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Carbon monoxide, the "silent killer" gas, is increasingly recognised as an important signalling molecule in human physiology, which has beneficial biological properties. A particular way of achieving controlled CO administration is based on the use of biocompatible molecules that only release CO when triggered by internal or external factors. These approaches include the development of pharmacologically effective prodrugs known as CO releasing molecules (CORMs), which can supply biological systems with CO in well-regulated doses. An overview of transition metal-based CORMs with cytotoxic properties is here reported. The mechanisms at the basis of the biological activities of these molecules and their potential therapeutical applications with respect to their stability and CO releasing properties have been discussed. The activation of metal-based CORMs is determined by the type of metal and by the nature and features of the auxiliary ligands, which affect the metal core electronic density and therefore the prodrug resistance towards oxidation and CO release ability. A major role in regulating the cytotoxic properties of these CORMs is played by CO and/or CO-depleted species. However, several mysteries concerning the cytotoxicity of CORMs remain as intriguing questions for scientists. [ABSTRACT FROM AUTHOR]

The lysozyme binding affinity and the electronic properties of [ReX(CO)3(terpy-κ2N1,N2)] (X = Br− and triazolateCOOCH2CH3,CF3) were reported. The triazolate complex was prepared in a [3 + 2] cycloaddition click reaction. The bromo compound reacted with lysozyme affording adducts with Re(CO)3+ fragments, while the triazolate compound persisted. A red shift of the MLCT band of the triazolate compound in progressively less polar solvents may be due to the negative solvatochromism. [ABSTRACT FROM AUTHOR]

Mono‐ and binuclear benzimidazole based half‐sandwich organoruthenium(II) compounds; [Run(triazolateCOOCH3,COOCH3)n(η6‐p‐Cym)nL]0/+/2+ (n = 1, L = LCH2CH3 (7) and HLSO3H (8); n = 2, L = LDTP (9)) were synthesized by [3+2] free catalyzed cycloaddition reaction of azide complexes 4–6 with electron‐poor alkyne dimethyl acetylene dicarboxylate. In comparison with the parent [RunCln(η6‐p‐Cym)nL]0/+/2 complexes (1–3), the lysozyme binding affinity of the corresponding triazolate compounds 7–9 was investigated by electrospray ionization mass spectrometry. Complexes bearing benzimidazole ligand with an alkylated sulfonate side chain (2 and 8) are able to bind lysozyme noncovalently, which have not been clearly seen by other investigated Ru(II) complexes. The complexes were assessed for their potential antimicrobial activity against some representative microbes. Complex 9 exhibits antifungal activity against C. albicans (MIC = 24 nm) and C. neoformans (MIC = 12 nm), perfect blood compatibility as well as no toxicity to non‐malignant cell line (human embryonic kidney cells (HEK293). [ABSTRACT FROM AUTHOR]

The photoinduced CO-releasing properties of [RuLPy(CO)2Cl2] (1), [Ru(LPy2Bz-ĸ²N¹,N²)(CO)2Cl2] (2), and [Ru(LPy2Bz-Et-ĸ³N¹,N²,N³)(CO)2(Cl)]·PF6 (3) [LPy = 2-(2-pyridyl)-benzimidazole, LPy2Bz = 2,6-bis(benzimidazole-2'-yl)pyridine, and LPy2Bz-Et = 2,6-bis(1-ethyl-benzimidazol-2'-yl)pyridine] in both DMSO and reduced myoglobin solution are reported. Complexes 1 and 2 release CO upon illumination at 365 nm. The bidentate chelation mode of LPy2Bz in 2 is changed into a meridional tridentate mode upon the ethylation of the benzimidazolic NH groups, 3. The extension of the conjugation system and the shift of the MLCT band into the visible region in 3 give rise to the RuII dicarbonyl complex capable of releasing CO at 468 nm. During illumination of 2, the chelation mode of LPy2Bz is changed from ĸ²N¹,N² to ĸ³N¹,N²,N³, as monitored by solution NMR spectroscopic studies. The spectral properties were studied by TD-DFT calculations. The interaction of 1-3 with hen-egg-white lysozyme, as a biocompatible carrier, has been studied by ESI-MS and UV/Vis spectroscopy in the dark and upon illumination. Stable protein adducts containing the RuII(CO)2 moiety, capable of photoinduced release of CO, are formed. [ABSTRACT FROM AUTHOR]

The reaction of bromazepam (7-bromo-1,3-dihydro-5-(2-pyridyl)-2 H-1,4-benzodiazepin-2-one, BZM) with Cr(III) ( 1), Fe(III) ( 2) and Ru(III) ( 3) salts gives complexes of the type [M(BZM)3]⋅3X (X = Cl or NO3). Structural characterization was extensively carried out using various analytical and spectral tools such as infrared, 1H NMR and UV-visible spectroscopies and magnetic, conductance, elemental and thermal analyses. BZM is a bidentate ligand and interacts with the metal ions via the pyridine and benzodiazepin-2-one nitrogen atoms. The magnetic and electronic properties of 2 and 3 are consistent with low-spin octahedral complexes. The three BZM molecules are non-isoenergetically coordinated to the metal ions and this is reflected in the values of the second-order interaction energy. The antibacterial activity was studied using Staphylococcus aureus and Escherichia coli. Coordination of BZM to Cr(III) or Ru(III) ions leads to a marked increase in toxicity with respect to the inactive Fe(III) complex 2. [ABSTRACT FROM AUTHOR]

New poly vinyl chloride (PVC) membrane, carbon paste (CP), and screen printed (SP) electrodes are constructed for iodide sensing. They are based on copper (II)-sulphamethazine Schiff base complex as suitable carrier. Mechanism was proved by FT-IR and UV-Vis spectroscopy. Computational study involving binding energies calculations at DFT/B3LYP level of theory confirmed the proposed mechanism and agreed the observed selectivity pattern. Responses are near-Nernstian (−55.0, −51.0 mV/concentration decade) for PVC, and SP electrodes, and super-Nernstian (−61.2 mV/concentration decade) for the CP electrode. Lower limit of detection (3.2×10−6 mol L−1) and improved selectivity over the highly interfering thiocyanate were obtained in comparison with the previously reported Schiff base complexes-based iodide sensors. [ABSTRACT FROM AUTHOR]