scholarly journals Gauge Dependence of the S Molecular Orbital Space Decomposition of Optical Rotation

2020 ◽  
Author(s):  
Ty Balduf ◽  
Marco Caricato
Keyword(s):  
Molecular Orbital ◽  
Optical Rotation ◽  
Structure Property ◽  
Chiral Molecules ◽  
Gauge Dependence ◽  
Space Decomposition ◽  
Structure Property Relationships ◽  
Small Set ◽  
Orbital Space

<div> <div> <div> <p>Optical rotation (OR) is a foundational technique for the detection and characterization of chiral molecules, but it is poorly understood how the observed property relates to the structure of the molecule. Over the years, several schemes have been developed to de- compose the OR into more chemically intuitive contributions. In this paper, we introduce two alternative formulations of our previously developed S molecular orbital space decomposition. These new expressions use the Modified Velocity Gauge-Magnetic (MVG-M) and -Electric (MVG-E) definitions of OR, rather than the Length Gauge Magnetic (LG-M) definition used in the original paper. Comparing these formulations across a small set of previously studied chiral molecules, we find that these different definitions produce consistent physical interpretations of the OR. These results further confirm the robustness of the S methodology for the investigation of structure-property relationships in chiral molecules.</p> </div> </div> </div>

scholarly journals Gauge Dependence of the S Molecular Orbital Space Decomposition of Optical Rotation

2020 ◽  
Author(s):  
Ty Balduf ◽  
Marco Caricato
Keyword(s):  
Molecular Orbital ◽  
Optical Rotation ◽  
Structure Property ◽  
Chiral Molecules ◽  
Gauge Dependence ◽  
Space Decomposition ◽  
Structure Property Relationships ◽  
Small Set ◽  
Orbital Space

<div> <div> <div> <p>Optical rotation (OR) is a foundational technique for the detection and characterization of chiral molecules, but it is poorly understood how the observed property relates to the structure of the molecule. Over the years, several schemes have been developed to de- compose the OR into more chemically intuitive contributions. In this paper, we introduce two alternative formulations of our previously developed S molecular orbital space decomposition. These new expressions use the Modified Velocity Gauge-Magnetic (MVG-M) and -Electric (MVG-E) definitions of OR, rather than the Length Gauge Magnetic (LG-M) definition used in the original paper. Comparing these formulations across a small set of previously studied chiral molecules, we find that these different definitions produce consistent physical interpretations of the OR. These results further confirm the robustness of the S methodology for the investigation of structure-property relationships in chiral molecules.</p> </div> </div> </div>

scholarly journals Correction: Synthesis and characterization of novel Li-stuffed garnet-like Li5+2xLa3Ta2−xGdxO12 (0 ≤ x ≤ 0.55): structure–property relationships

2017 ◽  
Vol 46 (25) ◽  
pp. 8304-8305
Author(s):  
Dalia M. Abdel Basset ◽  
Suresh Mulmi ◽  
Mohammed S. El-Bana ◽  
Suzan S. Fouad ◽  
Venkataraman Thangadurai
Keyword(s):  
Synthesis And Characterization ◽  
Structure Property ◽  
Dalton Trans ◽  
Structure Property Relationships

Correction for ‘Synthesis and characterization of novel Li-stuffed garnet-like Li5+2xLa3Ta2−xGdxO12 (0 ≤ x ≤ 0.55): structure–property relationships’ by Dalia M. Abdel Basset, et al., Dalton Trans., 2017, 46, 933–946.

Aqueous-phase photooxygenation of enes, amines, sulfides and polycyclic aromatics by singlet (a1Δg) oxygen: prediction of rate constants using orbital energies, substituent factors and quantitative structure–property relationships

2017 ◽  
Vol 14 (7) ◽  
pp. 442 ◽  
Author(s):  
Tom M. Nolte ◽  
Willie J. G. M. Peijnenburg
Keyword(s):  
Singlet Oxygen ◽  
Molecular Orbital ◽  
Organic Solvents ◽  
Aqueous Phase ◽  
Rate Constant ◽  
Rate Constants ◽  
Quantitative Structure ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Quantitative Structure Property Relationships

Environmental contextTo aid the transition to sustainable chemistry there is a need to improve the degradability of chemicals and limit the use of organic solvents. Singlet oxygen, 1O2, is involved in organic synthesis and photochemical degradation; however, information on its aqueous-phase reactivity is limited. We developed cheminformatics models for photooxidation rate constants that will enable accurate assessment of aquatic photochemistry without experimentation. AbstractTo aid the transition to sustainable and green chemistry there is a general need to improve the degradability of chemicals and limit the use of organic solvents. In this study we developed quantitative structure–property relationships (QSPRs) for aqueous-phase photochemical reactions by singlet (a1Δg) oxygen. The bimolecular singlet oxygen reaction rate constant can be reliably estimated (R2 = 0.73 for naphtalenes and anthracenes, R2 = 0.86 for enes and R2 = 0.88 for aromatic amines) using the energy of the highest occupied molecular orbital (EHOMO). Additional molecular descriptors were used to characterise electronic and steric factors influencing the rate constant for aromatic enes (R2 = 0.74), sulfides and thiols (R2 = 0.72) and aliphatic amines. Mechanistic principles (frontier molecular orbital, perturbation and transition state theories) were applied to interpret the QSPRs developed and to corroborate findings in the literature. Depending on resonance, the speciation state (through protonation and deprotonation) can heavily influence the oxidation rate constant, which was accurately predicted. The QSPRs can be applied in synthetic photochemistry and for estimating chemical fate from photolysis or advanced water treatment.

Preparation and Characterization of Several Conducting Transition Metal Oxides

1989 ◽  
Vol 156 ◽  
Author(s):  
Aaron Wold ◽  
Kirby Dwight
Keyword(s):  
Transition Metal ◽  
Single Crystal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Structure Property ◽  
Metallic Behavior ◽  
Structure Property Relationships ◽  
Conduction Bands ◽  
Metal Metal

ABSTRACTThe structure-property relationships of several conducting transition metal oxides, as well as their preparative methods, are presented in this paper. The importance of preparing homogeneous phases with precisely known stoichiometry is emphasized. A comparison is also made of the various techniques used to prepare both polycrystalline and single crystal samples. For transition metal oxides, the metallic properties are discussed either in terms of metal-metal distances which are short enough to result in metallic behavior, or in terms of the formation of a П* conduction band resulting from covalent metal-oxygen interactions. Metallic behavior is observed when the conduction bands are populated with either electrons or holes. The concentration of these carriers can be affected by either cation or anion substitutions. The discussion in this presentation will be limited to the elements Re, Ti, V, Cr, Mo, and Cu.

Imidazole-Based Solvents and Membranes for CO2 Capture Applications

2014 ◽  
Vol 1673 ◽  
Author(s):  
Jason E. Bara ◽  
Matthew S. Shannon ◽  
W. Jeffrey Horne ◽  
John W. Whitley ◽  
Haining Liu ◽  
...  
Keyword(s):  
Flue Gas ◽  
Process Design ◽  
Predictive Models ◽  
Power Plants ◽  
Absorption Capacity ◽  
Computational Studies ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Imidazole Compounds

ABSTRACTImidazoles present a tunable, versatile and economical platform for the development of novel liquid solvents and polymer membranes for CO2 capture. An overview of our studies in this area is presented, with emphasis on characterization of structure-property relationships in imidazole-based materials through both experimental and computational studies. To this end, a growing library of systematically varied imidazole compounds has been synthesized using only commercial available starting materials and straightforward reactions. Using this library of compounds, we have sought to understand and develop predictive models for thermophysical properties relating to process design, including: density, viscosity, vapor pressure, pKa and CO2 absorption capacity. Furthermore, we have discovered that imidazoles are stable in the presence of SO2 and can form reversible 1:1 adducts, which can be beneficial as SO2 is typically present at ppm levels alongside CO2 in flue gas from coal-fired power plants.

Mechanical and Viscoelastic Characterization of Hyperbranched Polyisobutylenes

2002 ◽  
Vol 75 (5) ◽  
pp. 853-864 ◽  
Author(s):  
Judit E. Puskas ◽  
Christophe Paulo ◽  
Volker Altstädt
Keyword(s):  
Molecular Weight ◽  
Butyl Rubber ◽  
Structure Property ◽  
Carbocationic Polymerization ◽  
Molecular Weights ◽  
Structure Property Relationships ◽  
Molecular Weight Distributions ◽  
Weight Distributions ◽  
Living Carbocationic Polymerization

Abstract Structure-property relationships were investigated in hyperbranched polyisobutylenes, in comparison with commercial linear butyl rubber. The gel-free, soluble hyperbranched polyisobutylenes, synthesized by living carbocationic polymerization, had molecular weights, Mw≈400,000 to 1,000,000 g/mol, molecular weight distributions, MWD ≈1.2 to 2.6, and branching frequencies, BR ≈ 4 to 60. The mechanical and viscoelastic characterization of these polymers revealed interesting properties, including the characteristics of crosslinked rubbers.

Characterization of Aerogels – Challenges and Prospects

2014 ◽  
Vol 91 ◽  
pp. 54-63 ◽  
Author(s):  
Gudrun Reichenauer
Keyword(s):  
Catalyst Support ◽  
Optical Devices ◽  
Structure Property ◽  
Severe Problem ◽  
The Past ◽  
Structure Property Relationships ◽  
Potential Applications ◽  
Directed Development ◽  
Non Destructive

Aerogels are porous materials with potential applications in fields ranging from thermal insulation, catalyst support, filters, electrical storage, components in optical devices, mechanical damping all the way to drug release. However, careful reliable characterization is the base for both, understanding of fundamental structure - property relationships as well as a directed development of materials and composites for specific applications. The review therefore addressed severe problem upon aerogel characterization that have been identified in the past and presents reliable non-destructive alternatives and novel methods that can be applied for the characterization of aerogels as well as their gel precursors.

Micromechanical characterization of soft, biopolymeric hydrogels: stiffness, resilience, and failure

Soft Matter ◽  
2018 ◽  
Vol 14 (18) ◽  
pp. 3478-3489 ◽  
Author(s):  
Shruti Rattan ◽  
Linqing Li ◽  
Hang Kuen Lau ◽  
Alfred J. Crosby ◽  
Kristi L. Kiick
Keyword(s):  
Tissue Engineering ◽  
Local Structure ◽  
Structure Property ◽  
Detailed Understanding ◽  
Structure Property Relationships ◽  
Micromechanical Characterization

Detailed understanding of the local structure–property relationships in soft biopolymeric hydrogels can be instrumental for applications in regenerative tissue engineering.

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