A Combined Theoretical and Experimental Study of CH3NH3PbI3 Containing AVAI Films Prepared via an Intramolecular Exchange Process

2018 ◽  
Vol 122 (34) ◽  
pp. 19705-19711 ◽  
Author(s):  
Pongthep Prajongtat ◽  
Supa Hannongbua
Keyword(s):  
Experimental Study ◽  
Exchange Process ◽  
Intramolecular Exchange

The Thermal Isomerization of Coordinated Thiocyanate in Crystalline trans-[Co(NH3)4(15NH3)SCN](N14CS)2

1993 ◽  
Vol 46 (4) ◽  
pp. 503 ◽  
Author(s):  
DA Buckingham ◽  
CR Clark ◽  
GF Liddell ◽  
J Simpson
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Hydrogen Bonding ◽  
Solid State ◽  
Exchange Process ◽  
Thermal Isomerization ◽  
Asymmetric Unit ◽  
Open Structure ◽  
Solvent Cage ◽  
Intramolecular Exchange

Heating crystalline trans-[Co(NH3)4(15NH3)SCN](N14CS)2 in the dark at c. 60°C results in the following immediate products (partial formulae are shown): 39% trans-CoNCS2+ (without incorporation of ionic thiocyanate ), 31% cis-CoS14CN2+ and 30% cis-CoN14CS2+ (with incorporation of ionic thiocyanate ). A crystal structure of the unlabelled reactant [Co(NH3)5SCN](NCS)2 [a 14.001(5), b 14.176(5), c 14.774(5) Ǻ, β 117.12(3)°, P21/n, Z = 8, 2898 reflections with I > 2σ(I), R 3.85%, Rw 4.10%] identifies two independent cobalt(III) cations in the asymmetric unit, and a consideration of the four distinct lattice thiocyanates identifies one of these, S(4)C(4)N(4)-, as that most likely to be involved in replacing the originally coordinated SCN-; S(4) at Co(1), and N(4) at Co(2). Intramolecular (as distinct from intermolecular) isomerization of coordinated thiocyanate is suggested for the formation of trans-CoNCS2+. The solid-state incorporation of lattice N14CS- and S14CN- is compared to that found in aqueous solution where ion-paired N14CS- and S14CN- as well as H2O compete in a solvent-cage, intramolecular , exchange process. The structure of the coordination isomer [Co(NH3)5NCS]SO4.1.5H2O, containing the product CoNCS2+ cation [a 6.621(9), b 7.123(21), c 26.906(19) Ǻ, Pnma, Z = 4,524 reflections with I > 2σ(1), R 6.34%, Rw 7.67%], is reported. A reexamination of the crystal structure of [Co(NH3)5SCN]Cl2.H2O (ref. 1) suggests that hydrogen bonding to ammine ligands, rather than a more open structure or poorer positioning of lattice Cl-, is the reason for the non-incorporation of ionic Cl- on heating this material.

Dynamics of the13C spin‐exchange process in solids: A theoretical and experimental study

1986 ◽  
Vol 85 (12) ◽  
pp. 7077-7086 ◽  
Author(s):  
P. Mark Henrichs ◽  
M. Linder ◽  
J. Michael Hewitt
Keyword(s):  
Experimental Study ◽  
Spin Exchange ◽  
Exchange Process

Synthesis of 31P nmr spectroscopic study of [Ag(μ-R2PCH2PR2)3Ag]2+ (R = Me or Ph). Observation of an intramolecular "end-over-end" exchange of bridging R2PCH2PR2

1987 ◽  
Vol 65 (11) ◽  
pp. 2628-2633 ◽  
Author(s):  
Philip A. W. Dean ◽  
Jagadese J. Vittal ◽  
Radhey S. Srivastava
Keyword(s):  
Low Temperature ◽  
Good Yield ◽  
Nmr Spectra ◽  
31P Nmr ◽  
Variable Temperature ◽  
Exchange Process ◽  
Mixed Ligand ◽  
Enthalpy Of Activation ◽  
Intramolecular Exchange ◽  
New Compounds

Reaction of AgAsF6 with R2PCH2PR2 (R = Ph or Me) in a 2:3 ratio in MeNO2 or Me2CO produces the new compounds [Ag2(R2PCH2PR2)3](AsF6)2, which have been isolated in good yield. The analogous 107Ag-enriched compounds are produced using 107AgAsF6. The 2:3 compounds have interesting variable temperature 31P nmr spectra which have been studied in detail using the 107Ag-enriched compounds. The 31P nmr spectra of [107Ag2(Ph2PCH2PPh2)3](AsF6)2:[107Ag2(Me2PCH2PMe2)3](AsF6)2 mixtures at ambient probe temperature show the formation of the mixed ligand binuclear cations [107Ag2(Ph2PCH2PPh2)3−x(Me2PCH2PMe2)x]2+ (x = 1 or 2). By analogy, the two parent complexes also contain binuclear cations, and the limiting low temperature 31P nmr spectra of these can be interpreted in terms of the manxane structure, [107Ag(μ-R2PCH2PR2)3107Ag]2+. With increase in temperature, the 31P nmr spectra of the parents provide evidence for an intramolecular exchange process which is faster for R = Ph than for R = Me and which is shown to involve "end-over-end" exchange of bridging R2PCH2PR2. This type of exchange has not been observed previously for these ligands. With Me2CO as solvent, an approximate value of the enthalpy of activation for exchange is 59 kJ mol−1 for [107Ag((μ-Ph2PCH2PPh2)3107Ag]2+ and 50 kJ mol−1 for [107Ag(μ.-Me2PCH2PMe2)3107Ag]2+.

Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

1995 ◽  
Vol 53 ◽  
pp. 636-637
Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe
Keyword(s):  
Experimental Study ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Optical Parameters ◽  
Beam Tilting ◽  
Illumination Method ◽  
Restoration Method ◽  
Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

An Experimental Study of Some Properties of Stuttered Words

1962 ◽  
Vol 5 (4) ◽  
pp. 387-394 ◽  
Author(s):  
Bruce Quarrington ◽  
Jerome Conway ◽  
Nathan Siegel
Keyword(s):  
Experimental Study
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