Vieri Fusi

Bio: Vieri Fusi is an academic researcher from University of Urbino. The author has contributed to research in topics: Ligand & Protonation. The author has an hindex of 32, co-authored 155 publications receiving 3767 citations. Previous affiliations of Vieri Fusi include University of Florence & Universidade Nova de Lisboa.

Carboxy and Phosphate Esters Cleavage with Mono- and Dinuclear Zinc(II) Macrocyclic Complexes in Aqueous Solution. Crystal Structure of [Zn2L1(μ-PP)2(MeOH)2](ClO4)2 (L1 = [30]aneN6O4, PP- = Diphenyl Phosphate)

Abstract: The ligand [30]aneN6O4 (L1) binds two Zn(II) in aqueous solution. The stability constants of the L1 complexes have been determined at 308.1 K by means of potentiometric measurements. Dinuclear monohydroxo [Zn2L1OH]3+ and dihydroxo [Zn2L1(OH)2]2+ complexes are formed in aqueous solution from neutral to alkaline pH. The kinetics of promoted hydrolysis of p-nitrophenyl acetate (NA) was studied. Both hydroxo species promote p-nitrophenyl acetate (NA) hydrolysis at 298.1 K with second-order kinetics. The activity of these species in NA hydrolysis is similar to that found for the mononuclear L2−Zn-OH+ complex (L2 = [15]aneN3O2), indicating that the hydrolytic process takes place via a simple bimolecular mechanism. The hydrolysis rate of bis(p-nitrophenyl) phosphate (BNP) was measured in aqueous solution at 308.1 K in the presence of the L1 and L2 zinc complexes. The hydrolysis rate of BNP is increased almost 10-fold by the dinuclear [Zn2L1(OH)2]2+ complex with respect to the mononuclear L2−Zn-OH+ one. This resu...

Thermodynamics of phosphate and pyrophosphate anions binding by polyammonium receptors

Abstract: The interactions of phosphate and pyrophosphate anions with polyammonium cations deriving from 14 polyamines (five polyazacycloalkanes, four polyazacyclophanes, and five acyclic polyamines) in aqueous solution have been studied by means of potentiometric, microcalorimetric, and NMR measurements in solution. Very stable 1:1 receptor-to-anion complexes are formed. The stability trends of such complexes are not strictly determined by electrostatic forces, hydrogen bond interactions being of considerable importance in the complex formation, the thermodynamic data being consistent with different hydrogen bonding modes. ΔH°−TΔS° compensatory relationships hold for such complexation reactions. The crystal structures of (H4L1)(H2P2O7)2·2H2O and (H4L2)(H2P2O7)2·6H2O (L1 = 1,4,7,10,13,16-hexaazacyclooctadecane, L2 = 1,10-dimethyl-1,4,7,10,13,16-hexaazacyclooctadecane) have been solved by X-ray analysis, evidencing different substrate/anion binding characteristics.

Carboxy and Diphosphate Ester Hydrolysis by a Dizinc Complex with a New Alcohol-Pendant Macrocycle

Abstract: The synthesis of the new alcohol-pendant macrocycle 4-(2-hydroxyethyl)-1,4,7,16,19,22-hexaaza-10,13,25,28-tetraoxacyclotriacontane (L2) is reported. This ligand contains two different triamine moieties, one of them bearing an ethanolic sidearm. L2 binds two Zn(II) ions in aqueous solution. The stability constants of the L2 complexes have been determined at 298.1 and 308.1 K by means of potentiometric measurements. Besides a [Zn2L2]4+ species, a deprotonated [Zn2(L2-H)]3+ complex and a hydroxo [Zn2(L2-H)(OH)]2+ complex are formed in aqueous solution. Zn(II)-assisted deprotonation of the alcoholic group takes place at neutral pH, giving the [Zn2(L2-H)]3+ complex. In [Zn2(L2-H)]3+, the deprotonated R−O- function bridges the two metals, as shown by the crystal structure of [Zn2(L2-H)Br2]BPh4·MeOH. The hydroxo species [Zn2(L2-H)(OH)]2+ is formed at slightly alkaline pH's. This complex contains both a Zn(II)-bound alkoxide and a Zn(II)−OH nucleophilic function. Therefore, it may provide a simple model system fo...

Taking advantage of luminescent lanthanide ions

Abstract: Lanthanide ions possess fascinating optical properties and their discovery, first industrial uses and present high technological applications are largely governed by their interaction with light. Lighting devices (economical luminescent lamps, light emitting diodes), television and computer displays, optical fibres, optical amplifiers, lasers, as well as responsive luminescent stains for biomedical analysis, medical diagnosis, and cell imaging rely heavily on lanthanide ions. This critical review has been tailored for a broad audience of chemists, biochemists and materials scientists; the basics of lanthanide photophysics are highlighted together with the synthetic strategies used to insert these ions into mono- and polymetallic molecular edifices. Recent advances in NIR-emitting materials, including liquid crystals, and in the control of luminescent properties in polymetallic assemblies are also presented. (210 references.)

Artificial Molecular Machines.

Abstract: The miniaturization of components used in the construction of working devices is being pursued currently by the large-downward (top-down) fabrication. This approach, however, which obliges solid-state physicists and electronic engineers to manipulate progressively smaller and smaller pieces of matter, has its intrinsic limitations. An alternative approach is a small-upward (bottom-up) one, starting from the smallest compositions of matter that have distinct shapes and unique properties-namely molecules. In the context of this particular challenge, chemists have been extending the concept of a macroscopic machine to the molecular level. A molecular-level machine can be defined as an assembly of a distinct number of molecular components that are designed to perform machinelike movements (output) as a result of an appropriate external stimulation (input). In common with their macroscopic counterparts, a molecular machine is characterized by 1) the kind of energy input supplied to make it work, 2) the nature of the movements of its component parts, 3) the way in which its operation can be monitored and controlled, 4) the ability to make it repeat its operation in a cyclic fashion, 5) the timescale needed to complete a full cycle of movements, and 6) the purpose of its operation. Undoubtedly, the best energy inputs to make molecular machines work are photons or electrons. Indeed, with appropriately chosen photochemically and electrochemically driven reactions, it is possible to design and synthesize molecular machines that do work. Moreover, the dramatic increase in our fundamental understanding of self-assembly and self-organizational processes in chemical synthesis has aided and abetted the construction of artificial molecular machines through the development of new methods of noncovalent synthesis and the emergence of supramolecular assistance to covalent synthesis as a uniquely powerful synthetic tool. The aim of this review is to present a unified view of the field of molecular machines by focusing on past achievements, present limitations, and future perspectives. After analyzing a few important examples of natural molecular machines, the most significant developments in the field of artificial molecular machines are highlighted. The systems reviewed include 1) chemical rotors, 2) photochemically and electrochemically induced molecular (conformational) rearrangements, and 3) chemically, photochemically, and electrochemically controllable (co-conformational) motions in interlocked molecules (catenanes and rotaxanes), as well as in coordination and supramolecular complexes, including pseudorotaxanes. Artificial molecular machines based on biomolecules and interfacing artificial molecular machines with surfaces and solid supports are amongst some of the cutting-edge topics featured in this review. The extension of the concept of a machine to the molecular level is of interest not only for the sake of basic research, but also for the growth of nanoscience and the subsequent development of nanotechnology.