Hugo Valdés

Recent Advances in Catalysis with Transition-Metal Pincer Compounds

Pincer complexes are useful tools for organic synthesis. Their high stability and easy functionalization have allowed the development of novel catalytic systems that have had a tremendous impact in different areas of chemistry. Thus, catalytic reactions are nowadays a fundamental part of several synthetic routes, as they allow “greener” procedures with high atom efficiency. In this context, pincer complexes have contributed to the establishment of novel and efficient catalytic reactions. Thus, herein we summarize the most recent relevant advances involving pincer complexes as catalysts.

Strategies for the design and synthesis of pincer-based dendrimers: Potential applications

Abstract The excellent thermal and chemical stability and robustness of ECE-pincer metal complexes make these species promising candidates as medical and therapeutics tools; tools such as: biomarkers, sensors, anticarcinogenic agents, surface plasmon resonance enhancers, etc. In this sense, one of the main interests is the hybridization of organometallic species anchored or incorporated in biological molecules, i.e., mainly in enzymes. Also of interest is the preparation of dendritic ECE-pincer metal complexes as potential drug carriers. Thus far, several papers describing dendrimeric skeletons (e.g., PAMAM) have been reported with promising drug delivery abilities. However, to the best of our knowledge, there are no reports describing the utilization of dendritic ECE-pincer metal complexes as drug carriers. In addition, an incipient development of bioorganometallic conjugates, combining the properties of ECE-pincer metal complexes covalently anchored to diverse biological molecules (peptides, aminoacids, carbohydrates, anticarcinogenic agents, proteins, enzymes, etc.), have been synthetized in an effort to generate potential sensors or biomarkers, exploiting the properties of the biomolecules used (water solubility, size, chiral environment, etc.). In this chapter, we describe the development of metallopincer dendrimers and the potential applications of more compact metallopincer species in medical, therapeutic, and other fields.

Metal Pincer Catalysts in Aqueous Media

Abstract In this chapter, the role of water in metal pincer–catalyzed reactions is summarized. Briefly three categories can be described: (1) Water can act as polar and protic solvent for biphasic catalysis, with water-soluble pincer complexes in the catalyst phase. (2) The use of water in aqueous phase alcohol and aldehyde-reforming processes for low-temperature hydrogen generation. (3) The use of water in aqueous phase oxidation reactions where water acts as oxygen source, for example, for the oxidation of alcohols to carboxylic acids or the oxidation of amines to amides. Thus, water plays a role for potentially recyclable catalyst systems toward more sustainable organic synthesis or low-temperature energy storage and conversion systems.