Two new beta-aminoenones, NH-alkyl (2Z)-3-butylamino-4,4,4-trifluoro-1-(2-hydroxy-5-nitrophenyl)but-2-en-1-one (1) and its NH2 amino counterpart (2), were synthesized and characterized using experimental and theoretical methods. These closely related compounds differ only in their amino substitution. Spectroscopic data (IR, UV-vis and NMR spectra) reveal characteristic bands and shifts associated with push-pull electronic distribution and support the planar conformation and tautomeric stability of the enaminone core. X-ray diffraction revealed nearly planar conformations stabilized by intramolecular O-H & ctdot;O and N-H & ctdot;O hydrogen bonds forming two six-membered pseudo-rings, while compound 2 also exhibits polymeric contacts associated with its primary amine functionality. Hirshfeld surface and interaction energy analyses indicated that electrostatic and dispersive forces dominate crystal packing, with enhanced van der Waals contributions in 1 due to the butyl chain. QTAIM and NBO analyses confirmed the resonance-assisted hydrogen bonding (RAHB) character of these interactions and elucidated key charge transfer pathways. The antioxidant activity evaluated using the DPPH assay complements the structural results, suggesting that the radical scavenging potential depends on the amino substituent. These results highlight the importance of push-pull effects in modulating molecular reactivity, supramolecular architecture, and potential bioactivity.

This work investigates the tautomeric and conformational behavior of a carbohydrate-derived beta-diketone, specifically a glucosyl-substituted 1,3-dicarbonyl compound bearing a p-methoxyphenyl group, in solution and in the crystalline phase. NMR spectroscopy in CDCl3 reveals the predominance of an intramolecularly hydrogen-bonded enol tautomer, characterized by a strongly deshielded OH resonance at delta approximate to 16 ppm. Single-crystal X-ray diffraction shows that the compound crystallizes as a tautomeric solid solution composed of the enol form and its corresponding keto tautomer, with partial hydroxyl occupancy (similar to 40%), reflecting a frozen solution equilibrium. Density functional theory calculations combined with DP4+ statistical analysis support the assignment of the predominant enol tautomer in solution. These results highlight the close energetic proximity of the tautomeric forms and demonstrate the complementarity of spectroscopic, crystallographic, and theoretical approaches for elucidating the structural behavior of carbohydrate-derived beta-dicarbonyl systems.

Chromone derivatives are privileged scaffolds in organic and medicinal chemistry. Their functionalization with organosulfur groups opens opportunities to explore new structural and electronic properties. Two novel diethyldithiocarbamyl chromones were synthesized under mild conditions and characterized by IR, Raman, UV-vis, NMR spectroscopy, and single-crystal X-ray diffraction, and complemented with density functional theory (DFT) calculations. Spectroscopic analyses confirmed the characteristic vibrational modes of the chromone and dithiocarbamate moieties, in agreement with the most stable conformers. The UV-vis spectra showed intense absorptions in the 200-310 nm region, dominated by pi -> pi* and n -> pi* transitions. Notably, the LUMO+2 orbital was localized on the (sic) N-C = S-2 group in both compounds, highlighting a common electronic feature despite structural differences. Crystallographic studies demonstrated the planarity of the chromone core and resonance stabilization of the dithiocarbamate fragment. Hirshfeld surface and lattice energy analyses revealed that dispersive interactions govern crystal packing, complemented by occasional C-H & ctdot;O hydrogen bonds. This combined experimental and theoretical approach provides a clear picture of the structural and electronic behavior of these new derivatives. The findings emphasize how dithiocarbamate substitution shapes orbital contributions and electronic absorption, offering valuable insights for future applications in supramolecular design, functional materials, and medicinal chemistry.

This work deals with the synthesis and characterization of two novel N-acylhydrazones (H2L1 and H2L2) and its Cu(II) complexes [Cu(HL1)2] and [Cu(HL2)2]. The crystal structures of H2L1 and H2L2 were solved by X-ray diffraction and a detailed analysis of the intermolecular interactions that stabilize the crystal packing of both ligands has been performed by Hirshfeld analysis and their associated two-dimensional fingerprint plots. The strength and nature of the intermolecular contacts were evaluated by using different computational tools including the quantum theory of atoms in molecules (QTAIM) and noncovalent (NCI) isosurfaces. Two new Cu(II) complexes were synthesized and characterized by the conjunction of different techniques (FTIR, Elemental Analysis, HRMS, UV-vis spectroscopies and thermogravimetric analysis (TGA)). Cytotoxicity assays of both ligands and its copper(II) complexes against three human tumor cell lines: MG-63 (bone), HCT-116 (colon) and MDA-MB-231 (breast), and non-tumor cell line (L929 cells) revealed an enhancement of the effectiveness as compared with both the ligand and the free metal ion.

The crystal structure of [Co(H2O)(6)][Co(SMX)(3)](2) complex (SMX = sulfamethoxazole), hereafter CoSMXW, has been solved by X-ray diffraction methods. The complex CoSMXW was characterized by Infrared (IR), Raman, and UV-Vis spectroscopies. A comparison with the analogous Mn(II) complex, [Mn(H2O)(6)][Mn(SMX)(3)](2) (CSD refcode AJIFUW), indicates 3D isostructurality and packing similarity, as evident from X-ray diffraction and geometric descriptors such as dissimilarity index (X = 2.0 from XPac) and packing similarity (PSab = 0.3070 from CrystalCMP), respectively. This represents the first case of isostructurality observed among eleven metal complexes of sulfamethoxazole reported in the literature. A study of non-covalent interactions shows presence of structural motifs involving N-(HO)-O-& mldr; and N-(HS)-S-& mldr; (Motif I), N-(HO)-O-& mldr; (Motif II), O-(HO)-O-& mldr; and O-(HN)-N-& mldr; (Motif III) H-bonds, as well as C-H-& mldr;pi contacts (Motif IV) for [Co(H2O)(6)][Co(SMX)(3)](2) and AJIFUW. Energy analysis using CrystalExplorer indicates that the strongest dimer involves Motifs I and II with total energy of -70.3 kcal/mol for CoSMXW, which is only 2.1 kcal/mol longer than that for AJIFUW. Hirshfeld surface (HS) analysis reveals meaningless effect of metal replacement on the intermolecular contacts, confirming the energetic results. The volume of the crystal voids and the percentage of free space were calculated as 862.35 & Aring;(3) and 11.8 % for CoSMXW, and 911.42 & Aring;(3) and 12.2 % for AJIFUW. 3D topology and hierarchy of interactions were analyzed with energy framework diagrams. Further, structural motifs, HS, crystal voids and intermolecular energies for the SMX free ligand (CSD refcode SLFNMB08) were also studied. Finally, the present study was complemented with DFT calculations to evaluate the strength and nature of the non-covalent interactions by using the quantum theory of atoms in molecules (QTAIM) and NCIplots computational tools. In addition, we have used the potential energy density predictor obtained from QTAIM analysis to investigate the relative contribution of each interaction to the formation of the assemblies.

In this work, we report the synthesis and characterization of three novel ruthenium(II) p-cymene complexes coordinated with acylthiourea ligands (L1-L3), of general formula [Ru(η6-p-cymene)(PPh3)(L1-L3)Cl]PF6 (1-3). Single-crystal X-ray crystallography of the free ligands and their complexes [Ru(η6-p-cymene)(PPh3) (κ1-S)-(N-benzoyl-N´-cyclopropylthiourea)Cl]PF6 (1), Ru(η6-p-cymene)(PPh3) (κ1-S)-(N-2-furoyl-N´-cyclopropylthiourea)Cl]PF6 (2), [Ru(η6-p-cymene)(PPh3)] (κ1-S)-(N-thiophene-2-carbonyl-N´-cyclopropyl thiourea)Cl]PF6 (3) revealed that the acylthiourea ligands act as neutral monodentate donors, coordinating through the sulfur atom (κ1-S). Application of the Extended Transition State-Natural Orbitals for Chemical Valence method demonstrated that the dominant interaction in complexes 1-3 originates from the overlap between the sulfur lone pair of the ligands and a Ru d-orbital, which plays a decisive role in their stability. The Interacting Quantum Atom analysis showed that both the free and coordinated acylthiourea ligands stabilize their structure through an intramolecular N-H···O=C hydrogen bond. The cytotoxicity of complexes 1-3 was evaluated against the A549 (lung) and MDA-MB-231 (breast) human cancer cell lines. To assess their selectivity, the compounds were also tested against two non-cancerous cell models: MRC-5 (lung fibroblasts) and MCF-10 A (breast epithelial cells). The study revealed high cytotoxicity against the MDA-MB-231 cell line, with IC₅₀ values of 0.62 ± 0.05 μM (1), 0.66 ± 0.12 μM (2), and 0.53 ± 0.12 μM (3). Activity against the A549 cell line was also significant, with IC₅₀ values of 1.05 ± 0.11 μM (1), 2.60 ± 0.25 μM (2), and 1.04 ± 0.21 μM (3). The combination of phosphine and acylthiourea ligands appears critical for achieving high cytotoxic activity.

In this study, we report the synthesis, structural characterization by X-ray diffraction, vibrational (Infrared and Raman) investigation, Hirshfeld surface analysis, and DFT calculations of three new antipyrine derivatives (1,5dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) bearing amide groups (1-3). The compounds were synthesized in good yields and characterized spectroscopically. X-ray diffraction revealed that compound 1 crystallizes as a monohydrate in the monoclinic space group P21/c, while compound 3 also crystallizes as a monohydrate in the orthorhombic space group Pccn, exhibiting quasi-isomorphism with 1. Compound 2 crystallizes in the P21/c space group, forming H-bonded centrosymmetric dimers. The crystal packing is stabilized by N-H & sdot;& sdot;& sdot;O and C-H & sdot;& sdot;& sdot;O hydrogen bonds, along with C-H & sdot;& sdot;& sdot;pi interactions. FTIR and Raman spectroscopic analysis, supported by DFT calculations, identified key vibrational modes in the amide and pyrazole moieties. Hirshfeld surface analysis indicated that the molecular sheets are primarily formed by hydrogen bonds, with stabilization dominated by electrostatic energy contributions. DFT calculations (PBE0-D3/def2-TZVP) and QTAIM/NCIplot analyses revealed that the H-bonding interactions are energetically significant.

Acetyl-l-carnitine (ALC) is synthesized in the brain, liver, and kidneys and plays crucial roles in energy metabolism, acetylcholine production, protein synthesis, and neuronal protection, contributing to its antidepressant and neuroprotective properties. Zinc, a vital biometal, is essential for depression and neuroprotection, exhibiting antidepressive effects alone or combined with classical antidepressants. The pharmacological benefits of metal coordination complexes often result from synergistic or additive effects. In this study, we present a novel multifunctional zinc complex, Zn(ALC)Cl2(H2O), which crystallizes in the monoclinic chiral space group P21, featuring a distorted tetrahedral Zn(II) environment. This new compound demonstrates significantly higher antidepressant activity, reducing immobility in the forced swimming test by 54 % compared to commercial ALC. Additionally, it exhibits in vivo antinociceptive properties, increases latency time, and proves effective in a diabetic neuropathy model by preventing the glucose-induced decrease in intracellular GSH levels. In vitro studies indicate that the complex can cross the blood-brain barrier and offer neuroprotection against glutamate-induced excitotoxicity and oxygen-glucose deprivation, with a drug classification of 10 versus 5 for ALC. Furthermore, under astrocytosis conditions, the Zn complex neutralizes the toxic effects of TGFβ-treated astrocytes. These findings highlight Zn(ALC)Cl2(H2O) as a promising candidate for treating depression and neurodegenerative diseases.

Phenyl rings are present in nearly 45% of approved small-molecule drugs; however, their flat, aromatic nature can lead to poor solubility, metabolic instability, and limited target selectivity. Carboranes, as three-dimensional boron-rich bioisosteres, may offer a promising alternative to address these limitations. Here, we report the design, synthesis, and biological characterization of novel carborane-based analogs of erlotinib, exploring 3D bioisosterism to enhance anticancer activity. All the carborane-based analogs displayed better in vitro biological behavior than the parent compound, with the para-derivatives (13) and (17) emerging as promising leads, showing 2.5 to >12-fold greater cytotoxicity than erlotinib and up to ∼7-fold selectivities for glioblastoma over astrocytes. Compound (17) moderately inhibited both wild-type EGFR (IC5 0 = 9.23 μM) and the drug-resistant EGFRT790M mutant (IC5 0 = 7.19 μM). Molecular docking and dynamics simulations predicted binding within the ATP catalytic site, displaying a hinge-binding mode characteristic of EGFR inhibitors. Mechanistic studies revealed apoptosis as the predominant cell death pathway. In vivo, compound (17) showed excellent acute oral safety (LD5 0 > 2000 mg/kg in mice) with no alterations in biochemical blood parameters. Ames testing indicated no mutagenic potential. In silico ADMET profiling predicted high intestinal absorption, absence of P-gp interaction, weak hERG inhibition, and no carcinogenicity, with only compounds (16) and (17) predicted to cross the blood-brain barrier. Chemical stability assays demonstrated that all compounds, except (18), were stable for 24 h under physiologically relevant pH conditions (2.0, 7.0, and 8.6). Overall, these findings position compound (17) as a promising lead for glioblastoma tumors. Despite modest biochemical potency, its strong cellular efficacy suggests additional mechanisms of action beyond direct EGFR inhibition. Future efforts will focus on kinome-wide profiling and transcriptomic analyses to elucidate its broader target spectrum and optimize this scaffold for clinical translation.

We report here the synthesis of a caryolan-1-ol derivative, namely [(1R, 2S, 5R, 8S)-1-hydroxy-4,4,8-trimethyltricyclo[6.3.1.02,5]dodecan-6-one] (3), characterized by structural single-crystal X-ray diffraction, FTIR and 1H and 13C NMR spectroscopies. The crystal structure reveals weak noncovalent interactions along with O-H···O hydrogen bonding interactions that forms 1D network architectures. Hirshfeld surfaces and their two-dimensional fingerprint plots allow us to visualize the intermolecular contacts and their relative contributions to the total Hirshfeld surface for the compound. A comparative analysis against related compounds was carried out. The interaction energies for the molecular pair involving O-H···O hydrogen bonds indicated a dominant contribution to packing stabilization coming from the Coulombic components. Energy framework calculations afforded to analyse and visualize the topology of the intermolecular interactions responsible for the crystal packing, showing that dispersion energy prevail over the electrostatic one in the structure of 3. Theoretical calculations have been performed to analyse the unconventional noncovalent interactions observed in the solid-state structure of 3 using the quantum theory of atoms in molecules (QTAIM), noncovalent interactions plot (NCIplot) and natural bond orbital (NBO) computational tools.

(Z)-3-butylamino-4,4,4-trifluoro-1-(2-hydroxyphenyl)but-2-en-1-one (1), a new β-aminoenone, has been investigated in terms of its intra- and intermolecular interactions. Vibrational, electronic and nuclear magnetic resonance spectroscopies were used for the characterization, while X-ray diffraction methods afforded the determination of the crystal structure. The compound is arranged in the crystal lattice as centre-symmetric H-bonded dimeric aggregates (C2/c monoclinic space group). Both experimental (infrared, Raman, ultraviolet-visible transitions and X-ray diffraction data) and theoretical (Quantum Theory of Atoms in Molecules and Natural Bond Orbital approaches, calculated spectra and conformational analysis) methods were used to obtain a deep insight into the intra- and intermolecular contacts. The interactions were quali- and quantitatively analysed and the data compared with closely related compounds. In vitro experiments were carried out in this work to evaluate the antibacterial activity of 1 against Gram-positive and Gram-negative bacteria, particularly Pseudomonas aeruginosa (ATCC 27853) and Staphylococcus aureus (6538). Compound 1 demonstrated a discernible suppression of biofilm formation and quorum sensing of both bacterial strains, indicating that it may be developed as an antibacterial candidate to reduce bacterial resistance and persistence on surfaces across a range of industries.

In this article, we report the synthesis, spectroscopic and X-ray characterization of two fluorinated 2 '-hydroxychalcone derivatives (E)-3-(4-fluorophenyl)-1-(2-hydroxyphenyl)prop-2-en-1-one (1) and (E)-1-(2-hydroxyphenyl)-3-[(4-trifluoromethyl) phenyl]prop-2-en-1-one (2). These compounds were synthesized by Claisen-Schmidt condensation between 2 '-hydroxyacetophenone and 4-fluorobenzaldehyde and 4-(trifluoromethyl)benzaldehyde under basic conditions to afford the desired compounds in good yields. The structures were fully established using FTIR, UV-visible and 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The crystallographic analysis reveals that the supramolecular assembly in 1 is mainly governed by C-H & ctdot;O and C-H & ctdot;F H-bonds and C-H & ctdot;O, F & ctdot;F, and pi-stacking interactions were observed in 2. Hirshfeld surface analysis revealed that H & ctdot;H, H & ctdot;O/O & ctdot;H and H & ctdot;F/F & ctdot;H contacts dominate the crystal packing of both compounds. Lattice and intermolecular interaction energies for 1, 2, and two related compounds were computed by using the PIXEL procedure. Contact enrichment ratios showed the most favorable intermolecular interactions for all the four compounds. A detailed density functional theory (DFT) computational analyses were performed to evaluate the strength and nature of the intermolecular interactions which stabilize the crystal packing. Finally, possible pharmacological effects, mechanisms of action, metabolism-related actions, and toxic effects are predicted using PASSonline software. The four analyzed 2 '-hydroxy-chalcones exhibited high anti-hypoxic activity. Pharmacokinetic properties, as well as absorption, distribution, metabolism, excretion and toxicity properties were also predicted using the online SwissADME software.

Two new heterocycles, containing the vicinal triazole pharmacophore, were synthesized and studied exhaustively by spectroscopic methods, computational calculations and X-ray diffraction. The compounds (2-hydroxy-3,5dimethylphenyl)[5-(trifluoromethyl)-2H-1,2,3-triazol-4-yl]methanone (a) and (5-chloro-2-hydroxy-3-methylphenyl)[5-(trifluoromethyl)-2H-1,2,3-triazol-4-yl]methanone (b) are interesting because their structure allows the nitrogen atoms of the pharmacophore to remain free, increasing its interaction potential. Furthermore, 4,5-disubstituted vicinal triazoles have received less attention since they cannot be produced using click chemistry. The crystal structure of both compounds was determined by X-ray diffraction methods. Quantum chemical calculations were implemented to support the analysis of vibrational and electronic spectroscopic properties by Density Functional Theory (DFT). The study of the intermolecular interactions was undertaken through Molecular Electrostatic Potential (MEP) maps, Hirshfeld surfaces (HS), Natural Bond Orbitals (NBO) and Quantum Theory of Atoms in Molecules (QTAIM). Strong (O-H center dot center dot center dot O and N-H center dot center dot center dot O) and weak (C-H center dot center dot center dot F and N-H center dot center dot center dot F) hydrogen bonding interactions together with F center dot center dot center dot F, O center dot center dot center dot C and it center dot center dot center dot it stacking contacts are the basis on which the sheets and layers of the studied compounds are formed. The dispersive energy component predominates in the stabilization of the layers. The intramolecular hydrogen bonding is much stronger in compound a, since the interaction is influenced by the intramolecular N-H center dot center dot center dot O contacts. The second-order stabilization energy (E(2), NBO) and the interaction energy (Eint, QTAIM) associated with this interaction support the analysis.

This study details the synthesis of a novel ligand, (E)-5-chloro-N'-(2-hydroxy-3-methoxybenzylidene) thiophene-2-carbohydrazide ligand (for short, H2L), and its tetranuclear Cu(II) complex (Cu4L4), together with their X-ray crystal structures and the magnetic properties and EPR spectra of Cu4L4 within the 4-300 K temperature range. Furthermore, we report the spectroscopic characterization (FTIR and UV-Vis) of the compounds and perform a Hirshfeld analysis of their non-covalent interactions, along with certain quantum chemical calculations. H2L crystallizes in the monoclinic space group Cc with Z = 8 molecules per unit cell and the Cu4L4 complex crystallizes in the tetragonal space group P41/a with Z = 4. The complex is at a crystal site of S4 symmetry, conforming to a cubane-like Cu4O4 core. The main pathway for exchange interaction between neighboring copper ions in the core involves a relatively large overlap of the copper d(x2 - y2) electron ground state orbital with the sp2 lone-pair lobes of the bridging oxygen. Magnetic susceptibility in the 5-300 K range, mainly interpreted with the exchange Hamiltonian Ĥex = J(Ŝ1·Ŝ2 + Ŝ2·Ŝ3 + Ŝ3·Ŝ4 + Ŝ4·Ŝ1), confirms the expected relatively strong antiferromagnetic (AF) character of the complex (J = -61.5(1) cm-1). The powder room temperature Q-band EPR spectrum shows a very broad band (ΔBpp = 1980 Gauss) corresponding to a gyromagnetic g-factor of 2.13. The band intensity decreases sharply with temperature, as expected for a Cu(II) tetramer with a well isolated spin singlet (S = 0) ground state.

This study investigates the structural and conformational features of novel 6-N-aryl-galactosides, specifically 4-halo-6-deoxy-1,2:3,4-di-O-isopropylidene-6-N-phenylamino-alpha-D-galactopyranosides, using a combination of spectroscopic techniques. Comparative analyses were performed using single-crystal X-ray diffraction, FT-IR, and FT-Raman vibrational spectroscopy to elucidate structural similarities and differences among the derivatives. Two crystallographically independent molecules were observed in the asymmetric unit of the p-chloro compound, and four in that of the p-fluoro compound, all exhibiting close structural resemblance. Key inter-and intramolecular interactions governing crystal packing and conformational variability were identified. The 6-C substituent displayed notable flexibility in the solid state. Unlike the typical perpendicular orientation in C1-substituted glycosides, the C6-N-galactosides exhibited a planar arrangement of the aromatic and sugar rings. The pyranose ring adopted an degrees S2 twist-boat conformation, as confirmed by torsional analysis. These interactions also led to distinct supramolecular assemblies in the p-chloro and p-fluoro derivatives.

This study is devoted to the analysis of the C–H⋯π(CO) contacts established between the H-atom of one methyl group and the π-system of the carbonyl group from the acetoxy moiety.

Chemical connectivity of halogen bond (XB) of the diiodine with an ambidentate ligand of the N1-aryl-2-(trifluoromethyl)benzo[b][1,8]naphthyridin-4(1H)-one in solution and in solid state was presented. The organic ligand was characterized by featuring four basic moieties with different hardness (N-heteroarene, ketonic oxygen, methoxy oxygen and it-arene). The study in solution was performed through a simple steady state fluorescence measurements taking advantage on the use of a donor-acceptor (D-A) fluorophore having two key characteristics (i) presence of basic groups along the d-A chain and, (ii) a fluorescence dependent on an intramolecular charge-transfer (ICT) mechanism. It allowed us to distinguish unequivocally the binding preference of the ambidentate ligand toward the diiodine from the recognition of specific dye-fluorescence responses (ICTquenching, ICT-enhancement, etc.). Fluorometric studies allowed us to elucidate that the diiodine interacts dominantly through the borderline function (N-heteroarene) of ligand under a wide range of diiodine concentration and discretely through the harder ketonic oxygen. UV-Vis spectroscopic confirmed the binding of the diiodine through N-arene moiety, giving typical association constants of 20-40 M-1 for the tested ambidentate ligands. Additionally, the fluorometry allowed us to verify the reversibility of the XB in solution through synchronized radioactivity- and absorption-fluorescence experiments based on nuclear and chemical decomposition of the diiodine, respectively, where the total recovery of the ICT-fluorescence, which was quenched under diiodine binding, confirmed the reversibility of the XB. Further studies in solid state (Raman spectroscopy) confirmed the binding preference of the diiodine toward the borderline N-arene. Experimental evidences of XB were supported and interpreted from DFT-calculations.

A series of six closely related acyl thiourea derivatives featuring adamantyl/noradamantyl groups at the 1-acyl position and 3-trihalophenyl substituents at the thiourea moiety are comprehensively characterized through spectroscopic, computational, and X-ray crystallographic methods. Vibrational spectroscopy (IR and Raman) reveals significant redshifts in the NH and CO stretching bands, confirming the presence of strong intramolecular NH···OC hydrogen bonds. Conformational analysis using molecular mechanics and DFT calculations identifies several conformers, with the most stable adopting an S-shaped geometry where the CO and CS bonds are oppositely oriented-a configuration that was experimentally validated by single-crystal X-ray diffraction. In the solid state, crystal packing is governed by hydrogen-bonding interactions (H···OC and H···SC) facilitated by the acyl-thiourea core. The bulky adamantyl/noradamantyl groups impose steric constraints, whereas the halogenated phenyl rings promote stabilizing π-stacking and halogen interactions. Biological evaluation demonstrates limited antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Burkholderia cenocepacia, and Staphylococcus aureus, but moderate cytotoxicity against A549, 16HBE14o-, and HaCaT cell lines (IC50 = 25-100 μM).

A new complex fac-[(ferroceneCO2)ReI(CO)3(dppz)] (dppz = dipyrido[3,2-a:2',3'-c]phenazine) was obtained and fully characterized by elemental analysis, 1H and 13C NMR, ESI-mass, IR and UV-vis spectroscopy. We also report new insights into the structural and photophysical properties of the fac-[(ferroceneCO2)ReI(CO)3L], where L = 2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen), parent complexes. For all complexes, our results showed that: (i) no singlet oxygen generation was detected in acetonitrile solutions and (ii) they exhibited a very low luminescence quantum yield. However, photoacoustic measurements showed that under photoexcitation the complexes released all the absorbed energy to the medium as prompt heat. The antimicrobial activity of the ferroceneCO2-Re(CO)3(phen) complex was detected against both bacteria from American Type Culture Collections (ATCC) and clinically isolated bacterial strains. Antibacterial activity was rationalized in relation to extension of the π-system of the diamine ligands. Additionally, the ferroceneCO2-Re(CO)3(phen) complex showed no mutagenic potential.