Study of the shape and internal mobility of molecules by broadening of the dispersion lines

Vuks, M. F.; Tukhvatullin, F. Kh.

doi:10.1007/bf00655128

Cited by 14 publications

(20 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Birefringence (Δn) arises when the refractive index varies depending on the direction of light propagation through a crystal, and can be traced to the anisotropic arrangement of the atoms and molecules within the material. [36,37] The magnitude of birefringence depends on a number of factors, including the polarizability anisotropy of the building blocks (which is high for bbp), the orientation of these components within the lattice and the crystal-growth habit. [24,25] The magnitude of Δn was determined by optical microscopy for all compounds at 546 nm; the results are summarized in Table 3.…”

Section: Birefringencementioning

confidence: 99%

Correlating Structural Features and ²⁰⁷Pb NMR Parameters with the Stereochemical Activity of Pb^II Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes

et al. 2016

View full text Add to dashboard Cite

A series of PbII materials containing the highly anisotropic tridentate ligand 2,6‐bis(benzimidazol‐2‐yl)pyridine (bbp) and [Au(CN)2]–, Hg(CN)2 or halide bridging units, [Pb(bbp)Br2]·2H2O, Pb(bbp)I2, [Pb(bbp)I]2(µ‐I)[Au(CN)2], [Pb(bbp)Br]2(µ‐Br)[Au(CN)2], [Pb(bbp)Br2][Hg(CN)2], Pb(bbp)Cl[Au(CN)2]·0.25H2O and Pb(H2O)(bbp)2[Au(CN)2]2, have been prepared, structurally characterised and investigated spectroscopically by 207Pb solid‐state NMR spectroscopy. Of these, five possess similar coordination geometries, providing an ideal series to investigate structural parameters as indicators for stereochemical activity by correlation with the 207Pb chemical shift span parameter (Ω). The bond length of the substituent opposite to the stereochemically active lone pair and the angle between axial ligands were found to correlate weakly with Ω for these compounds (R2 = 0.85 and 0.66, respectively) and an expanded set of compounds with varying components and structures (R2 = 0.60 and 0.67, respectively), which indicates that these (or similar) structural parameters or Ω can be used to estimate the degree of lone‐pair activity. Compounds were also found to be highly birefringent with values ranging from 0.31(5) for Pb(H2O)(bbp)2[Au(CN)2]2 to 0.660(4) for [Pb(bbp)Br2]·2H2O, the latter being amongst the most birefringent compounds reported.

show abstract

Section: Birefringencementioning

confidence: 99%

Correlating Structural Features and ²⁰⁷Pb NMR Parameters with the Stereochemical Activity of Pb^II Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes

et al. 2016

View full text Add to dashboard Cite

show abstract

“…The refractive index in a given direction can be defined by the Lorentz-Lorenz equation [2] and is therefore dependent on the relative orientation of the anisotropic polarizable components of a material with respect to the different axes of the material. [14] Therefore, highly birefringent compounds maximize polarizability in one direction of a crystal over another, leading to axes of high polarizability (high refractive index) and low polarizability (low refractive index) within the material. One method by which to introduce polarizability anisotropy into a structure is to include highly anisotropic, organic aromatic components and subsequently orient the molecules parallel to one another to create structural ordering.…”

Section: Introductionmentioning

confidence: 99%

“…[35] Rather than introducing single polarizable bonds to the ligands or cyano-metallate building blocks, another route to increasing the polarizability anisotropy within a material is to introduce a capping ligand with an extended p-system. [14] This needs to be accomplished whilst maintaining the optical transparency of the ligand, which is required for potential applications. We turned to the easily synthesised [36] and readily functionalized [37,38] bis(benzimidazole)pyridine (BBP) unit as a capping ligand in order to incorporate additional potentially planar ligand components.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular Assembly of Bis(benzimidazole)pyridine: An Extended Anisotropic Ligand For Highly Birefringent Materials

Thompson

Ovens

Williams

et al. 2013

Chemistry A European J

View full text Add to dashboard Cite

Four new bis(benzimidazole)pyridine (BBP)-containing compounds Zn(BBP)Cl[Au(CN)2], Mn(BBP)[Au(CN)2]2·H2O, Mn(BBP)Br2(MeOH) and Mn(BBP)Cl2(MeOH)·MeOH have been synthesized and structurally characterized and their birefringence values (Δn) determined. The structure of Zn(BBP)Cl[Au(CN)2] contains a hydrogen-bonded dimer of Zn(BBP)Cl[Au(CN)2] units which propagate into a 1D chain through Au-Au interactions, although the crystals are of poor optical quality. The supramolecular structure of Mn(BBP)[Au(CN)2]2·H2 O forms a 1D coordination polymer through chains of Mn(BBP)[Au(CN)2]2 units, each containing one bridging Au(CN)2 and one forming a 2D sheet through Au-Au interactions. The supramolecular structures of Mn(BBP)Br2(MeOH) and Mn(BBP)Cl2(MeOH)·MeOH are very similar, consisting of a complex hydrogen-bonded network between NH imidazole, methanol and halide groups to align BBP building blocks. In the plane of the primary crystal growth direction, the birefringence values of the three Mn-containing materials were Δn=0.08(1), 0.538(3) and 0.69(3), respectively. The latter two birefringence values are larger than in the related 2,2';6'2''-terpyridine systems, placing them among the most birefringent solids reported. These compounds illustrate the utility of extending the π-system of the building block and incorporating hydrogen-bonding sites as design elements for highly birefringent materials and also illustrates the effect on the measurable birefringence of the crystal quality, growth direction and structural alignment of the anisotropic BBP building blocks.

show abstract

“…where θ i is the angle between the molecular-chain direction and the perpendicular direction of film. P 200 can be analyzed based on the Vuks equation [30] as follows…”

Section: Analysis Of Molecular Packing In Pi Filmsmentioning

confidence: 99%

Anisotropic Linear and Volumetric Thermal‐Expansion Behaviors of Self‐Standing Polyimide Films Analyzed by Thermomechanical Analysis (TMA) and Optical Interferometry

Ando

Sekiguchi

Mizoroki

et al. 2017

Macro Chemistry & Physics

View full text Add to dashboard Cite

The relationships between the molecular structure, polymer chain orientation, β‐transition temperature, and the coefficients of in‐plane and out‐of‐plane linear thermal expansions (CTE, α), as well as the coefficients of volumetric thermal expansion (CVE, β), are extensively examined for ten types of self‐standing aromatic polyimide (PI) films via thermomechanical analysis, near‐infrared optical interferometry, and dynamic mechanical analysis. The out‐of‐plane CTEs (α⊥) of PI films having rigid‐rod structures are 20–40 times larger than their in‐plane CTEs (α//), whereas the α⊥ values of PI films having bent linkages in the main chains are comparable to their α// values. In addition, the values of normalized anisotropy in CTE for PIs (η), defined as (α⊥ −α//)/β, are proportional to the orientation coefficients (P200) estimated from the in‐plane/out‐of‐plane birefringence (Δn) and molecular polarizability tensor. Furthermore, larger CVE values are observed for PIs exhibiting lower β‐relaxation temperatures (Tβ), at which localized molecular motion occurs. In contrast, smaller CVE values are observed for PIs exhibiting higher Tβs because their local molecular motions are suppressed due to the structural rigidity and dense molecular packing.

show abstract

Study of the shape and internal mobility of molecules by broadening of the dispersion lines

Cited by 14 publications

References 4 publications

Correlating Structural Features and ²⁰⁷Pb NMR Parameters with the Stereochemical Activity of Pb^II Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes

Correlating Structural Features and ²⁰⁷Pb NMR Parameters with the Stereochemical Activity of Pb^II Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes

Supramolecular Assembly of Bis(benzimidazole)pyridine: An Extended Anisotropic Ligand For Highly Birefringent Materials

Anisotropic Linear and Volumetric Thermal‐Expansion Behaviors of Self‐Standing Polyimide Films Analyzed by Thermomechanical Analysis (TMA) and Optical Interferometry

Contact Info

Product

Resources

About

Study of the shape and internal mobility of molecules by broadening of the dispersion lines

Cited by 14 publications

References 4 publications

Correlating Structural Features and 207Pb NMR Parameters with the Stereochemical Activity of PbII Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes

Correlating Structural Features and 207Pb NMR Parameters with the Stereochemical Activity of PbII Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes

Supramolecular Assembly of Bis(benzimidazole)pyridine: An Extended Anisotropic Ligand For Highly Birefringent Materials

Anisotropic Linear and Volumetric Thermal‐Expansion Behaviors of Self‐Standing Polyimide Films Analyzed by Thermomechanical Analysis (TMA) and Optical Interferometry

Contact Info

Product

Resources

About

Correlating Structural Features and ²⁰⁷Pb NMR Parameters with the Stereochemical Activity of Pb^II Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes

Correlating Structural Features and ²⁰⁷Pb NMR Parameters with the Stereochemical Activity of Pb^II Lone Pairs in Birefringent Pb[2,6‐bis(benzimidazol‐2‐yl)pyridine] Complexes