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The titled carbon monoxide releasing molecule is capable of release CO upon illumination at 468 nm and demonstrates selective cytotoxicity towards human acute monocytic leukaemia in the dark without causing any harmful effect to the normal mice bone marrow stromal cells. [Display omitted] The reaction between bromo pentacarbonyl manganese(I) and two equivalents of 1-(chloromethyl)-1H-benzotriazole (BTZ-CH 2 Cl) afforded visible-light induced carbon monoxide releasing molecule of the general formula, fac -[MnBr(CO) 3 (BTZ-CH 2 Cl) 2 ]. The solvatochromism, dark-stability and photolysis profile of the titled complex was examined in organic solvents with various hydrogen-bonding propensities, coordinating capabilities, and solvent polarities as well as in the presence of proteins. The number of CO equivalents released from the titled complex upon the exposure to a 468 nm LED light was determined using myoglobin assay. The titled complex displayed selective cytotoxicity towards human acute monocytic leukaemia in the dark without causing any harmful effect to the normal mice bone marrow stromal cells. [ABSTRACT FROM AUTHOR]

Introduction of tetrazolate moiety in the coordination sphere of Pd(II) complex, functionalized with tridentate benzimidazole ligand, via the catalyst [3+2] cycloaddition reaction, gave rise to potential antibacterial properties. [Display omitted] Two [PdN 3 L]PF 6 complexes (L = 2,6-bis(1-ethyl-benzimidazol-2́-yl)pyridine (LBZ) and 4-(2-pyridyl)-2,2′:6′,2′'-terpyridine (LPY)) underwent catalyst-free 1,3-dipolar cycloaddition coupling with phenyl isothiocyanate at the room temperature giving the corresponding tetrazole–thiolato complexes. 1H NMR studies showed that the N1-isomer appeared first in the catalyst-free coupling, then gradually isomerized to the more stable tetrazole–thiolato isomer. The interconversion of N1-isomer into the S-isomer is accompanied by a decrease of the greater steric demand of the 5-membered ring. Tetrazolate complex of LBZ displayed higher antifungal activity (MIC ≤ 0.25 μg/mL) than the chloride analogue (MIC = 0.5–1.0 μg/mL) and the reference drug, Fluconazole (MIC = 0.125–8.0 μg/mL) against Candida albicans and Cryptococcus neoformans. The treated non-cancerous human embryonic kidney cells (HEK293) showed no cytotoxicity and no haemolysis release at the measured concentrations of the chloride complex of LBZ and tetrazolate complex of LPY. [ABSTRACT FROM AUTHOR]

The photophysical properties and lysozyme affinities of [ReX(CO) 3 (L– k2N1,N2)] (L = 4′-(4-phenyl morpholine)-2,2′:6′,2′'-terpyridine, X = Br– (1), N 3 – (2), and triazolate (3)) complexes were investigated. • The kinetically formed triazolate N(1) type favored the isomerization to N(2) form. • Negative solvatochromism was observed in the case of triazolate compound. • The promising antimicrobial activity of the ligand was diminished upon complex formation. • Probability of exchange of the bromo ligand with the coordinating solvents. [ReX(CO) 3 (L– k2N1,N2)] (L = 4′-(4-phenyl morpholine)-2,2′:6′,2′'-terpyridine, X = Br– (1), N 3 – (2), and triazolate (3)) complexes were synthesized, and characterized using different spectroscopic and analytical tools including single-crystal X-ray diffraction analysis of 2. The 1,3-dipolar cycloaddition reaction between 2 , and 4,4,4-trifluoro-2-butynoic acid ethyl ester afforded triazolate 3. Although, the crystal structure of 2 showed that the azide ligand is terminally coordinated to Re(CO) 3 + unit, the 19F and 1H NMR analyses of 3 provided conversant evidences that the kinetically formed N(1) triazolate bound isomer favoured the isomerization to N(2) form. The photophysical properties of 1–3 were investigated by recording the absorption spectra of the compounds in solvents of different polarities. Complexes 1 and 3 were screened for their potential antimicrobial activities. The protein binding affinity of 1 , and 3 towards hen white egg lysozyme revealed that the bromide complex exchanges Br– with that protein, while the triazolate analogue sticked around. [ABSTRACT FROM AUTHOR]

• Toxicity of morpholine ligand to normal cell line was diminished by metal carbonyl formation and inorganic click reaction. • Extension of iClick reaction to two metal centers complexes. • Photoactivation at 525 nm. • The investigated ligands and complexes exhibited lower haemolysis values. • Solubility of tricarbonyl Mn(I) compexes increased by inorganic click reaction. The photoinduced fac -[MnBr(CO) 3 (L– k2N1,N2)] (L = 4′-(2-pyridyl)-2,2′:6′,2′'-terpyridine (LPy) (1) and 4′-(4-phenyl morpholine)-2,2′:6′,2′'-terpyridine (Lmorph) (2)) and fac -[Mn 2 Br 2 (CO) 6 (LDTP– k2N1,N2)] (LDTP = 1,4-bis(2,2′:6′,2′'-terpyridin-4′yl)benzene) (3) complexes, capable of release CO at 525 nm, were synthesized and fully characterized using different analytical and spectral tools. Compounds 1 – 3 had poor solubility or decomposed in most of the organic solvents, and thus they are unsuitable for the phototherapeutic CO applications. Reaction between azide complexes (4 – 6), prepared by exchange of the axial Br− ligand of 1 – 3 , with ethyl 4,4,4-trifluoro-2-butynoate afforded triazolate complexes (7 – 9), which had good solubility in the organic solvents. The potential of 7 – 9 to act as photoinduced CO releasing molecules was studied at two excitation wavelengths, 468 and 525 nm. The ligand Lmorph and its complex (8) were strongly potent to Escherichia coli , Candida Albicans and Cryptococcus neoformans. All the ligands and complexes (except 8) exhibited cytotoxicity to the normal human cell line; human embryonic kidney cells (HEK293), but they had good compatibility with the human red blood cells (RBCs) at 32 μg/mL. [ABSTRACT FROM AUTHOR]

To recognize the metalation site for lysozyme, the interactions between HEWL and imidazole (a model of histidine) were investigated. The coordination of thiourea based Ru(II) cymene complexes proceeds via the detachment of the heterocyclic coordination arm. Half-sandwich (η6- p -cymene) complexes bearing either neutral functionalized N,S -bidentate thiourea ligands or a mono-negative N,N -aminoquinoline ligand were screened for their antibacterial and antifungal activities as well as cell viability against non-malignant HEK293 (human embryonic kidney cells). The haemolysis parameters (HC 10 and HC 50) were determined to get some information about the compatibility of the toxic compounds with the blood components. The protein binding affinity of hen white egg lysozyme (HEWL), a model protein, towards the synthesized (η6- p -cymene) complexes was investigated by ESI-MS. Metalation of HEWL was achieved through both covalent and non-covalent modes of interaction. To recognize if the metalation site of HEWL is the His15 side chain, the reactions between the complexes and imidazole were theoretically and experimentally studied by quantum chemical calculations, UV–Vis and NMR. Exchange of the nitrogen coordination site of the thiourea ligand from the pyridine to the benzothiazole moiety induced higher potency against Staphylococcus aureus , Candida albicans and Cryptococcus neoformans var. grubii. [ABSTRACT FROM AUTHOR]

We synthesized two biocompatible photoactivatable fac -[MnBr(CO) 3 (N∧O)] complexes with desirable properties such as water solubility and stability in anaerobic aqueous media, a low-power visible light requirement for CO release (468 nm), and a long half-life time of the CO release kinetics. [Display omitted] Two water-soluble fac -Mn(CO) 3 based complexes of the general formula fac -[MnBr(CO) 3 (N∧O)] (N∧O = pyridine-2-carboxaldehyde (A), and 2-acetylpyridine (B)) were described for their potential CO releasing properties upon illumination at 468 nm, solvatochromism features and cytotoxicity against different malignant cell lines in both the dark and upon the exposure to light source. Negative solvatochromism may be responsible for the red shift of the metal-to-ligand charge transfer band in increasingly less polar solvents. Compound B , which had been functionalized with 2-acetylpyridine, released CO in water faster than complex A , suggesting the role of the methyl group in regulating the CO release kinetics. According to myoglobin assay, the CO release pathway in water is slower than in DMSO revealing to the role of the solvent in controlling the CO release kinetics of Mn(I) carbon monoxide releasing molecules. [ABSTRACT FROM AUTHOR]