Effect of Metal-Ligand Coordination Complexes on Molecular Dynamics and Structure of Cross-Linked Poly(dimethylosiloxane)

Poly(dimethylosiloxane) (PDMS) cross-linked by metal-ligand coordination has a potential functionality for electronic devices applications. In this work, the molecular dynamics of bipyridine (bpy)–PDMS-MeCl2 (Me: Mn2+, Fe2+, Ni2+, and Zn2+) are investigated by means of broadband dielectric spectroscopy and supported by differential scanning calorimetry and density functional theory calculations. The study of molecular motions covered a broad range of temperatures and frequencies and was performed for the first time for metal-ligand cross-linked PDMS. It was found that the incorporation of bpy moieties into PDMS chain prevents its crystallization. The dielectric permittivity of studied organometallic systems was elevated and almost two times higher (ε′ ~4 at 1 MHz) than in neat PDMS. BpyPDMS-MeCl2 complexes exhibit slightly higher glass transition temperature and fragility as compared to a neat PDMS. Two segmental type relaxations (α and αac) were observed in dielectric studies, and their origin was discussed in relation to the molecular structure of investigated complexes. The αac relaxation was observed for the first time in amorphous metal-ligand complexes. It originates from the lower mobility of PDMS polymer chains, which are immobilized by metal-ligand coordination centers via bipyridine moieties.

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Effects of Counter Anions on AC and DC Electrical Conductivity in Poly(Dimethylsiloxane) Crosslinked by Metal-Ligand Coordination

Polymers ◽

10.3390/polym13060956 ◽

2021 ◽

Vol 13 (6) ◽

pp. 956

Author(s):

Angelika Wrzesińska ◽

Aleksandra Wypych-Puszkarz ◽

Izabela Bobowska ◽

Jacek Ulański

Keyword(s):

Electrical Conductivity ◽

Field Effect Transistors ◽

Metal Salt ◽

Dielectric Materials ◽

Organic Field Effect Transistors ◽

Broadband Dielectric Spectroscopy ◽

Dc Electrical Conductivity ◽

Ligand Coordination ◽

First Time ◽

Metal Ligand

There is an urgent need for the development of elastic dielectric materials for flexible organic field effect transistors (OFETs). In this work, detailed analysis of the AC and DC electrical conductivity of a series of flexible poly(dimethylsiloxane) (PDMS) polymers crosslinked by metal-ligand coordination in comparison to neat PDMS was performed for the first time by means of broadband dielectric spectroscopy. The ligand was 2,2-bipyridine-4,4-dicarboxylic amide, and Ni2+, Mn2+, and Zn2+ were introduced for Cl−, Br−, and I− salts. Introduction of metal salt and creation of coordination bonds resulted in higher permittivity values increasing in an order: neat PDMS < Ni2+ < Mn2+ < Zn2+; accompanied by conductivity values of the materials increasing in an order: neat PDMS < Cl− < I− < Br−. Conductivity relaxation time plot as a function of temperature, showed Vogel-Fulcher–Tammann dependance for the Br− salts and Arrhenius type for the Cl− and I− salts. Performed study revealed that double-edged challenge can be obtained, i.e., dielectric materials with elevated value of dielectric permittivity without deterioration too much the non-conductive nature of the polymer. This opens up new perspectives for the production of flexible dielectrics suitable for gate insulators in OFETs. Among the synthesized organometallic materials, those with chlorides salts are the most promising for such applications.

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Graphene adlayer growth between nonepitaxial graphene and Ni(111) substrate: a promising theoretical scheme

Physical Chemistry Chemical Physics ◽

10.1039/d0cp04667a ◽

2020 ◽

Author(s):

Lijuan Meng ◽

Jinlian Lu ◽

Yujie Bai ◽

Lili Liu ◽

Tang Jingyi ◽

...

Keyword(s):

Molecular Dynamics ◽

Density Functional Theory ◽

Chemical Vapor Deposition ◽

Molecular Dynamics Simulations ◽

Vapor Deposition ◽

Density Functional ◽

Chemical Vapor ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

Dynamics Simulations

Understanding the fundamentals of chemical vapor deposition bilayer graphene growth is crucial for its synthesis. By employing density functional theory calculations and classical molecular dynamics simulations, we have investigated the...

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H2O coordination in macropa complexes of f elements (Ac, La, Lu): feasibility of the 11th coordination site

Structural Chemistry ◽

10.1007/s11224-020-01717-3 ◽

2021 ◽

Author(s):

Attila Kovács ◽

Zoltán Varga

Keyword(s):

Aqueous Solution ◽

Metal Ion ◽

Density Functional ◽

Molecular Level ◽

Density Functional Theory Calculations ◽

Functional Theory ◽

Coordination Site ◽

Additional Ligand ◽

Ligand Coordination ◽

Bonding Properties

AbstractThe feasibility of an additional ligand coordination at the 11th coordination site of actinium, lanthanum, and lutetium ions in 10-fold coordinated macropa complexes has been studied by means of density functional theory calculations. The study covered the two main macropa conformers, Δ(δλδ)(δλδ) and Δ(λδλ)(λδλ), favoured by larger (Ac3+, La3+) and smaller (Lu3+) ions, respectively. At the molecular level, the coordination of H2O is the most favourable to the largest Ac3+ while only slightly less to La3+. Protonation of the picoline arms enhances the coordination by shifting the metal ion closer to the open site of the ligand. The choice of macropa conformer has only a slight influence on the strength and bonding properties of the H2O coordination. Aqueous solution environment decreases considerably the energy gain of H2O coordination at the 11th coordination site.

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Molecular Insights into Cage Occupancy of Hydrogen Hydrate: A Computational Study

Processes ◽

10.3390/pr7100699 ◽

2019 ◽

Vol 7 (10) ◽

pp. 699 ◽

Cited By ~ 2

Author(s):

Ma ◽

Zhong ◽

Liu ◽

Zhong ◽

Yan ◽

...

Keyword(s):

Molecular Dynamics ◽

Hydrogen Storage ◽

Molecular Dynamics Simulations ◽

Density Functional ◽

Storage Capacity ◽

Computational Study ◽

Density Functional Theory Calculations ◽

Hydrogen Storage Capacity ◽

Large Cage ◽

Dynamics Simulations

Density functional theory calculations and molecular dynamics simulations were performed to investigate the hydrogen storage capacity in the sII hydrate. Calculation results show that the optimum hydrogen storage capacity is ~5.6 wt%, with the double occupancy in the small cage and quintuple occupancy in the large cage. Molecular dynamics simulations indicate that these multiple occupied hydrogen hydrates can occur at mild conditions, and their stability will be further enhanced by increasing the pressure or decreasing the temperature. Our work highlights that the hydrate is a promising material for storing hydrogen.

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Solvent Effect on the Structure and Properties of RGD Peptide (1FUV) at Body Temperature (310 K) Using Ab Initio Molecular Dynamics

Polymers ◽

10.3390/polym13193434 ◽

2021 ◽

Vol 13 (19) ◽

pp. 3434

Author(s):

Khagendra Baral ◽

Puja Adhikari ◽

Bahaa Jawad ◽

Rudolf Podgornik ◽

Wai-Yim Ching

Keyword(s):

Molecular Dynamics ◽

Body Temperature ◽

Ab Initio ◽

Density Functional ◽

Density Functional Theory Calculations ◽

Rgd Peptide ◽

Ab Initio Molecular Dynamics ◽

Quantum Mechanical ◽

Aqueous Environment ◽

Structure And Properties

The structure and properties of the arginine-glycine-aspartate (RGD) sequence of the 1FUV peptide at 0 K and body temperature (310 K) are systematically investigated in a dry and aqueous environment using more accurate ab initio molecular dynamics and density functional theory calculations. The fundamental properties, such as electronic structure, interatomic bonding, partial charge distribution, and dielectric response function at 0 and 310 K are analyzed, comparing them in dry and solvated models. These accurate microscopic parameters determined from highly reliable quantum mechanical calculations are useful to define the range and strength of complex molecular interactions occurring between the RGD peptide and the integrin receptor. The in-depth bonding picture analyzed using a novel quantum mechanical metric, the total bond order (TBO), quantifies the role played by hydrogen bonds in the internal cohesion of the simulated structures. The TBO at 310 K decreases in the dry model but increases in the solvated model. These differences are small but extremely important in the context of conditions prevalent in the human body and relevant for health issues. Our results provide a new level of understanding of the structure and properties of the 1FUV peptide and help in advancing the study of RGD containing other peptides.

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The mechanism of aquaporin inhibition by gold compounds elucidated by biophysical and computational methods

Chemical Communications ◽

10.1039/c7cc00318h ◽

2017 ◽

Vol 53 (27) ◽

pp. 3830-3833 ◽

Cited By ~ 24

Author(s):

Andreia de Almeida ◽

Andreia F. Mósca ◽

Darren Wragg ◽

Margot Wenzel ◽

Paul Kavanagh ◽

...

Keyword(s):

Molecular Dynamics ◽

Density Functional Theory ◽

Computational Methods ◽

Density Functional ◽

Electrochemical Studies ◽

Functional Theory ◽

Mechanism Of Inhibition ◽

Gold Compounds ◽

First Time

The mechanism of inhibition of water and glycerol permeation via human aquaglyceroporin-3 (AQP3) by gold(iii) complexes has been described, for the first time, using molecular dynamics (MD), combined with density functional theory (DFT) and electrochemical studies.

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Predicted polymorph manipulation in an exotic double perovskite oxide

Journal of Materials Chemistry C ◽

10.1039/c9tc03367j ◽

2019 ◽

Vol 7 (39) ◽

pp. 12306-12311 ◽

Cited By ~ 4

Author(s):

He-Ping Su ◽

Shu-Fang Li ◽

Yifeng Han ◽

Mei-Xia Wu ◽

Churen Gui ◽

...

Keyword(s):

Phase Transition ◽

Density Functional Theory ◽

First Principles ◽

Density Functional ◽

Double Perovskite ◽

Density Functional Theory Calculations ◽

Perovskite Oxide ◽

Functional Theory ◽

First Time ◽

Perovskite Type

First-principles density functional theory calculations, for the first time, was used to predict the Mg3TeO6-to-perovskite type phase transition in Mn3TeO6 at around 5 GPa.

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