**Acknowledgements**

**3.2. Imaging and binding of photo-triggered DNA**

[(η6-*p*-cym)Ru(bpm)(H<sup>2</sup>

14 Recent Progress in Organometallic Chemistry

interact with nucleotides [119].

**4. Conclusions**

(CO)3]<sup>+</sup>

The simple and powerful strategy for selective destruction of cancer cells is to target the metal complexes to the tumor cells by photoactivation. Peptides releases the aqua species,

cyclometalated iridium (III) polypyridine indole complexes, which have the intense luminescence (*λ*em= 540–616 nm, *τ* = 0.13–5.15 μs) [112]. Another interesting feature of these complexes is that they can deliver CO in the body [113], for example, MnI carbonyl complex [Mn(pqa)

[115]. The release of CO from these complexes is visibly monitored by time-resolved IR spectroscopy [116]. This property is also used to deliver other biologically active species also. [Rh(bpy)2(chrysi)]3+ targets single-base mismatches in DNA by noncovalent binding in UV/ visible region. As there is deficiency of mismatch repair in cancer cells, this technique can be used to detect the cancer cells [117, 118]. The other luminescent N-heterocylic carbene (NHC) cyclometalated platinum(II) complexes, which are localized in cytoplasmic structures, do not

Unfortunately, like the macro organometallic complexes, the nanoparticles also carry some serious adverse effects. Though the adverse effects of nanoparticles depend on individual factors such as genetics, existing disease conditions, exposure, nanoparticle chemistry, size, shape, agglomeration state, and electromagnetic properties, the key to understanding the toxicity of nanoparticles is their size. Thus, it is very essential to understand the basic nature, structure, and the photophysics behind these particles. Nanoparticles are smaller than mammalian cells and cellular organelles, which allows them to penetrate these biological structures and disrupt their normal function. Nanoparticles are effective in glycoma treatment. This brain cancer is particularly difficult to treat as neurosurgery is ineffective, while chemotherapy suffers from the inability of therapeutics to cross the blood. Although the lack of self-error-correcting mechanism result in defect sites in these nanostructures, the high efficiency and relative simplicity of the novel approach demonstrates the potential power of using irreversible covalent bonds to generate adverse range of shape-persistent and robust nanostructures that is likely to enrich the repertoire of self-assembled nanomaterials and multidrug delivery. Finally, toxicity of nanoparticles could also be potentially utilized to destroy the cancer cells. Bioorganometallic compounds offer hope in the fight against the deadly diseases such as Malaria, HIV/AIDS, and EVD that have continued to devastate humans. There are expected challenges in this area of collaborative research as organometallic compounds are ideally synthesized under inert atmosphere in the absence of oxygen and water. These challenges are not too difficult to surmount, we therefore implore researchers to orient more into this relatively new multidisciplinary research area in the search for novel and potent anticancer and other drug candidates

with reduced side effects, which can be a great service to the mankind.

(pqa =(2-pyridylmethyl)(2-quinolylmethyl)amine) [114] and manganese complexes

O)]2+in the visible range which bind to DNA. The other example is the

The author acknowledges the financial assistance by the DST WOS-A (CS-1005/2014). The author is also thankful to her mentor Dr. G. Narahari Sastry, Head, Center for Molecular Modeling for the support.
