Biomimetic Mn-catalases based on dimeric manganese complexes in mesoporous silica for potential antioxidant agent

Two new structural and functional models of the Mn-catalase with formula [{Mn(III)(bpy)(H2O)}(μ-2-MeOC6H4CO2)2(μ-O){Mn(III)(bpy)(X)}]X, where X = NO3 (1) and ClO4 (2) and bpy = 2,2'-bipyridine, were synthesized and characterized by X-ray diffraction. In both cases, a water molecule and an X ion occupy the monodentate positions. The magnetic properties of these compounds reveal a weak antiferromagnetic behavior (2J = -2.2 cm(-1) for 1 and -0.7 cm(-1) for 2, using the spin Hamiltonian H = -2J S1·S2) and negative zero-field splitting parameter DMn (-4.6 cm(-1) and -3.0 cm(-1) for 1 and 2, respectively). This fact, together with the nearly orthogonal orientation of the Jahn-Teller axes of the M…

Structural and magnetic studies of mononuclear lanthanide complexes derived from Ν-rich chiral Schiff bases.

Zn(II) complexes containing N, N,N and N,N,N pyridine (dPy) ligands tend to display improved fluorescence efficiencies in comparison with their starting ligands benefiting from the chelation enhanced effect (CHEF) and preventing photoinduced electron transfer (PET) mechanisms by the coordination of their lone pair electrons. Nevertheless, the size of Zn(II) makes steric crowding an important factor to be considered, since it can promote the elongation of the coordination bonds that weakens their strength and favors the reduction of fluorescence efficiencies through PET processes. For that reason, in this contribution we have performed a systematic study of Zn(II) compounds based on α-acetam…

Coordination compounds of methazolamide. Synthesis, spectroscopic studies and crystal structures of [M(Methazolamidato)2(py)2(OH2)2] (M  CoII, NiII and CuII)

Abstract The synthesis and X-ray crystallographic characterization of three monomeric transition-metal coordination compounds with the ligand methazolamide {[N(4-methyl-2- sulphamoyl-Δ21,3,4-thiodiazolin-5-ylidene)],acetamide} (abbreviated as Hmacm) are described, via [M(macm)2(py)2(OH2)2] [M  Co(1), Ni(2) and Cu(3)]. In all the compounds the metal ion, lying on the centre of symmetry, is surrounded by two sulphonamidato nitrogen atoms and two pyridine nitrogen atoms in equatorial sites and two oxygen water molecules in axial positions. The coordination geometry of the metal is an almost regular octahedron around the cobalt(II) and nickel(II) ions. In contrast, the copper(II) ion has a sig…

From Bowls to Capsules: Assembly of Hexanuclear Ni II Rings Tailored by Alkali Cations

An anionic hexanuclear NiII metallamacrocycle with endo and exo linking sites has been employed as a building block to generate a series of capsules and bowls of nanometric size. The supramolecular arrangement of the {Ni6 } rings was tailored by the size of the alkali cations, showing the transition from {Ni6 -M2 -Ni6 } capsules (M=LiI and NaI ) to {Ni6 -M} bowls (M=KI and CsI ). The alkyl co-cations are determinant to stabilize the assemblies by means of CH⋅⋅⋅π interactions on the exo side of the metallamacrocycles. The effect on the topology of the supramolecular assemblies of the cation size, cation charge, Et3 NH+ or Me4 N+ counter cations has been analyzed. Magnetic measurements reveal…

Luminescent Pt-II and Pt-IV Platinacycles with Anticancer Activity Against Multiplatinum-Resistant Metastatic CRC and CRPC Cell Models

Platinum-based chemotherapy persists to be the only effective therapeutic option against a wide variety of tumours. Nevertheless, the acquisition of platinum resistance is utterly common, ultimately cornering conventional platinum drugs to only palliative in many patients. Thus, encountering alternatives that are both effective and non-cross-resistant is urgent. In this work, we report the synthesis, reduction studies, and luminescent properties of a series of cyclometallated (C,N,N')PtIV compounds derived from amine- imine ligands, and their remarkable efficacy at the high nanomolar range and complete lack of cross57 resistance, as an intrinsic property of the platinacycle, against multipl…

Chiral Oxazolidine Complexes Derived from Phenolic Schiff Bases

Schiff bases derived from pyridyl- or salicyl-aldehydes and aminoalcohols can evolve to heterocyclic oxazolidines, which in the presence of cations allow the formation of uncommon coordination compounds. In this work, we report new NiII and mixed valence MnII/ MnIV complexes derived from pyridyl oxazolidines and the unprecedented characterization of enantiomerically pure oxazolidines derived from the condensation of o-vanillin with phenylglycinol in the presence of NiII cations. The different reactivity of the pyridinic or phenolic Schiff bases has been compared, and the new systems have been structurally, optically, and magnetically characterized.

Luminescent PtII and PtIV Platinacycles with Anticancer Activity Against Multiplatinum‐Resistant Metastatic CRC and CRPC Cell Models

Abstract: Platinum‐based chemotherapy persists to be the only effective therapeutic option against a wide variety of tumours. Nevertheless, the acquisition of platinum resistance is utterly common, ultimately cornering conventional platinum drugs to only palliative in many patients. Thus, encountering alternatives that are both effective and non‐cross‐resistant is urgent. In this work, we report the synthesis, reduction studies and luminescent properties of a series of cyclometallated (C,N,N’) PtIV compounds derived from amine‐imine ligands, and their remarkable efficacy at the high nanomolar range and complete lack of cross‐resistance, as an intrinsic property of the platinacycle, against …

Cover Feature: From Bowls to Capsules: Assembly of Hexanuclear Ni II Rings Tailored by Alkali Cations (Chem. Eur. J. 49/2020)

CCDC 1993846: Experimental Crystal Structure Determination

Related Article: Júlia Mayans, Daniel Gómez, Mercè Font-Bardia, Albert Escuer|2020|Cryst.Growth Des.|20|4176|doi:10.1021/acs.cgd.0c00466

CCDC 1993844: Experimental Crystal Structure Determination

Related Article: Júlia Mayans, Daniel Gómez, Mercè Font-Bardia, Albert Escuer|2020|Cryst.Growth Des.|20|4176|doi:10.1021/acs.cgd.0c00466

CCDC 1040032: Experimental Crystal Structure Determination

Related Article: Luis Escriche-Tur, Montserrat Corbella, Mercè Font-Bardia, Isabel Castro, Laurent Bonneviot, and Belén Albela|2015|Inorg.Chem.|54|10111|doi:10.1021/acs.inorgchem.5b01425

CCDC 1993843: Experimental Crystal Structure Determination

Related Article: Júlia Mayans, Daniel Gómez, Mercè Font-Bardia, Albert Escuer|2020|Cryst.Growth Des.|20|4176|doi:10.1021/acs.cgd.0c00466

CCDC 1040033: Experimental Crystal Structure Determination

Related Article: Luis Escriche-Tur, Montserrat Corbella, Mercè Font-Bardia, Isabel Castro, Laurent Bonneviot, and Belén Albela|2015|Inorg.Chem.|54|10111|doi:10.1021/acs.inorgchem.5b01425

CCDC 1993845: Experimental Crystal Structure Determination

Related Article: Júlia Mayans, Daniel Gómez, Mercè Font-Bardia, Albert Escuer|2020|Cryst.Growth Des.|20|4176|doi:10.1021/acs.cgd.0c00466

CCDC 1993842: Experimental Crystal Structure Determination

Related Article: Júlia Mayans, Daniel Gómez, Mercè Font-Bardia, Albert Escuer|2020|Cryst.Growth Des.|20|4176|doi:10.1021/acs.cgd.0c00466