@article {46765, title = {Evaluation of biomolecular interactions and cytotoxic activity of organometallic binuclear Ru(II) complexes of ferrocenyl thiosemicarbazones}, journal = {Journal of Biomolecular Structure \& Dynamics}, year = {2020}, month = {JUL}, type = {Article; Early Access}, abstract = {

{Four new ferrocenyl substituted thiosemicarbazone ligands (L1-L4) and their corresponding binuclear ruthenium(II) arene complexes of the general type [(eta(6)-pcym)(L)Ru(mu-im)Ru(L)(eta(6)-p-cym)]Cl (C1-C4) and [(eta(6)-pcym)(L)Ru(mu-azpy)Ru(L)(eta(6)-p-cym)]Cl-2(C5-C8) (cym = cymene

}, keywords = {binuclear ruthenium(II) complexes, BSA binding interactions, DNA, Ferrocenyl thiosemicarbazone, HeLa human cervical carcinoma}, issn = {0739-1102}, doi = {10.1080/07391102.2020.1798284}, author = {Khanvilkar, Priyanka and Dash, Soumya R. and Vohra, Alisagar and Devkar, Ranjitsinh and Chakraborty, Debjani} } @article {47355, title = {Imidazole/4,4 {\textquoteleft}-azopyridine bridging binuclear Ru(II) complexes: design, synthesis, bimolecular interactions and cytotoxicity against HeLa cell line}, journal = {Journal of the Iranian Chemical Society}, volume = {18}, year = {2021}, month = {DEC}, type = {Article}, abstract = {

Binuclear Ru(II)-arene complexes [(eta(6)-pcym)(Flq)Ru(mu-im/mu-azpy)Ru(Flq)(eta(6)-p-cym)]Cl (C1-C8) (cym = cymene; Flq = fluoroquinolones; im = imidazole; azpy = 4,4 {\textquoteleft} azo pyridine) have been synthesized and characterized by elemental analysis, molar conductivity and various spectral techniques (ESI-MS, IR, UV-Vis and H-1-NMR). The geometry of the complexes was optimized by DFT calculations, which revealed a pseudo-octahedral coordination around each metal centre. Binding of the synthesized complexes with CT-DNA and BSA was studied spectroscopically, and it has been established that the presence of two hydrophobic planar arene moieties enhances the binding efficacies of the binuclear complexes to the macromolecules, compared to their mononuclear analogues. The results of competitive binding between C1-C8 and ethidium bromide (EB) towards DNA have shown that the complexes are able to displace EB from DNA-EB adduct and interact with DNA via intercalation. The complexes display cytotoxicity against the HeLa human cervical cancer cell lines with IC50 values in the range of 30.1-120.9 mu M.

}, keywords = {Binuclear ruthenium (II) complexes, BSA binding interactions, DFT calculations, DNA, Fluoroquinolones (FQs), HeLa human cervical carcinoma}, issn = {1735-207X}, doi = {10.1007/s13738-021-02271-3, Early Access Date = MAY 2021}, author = {Khanvilkar, Priyanka and Dash, Soumya R. and Pulipaka, Ramadevi and Shirsath, Kavita and Devkar, Ranjitsinh and Chakraborty, Debjani} } @article {47648, title = {Organoruthenium (II) complexes featuring pyrazole-linked thiosemicarbazone ligands: synthesis, DNA/BSA interactions, molecular docking, and cytotoxicity studies}, journal = {Applied Organometallic Chemistry}, volume = {35}, year = {2021}, month = {OCT}, pages = {e6343}, type = {Article}, abstract = {A series of pyrazol-derived thiosemicarbazone ligands (L1-L4) were synthesized and reacted with [Ru(p-cymene)(mu-Cl)Cl](2) to yield a series of {\textquoteleft}{\textquoteleft}piano-stool{\textquoteright}{\textquoteright}-type binuclear ruthenium (II)-arene-thiosemicarbazone complexes (C1-C8) of the general type [(Ru(eta(6)-p-cym)L)(2)(mu-im/azpy)] Cl1-2 (L = diphenylpyrazole thiosemicarbazone; cym = p-cymene; im = imidazole; azpy = 4,4 {\textquoteleft}-azopyridine). The thiosemicarbazone ligands act as N and S donors binding to the Ru(II) center via the imine nitrogen and the thione sulfur atoms. The complexes were characterized by NMR, FTIR, UV-Vis spectroscopy, and ESI+ mass spectrometry. The binding of the complexes to calf thymus deoxyribonucleic acid (CT-DNA) and bovine serum albumin (BSA) was evaluated, and it has been established that the binuclear complexes have good binding efficacies with DNA (K-b = 10(4)-10(5) M-1) and BSA (K-a = 10(5)-10(6) M-1). This is attributed to the arene moieties present in the ligands of the complexes that can have hydrophobic interactions with DNA/BSA. Ethidium bromide (EB) displacement studies and DNA viscosity measurements revealed intercalative interaction of the complexes with DNA. Static interaction of the complexes with BSA was revealed by fluorescence quenching studies. Molecular docking studies confirmed base stacking, H-bonding, and hydrophobic interactions with the biomolecules. In vitro antiproliferative studies of the complexes affirmed that the complexes are cytotoxic towards the HeLa (human cervical cancer) cell line with IC50 values in range of 17.3-41.3 mu M.}, keywords = {Binuclear ruthenium (II) complexes, BSA binding interactions, DNA, HeLa human cervical carcinoma, pyrazole-derived thiosemicarbazone}, issn = {0268-2605}, doi = {10.1002/aoc.6343}, author = {Khanvilkar, Priyanka and Dash, Soumya R. and Banerjee, Devjani and Vohra, Aliasgar and Devkar, Ranjitsinh and Chakraborty, Debjani} } @article {48133, title = {Reactivity of four coordinate iridium complex towards hydrogen: an experimental and computational study}, journal = {Journal of Organometallic Chemistry}, volume = {965}, year = {2022}, month = {MAY}, pages = {122317}, type = {Article}, abstract = {

Reaction of a four coordinate, 16-electron Ir complex, [Ir-(iPr)4(POCOP)(PPh3)] (4 ) (((iPr)4)(POCOP= 2,6-bis(di-isopropyl phosphinito)benzene, kappa(3)-C6H3-1,3-[OP((iPr))(2)](2)), with H-2 resulted in an oxidative addition product, cis-dihydride complex, cis-[Ir(H)(2) ((iPr)4)(POCOP)(PPh3)] ( cis-5 ) presumably via the intermediacy of a sigma complex, [Ir(eta(2)-H-2)((iPr)4)(POCOP)(PPh3)]. The cis-dihydride complex completely isomerizes to the trans-dihydride complex trans-[Ir(H)(2) ((iPr)4)(POCOP)(PPh3)] ( trans-5 ) under ambient conditions in about 3 h. It was found that the steric and electronic features on the iridium center have significant influence on the approach of H-2 onto the metal center followed by oxidative addition and isomerization. The isomerization process was studied in detail and all the mechanistic aspects have been elucidated using a combination of both experimental work and computation. The cis-dihydride complex isomerizes to the trans-dihydride by compensating the trans influence of the strongly trans-directing hydride ligand. A mechanism involving the exchange of the position of PPh3 with a hydride ligand cis to itself via PPh3 dissociation and re-coordination thereby resulting in the formation of the trans-dihydride complex, has been proposed for the isomerization. The cis-dihydride was found to be a highly active catalyst for hydrogenation of ethy-lene. A competing reactivity study of cis-dihydride between isomerization versus insertion of C2H4 into the Ir-H bond, was studied experimentally and computationally. (c) 2022 Elsevier B.V. All rights reserved.

}, keywords = {Hydrogenation, Insertion, iridium complex, isomerization, Oxidative addition, Reductive elimination}, issn = {0022-328X}, doi = {10.1016/j.jorganchem.2022.122317}, author = {Agrawal, Nisha K. and Dash, Soumya R. and Vanka, Kumar and Nethaji, Munirathinam and Jagirdar, Balaji R.} } @article {48301, title = {Dual routes toward observation of a trans-H2/hydride complex in an iridium pincer system and hydrogenation catalytic activity}, journal = {Organometallics}, volume = {42}, year = {2023}, month = {MAR}, pages = {441-456}, type = {Article}, abstract = {

The Abstraction of chloride from a six- coordinate complex, trans-[ Ir(H)(Cl)((iPr)4)(POCOP)(PPh3)] (1) [((iPr)4)(POCOP) = 2,6-bis(di-iso-propylphosphinito)benzene,kappa(3)-C6H3-1,3-[OP(Pr-i)(2 )](2)], using NaBAr4f leads to the generation of a dinitrogen complex, trans-[Ir(H)(N-2)((iPr)4)(POCOP)(PPh3)][BAr4f] (6). Addition of H-2 to [Ir(H)(N-2)((iPr)4)(POCOP)(PPh3)](+) (6) under extremely mild conditions (1 bar, 298 K) resulted in the reversible coordination of H-2 to generate the cis-[Ir(H)(eta H-2-(2))((iPr)4)(POCOP)(PPh3)](+) (cis-11) complex. The cis-[Ir(H)(eta(2)-H-2)((iPr)4)(POCOP)(PPh3)](+) complex (cis-11) isomerized to a trans isomer, trans-[Ir(H)(eta(2)-H-2)((iPr)4)(POCOP)(PPh3)](+) (trans-11), at 253 K. The isomerization process has been studied and supported by computations. Employing an alternative route, protonation of the trans-[Ir(H)(2)((iPr)4)(POCOP)(PPh3)] complex (2) at 183 K resulted in the formation of an identical, trans-[Ir(H)(eta(2)-H-2)((iPr)4)(POCOP)(PPh3)](+) complex (trans-11); upon warming the sample, the trans-H-2/hydride complex isomerized to the cis isomer above 253 K. Two independent routes to obtain trans-[Ir(H)(eta(2)-H-2)((iPr)4)(POCOP)(PPh3)](+) (trans-11) species have been established. Reaction of trans-[Ir(H)(N-2)((iPr)4)(POCOP)(PPh3)][BAr4f] (6) with C2H4 gave the cis-[Ir(H)(eta(2)-C2H4)((iPr)4)(POCOP)(PPh3)](+) complex (cis-15), which also undergoes isomerization to yield an equilibrium mixture of cis/trans-[Ir(H)(eta(2)-C2H4)((iPr)4)(POCOP)(PPh3)](+) complexes (cis-15 and trans-15) at 253 K. The trans-[Ir(H)(N-2)((iPr)4)(POCOP)(PPh3)](+) complex (6) is an excellent catalyst for hydrogenation of ethylene to ethane under very mild conditions.

}, issn = {0276-7333}, doi = {10.1021/acs.organomet.2c00641}, author = {Agrawal, Nisha K. and Dash, Soumya R. and Vanka, Kumar and Jagirdar, Balaji R.} } @article {48791, title = {H-atom site exchange in an iridium trans-dihydrogen/hydride complex, trans-[Ir(H)(?2-H2)(iPr)4(POCOP)(DMAP)]+}, journal = {Dalton Transactions}, volume = {52}, year = {2023}, month = {OCT }, pages = {13858-13863}, type = {Article}, abstract = {

Treatment of trans-[Ir(H)(N)(2)((iPr)4)(POCOP)(DMAP)][BAr4f] (2) with H-2 (1 bar) under ambient conditions (298 K) results in the formation of a trans-[Ir(H)(?(2)-H-2)((iPr)4)(POCOP)(DMAP)][BAr4f] (3) complex. Complex 3 exhibits H-atom site exchange between the bound H-2 and the hydride ligands which are mutually trans to one another. A plausible mechanism of this exchange involves metal-ligand cooperativity as studied by computations.

}, issn = {1477-9226}, doi = {10.1039/d3dt02366d}, author = {Agrawal, Nisha K. and Gayathridevi, S. and Dash, Soumya R. and Vanka, Kumar and Jagirdar, Balaji R.} }