Synthesis, characterization, interactions with DNA and bovine serum albumin (BSA), and antibacterial activity of cyclometalated iridium(III) complexes containing dithiocarbamate derivatives

<div><p>Three mononuclear cyclometalated iridium(III) complexes having dithiocarbamate ligands, [Ir^III(2-C₆H₄py)₂(L)] (where 2-C₆H₄py = 2-phenylpyridine; and <b>L</b>^<b>1</b><b>H</b> = 4-MePipzcdtH, <b>L</b>^<b>2</b><b>H</b> = MorphcdtH, and <b>L</b>^<b>3</b><b>H</b> = 4-BzPipercdtH for <b>1</b>, <b>2</b>, and <b>3</b>, respectively), were synthesized from [Ir(2-C₆H₄py)₂Cl]₂·1/4CH₂Cl₂ by displacing the two bridging chlorides with one dithiocarbamate ligand. The complexes were characterized using physicochemical and spectroscopic tools along with structural analysis of [Ir(2-C₆H₄py)₂(L²)] (<b>2</b>) by single crystal X-ray diffraction. Structural analysis of <b>2</b> showed a distorted octahedron in which the nitrogen donor of one 2-phenylpyridine and the carbon donor of another 2-phenylpyridine are in axial positions, <i>trans</i> to one another. Electrochemical analysis by cyclic voltammetry showed the irreversible two-electron equivalent reduction voltammograms of <b>1</b>, <b>2</b>, and <b>3</b> attributable to Ir(III) to Ir(I). Electronic characterizations of these complexes are consistent with significant delocalization of the sulfur electron density onto the empty metal d-orbital. The intercalative interaction of the complexes with calf thymus DNA was evaluated using absorption, fluorescence quenching, and viscosity measurements. The binding affinities of these complexes with bovine serum albumin were estimated in terms of quenching constants using the Stern–Volmer equation. Study of antibacterial activities of the complexes by agar disk diffusion against some species of pathogenic bacteria was also performed.</p></div

Efficient and Convenient Methods for Synthesis of Some Phthalazine Derivatives and Their Evaluation of Cytotoxicity

<div><p></p><p>A systematic study of the reaction of 1,4-dihydrazinophthalazine (DHPH) with 1,3-dicarbonyls [<i>viz.</i>, acetylacetone (acac), dibenzoylmethane (bzbz), and 1-benzoylacetone (bzac)] varying the reaction conditions was carried out to obtain the phthalazine derivatives (<b>1</b>–<b>4</b>). One-pot reaction of DHPH with acac led to the formation of two compounds <b>1</b> and <b>2</b>, with various factors such as the presence of the acid or base, amount of the acac, time of reflux, and the temperature. The reaction conditions of DHPH with bzbz or bzac are sort of different to isolate the products <b>3</b> and <b>4</b>, respectively. The derivatives (<b>1</b>–<b>4</b>) have been characterized by elemental analyses, ¹H NMR, and electrospray ionization–mass spectrometry (ESIMS) and the cytotoxic activity of the compounds <b>1</b>–<b>4</b> was evaluated on HeLa cell line.</p> <p>[Supplementary materials are available for this article. Go to the publisher's online edition of <i>Synthetic Communications</i>® for the following free supplemental resource(s): Full experimental and spectral details.]</p> </div