Disclosing the Antifungal Mechanisms of the Cyclam Salt H[H(PhCH)Cyclam]Cl against and .

Mycoses are one of the major causes of morbidity/mortality among immunocompromised individuals. Considering the importance of these infections, the World Health Organization (WHO) defined a priority list of fungi for health in 2022 that include as belonging to the critical priority group and () to the medium priority group. The existence of few available antifungal drugs, their high toxicity, the acquired fungal resistance, and the appearance of new species with a broader spectrum of resistance, points out the need for searching for new antifungals, preferably with new and multiple mechanisms of action.

Use of Limestone Sludge in the Preparation of ɩ-Carrageenan/Alginate-Based Films.

The use of processed limestone sludge as a crosslinking agent for films based on Na-alginate and ɩ-carrageenan/Na-alginate blends was studied. Sorbitol was tested as a plasticizer. The produced gel formulations included alginate/sorbitol and carrageenan/alginate/sorbitol mixtures, with tested sorbitol concentrations of 0.

A Cyclam Salt as an Antifungal Agent: Interference with spp. and Mechanisms of Virulence.

The importance of fungal infections, particularly those caused by yeasts, is increasing among the medical community. and are amongst the high-priority fungal species identified by the World Health Organization (WHO) and are considered in the critical group, while is included in the medium-priority group. The cyclam salt H[H(PhCH)Cyclam]Cl proved to be active against the growth of these three yeasts, and the aim of this work was to verify its interference with their virulence mechanisms, whether shared or unique.

Reactions of Heteroallenes with Salan-based Ti(IV) Complexes: A Joint Experimental and Computational Study.

The reaction of Ti(NMe) with the salan ligand precursor HNOH led to the formation of [(L*)Ti(NHMe)] (L*=NO ) that forms [(HNO)TiCl] upon reaction with two equiv. of MeSiCl. [(L*)Ti(py)] was obtained from the reaction of [Ti(NBu)Cl(py)] with the sodium salt HNONa.

Synthesis, Characterization, and Reactivity Studies of New Cyclam-Based Y(III) Complexes.

[(BnCyclam)Y(N(SiMe))] was prepared by reaction of HBnCyclam with Y[N(SiMe)]. The protonation of the macrocycle ligand in [(BnCyclam)Y(N(SiMe))] is observed upon reaction with [HNMe][BPh] leading to the formation of [(HBnCyclam)Y(N(SiMe))][BPh]. DFT analysis of [(BnCyclam)Y(N(SiMe))] showed that the HOMO is located on the anionic nitrogen atoms of the cyclam ring indicating that protonation follows orbital control.

Synthesis and Application of New Salan Titanium Complexes in the Catalytic Reduction of Aldehydes.

Complexes of formula [(HNO)TiCl] and [(HNO)Ti(OPr)] (HNOH = HOPh'CHNH(CH)NHCHPh'OH, where Ph' = 2,4-(CMePh)CH) were synthesized by the reaction of the salan ligand precursor HNOH with TiCl and Ti(OPr), respectively, in high yields. The dichlorido complex [(HNO)TiCl] revealed to be an efficient catalyst for the reduction of benzaldehyde in toluene. Full conversion was observed after 24 h at 55 °C in THF.

Bacterial Nosocomial Infections: Multidrug Resistance as a Trigger for the Development of Novel Antimicrobials.

Nosocomial bacterial infections are associated with high morbidity and mortality, posing a huge burden to healthcare systems worldwide. The ongoing COVID-19 pandemic, with the raised hospitalization of patients and the increased use of antimicrobial agents, boosted the emergence of difficult-to-treat multidrug-resistant (MDR) bacteria in hospital settings. Therefore, current available antibiotic treatments often have limited or no efficacy against nosocomial bacterial infections, and novel therapeutic approaches need to be considered.

Investigations into the Structure/Antibacterial Activity Relationships of Cyclam and Cyclen Derivatives.

A series of cyclam- and cyclen-derived salts are described in the present work; they were designed specifically to gain insights into their structure and antibacterial activity towards and , used respectively, as Gram-positive and Gram-negative model organisms. The newly synthesized compounds are monosubstituted and -disubstituted tetraazamacrocycles that display benzyl, methylbenzyl, trifluoromethylbenzyl, or trifluoroethylbenzyl substituents appended on the nitrogen atoms of the macrocyclic ring. The results obtained show that the chemical nature, polarity, and substitution patterns of the benzyl groups, as well as the number of pendant arms, are critical parameters for the antibacterial activity of the cyclam-based salts.

Co Cryptates Convert CO into CO and CH under Visible Light.

Three Co octaazacryptates, with different substituents on the aromatic rings (Br, NO , CCH), were synthesised and characterised. These and the already published non-substituted cryptate catalysed CO photoreduction to CO and CH under blue visible light at room temperature. Although CO was observed after short irradiation times and a large range of catalyst concentrations, CH was only observed after longer irradiation periods, such as 30 h, but with a small catalyst concentration (25 nm).

Cooperative Metal-Ligand Hydroamination Catalysis Supported by C-H Activation in Cyclam Zr(IV) Complexes.

Complexes of the type (RCyclam)ZrCl (where R = CH═C(H)CH (All), CH═C(Me)CH (All), and PhCH (Bn)) react with suitable Grignard reagents to produce the corresponding alkyl derivatives (RCyclam)ZrR' (R' = Me, CHPh). Thermally induced double metalation of the pending arms of the cyclam ligand led to the formation of complexes ((CH═C(H)CH)Cyclam)Zr, 14, ((CH═C(Me)CH)Cyclam)Zr, 15, or ((CHCH)Cyclam)Zr, 16. These reactions proceed through C(sp)-H bond activation and R'H elimination and convert the original dianionic tetracoordinated cyclam-based ligands in tetraanionic hexacoordinated ligands that establish two new Zr-C bonds.

Stable, Yet Highly Reactive Nonclassical Iron(II) Polyhydride Pincer Complexes: Z-Selective Dimerization and Hydroboration of Terminal Alkynes.

The synthesis, characterization, and catalytic activity of nonclassical iron(II) polyhydride complexes containing tridentate PNP pincer-type ligands is described. These compounds of the general formula [Fe(PNP)(H)(η-H)] exhibit remarkable reactivity toward terminal alkynes. They efficiently promote the catalytic dimerization of aryl acetylenes giving the corresponding conjugated 1,3-enynes in excellent yields with low catalyst loadings.

Synthesis, antimicrobial activity and toxicity to nematodes of cyclam derivatives.

The antimicrobial activity and toxicity to nematodes of the cyclam salt [H{H(PhCH)Cyclam}](CHCOO)⋅(CHCOOH) were evaluated. Estimated minimum inhibitory concentrations (MICs) of 9, 261 and 15 µg/mL were obtained for Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, respectively. For selected Candida spp.

Reactions of heteroallenes with cyclam-based Zr(IV) complexes.

This work describes reactions of heteroallenes with diamido-diamine cyclam-based Zr(iv) complexes of the general formula (Bn2Cyclam)ZrX2 (X = O(t)Bu, , O(i)Pr, , SPh, , NH(t)Bu, ) as well as the di-orthometallated species ((C6H4CH2)2Cyclam)Zr, . The reactions of isocyanates or isothiocyanates with , or resulted in the formation of N-bonded ureate or thioureate cyclam complexes upon [2 + 2] cycloaddition of the Zr-Namido bonds of the cyclam to the heteroallene (). DFT calculations showed that κ(2)-N,N'-ureate bonding is favoured over κ(2)-N,O-ureates, which in turn may be formed in reactions with bulky isocyanates as 1-naphthyl isocyanate (NpN[double bond, length as m-dash]C[double bond, length as m-dash]O).

Synthesis and structural characterization of novel cyclam-based zirconium complexes and their use in the controlled ROP of rac-lactide: access to cyclam-functionalized polylactide materials.

Novel Bn(2)Cyclam-based zirconium complexes of the type (Bn(2)Cyclam)Zr(X)(X') (3, X = X' = OPh; 4, X = X' = SPh; 5, X = Cl, X' = O(i)Pr) were synthesized in good yields via metathesis routes involving the reaction of the dichloro precursor (Bn(2)Cyclam)Zr(Cl)(2) and the appropriate lithium salts. The molecular structures of compounds 3, 4 and 5, as determined by X-ray crystallographic studies, all confirmed the effective chelation of the Bn(2)Cyclam ligand in a κ(4)-N(2)N(2)' fashion, with the hexa-coordinated Zr center adopting a trigonal prismatic geometry. Complexes 3-5 as well as the diisopropoxide derivative (Bn(2)Cyclam)Zr(O(i)Pr)(2) (2) were all found to initiate the ring-opening polymerization (ROP) of rac-lactide in a controlled manner, as deduced from SEC data and linear correlations between molecular weight numbers (M(n)) and monomer conversion as the ROP proceeds.

Cyclam functionalization through isocyanate insertion in Zr-N bonds.

The insertion of isocyanates in (Bn(2)Cyclam)ZrX(2) is regioselective; (Bn(2)Cyclam)Zr(OR)(2) produces urea-like moieties by the insertion of RN═C═O in the Zr-N(amido) bonds of the cyclam ring. Depending on the bulkiness of the isocyanate R groups, O- and N-bound ureates are formed. (Bn(2)Cyclam)Zr(NH(t)Bu)(2) reacts with MesN═C═O at the terminal Zr-N bonds.