scholarly journals Structural patterns at all scales in a nonmetallic chiral Au133(SR)52 nanoparticle

2015 ◽  
Vol 1 (2) ◽  
pp. e1500045 ◽  
Author(s):  
Chenjie Zeng ◽  
Yuxiang Chen ◽  
Kristin Kirschbaum ◽  
Kannatassen Appavoo ◽  
Matthew Y. Sfeir ◽  
...  
Keyword(s):  
Surface Characterization ◽  
Gold Atom ◽  
Complex Surface ◽  
Metal Core ◽  
Structural Ordering ◽  
X Ray Crystallography ◽  
Thiolate Ligands ◽  
Pattern Structures ◽  
Surface Patterns ◽  
Conceptual Advance

Structural ordering is widely present in molecules and materials. However, the organization of molecules on the curved surface of nanoparticles is still the least understood owing to the major limitations of the current surface characterization tools. By the merits of x-ray crystallography, we reveal the structural ordering at all scales in a super robust 133–gold atom nanoparticle protected by 52 thiolate ligands, which is manifested in self-assembled hierarchical patterns starting from the metal core to the interfacial –S–Au–S– ladder-like helical “stripes” and further to the “swirls” of carbon tails. These complex surface patterns have not been observed in the smaller nanoparticles. We further demonstrate that the Au133(SR)52 nanoparticle exhibits nonmetallic features in optical and electron dynamics measurements. Our work uncovers the elegant self-organization strategies in assembling a highly robust nanoparticle and provides a conceptual advance in scientific understanding of pattern structures.

scholarly journals Production of Hydrophobic Zein-Based Films Bioinspired by The Lotus Leaf Surface: Characterization and Bioactive Properties

2019 ◽  
Vol 7 (8) ◽  
pp. 267 ◽  
Author(s):  
Luís ◽  
Domingues ◽  
Ramos
Keyword(s):  
Contact Angle ◽  
Essential Oil ◽  
Food Packaging ◽  
Surface Characterization ◽  
Antibacterial Properties ◽  
Complex Surface ◽  
Scanning Calorimetry ◽  
Water Contact ◽  
Lotus Leaf ◽  
Surface Patterns

Hydrophobic zein-based functional films incorporating licorice essential oil were successfully developed as new alternative materials for food packaging. The lotus-leaf negative template was obtained using polydimethylsiloxane (PDMS). The complex surface patterns of the lotus leaves were transferred onto the surface of the zein-based films with high fidelity (positive replica), which validates the proposed proof-of-concept. The films were prepared by casting method and fully characterized by Scanning Electron Microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC). The grammage, thickness, contact angle, mechanical, optical and barrier properties of the films were measured, together with the evaluation of their biodegradability, antioxidant and antibacterial activities against common foodborne pathogens (Enterococcus faecalis and Listeria monocytogenes). The zein-based films with the incorporation of licorice essential oil presented the typical rugosities of the lotus leaf making the surfaces very hydrophobic (water contact angle of 112.50°). In addition to having antioxidant and antibacterial properties, the films also shown to be biodegradable, making them a strong alternative to the traditional plastics used in food packaging.

scholarly journals Unique Digoldgermanes: Structural Characteristics, Dynamic Behaviour and Distinctive Reactions

2021 ◽  
Author(s):  
Liliang Wang ◽  
Guorong Zhen ◽  
Yinhuan Li ◽  
Mitsuo Kira ◽  
Liping Yan ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Dynamic Behaviour ◽  
Structural Characteristics ◽  
Bond Formation ◽  
Gold Atom ◽  
Addition Product ◽  
X Ray ◽  
Ambient Temperatures ◽  
X Ray Crystallography ◽  
H Nmr

Abstract Digoldgermanes with a gold coordinated by a dialkylgermylene ligand, R’2Ge(AuPR3)(AuGeR’2) (3a; R = Me, 3b; R = Et), were synthesized as green solids through the reactions of stable dialkylgermylene 1 with R3PAuCl followed by the reduction with KC8 at ambient temperatures. The structural characteristics of 3a and 3b were elucidated using NMR spectroscopy, X-ray crystallography, and DFT calculations. An intense absorption maximum was observed at 590 nm in the UV-vis spectrum of 3a in hexane. A pendular motion of AuPR3 group between Ge(IV) and Ge(II) of 3a and 3b occurring in the NMR time scale was found by the dynamic 1H NMR analysis, suggesting that the Ge(II) ligand has an enhanced electrophilicity to be attacked by the nucleophilic gold atom which closes to ‒1 oxidation state. DFT calculations of 3a revealed the existence of high-lying σ(Ge-Au) type HOMO and low-lying LUMO with germylene pπ nature. We show the bond formation and activation alternatively at Au or Ge atom, a methylation of digoldgermane 3a with MeOTf affords methylgermane 5. Moreover, the digoldgermane 3a reacts with Cl− ion of Ph4PCl and CH3C(O)Cl smoothly to form the corresponding chloride-addition product 7 and chlorogoldgermane 9, respectively. Cyclic trimerization reactions of aromatic isocyanates were high-efficiently catalyzed by 3a giving the corresponding 1,3,5-triaryl isocyanurates.

scholarly journals Synthesis, Crystal Structures, Electronic Spectra, and Magnetic Properties of Thiolato-Bridged Trinuclear Cobalt(II) Complexes with N, N, S-Tridentate Thiolate Ligands

2021 ◽  
Vol 3 (1) ◽  
pp. 0210102
Author(s):  
Masahiro Mikuriya ◽  
Atsushi Fujita ◽  
Takanori Kotera ◽  
Daisuke Yoshioka ◽  
Hiroshi Sakiyama ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Single Crystal ◽  
Electronic Spectra ◽  
Coordination Mode ◽  
Linear Arrangement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Thiolate Ligands ◽  
Trinuclear Complexes ◽  
I 11

New trinuclear CoII complexes, [{Co(apaet)2}2Co]X2 (apaet– = 2-[(3-aminopropyl)amino]ethanethiolato; X = SCN (1), ClO4 (2), NO3 (3), Cl (4), Br (5), I (6)) and [{Co(apampt)2}2Co]X2 (apampt– = 1-[(3-aminopropyl)amino]-2-methylpropane-2-thiolato; X = NO3(7), ClO4 (8), Cl (9), Br (10), I (11)), and mononuclear CoIII complexes, [Co(apaet)2]X (X = ClO4 (12), NO3 (13)), were synthesized. Single-crystal X-ray crystallography of 1 and 7 confirmed that the trinuclear complexes have a linear arrangement of octahedral CoIIS2N4-tetrahedral CoIIS4-octahedral CoIIS2N4 chromophores where two thiolate ligands are coordinated to each terminal Co atom in a mer coordination mode and the two thiolato S atoms are further bound to the central Co atom, which is consistent with the electronic spectra and antiferromagnetic properties

A MULTIFUNCTIONAL AND PORTABLE OPTICAL SENSOR FOR QUANTITATIVE CHARACTERIZATION OF 3D SURFACE TEXTURE PROPERTIES

2010 ◽  
Vol 07 (04) ◽  
pp. 269-284
Author(s):  
YANTAO SHEN ◽  
YONGXIONG WANG ◽  
NING XI
Keyword(s):  
Mechanical Properties ◽  
Surface Texture ◽  
Surface Characterization ◽  
Texture Features ◽  
Mechanical Impedance ◽  
Quantitative Characterization ◽  
Texture Properties ◽  
Surface Patterns ◽  
3D Surface Texture

Surface characterization technologies are generally sorted into two categories: noncontact and contact-based technologies. Among these technologies, no one can stand out to simultaneously and rapidly measure both surface patterns/textures and mechanical properties such as softness, friction, and mechanical impedance. In this paper, we have addressed this problem and developed a multifunctional and portable surface texture sensor through combination of both contact and noncontact optical surface profiling mechanisms. The developed sensor relying on an optomechanical principle can be efficiently used for quantitative characterization of surface texture properties including 3D texture pattern, roughness, and even mechanical properties like softness, etc. As one of the important applications, we have used the sensor to measure and analyze texture properties of extensive automotive interior leather sample surfaces. The results demonstrate that the sensor can effectively assist the interior designer to quantify and classify essential texture features of automobile interior surfaces.

scholarly journals Gold Nanoparticles Bearing an α-Lipoic Acid-based Ligand Shell: Synthesis, Model Complexes and Studies Concerning Phosphorescent Platinum(II)-Functionalisation

2010 ◽  
Vol 65 (9) ◽  
pp. 1089-1096 ◽  
Author(s):  
Ulrich Siemeling ◽  
Frauke Bretthauer ◽  
Clemens Bruhn ◽  
Tim-Patrick Fellinger ◽  
Wah-Leung Tong ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Lipoic Acid ◽  
Precious Metal ◽  
Platinum Complexes ◽  
Metal Core ◽  
Model Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ligand Shell ◽  
Surface Functionalisation

The surface functionalisation of gold nanoparticles (GNPs) with luminescent platinum complexes has been investigated, utilising α-lipoic acid derivatives for GNP stabilisation. Model complexes have been studied to mimic the chemisorption chemistry required to afford GNPs protected by an α-lipoic acid-based ligand shell with terminal functionalisation suitable for metal coordination, and the unambiguous binding of the cyclic disulfide moiety at a zero-valent precious metal core through oxidative addition has been confirmed by X-ray crystallography. Subsequently, gold nanoparticles bearing the α-lipoic acid-based ligand shell have been prepared and characterised, and a synthetic methodology for the immobilisation of PtII luminophores onto their surface has been established.

Chiral Structure of Thiolate-Protected 28-Gold-Atom Nanocluster Determined by X-ray Crystallography

2013 ◽  
Vol 135 (27) ◽  
pp. 10011-10013 ◽  
Author(s):  
Chenjie Zeng ◽  
Tao Li ◽  
Anindita Das ◽  
Nathaniel L. Rosi ◽  
Rongchao Jin
Keyword(s):  
Gold Atom ◽  
Chiral Structure ◽  
X Ray ◽  
X Ray Crystallography

Laser Interference Nanolithography with a 405nm Fiber Semiconductor Laser

2013 ◽  
Vol 552 ◽  
pp. 262-267 ◽  
Author(s):  
Jia Xu ◽  
Zuo Bin Wang ◽  
Zhan Kun Weng ◽  
Zhi Ming Li ◽  
Xiao Juan Sun ◽  
...  
Keyword(s):  
Semiconductor Laser ◽  
Low Cost ◽  
Exposure Dose ◽  
Surface Pattern ◽  
Laser Interference ◽  
Feature Size ◽  
Nano Fabrication ◽  
Pattern Structures ◽  
Environmental Variations ◽  
Surface Patterns

This paper presents a method of laser interference nanolithography for the formation of interference patterns on the resist using a fiber semiconductor laser with a wavelength of 405nm. In the method, surface pattern structures are fabricated through the control of the incident angles of two interfering beams, the exposure dose of laser radiation and the development time. The angle adjustment becomes more convenient and the influence of environmental variations on the system has been reduced due to the use of fiber optic components. In the work, a feature size of down to 63nm and a pattern period of 215nm were achieved. The experimental results have shown that the method can be used for low cost micro and nano fabrication of periodical surface patterns with the features of low cost, simplicity and flexibility.

From partial to complete optical erasure of azobenzene–polymer gratings: effect of molecular weight

2015 ◽  
Vol 3 (42) ◽  
pp. 11011-11016 ◽  
Author(s):  
Jaana Vapaavuori ◽  
Robin H. A. Ras ◽  
Matti Kaivola ◽  
C. Geraldine Bazuin ◽  
Arri Priimagi
Keyword(s):  
Modulation Depth ◽  
Complex Surface ◽  
Ambient Conditions ◽  
Azobenzene Polymer ◽  
High Modulation ◽  
All Optical ◽  
Surface Patterns ◽  
Spatially Varying ◽  
Polymer Gratings ◽  
Grating Vector

We demonstrate complete all-optical erasure of high-modulation-depth azopolymer surface patterns at ambient conditions. Applying selective optical erasure and rewriting can be translated into complex surface patterns with spatially varying grating vector directions.

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