Search results for "molecular materials"

Combining Cyanometalates and Coordination Clusters: An Alternative Synthetic Route toward Original Molecular Materials

2013

International audience; With the discovery of molecules or molecule-based compounds that can display blocked magnetization, magnetic ordering or switchable magnetic bistability, the research efforts devoted to molecular magnetic materials have considerably increased over the past two decades, fully exploiting the advantages of the bottom-up approach. 1-4 This research field focuses on promising properties for potential technological applications such as information storage, quantum computing and spintronics at the molecular scale, but it also provides fundamental insights into original quantum phenomena. 5,6 Coordination chemists have developed efficient synthetic tools for the preparation …

Organized assemblies of magnetic clusters

2003

Abstract In this work we have explored the possibilities to create layered organizations of the Mn 12 single-molecule magnets using the Langmuir–Blodgett technique or attaching these clusters onto a metal surface by preparing self-assembled monolayers (SAMs). In the first part we discuss the use of the Langmuir–Blodgett (LB) technique in order to obtain organized magnetic films formed by monolayers of these clusters. Two strategies have been used with this aim. The first one consists of mixing Mn 12 acetate or benzoate derivatives with an amphiphile, while the second procedure is based on the use of Mn 12 derivatives specifically designed to form LB films. An alternative method is that of p…

New n-type molecular semiconductor–doped insulator (MSDI) heterojunctions combining a triphenodioxazine (TPDO) and the lutetium bisphthalocyanine (Lu…

2018

International audience; Molecular semiconductor–doped insulator (MSDI) heterojunctions were designed using a new family of sublayers, namely triphenodioxazines (TPDO). The device obtained by combining the tetracyano triphenodioxazine bearing two triisopropylsilylethynyl moieties as a sublayer with the lutetium bisphthalocyanine (LuPc2) as a top layer showed a nonlinear current–voltage characteristic independent of the sign of the polarization, which is the signature of MSDI heterojunctions. Thus, a TPDO was used in a chemical sensor for the first time. Despite LuPc2 being the only material exposed to the atmosphere, the positive response of the device under ammonia revealed the key role pla…

Hybrid molecular materials formed by alternating layers of bimetallic oxalate complexes and tetrathiafulvalene molecules: Synthesis, structure, and m…

1996

Materials for molecular electronics and magnetism

2021

Functional molecular materials exhibiting, in particular, electrical, magnetic or optical properties have been an active focus of research over the last 50 years. These materials have been a source of inspiration in two interrelated areas of research, namely, molecular electronics and molecular magnetism, with important implications in biomedical areas. This themed issue highlights recent progress and perspectives in these important areas of materials science. The issue covers topics from the chemical design and manipulation of novel molecular materials with unprecedented control over their properties, even at the single-molecule level, to exciting applications of these special molecular sy…

Molecular Material‐Based Conductimetric Gas Sensors

2012

Polyoxometalates: From Magnetic Models to Multifunctional Materials

2002

In this article we have presented some recent achievements of the polyoxometalates in the fields of molecular magnetism and functional molecular materials. In the context of the molecular magnetism we have shown that POMs provide ideal examples of magnetic clusters with coexisting ferro and antiferromagnetic exchange interactions which can be investigated using a variety of magnetic techniques, including the Inelastic Neutron Scattering spectroscopy, to get a thorough characterization of the magnetic levels in these large clusters, and to test the validity of the spin hamiltonians commonly used in magnetism.

Hybrid Materials Based on Polyoxometalates with Solid State Properties

2003

Molecular materials with cooperative physical properties constitute one of the most active focus of interest in contemporary materials science. An attractive chemical feature of these materials derives from the possibility of building them from molecular bricks using the advantages provided by molecular chemistry and the knowledge achieved over the last 20 years in the so-called molecular engineering. From the point of view of the physical properties, it is well known that molecular materials can exhibit the properties typically associated with the inorganic network solids, as for example metallic conductivity and superconductivity [1], ferromagnetism [2] and non-linear optics [3].

Tuning Of Organic Heterojunction Conductivity By The Substituents' Electronic Effects In Phthalocyanines For Ambipolar Gas Sensors

2021

Abstract Exploiting organic heterojunction effects in electrical devices are an important strategy to improve the electrical conductivity, which can be utilized into improving the conductometric gas sensors performances. In this endeavor, the present article reports fabrication of organic heterostructures in a bilayer device configuration incorporating octa-substituted nickel phthalocyanines (NiPc) and radical lutetium bis-phthalocyanine (LuPc2) and investigates their sensing properties towards NH3 vapor. NiPc having hexyl sulfanyl, hexyl sulfonyl and p-carboxyphenoxy moieties are synthesized, which electronic effects are electron donating, accepting and moderate accepting, respectively, al…

Schmelz- und kristallisationserscheinungen bei makromolekularen substanzen. I. Kristallisationskinetische untersuchungen an isotaktischem polypropylen

1960

Die Messung der Bruttokristallisation hochpolymerer Substanzen erlaubt erst mit Hilfe der AVRAMIschen Theorie Ruckschlusse auf die Kristallisationskinetik (Keimbildung und Wachstumsgeschwindigkeit). Die Frage, ob die fur niedermolekulare Stoffe entwickelte AVRAMIsche Theorie wirklich auf Hochpolymere ubertragen werden kann, bedarf einer eingehenden Prufung. Es wurden daher mittels mikroskopischer Untersuchungen die Keimbildung und die Wachstumsgeschwindigkeit von isotaktischem Polypropylen in Abhangigkeit von der Kristallisationstemperatur getrennt gemessen und die so ermittelten Werte mit den aus der Bruttokristallisation nach AVRAMI berechneten Zahlen verglichen. Die ubereinstimmung ist v…