Syntheses, structures, and reactivities of the sulfur-bridged trinuclear complexes [(L)Ru(CO)(PPh3)]2(.mu.-MS4) (L = PhNCHS, CH2CH2(C5H4N), CH2CH2C(O)OMe; M = Mo, W). Photochemical and chemical reactions and isolation of a trinuclear complex having a coordinatively unsaturated ruthenium atom

1992 ◽  
Vol 31 (1) ◽  
pp. 26-35 ◽  
Author(s):  
Masao Kato ◽  
Masaki Kawano ◽  
Hirokazu Taniguchi ◽  
Mikimasa Funaki ◽  
Hiroshi Moriyama ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Trinuclear Complex ◽  
Trinuclear Complexes ◽  
Ruthenium Atom

Isolation and Studies of Thioether-functionalized Pyrazole Derived Cu(I)-based Cyclic Trinuclear Complex and Its Coordination Polymers with [Cu2I2] and [BiBr3] Nodes

2021 ◽  
Author(s):  
Zhi-Qing Lin ◽  
Sai-Li Zheng ◽  
Jie-Ying Hu ◽  
Hua-Qun Zhou ◽  
Zihao Feng ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Molecular Level ◽  
Trinuclear Complex ◽  
Coinage Metal ◽  
Trinuclear Complexes

Cu(I)-based cyclic trinuclear complexes (CTCs) represent one of the most intensively investigated candidates in coinage metal-derived CTCs because of their rich photoluminescent properties. Beyond molecular level, coordination polymers built upon...

Macrocyclic Thiophene-Appended Cyanido-Bridged CoIII/FeII Complexes: Precursors to Mixed-valent Poly-thiophene Hybrid Materials

2009 ◽  
Vol 62 (10) ◽  
pp. 1214 ◽  
Author(s):  
Sharizal Hasan ◽  
Nathan L. Kilah ◽  
Manuel Martinez ◽  
Paul V. Bernhardt
Keyword(s):  
Hybrid Materials ◽  
Transition Metal Ions ◽  
Spectroscopic Properties ◽  
Trinuclear Complex ◽  
Metal Charge ◽  
Trinuclear Complexes ◽  
Redox Active ◽  
Charge Transfer Transitions ◽  
Active Transition ◽  
Metal Charge Transfer

The new cyanido-bridged mixed valent FeII/CoIII macrocyclic complexes [L2CoIII(μ-NC)FeII(CN)5]– and trans-[L2CoIII(μ-NC)FeII(CN)4(μ-CN)CoIIIL2]2+ have been prepared and characterized spectroscopically. The trinuclear complex trans-[L2Co(μ-NC)Fe(CN)4(μ-CN)CoL2](ClO4)2·11H2O has been characterized crystallographically. The di- and trinuclear complexes exhibit metal-to-metal charge transfer transitions characteristic of Class II mixed valent chromophores and their redox and spectroscopic properties have been analyzed by Hush theory. The thiophene group attached to the macrocycle L2 in these complexes may serve as a precursor to conducting polythiophene-based hybrid materials incorporating redox active transition metal ions.

scholarly journals Halogen-bonded network of trinuclear copper(II) 4-iodopyrazolate complexes formed by mutual breakdown of chloroform and nanojars

2016 ◽  
Vol 72 (11) ◽  
pp. 1517-1520 ◽  
Author(s):  
Stuart A. Surmann ◽  
Gellert Mezei
Keyword(s):  
Halogen Bonding ◽  
Title Complex ◽  
Trinuclear Complex ◽  
Structural Description ◽  
Two Dimensional ◽  
Halogen Bonds ◽  
Trinuclear Complexes ◽  
Complete Breakdown ◽  
Solvent Molecules ◽  
Substituted Pyrazoles

Crystals of bis(tetrabutylammonium) di-μ3-chlorido-tris(μ2-4-iodopyrazolato-κ2N:N′)tris[chloridocuprate(II)] 1,4-dioxane hemisolvate, (C16H36N)2[Cu3(C3H2IN2)3Cl5]·0.5C4H8O or (Bu4N)2[CuII3(μ3-Cl)2(μ-4-I-pz)3Cl3]·0.5C4H8O, were obtained by evaporating a solution of (Bu4N)2[{CuII(μ-OH)(μ-4-I-pz)}nCO3] (n= 27–31) nanojars in chloroform/1,4-dioxane. The decomposition of chloroform in the presence of oxygen and moisture provides HCl, which leads to the breakdown of nanojars to the title trinuclear copper(II) pyrazolate complex, and possibly CuIIions and free 4-iodopyrazole. CuIIions, in turn, act as catalyst for the accelerated decomposition of chloroform, ultimately leading to the complete breakdown of nanojars. The crystal structure presented here provides the first structural description of a trinuclear copper(II) pyrazolate complex with iodine-substituted pyrazoles. In contrast to related trinuclear complexes based on differently substituted 4-R-pyrazoles (R= H, Cl, Br, Me), the [Cu3(μ-4-I-pz)3Cl3] core in the title complex is nearly planar. This difference is likely a result of the presence of the iodine substituent, which provides a unique, novel feature in copper pyrazolate chemistry. Thus, the iodine atoms form halogen bonds with the terminal chlorido ligands of the surrounding complexes [mean length of I...Cl contacts = 3.48 (1) Å], leading to an extended two-dimensional, halogen-bonded network along (-110). The cavities within this framework are filled by centrosymmetric 1,4-dioxane solvent molecules, which create further bridgesviaC—H...Cl hydrogen bonds with terminal chlorido ligands of the trinuclear complex not involved in halogen bonding.

Surface reactions observed by photoemission electron microscopy (PEEM)

1992 ◽  
Vol 50 (1) ◽  
pp. 286-287
Author(s):  
H.H. Rotermund
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Work Function ◽  
Chemical Reactions ◽  
Reaction Diffusion ◽  
Dynamic Processes ◽  
Clean Surface ◽  
Crystal Surfaces ◽  
Single Crystal Surfaces ◽  
Photoemission Electron

Chemical reactions at a surface will in most cases show a measurable influence on the work function of the clean surface. This change of the work function δφ can be used to image the local distributions of the investigated reaction,.if one of the reacting partners is adsorbed at the surface in form of islands of sufficient size (Δ>0.2μm). These can than be visualized via a photoemission electron microscope (PEEM). Changes of φ as low as 2 meV give already a change in the total intensity of a PEEM picture. To achieve reasonable contrast for an image several 10 meV of δφ are needed. Dynamic processes as surface diffusion of CO or O on single crystal surfaces as well as reaction / diffusion fronts have been observed in real time and space.

Microwaves: Application in Electron Microscopy

1990 ◽  
Vol 48 (3) ◽  
pp. 140-141
Author(s):  
Anthony S-Y Leong ◽  
David W Gove
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Tissue Fixation ◽  
Primary Method ◽  
Dipolar Molecules ◽  
Wide Range ◽  
Time Required ◽  
Cryostat Sections

Microwaves (MW) are electromagnetic waves which are commonly generated at a frequency of 2.45 GHz. When dipolar molecules such as water, the polar side chains of proteins and other molecules with an uneven distribution of electrical charge are exposed to such non-ionizing radiation, they oscillate through 180° at a rate of 2,450 million cycles/s. This rapid kinetic movement results in accelerated chemical reactions and produces instantaneous heat. MWs have recently been applied to a wide range of procedures for light microscopy. MWs generated by domestic ovens have been used as a primary method of tissue fixation, it has been applied to the various stages of tissue processing as well as to a wide variety of staining procedures. This use of MWs has not only resulted in drastic reductions in the time required for tissue fixation, processing and staining, but have also produced better cytologic images in cryostat sections, and more importantly, have resulted in better preservation of cellular antigens.

Fine structure and properties of defects in naturally occurring silicates and oxides

1990 ◽  
Vol 48 (4) ◽  
pp. 460-461
Author(s):  
David R. Veblen
Keyword(s):  
Chemical Reactions ◽  
High Resolution Electron Microscopy ◽  
Extended Defects ◽  
Single Chain ◽  
Naturally Occurring ◽  
Resolution Electron ◽  
Fine Structures ◽  
Image Simulations ◽  
Similar Crystal Structure

Extended defects and interfaces control many processes in rock-forming minerals, from chemical reactions to rock deformation. In many cases, it is not the average structure of a defect or interface that is most important, but rather the structure of defect terminations or offsets in an interface. One of the major thrusts of high-resolution electron microscopy in the earth sciences has been to identify the role of defect fine structures in reactions and to determine the structures of such features. This paper will review studies using HREM and image simulations to determine the structures of defects in silicate and oxide minerals and present several examples of the role of defects in mineral chemical reactions. In some cases, the geological occurrence can be used to constrain the diffusional properties of defects.The simplest reactions in minerals involve exsolution (precipitation) of one mineral from another with a similar crystal structure, and pyroxenes (single-chain silicates) provide a good example. Although conventional TEM studies have led to a basic understanding of this sort of phase separation in pyroxenes via spinodal decomposition or nucleation and growth, HREM has provided a much more detailed appreciation of the processes involved.

Gum Arabic in Chemical Reactions

1883 ◽  
Vol 15 (366supp) ◽  
pp. 5844-5844
Author(s):  
MM. Jules Lefort ◽  
P. Thibault
Keyword(s):  
Chemical Reactions ◽  
Gum Arabic
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