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In this paper we describe the synthesis of new N-heterocyclic carbene (NHC) gold(I) derivatives with flavone-derived ligands with a propargyl ether group. The compounds were screened for their antimicrobial and anticancer activities, showing greater activity against bacteria than against colon cancer cells (Caco-2). Complexes [Au(L2b)(IMe)] (1b) and [Au(L2b)(IPr)] (2b) were found to be active against both Gram-positive and Gram-negative strains. The mechanism of action of 1b was evaluated by measurement of thioredoxin reductase (TrxR) and dihydrofolate reductase (DHFR) activity, besides scanning electron microscopy (SEM). Inhibition of the enzyme thioredoxin reductase is not observed in either Escherichia Coli or Caco-2 cells; however, DHFR activity is compromised after incubation of E. coli cells with complex 1b. Moreover, loss of structural integrity and change in bacterial shape is observed in the images obtained from scanning electron microscopy (SEM) after treatment E. coli cells with complex 1b.

In this work, we report the synthesis and characterization of a mono-nuclear “two wall” aryl-extended calix[4]pyrrole receptor (2Au) decorated with an acetylide-gold(I)-PTA complex at its upper rim. We describe the 1H NMR titration experiments of 2Au and its “two wall” aryl-extended calix[4]pyrrole synthetic precursors: the non-symmetric mono-iodo-mono-ethynyl 2 and the symmetric bis-iodo 3 with TBACl in dichloromethane and acetone solution. In acetone solution, we use isothermal titration calorimetry (ITC) experiments to thermodynamically characterize the formed 1:1 chloride complexes and perform pair-wise competitive binding experiments. In both solvents, we measured a decrease in the binding constant of the mono-nuclear 2Au complex for chloride compared to the parent mono-iodo-mono-ethynyl 2. In turn, receptor 2 also shows a reduction in binding affinity for chloride compared to its precursor bis-iodo calix[4]pyrrole 3. The free energy differences (∆G) of the 1:1 chloride complexes cannot be exclusively attributed to their dissimilar electrostatic surface potential values either at the center of the meso-phenyl wall or its para-substituent. We conclude that solvation/desolvation processes play an important role in the stabilization of the chloride complexes. In acetone solution and in the presence of TBACl, 6Au, a reference compound for the acetylide Au(I)•PTA unit, produces a bis(alkynyl)gold(I) anionic complex [7Au]−. Thus, the observation of two separate sets of signals for the bound aromatic calix[4]pyrrole protons, when more than 1 equiv. of the salt is added, is assigned to the formation of the chloride complexes of 2Au and of the “in situ” formed calix[4]pyrrole anionic dimer [8Au]−. Finally, preliminary data obtained in cell viability assays of 2Au and 6Au with human cancer cells lines assign them with moderate activities showing that the calix[4]pyrrole unit is not relevant.

More than half a century after the discovery of the ferrocene structure in 1951, it remains as a suitable building block in many research areas, including catalysis with the development of key chiral catalysts. On the other hand, gold-mediated catalysis has been raised in recent years, allowing the creation of a great variety of C−C bonds and C-heteroatom bonds. In this context, this review covers the recent advances made with the combination of these two iconic figures in the organometallic chemistry field, since the first gold catalyzed reaction using a ferrocene ligand reported in 1986. The combination of the excellent properties and versatility of this metallocene, has allowed the obtainment of a plethora of ligands for metal catalysis, although their use joined to gold catalysis is still scarcely explored.

Two new families of dithiocarbamate gold(I) complexes derived from benzenesulfonamide with phosphine or carbene as ancillary ligands have been synthesized and characterized. In the screening of their in vitro activity on human colon carcinoma cells (Caco-2), we found that the more lipophilic complexes—those with the phosphine PPh3—exhibited the highest anticancer activity whilst also displaying significant cancer cell selectivity. [Au(S2CNHSO2C6H5)(PPh3)] (1) and [Au(S2CNHSO2-p-Me-C6H4)(IMePropargyl)] (8) produce cell death, probably by intrinsic apoptosis (mitochondrial membrane potential modification) and caspase 3 activation, causing cell cycle arrest in the G1 phase with p53 activation. Besides this, both complexes might act as multi-target anticancer drugs, as they inhibit the activity of the enzymes thioredoxin reductase (TrxR) and carbonic anhydrase (CA IX) with the alteration of the redox balance, and show a pro-oxidant effect.

In luminescent species triplet harvesting and emission through phosphorescence or thermally activated delayed fluorescence (TADF) (Figure 1) represent advantageous mechanisms which make them interesting species for OLED design. Our interest is focused on group 11 complexes displaying such properties. In this work different group 11 N-heterocyclic carbene complexes with different ancillary P, N or C ligands (L) (Figure 2) are studied. The complexes presented have been characterised by different analytical techniques: nuclear magnetic resonance (NMR), mass spectrometry and X-ray crystallography. In addition, the optical properties of the complexes, emission and excitation energies, lifetimes and quantum yields have been analysed.

Nitrogen-containing compounds, particularly amines and their derivatives, are important intermediates for pharmaceuticals, and for many others interesting compounds. The alkylation of amines is a widely used organic reaction involving an amine and an alkylating reagent having a good leaving group. The most prominent processes to obtain this alkylation of amines with allylic alcohols normally use a transition metal as catalyst to activate the hydroxyl group, promoting a nucleophilic substitution. (Scheme 1. N-alkylation of anilines with allylic alcohols under mild reaction conditions). In this study, we have replaced the use of common organic solvents and metals as catalysts in the model reaction between anilines and allylic alcohols by greener and milder conditions, including room temperature (Scheme 1). This is an improvement over most examples reported in the literature, where higher temperatures and stronger reaction conditions are usually used. These features make our approach an attractive metal-free green alternative to develop this process.

Perylenediimes (PDIs) are very interesting compounds due to their outstanding electrooptical properties, high fluorescence quantum yields, and huge versatility in their synthetic chemistry. Although PDIs are mainly used in optoelectronic applications, the number of biological studies using PDIs has been growing in the last few years. Here, we report on the synthesis and biological studies of two new families of PDIs as phototherapeutic agents. (Figure 1: a) Imidazolium-PDI, b) [AgPy2(PPh3)]-PDI). Thus, we have prepared water-soluble PDIs based on imidazolium salts as photosensitizes to generate singlet oxygen (1O2), which plays a key role in photodynamic therapy. Internalization and cytotoxicity assays were carried out in HeLa and SHSY5Y human neuroblastoma cells lines. On the other hand, taking advantage of the medicinal potential of some metals, we have synthesized new PDIs linked to silver and copper complexes to study their behavior as metallodrugs. Biological assays were also carried out in HeLa cells line.

The use of non-steroidal anti-inflammatory drugs (NSAIDs) as chemopreventive agents for cancer has increased in importance in recent years, particularly those related to the gastrointestinal tract. The enzyme cyclooxygenase COX-2, which is involved in inflammatory reactions that can lead to tumorigenesis, is considered as one of the therapeutic target of NSAIDs. Recent studies have shown that modification of the structure of NSAIDs and their coordination to metal centers can improve their selectivity towards cyclooxygenases (COX-1/COX-2), being also able to inhibit lipoxygenase (LOX) enzymes. However, these systems have never been studied using gold(I) as the metal center. Thus, the main objective of this work is focused on the preparation of new gold(I) complexes with NSAID moieties and the study of their biological properties. For this purpose, the carboxyl group of the NSAIDs molecules has been functionalized following different strategies (Scheme 1). The first one consists on the introduction of a propargyl group into the NSAID structure and the subsequent coordination to the gold(I) metal center. The second strategy was the coupling of an amino acid such as methionine, followed by coordination to the gold(I) center.

Benzopyran moiety is a key molecular structure present in a wide range of biologically active compounds. In particular, 2-amino and 3-cyano substituted chromene derivatives have shown some pharmacological applications, what has contributed to the interest of searching new efficient methods for their preparation. Therefore, in the last years, some representatives enantioselective organocatalyzed synthesis of 2-amino-3-cyano-4H-chromene derivatives have been reported. In addition, 4-phosphonate substitution seems to be interesting for their potential antioxidant and anticancer activity. Hence, we present the first asymmetric synthesis of (2-amino-3-cyano-4H-chromen-4-yl) phosphonates derivatives via a phospha-Michael addition to iminocromenes derivatives. Target compounds are obtained with excellent yields and enantiomeric excesses, under smooth reaction conditions, thanks to the activation of the substrates by a chiral organocatalyst, which makes this methodology very attractive for the pharmaceutical industry.