Solid-state piezochromism in poly(di-n-hexylgermane)

Song, Kigook; Miller, R. D.; Rabolt, John F.

doi:10.1021/ma00064a041

Cited by 9 publications

(9 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They are interesting because of their attractive spectroscopic and semiconducting properties [1,2], photoluminescence, piezochromism, thermochromism [3,4], etc. In recent years interest is focused on electronic and optical properties which are dominated by r-delocalization on electrons along the main chain.…”

Section: Introductionmentioning

confidence: 99%

Phonon dispersion in poly(dimethylsilane)

Agarwal

Tandon

Gupta

2006

Journal of Organometallic Chemistry

View full text Add to dashboard Cite

Section: Introductionmentioning

confidence: 99%

Phonon dispersion in poly(dimethylsilane)

Agarwal

Tandon

Gupta

2006

Journal of Organometallic Chemistry

View full text Add to dashboard Cite

“…Pt and Pd complexes with d 8 electronic configuration normally prefer square-planar coordination geometry, while metal ions with d 7 and d 6 For Pd(NH3)2Cl3, isotropic compression in all three directions of the orthorhombic unit cell was observed, including compression along the intrachain Pd(II)---ClPd(IV) distance. Observation of the absorption spectra revealed that the IT band was very strong for most of the complexes, even at ambient pressure, and measurement became impossible at elevated pressures.…”

Section: Mixed-valent Pd(ii)/pd(iv) Complexesmentioning

confidence: 99%

Piezochromism and Related Phenomena Exhibited by Palladium Complexes

Takagi¹,

Noda²,

Itoh³

et al. 2004

Platinum Metals Review

View full text Add to dashboard Cite

Piezochromic phenomena colour changes in solid specimens or solution samples induced by external pressures are explained by pressure perturbation to the HOMO and/or LUMO (highest occupied molecular orbital and/or lowest unoccupied molecular orbital) energy levels of the related electronic transition. The piezochromism of solid inorganic and organic materials has been investigated by examining phase transition phenomena. Specific electronic properties of the solids, acquired by tuning the external pressure, may be used as electronic devices and as pressure sensors.Changes in the absorption and emission spectra of metal complexes in solution are related to changes in solvent polarity at each pressure: a gradual increase of the dielectric constant of the solvent with pressure affects the energies of the HOMO and LUMO levels involved in the electronic transitions within the metal complexes, and a corresponding colour change may be observed. However, such a pressure perturbation to the dielectric constant of solvents is usually small (1) and the piezochromic effect of samples in solution is rather ambiguous partly because of the narrow range of applied pressures (< 5000 bar).It is known that the compressibility of solids is much smaller (< 0.001%) than that of liquids. This small compressibility is explained by the difficulty of intermolecular and/or interionic compression in the crystals that comprise the solid and by the difficulty of compression along the bond axis in the molecules or complex ions. For example, lateral compression between the chains takes place for alkylsilicon and alkylgermanium polymers at relatively low pressures (ca. 10,000 bar), followed by compression along the SiSi and GeGe axes at higher pressures (> 20,000 bar) (27). Moreover, deformation of compounds by the external pressure does not take place in a free way: there is a quantum mechanical restriction symmetry rules (8, 9) that governs the direction of deformation. Specific interactions, such as hydrogen bonding and ion-pair interactions, also perturb the structures at elevated pressures (10). In addition to knowing the symmetry rules, it is essential to comprehend the theories of electronic transitions and molecular symmetry and vibrations for a proper understanding of piezochromic effects (11). In this short review the effects of pressure perturbations on the absorption and emission spectra that are exhibited by solid palladium complexes are Piezochromic phenomena are explained by pressure perturbation to the HOMO and/or LUMO energy levels of the related electronic transition. The piezochromism of solid inorganic and organic materials has been investigated by examination of the phase transition phenomena. Specific electronic properties of the solids, acquired by tuning the external pressure, may be used as electronic devices and as pressure sensors. The effects of pressure perturbations on the absorption and emission spectra exhibited by solid palladium complexes are reviewed here. Related phenomena exhibited by platinum complexes and ot...

show abstract

“…In the 1970s, polysilanes attracted interest as the precursor of silicon carbide fiber, and polysilanes evoked considerable scientific interest since the synthesis of soluble substituted polysilanes in the 1980s. One of the most interesting properties of polysilanes is their remarkable electronic absorption spectra. − These polymers have UV absorption bands, which resulted from the σ-electron delocalization along the main chain. − Besides the electronic absorption, some polysilanes also show thermochromism, piezochromism, photoluminescence, photodegradation, conductivity, etc., and a number of new applications are expected. − Modern interest in polysilanes is generated by these unique electronic properties, which are attributed to σ-electron delocalization along main chains. It is of interest to form well-oriented polysilanes films, which are expected to have anisotropic electronic properties. − The vibrational spectroscopy is one of the most important methods to characterize oriented films, because it can give information on chemical structures, etc., as well as molecular orientation.…”

Section: Introductionmentioning

confidence: 99%

“…It is of interest to form well-oriented polysilanes films, which are expected to have anisotropic electronic properties. − The vibrational spectroscopy is one of the most important methods to characterize oriented films, because it can give information on chemical structures, etc., as well as molecular orientation. Though studies on the vibrational spectroscopy of polysilanes have been done, ,,− most studies on oriented polysilanes have been done with UV spectra and X-ray diffraction.…”

Section: Introductionmentioning

confidence: 99%

Infrared Spectroscopic Studies on the Molecular Orientation of Vacuum-Deposited Thin Films of Poly(dimethylsilane) and a Linear Oligosilane

et al. 1998

View full text Add to dashboard Cite

Thin films of poly(dimethylsilane) (PDMS) and permethyldodecasilane (DM12) were prepared by the vacuum-deposition method, and the molecular orientation in the films was investigated. Welloriented films of DM12 were prepared without detectable degradation; however, degradation occurred in the films of PDMS, though well-oriented films were also obtained. Infrared and UV spectra of the vacuumdeposited films were measured with inclined sample alignment. In the spectra of films deposited to substrates at room temperature, a methyl rocking (parallel) band and a sharp UV absorption, which have the same polarity parallel to the chain axis, became stronger when the samples were inclined. Both of the absorptions also showed large dichroism when the samples were inclined. These results suggest that the PDMS and DM12 molecules in the films were oriented perpendicular to the substrate. The infrared spectra of vacuum-deposited PDMS films show Si-H and Si-O bonds formation; i.e., PDMS molecules were degraded during the deposition process. In clear contrast, the infrared spectra of the vacuum-deposited films of DM12 showed no molecular degradation.

show abstract

Solid-state piezochromism in poly(di-n-hexylgermane)

Cited by 9 publications

References 0 publications

Phonon dispersion in poly(dimethylsilane)

Phonon dispersion in poly(dimethylsilane)

Piezochromism and Related Phenomena Exhibited by Palladium Complexes

Infrared Spectroscopic Studies on the Molecular Orientation of Vacuum-Deposited Thin Films of Poly(dimethylsilane) and a Linear Oligosilane

Contact Info

Product

Resources

About