a complex. Thus, chelation increases the lipophilic character in complexes and results in an enhancement of activity [30, 31]. The antibacterial results, **Table 7**, showed that the complexes shows moderate activity against the bacteria *E. coli* and *S. aureus*.

#### **7. Antifungal activity**

**Table 7** showed that metal complexes exhibited significant antifungal activity than chalcones at the same concentration against the fungi *P. notatum*. The order of inhibition with respect to metal complexes was VL2 > VL4 > VL1 > VL3.

It was concluded from above data that electron withdrawing substituents like nitro, cyno at para position in ring A decreases the antibacterial and antifungal activity. Electron donating group like hydroxyl, methoxy at para position increases the activity. Presence of halogen group at meta position in ring A shows good activity than the unsubstituted ring. The increased activity of the chelates can be explained based on the overtone concept and the Tweedy chelation theory [32]. According to the overtone concept of cell permeability, the lipid membrane that surrounds the cell favors the passage of only lipid-soluble material.

#### **8. Conclusion**

Based on the results the following conclusion maybe drawn. The higher decomposition temperature and electrical conductance studies show the presence of strong metal-ligand bonding and non-electrolytic nature of the complexes, respectively. Room temperature magnetic studies are indicative of paramagnetic nature

**79**

**Author details**

Vikas Vilas Borge\* and Raju M. Patil

provided the original work is properly cited.

Department of Chemistry, The Institute of Science, Mumbai, India

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: vikasborge@gmail.com

*Stability of Vanadium Chalcone Complexes DOI: http://dx.doi.org/10.5772/intechopen.88072*

and square pyramidal geometry of the VO(II) complexes which is supported by the electronic spectra. The IR spectra shows bonding of the metal through O-donor atoms of the ligands. In this study VO(II) complexes shows the moderate activity against *Escherichia coli*, *Staph aureus* bacteria and against *P. notatum* fungi.

*Stability of Vanadium Chalcone Complexes DOI: http://dx.doi.org/10.5772/intechopen.88072*

*Stability and Applications of Coordination Compounds*

**6. Antibacterial activity**

**Table 7.**

*complexes.*

*E. coli* and *S. aureus*.

**7. Antifungal activity**

It is known that killing of bacteria by chelated ligand is more powerful than non-chelated ligand, therefore chelated ligand acts as potent bactericidal agents. It was observed that due to delocalization of the *π* electrons over whole ligand and partial sharing of its positive charge with donor groups reduce the polarity of a metal ion in a complex. Thus, chelation increases the lipophilic character in complexes and results in an enhancement of activity [30, 31]. The antibacterial results, **Table 7**, showed that the complexes shows moderate activity against the bacteria

*Antibacterial and antifungal activities (inhibition zone of bacterial growth, mm) of the ligand and metal* 

**Antibacterial activity Antifungal activity**

**1.0 mg ml<sup>−</sup><sup>1</sup> 1.0 mg ml<sup>−</sup><sup>1</sup> 250 μg disc<sup>−</sup><sup>1</sup>**

*Compound E. coli S. aureus P. notatum*

L1 6 5 8 VL1 9 8 9 L2 8 9 11 VL2 11 13 13 L3 5 4 6 VL3 7 6 7 L4 7 8 10 VL4 9 11 12 Neomycin 26 27 —

**Table 7** showed that metal complexes exhibited significant antifungal activity than chalcones at the same concentration against the fungi *P. notatum*. The order of

It was concluded from above data that electron withdrawing substituents like nitro, cyno at para position in ring A decreases the antibacterial and antifungal activity. Electron donating group like hydroxyl, methoxy at para position increases the activity. Presence of halogen group at meta position in ring A shows good activity than the unsubstituted ring. The increased activity of the chelates can be explained based on the overtone concept and the Tweedy chelation theory [32]. According to the overtone concept of cell permeability, the lipid membrane that

Based on the results the following conclusion maybe drawn. The higher decom-

position temperature and electrical conductance studies show the presence of strong metal-ligand bonding and non-electrolytic nature of the complexes, respectively. Room temperature magnetic studies are indicative of paramagnetic nature

inhibition with respect to metal complexes was VL2 > VL4 > VL1 > VL3.

surrounds the cell favors the passage of only lipid-soluble material.

**78**

**8. Conclusion**

and square pyramidal geometry of the VO(II) complexes which is supported by the electronic spectra. The IR spectra shows bonding of the metal through O-donor atoms of the ligands. In this study VO(II) complexes shows the moderate activity against *Escherichia coli*, *Staph aureus* bacteria and against *P. notatum* fungi.
