Luminescent PhotoCORMs: Enabling/Disabling CO Delivery upon Blue Light Irradiation.

The new luminescent carbonyl compounds [Mn(Oxa-H)(CO)3Br] (1) and [Mn(Oxa-NMe2)(CO)3Br] (2) were synthesized and fully characterized. Complexes 1 and 2 showed CO release under blue light (λ453). Spectroscopic techniques and TD-DFT and SOC-TD-DFT calculations indicated that 1 and 2 release the Oxa-H and Oxa-NMe2 coligands in addition to the carbonyl ligands, increasing the luminescence during photoinduction.

New AlIIIZnII and AlIIICuII dinuclear complexes: Phosphatase-like activity and cytotoxicity.

Herein, we report the synthesis and characterization of the first two AlIII(µ-OH)MII (M = Zn (1) and Cu (2)) complexes with the unsymmetrical ligand H2L{2-[[(2-hydroxybenzyl)(2-pyridylmethyl)]aminomethyl]-6-bis(pyridylmethyl)aminomethyl}-4-methylphenol. The complexes were characterized through elemental analysis, X-ray crystallography, IR spectroscopy, mass spectrometry and potentiometric titration. In addition, complex 2 was characterized by electronic spectroscopy. Kinetics studies on the hydrolysis of the model substrate bis(2,4-dinitrophenyl)phosphate by 1 and 2 show Michaelis-Menten behavior, with 1 being slightly more active (8.31%) than 2 (at pH 7.0). The antimicrobial effect of the compounds was studied using four bacterial strains (Staphylococcus aureus, Pseudomonas aeuruginosa, Shigella sonnei and Shigella dysenteriae) and for both complexes the inhibition of bacterial growth was superior to that caused by sulfapyridine, but inferior to that of tetracycline. The dark cytotoxicity and photocytotoxicity (under UV-A light) of the complexes in a chronic myelogenous leukemia cell line were investigated. Complexes 1 and 2 exhibited significant cytotoxic activity against K562 cells, which undergoes a 2-fold increase on applying 5 min of irradiation with UV-A light. Complex 2 was more effective and a good correlation between cytotoxicity and intracellular concentration was observed, the intracellular copper concentration required to inhibit 50% of cell growth being 3.5 × 10-15 mol cell-1.

Di-µ-chlorido-bis-[chlorido(1,4,6-trimethyl-6-nitro-1,4-diazepine)copper(II)].

The title neutral copper complex, [Cu(2)Cl(4)(C(8)H(17)N(3)O(2))(2)], shows a binuclear center with a Cu-(µ-Cl)(2)-Cu core, in which each copper ion is coordinated by the N,N,O donor atoms of the tridentate ligand 1,4,6-trimethyl-6-nitro-1,4-diazepine (meaaz-NO(2)) and three chloride exogenous ligands. Each metal ion is facially coordinated by meaaz-NO(2) through N,N,O donor atoms, whereas two bridging and one terminal chloride ions occupy the other face of the highly Jahn-Teller-distorted octa-hedron. Two N atoms from tertiary amine groups of the meaaz-NO(2) ligand and two exogenous Cl atoms with short Cu-N and Cu-Cl distances define the equatorial plane. The coordination around each Cu(II) ion is completed by another Cl atom and an O atom from the NO(2) group, in the axial positions. The binuclear complex exhibits a centrosymmetric structure with point symmetry .

Dopamine polymerization promoted by a catecholase biomimetic CuII(µ-OH)CuII complex containing a triazine-based ligand.

We describe herein the catecholase-like catalytic activity and dopamine polymerization by using a dinuclear [LCuII(µ-OH)2CuII](ClO4)2 (1) complex where L is the dinucleating triazine-based ligand 6-chloro-N2,N2,N4,N4-tetrakis(pyridin-2-ylmethyl)-1,3,5-triazine-2,4-diamine. The kinetic parameters (kcat = 0.318 s-1, KM = 1.6 × 10-3 mol L-1, and kcat/KM = 198.8 L s-1 mol-1), mechanistic insights into the oxidation of 3,5-di-tert-butyl catechol and early characterization of poly(dopamine) are presented.

Synthesis, characterization, hydrolase and catecholase activity of a dinuclear iron(III) complex: Catalytic promiscuity.

Herein, we report the synthesis and characterization of the new di-iron(III) complex [(bbpmp)(H2O)(Cl)Fe(III)(µ-Ophenoxo)Fe(III)(H2O)Cl)]Cl (1), with the symmetrical ligand 2,6-bis{[(2-hydroxybenzyl)(pyridin-2-yl)methylamino]methyl}-4-methylphenol (H3bbpmp). Complexes 2 with the unsymmetrical ligand H2bpbpmp - {2-[[(2-hydroxybenzyl)(2-pyridylmethyl)]aminomethyl]-6-bis(pyridylmethyl) aminomethyl}-4-methylphenol and 3 with the ligand L(1)=4,11-dimethyl-1,8-bis{2-[N-(di-2-pyridylmethyl)amino]ethyl}cyclam were included for comparison purposes. Complex 1 was characterized through elemental analysis, X-ray crystallography, magnetochemistry, electronic spectroscopy, electrochemistry, mass spectrometry and potentiometric titration. The magnetic data show a very weak antiferromagnetic coupling between the two iron centers of the dinuclear complex 1 (J=-0.29cm(-1)). Due to the presence of labile coordination sites in both iron centers the hydrolysis of both the diester model substrate 2,4-BDNPP and DNA was studied in detail. Complex 1 was also able to catalyze the oxidation of the substrate 3,5-di-tert-butylcatechol (3,5-DTBC) to give the corresponding quinone, and thus it can be considered as a catalytically promiscuous system.