Crystal structure and ferromagnetic behavior of a cis-Co(II) complex with nitronyl nitroxide

2000 ◽  
Vol 78 (3) ◽  
pp. 322-327
Author(s):  
Bai-Wang Sun ◽  
Qi-Hua Zhao ◽  
Dai-Zheng Liao ◽  
Zong-Hui Jiang ◽  
Shi-Ping Yan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Property ◽  
Charge Transfer ◽  
Key Words ◽  
Nitroxide Radical ◽  
Ferromagnetic Behavior ◽  
Nitronyl Nitroxide ◽  
X Ray ◽  
Ferromagnetic Exchange ◽  
A Charge

Bis(hexafluoroacetylacetonate)cobalt(II), Co(hfac)2, reacted with the nitronyl nitroxide radical 2-(4-methylphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, NITPhMe, to yield an octahedral adduct of formula Co(hfac)2(NITPhMe)2. The X-ray crystal structure shows that it crystallizes in the space group P1, with a = 9.837(3), b = 11.618(3), c = 20.502(4) Å, α = 81.22(2), β = 87.93(2), γ = 72.24(3)º, V = 2205(1) Å3, Z = 2. The mechanism of ferromagnetic exchange between cobalt(II) and the radical can be qualitatively understood in terms of a charge-transfer interaction (J being 25.7 cm-1, the Hamiltonian is written in the form H = -2J(SRad1·SCo + SCo·SRad2)).Key words: crystal structure, cobalt(II) complex, nitronyl nitroxide, magnetic property.

scholarly journals Intermolecular interactions and charge transfer in the 2:1 tetrathiafulvalene bromanil complex, (TTF)2-BA

2011 ◽  
Vol 67 (3) ◽  
pp. 244-249 ◽  
Author(s):  
Pilar García-Orduña ◽  
Slimane Dahaoui ◽  
Claude Lecomte
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Charge Transfer ◽  
Room Temperature ◽  
Charge Transfer Complex ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Donor And Acceptor ◽  
A Charge

The crystal structure of the 2:1 charge-transfer complex of tetrathiafulvalene [2,2′-bis(1,3-dithiolylidene)] and bromanil (tetrabromo-1,4-benzoquinone) [(TTF)2-BA, (C6H4S4)2–C6Br4O2] has been determined by X-ray diffraction at room temperature, 100 and 25 K. No structural phase transition occurs in the temperature range studied. The crystal is made of TTF–BA–TTF sandwich trimers. A charge-transfer estimation between donor and acceptor (0.2 e) molecules is proposed in comparison to the molecular geometries of TTF–BA and TTF and BA isolated molecules. Displacement parameters of the molecules have been modeled with the TLS formalism.

Preparation, characterization and X-ray crystal structure of a charge transfer salt (DMNP)4[SiW12O40] · 2DMF

Polyhedron ◽  
1997 ◽  
Vol 16 (4) ◽  
pp. 713-719 ◽  
Author(s):  
Xiao-Min Zhang ◽  
Bao-Zhen Shan ◽  
Xiao-Zeng You ◽  
Zhou Zhong-Yuan ◽  
Zhou Xiang-Ge
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
X Ray ◽  
A Charge

scholarly journals Isolation and X-ray Crystal Structure of an Electrogenerated TEMPO–N3 Charge-Transfer Complex

2021 ◽  
Author(s):  
Hosea M. Nelson ◽  
Juno C. Siu ◽  
Ambarneil Saha ◽  
Duilio Cascio ◽  
Samantha N. MacMillan ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Charge Transfer Complex ◽  
X Ray

scholarly journals Isolation and X-ray Crystal Structure of an Electrogenerated TEMPO–N3 Charge-Transfer Complex

2020 ◽  
Author(s):  
Hosea Nelson ◽  
Juno Siu ◽  
Ambarniel Saha ◽  
Duilio Cascio ◽  
Song-Bai Wu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Theoretical Analysis ◽  
Charge Transfer Complex ◽  
Reactive Intermediates ◽  
Structural Elucidation ◽  
Catalytic Reactions ◽  
X Ray ◽  
Increasing Demand ◽  
Computational Predictions

Recent advances in radical-based catalytic reactions have created an increasing demand for the understanding of their mechanistic underpinnings. Structural elucidation of transient reactive intermediates via diffraction techniques, though rarely possible, is one of the most decisive ways to support such mechanistic hypotheses. Here we present the isolation, structural elucidation, and theoretical analysis of an electrochemically generated and catalytically relevant charge-transfer species formed between the azidyl radical and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO). The unusual bent N–N–N angle and the pancake bonding between these two fragments highlight the weak bonding interactions present in this complex. This X-ray structure validates computational predictions as well as mechanistic proposals of TEMPO-mediated radical azidation reactions.

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