The synthesis, structure, and electrochemical properties of Fe(C≡CC≡N)(dppe)Cp and related compounds

2006 ◽  
Vol 84 (2) ◽  
pp. 154-163 ◽  
Author(s):  
Mark E Smith ◽  
Richard L Cordiner ◽  
David Albesa-Jové ◽  
Dmitri S Yufit ◽  
František Hartl ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Charge Transfer ◽  
Electrochemical Properties ◽  
Key Words ◽  
Ground State ◽  
Structural Data ◽  
Sequential Reaction ◽  
Heterobimetallic Complexes ◽  
Related Compounds ◽  
Degree Of Charge Transfer

The cyanoacetylide complex Fe(C≡CC≡N)(dppe)Cp (3) is readily obtained from sequential reaction of Fe(C≡CSiMe3)(dppe)Cp with methyllithium and phenyl cyanate. Complex 3 is a good metalloligand, and coordination to the metal fragments [RhCl(CO)2], [Ru(PPh3)2Cp]+, and [Ru(dppe)Cp*]+ affords the corresponding cyanoaceylide-bridged heterobimetallic complexes. In the case of the 36-electron complexes [Cp(dppe)Fe-C≡CC≡N-MLn]n+, spectroscopic and structural data are consistent with a degree of charge transfer from the iron centre to the rhodium or ruthenium centre via the C3N bridge, giving rise to a polarized ground state. Electrochemical and spectroelectrochemical methods reveal significant interactions between the metal centres in the oxidized (35 electron) derivatives, [Cp(dppe)Fe-C≡CC≡N-MLn](n+1)+. Key words: cyanide, cyanoacetylide, crystal structure.

scholarly journals Crystal Structure of the N112A Mutant of the Light-Driven Sodium Pump KR2

Crystals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 496
Author(s):  
Nina Maliar ◽  
Kirill Kovalev ◽  
Christian Baeken ◽  
Taras Balandin ◽  
Roman Astashkin ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ground State ◽  
Rational Design ◽  
Sodium Pump ◽  
Ion Selectivity ◽  
Structural Data ◽  
Functional Variants ◽  
Model Protein ◽  
The Moment ◽  
A Minor

The light-driven sodium pump KR2, found in 2013 in the marine bacteria Krokinobacter eikastus, serves as a model protein for the studies of the sodium-pumping microbial rhodopsins (NaRs). KR2 possesses a unique NDQ (N112, D116, and Q123) set of the amino acid residues in the functionally relevant positions, named the NDQ motif. The N112 was shown to determine the Na+/H+ selectivity and pumping efficiency of the protein. Thus, N112A mutation converts KR2 into an outward proton pump. However, no structural data on the functional conversions of the light-driven sodium pumps are available at the moment. Here we present the crystal structure of the N112A mutant of KR2 in the ground state at the resolution of 2.4 Å. The structure revealed a minor deflection in the central part of the helix C and a double conformation of the L74 residue in the mutant. The organization of the retinal Schiff base and neighboring water molecules is preserved in the ground state of KR2-N112A. The presented data provide structural insights into the effects of the alterations of the characteristic NDQ motif of NaRs. Our findings also demonstrate that for the rational design of the KR2 variants with modified ion selectivity for optogenetic applications, the structures of the intermediate states of both the protein and its functional variants are required.

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.

Crystal Structure of Bis(4-methylimidazole)tetraphenylporphyrinatoiron(III) Chloride and Related Compounds. Correlation of Ground State with Fe−N Bond Lengths

2000 ◽  
Vol 39 (13) ◽  
pp. 2874-2881 ◽  
Author(s):  
Jack Silver ◽  
Paul J. Marsh ◽  
Martyn C. R. Symons ◽  
Dimitri A. Svistunenko ◽  
Christopher S. Frampton ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ground State ◽  
Bond Lengths ◽  
Related Compounds

Fluorescence Quenching of Aminodiphenylamines with Chloromethanes

2002 ◽  
Vol 67 (8) ◽  
pp. 1154-1164 ◽  
Author(s):  
Nachiappan Radha ◽  
Meenakshisundaram Swaminathan
Keyword(s):  
Charge Transfer ◽  
Fluorescence Quenching ◽  
Ground State ◽  
Rate Constants ◽  
Quenching Mechanism ◽  
Quenching Rate ◽  
Charge Transfer Interaction ◽  
Electronically Excited ◽  
A Charge

The fluorescence quenching of 2-aminodiphenylamine (2ADPA), 4-aminodiphenylamine (4ADPA) and 4,4'-diaminodiphenylamine (DADPA) with tetrachloromethane, chloroform and dichloromethane have been studied in hexane, dioxane, acetonitrile and methanol as solvents. The quenching rate constants for the process have also been obtained by measuring the lifetimes of the fluorophores. The quenching was found to be dynamic in all cases. For 2ADPA and 4ADPA, the quenching rate constants of CCl4 and CHCl3 depend on the viscosity, whereas in the case of CH2Cl2, kq depends on polarity. The quenching rate constants for DADPA with CCl4 are viscosity-dependent but the quenching with CHCl3 and CH2Cl2 depends on the polarity of the solvents. From the results, the quenching mechanism is explained by the formation of a non-emissive complex involving a charge-transfer interaction between the electronically excited fluorophores and ground-state chloromethanes.

Charge Transfer Between CO22+ and Ar or Ne at Collision Energies 3-10 eV

2003 ◽  
Vol 68 (1) ◽  
pp. 178-188 ◽  
Author(s):  
Libor Mrázek ◽  
Ján Žabka ◽  
Zdeněk Dolejšek ◽  
Zdeněk Herman
Keyword(s):  
Charge Transfer ◽  
Excited States ◽  
Ground State ◽  
Scattering Method ◽  
Translational Energy ◽  
Centre Of Mass ◽  
Energy Distributions ◽  
Zener Model ◽  
Beam Scattering ◽  
Product Ions

The beam scattering method was used to investigate non-dissociative single-electron charge transfer between the molecular dication CO22+ and Ar or Ne at several collision energies between 3-10 eV (centre-of-mass, c.m.). Relative translational energy distributions of the product ions showed that in the reaction with Ar the CO2+ product was mainly formed in reactions of the ground state of the dication, CO22+(X3Σg-), leading to the excited states of the product CO2+(A2Πu) and CO2+(B2Σu+). In the reaction with Ne, the largest probability had the process from the reactant dication excited state CO22+(1Σg+) leading to the product ion ground state CO2+(X2Πg). Less probable were processes between the other excited states of the dication CO22+, (1∆g), (1Σu-), (3∆u), also leading to the product ion ground state CO2+(X2Πg). Using the Landau-Zener model of the reaction window, relative populations of the ground and excited states of the dication CO22+ in the reactant beam were roughly estimated as (X3Σg):(1∆g):(1Σg+):(1Σu-):(3∆u) = 1.0:0.6:0.5:0.25:0.25.

scholarly journals Crystal Chemical Relations in the Shchurovskyite Family: Synthesis and Crystal Structures of K2Cu[Cu3O]2(PO4)4 and K2.35Cu0.825[Cu3O]2(PO4)4

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 807
Author(s):  
Ilya V. Kornyakov ◽  
Sergey V. Krivovichev
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Structural Complexity ◽  
Crystal Chemical ◽  
X Ray Diffraction ◽  
Complexity Measures ◽  
X Ray ◽  
The Family ◽  
Similarities And Differences ◽  
Related Compounds

Single crystals of two novel shchurovskyite-related compounds, K2Cu[Cu3O]2(PO4)4 (1) and K2.35Cu0.825[Cu3O]2(PO4)4 (2), were synthesized by crystallization from gaseous phase and structurally characterized using single-crystal X-ray diffraction analysis. The crystal structures of both compounds are based upon similar Cu-based layers, formed by rods of the [O2Cu6] dimers of oxocentered (OCu4) tetrahedra. The topologies of the layers show both similarities and differences from the shchurovskyite-type layers. The layers are connected in different fashions via additional Cu atoms located in the interlayer, in contrast to shchurovskyite, where the layers are linked by Ca2+ cations. The structures of the shchurovskyite family are characterized using information-based structural complexity measures, which demonstrate that the crystal structure of 1 is the simplest one, whereas that of 2 is the most complex in the family.

Zum Mineral Johillerit verwandte Oxovanadate RbCd4V3O12 und TlCd4V3O12 / Oxovanadates RbCd4V3O12 and TlCd4V3 O12 Related to the Mineral Johillerite

1997 ◽  
Vol 52 (5) ◽  
pp. 663-668 ◽  
Author(s):  
B. Mertens ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Single Crystals ◽  
Solid State Reactions ◽  
Space Group ◽  
Related Compounds

Abstract Single crystals of I RbCd4V3O12 and TlCd4V3O12 II have been prepared by solid state reactions in closed iron tubes. The compounds crystallize closely related to the Johillerite structure in the space group C62h- C2/c with I: a = 13.058(3); b - 13.528(3), c = 7 .0 6 0 (2 )Å , β = 114.88(2)°; II: a = 12.999(6), b = 13.527(7), c = 7.055(3) Å , β = 114.88(4)°, Z = 4. Special features are the loss of Cu2+ in order to gain an additional Cd2+ position. The crystal structure is discussed with respect to related compounds of the Johillerite type.

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

The doping effect on the crystal structure and electrochemical properties of LiMnxM1−xPO4 (M=Mg, V, Fe, Co, Gd)

2011 ◽  
Vol 196 (10) ◽  
pp. 4747-4755 ◽  
Author(s):  
Gang Yang ◽  
Huan Ni ◽  
Haidong Liu ◽  
Po Gao ◽  
Hongmei Ji ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrochemical Properties ◽  
Doping Effect
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