Single source precursors molecular structures

The bis-Cp titanium bis(/-butanethiolato) and bis(ethanethiolato) complexes have been used as a single-source precursors for the preparation of thin films of titanium sulfides by metal-organic chemical vapour deposition (MOCVD). The crystal and molecular structures of the precursor complexes have been determined for comparison with homologous complexes of the general formula Cp2Ti(SR)2.1618... 

Chemistry plays an important role in the fabrications of new functional materials with desired properties from conceptual point of view via tuning of microstructural properties. The synthetic approach of functional Inorganic nanomaterials with their novel properties and with their applications is a powerful driving force for the scientists in materials science. The synthesis of single source precursor was carried out based on molecular structure design concept (MSDC) for the stabilization via transformation into a solid crystalline nanostructure material with improved structural and properties. Single source precursor is a molecular entity which contains all the necessary elements of a final product in a well-defined structural formula [36-42]. It is of three types as shown below ... 

Kessler V.G., Hnbert-Pfalzgraf L.G., Daniele S., Gleizes A. Single-source precursors for BaTiOg Synthesis and characterization of 6-diketonato alkoxides and molecular structure of Ba2Ti2(thd)4(m3-OEt)2( -OEt)4(OEt)2(EtOH)2. Chem. Mater. 1994 6 2336... 

Figure 25.13 Sol-gel processing of tetrakis(2-hydroxyethyl)orthosilicate and a single-source precursor/organofunctional silane (the molecular structure of the different precursor molecules are presented as schematic sketch).

The continued development of new single-source molecular precursors should lead to increasingly complex mixed-element oxides with novel properties. Continued work with grafting methods will provide access to novel surface structures that may prove useful for catalytic apphcations. Use of molecular precursors for the generation of metal nanoparticles supported on various oxide supports is another area that shows promise. We expect that the thermolytic molecular precursor methods outlined here will contribute significantly to the development of new generations of advanced materials with tailored properties, and that it will continue to provide access to catalytic materials with improved performance. 

Gci c j,Si tSnj, layers grown over time directly on Si wafers. We also describe synthesis of films and nanometer-scale islands of Sii (Ge ( grown on Si(l 00) substrates via a unique single-source molecular precursor method. This new approach allows precise control of concentration and structure at the atomic level and it is particularly useful for development of composi-tionally homogeneous and uniform assemblies of nanoscale structures. 

Basic principles required for the formation with structural description of hetero-metaUic alkoxides used as single-source molecular precursors toward the synthesis of nanomaterials with required functional properties at the nanoscale. 

Chapter 2 highlights the state of the art with cost-effective synthesis of ultra-pure functional nanomaterials from single source molecular precursors, to understand the structural-functional surface properties relationship based on chemical-thermal stability of metal ions as well as Lewis acidic behavior of the metal ion in the coordinated state. 

Strnctnral characterization The as-prepared and vacuum-dried powders of CdSe, CdTe and ZnSe, synthesized by the solvothermal decomposition of single-source molecular precursors, injected in quinoline as a coordinating solvent as described above, have been subjected to structural characterization. Room temperature XRD patterns of these nanopowders are shown in Fig. 18. The observed pattern of CdSe nanoparticles matches closely with that reported in JCPDS file No.08-0459, whereas that of CdTe matches closely with JCPDS File No.39 -8053 and of ZnSe with File No. 37-1463. 

A single instrument — a hybrid of a quadrupole and a TOF analyzer — can measure a full mass spectrum of ions produced in an ion source. If these are molecular ions, their relative molecular mass is obtained. Alternatively, precursor ions can be selected for MS/MS to give a fragment-ion spectrum characteristic of the precursor ions chosen, which gives structural information about the original molecule. 

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