scispace - formally typeset
Search or ask a question
Author

Carlos M. Quintero

Bio: Carlos M. Quintero is an academic researcher from University of Toulouse. The author has contributed to research in topics: Spin crossover & Spin transition. The author has an hindex of 13, co-authored 16 publications receiving 903 citations. Previous affiliations of Carlos M. Quintero include Centre national de la recherche scientifique & Hoffmann-La Roche.

Papers
More filters
Journal ArticleDOI
TL;DR: The development of bilayer actuator devices using molecular spin crossover materials is reported on, demonstrating the versatility of this approach by fabricating actuators from four differentspin crossover materials and by using both thermal variation and light to induce motion in a controlled direction.
Abstract: Molecular actuators hold potential in a number of sensing applications but require careful design to ensure specific functionality. Shepherd et al. report a new platform for molecular actuators based on spin crossover materials, whose response can be controlled by various stimuli or chemical modification.

211 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide an overview of advances and presents the prospects for integrating switchable molecular materials as active elements into actuator devices, with particular emphasis on micro-and nanoscale systems.

191 citations

Journal ArticleDOI
TL;DR: The primary advantage of this two-component fluorescent thermometry system is that the nanoparticles are modified easily, which enables fine control of the thermometric properties, while the optical properties remain virtually unchanged.
Abstract: Temperature plays a fundamental role in all fields of science; hence the development of methods for measuring this property remains in vogue. Within this vast field, fluorescent thermometry appears as a simple, noninvasive and cost-effective method for providing good spatial, temporal and thermal resolution in both solid and liquid phases, even in distant or inaccessible environments. Here we describe the properties of a two-component fluorescent thermometry system comprised of Fe(II)-triazole type spin-crossover nanoparticles (temperature sensor) and an appropriate fluorophore (signal transducer). The primary advantage of this system is that the nanoparticles are modified easily, which enables fine control of the thermometric properties, while the optical properties (i.e. the signal detection) remain virtually unchanged. This system could thus be adapted in a straightforward manner to various problems where the use of fluorescent thermometry would be beneficial.

143 citations

Journal ArticleDOI
TL;DR: The fabrication of large-area vertical junctions with a molecular spin-crossover complex displaying concerted changes of spin degrees of freedom and charge-transport properties is reported.
Abstract: The fabrication of large-area vertical junctions with a molecular spin-crossover complex displaying concerted changes of spin degrees of freedom and charge-transport properties is reported. Fabricated devices allow spin-state switching in the spin-crossover layer to be triggered and probed by optical means, while detecting associated changes in electrical resistance in the junctions.

87 citations

Journal ArticleDOI
TL;DR: In this article, composites of the spin crossover complex were synthesized and investigated for their spin crossover properties by optical reflectivity, Raman spectroscopy and calorimetry.
Abstract: Composites of the spin crossover complex [Fe(trz)(H-trz)2](BF4) (H-trz = 1,2,4-4H-triazole and trz = 1,2,4-triazolato) dispersed in a poly(methylmethacrylate) (PMMA) matrix were synthesized and investigated for their spin crossover properties by optical reflectivity, Raman spectroscopy and calorimetry. These composite films were used to fabricate bilayer cantilevers that can perform efficient and tuneable mechanical actuation based on the spin transition. A prototype device that uses the spin transition phenomenon to convert electrical energy into mechanical motion through Joule heating is described. This device is used to perform oscillatory actuation driven by a modulated current. The ability to tune the performance of this electromechanical system is demonstrated by varying the working temperature, the applied ac current and its frequency.

79 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: A general overview of recent examples of luminescent and non-luminescent thermometers working at nanometric scale and the challenges and opportunities in the development for highly sensitive ratiometric thermometers operating at the physiological temperature range with submicron spatial resolution is offered.
Abstract: Non-invasive precise thermometers working at the nanoscale with high spatial resolution, where the conventional methods are ineffective, have emerged over the last couple of years as a very active field of research. This has been strongly stimulated by the numerous challenging requests arising from nanotechnology and biomedicine. This critical review offers a general overview of recent examples of luminescent and non-luminescent thermometers working at nanometric scale. Luminescent thermometers encompass organic dyes, QDs and Ln3+ions as thermal probes, as well as more complex thermometric systems formed by polymer and organic–inorganic hybrid matrices encapsulating these emitting centres. Non-luminescent thermometers comprise of scanning thermal microscopy, nanolithography thermometry, carbon nanotube thermometry and biomaterials thermometry. Emphasis has been put on ratiometric examples reporting spatial resolution lower than 1 micron, as, for instance, intracellular thermometers based on organic dyes, thermoresponsive polymers, mesoporous silica NPs, QDs, and Ln3+-based up-converting NPs and β-diketonate complexes. Finally, we discuss the challenges and opportunities in the development for highly sensitive ratiometric thermometers operating at the physiological temperature range with submicron spatial resolution.

1,209 citations

Journal ArticleDOI
TL;DR: This critical review discusses recent work in the field of molecule-based spin crossover materials with a special focus on these emerging issues, including chemical synthesis, physical properties and theoretical aspects as well (223 references).
Abstract: Recently we assisted a strong renewed interest in the fascinating field of molecular spin crossover complexes by (1) the emergence of nanosized spin crossover materials through direct synthesis of coordination nanoparticles and nanopatterned thin films as well as by (2) the use of novel sophisticated high spatial and temporal resolution experimental techniques and theoretical approaches for the study of spatiotemporal phenomena in cooperative spin crossover systems. Besides generating new fundamental knowledge on size-reduction effects and the dynamics of the spin crossover phenomenon, this research aims also at the development of practical applications such as sensor, display, information storage and nanophotonic devices. In this critical review, we discuss recent work in the field of molecule-based spin crossover materials with a special focus on these emerging issues, including chemical synthesis, physical properties and theoretical aspects as well (223 references).

1,084 citations

Journal ArticleDOI
TL;DR: The article deals with coordination compounds of iron(II) that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere, and the variety of physical techniques usually applied for their characterization.
Abstract: The article deals with coordination compounds of iron(II) that may exhibit thermally induced spin transition, known as spin crossover, depending on the nature of the coordinating ligand sphere. Spin transition in such compounds also occurs under pressure and irradiation with light. The spin states involved have different magnetic and optical properties suitable for their detection and characterization. Spin crossover compounds, though known for more than eight decades, have become most attractive in recent years and are extensively studied by chemists and physicists. The switching properties make such materials potential candidates for practical applications in thermal and pressure sensors as well as optical devices. The article begins with a brief description of the principle of molecular spin state switching using simple concepts of ligand field theory. Conditions to be fulfilled in order to observe spin crossover will be explained and general remarks regarding the chemical nature that is important for the occurrence of spin crossover will be made. A subsequent section describes the molecular consequences of spin crossover and the variety of physical techniques usually applied for their characterization. The effects of light irradiation (LIESST) and application of pressure are subjects of two separate sections. The major part of this account concentrates on selected spin crossover compounds of iron(II), with particular emphasis on the chemical and physical influences on the spin crossover behavior. The vast variety of compounds exhibiting this fascinating switching phenomenon encompasses mono-, oligoand polynuclear iron(II) complexes and cages, polymeric 1D, 2D and 3D systems, nanomaterials, and polyfunctional materials that combine spin crossover with another physical or chemical property.

586 citations

Journal ArticleDOI
Osamu Sato1
TL;DR: Recent advances in the development of stimuli-responsive, switchable crystalline compounds - referred to here as dynamic molecular crystals - are discussed and how different approaches can serve to prepare functional materials are suggested.
Abstract: The development of molecular materials whose physical properties can be controlled by external stimuli - such as light, electric field, temperature, and pressure - has recently attracted much attention owing to their potential applications in molecular devices. There are a number of ways to alter the physical properties of crystalline materials. These include the modulation of the spin and redox states of the crystal's components, or the incorporation within the crystalline lattice of tunable molecules that exhibit stimuli-induced changes in their molecular structure. A switching behaviour can also be induced by changing the molecular orientation of the crystal's components, even in cases where the overall molecular structure is not affected. Controlling intermolecular interactions within a molecular material is also an effective tool to modulate its physical properties. This Review discusses recent advances in the development of such stimuli-responsive, switchable crystalline compounds - referred to here as dynamic molecular crystals - and suggests how different approaches can serve to prepare functional materials.

581 citations

Journal ArticleDOI
TL;DR: This paper presents a meta-analyses of the chiral stationary phase of the H2O/O2 mixture and shows clear trends in the direction of increasing chiral insensitivity to Naumov’s law.
Abstract: Pancě Naumov,*,† Stanislav Chizhik,‡,§ Manas K. Panda,† Naba K. Nath,† and Elena Boldyreva*,‡,§ †New York University Abu Dhabi, P.O. Box 129188, Abu Dhabi, United Arab Emirates ‡Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of Russian Academy of Sciences, ul. Kutateladze, 18, Novosibirsk 630128, Russia Novosibirsk State University, ul. Pirogova, 2, Novosibirsk 630090, Russia

572 citations