Charge Distribution of the Azide Ion

Gora, Thaddeus; Kemmey, P. J.

doi:10.1063/1.1678800

Cited by 34 publications

(5 citation statements)

References 12 publications

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“…Therefore, it is natural to invoke the nearby Thr-199 as the group that modifies the potential-energy function and controls the charges of Zn-bound azide. The charge on N (2) in isolated azide is Ϸϩ1 electron (e), whereas the end atoms each have a ϷϪ1 e charge (33). Recent calculations (34) have shown that the Zn-bound azide N (2) becomes more positive by 0.…”

Section: Discussionmentioning

confidence: 99%

Protein fluctuations are sensed by stimulated infrared echoes of the vibrations of carbon monoxide and azide probes

Lim

Hamm²,

Hochstrasser³

1998

Proc. Natl. Acad. Sci. U.S.A.

143

181

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The correlation functions of the fluctuations of vibrational frequencies of azide ions and carbon monoxide in proteins are determined directly from stimulated photon echoes generated with femtosecond infrared pulses. The asymmetric stretching vibration of azide bound to carbonic anhydrase II exhibits a pronounced evolution of its vibrational frequency distribution on the time scale of a few picoseconds, which is attributed to modifications of the ligand structure through interactions with the nearby Thr-199. When azide is bound in hemoglobin, a more complex evolution of the protein structure is required to interchange the different ligand configurations, as evidenced by the much slower relaxation of the frequency distribution in this case. The time evolution of the distribution of frequencies of carbon monoxide bound in hemoglobin occurs on the Ϸ10-ps time scale and is very nonexponential. The correlation functions of the frequency fluctuations determine the evolution of the protein structure local to the probe and the extent to which the probe can navigate those parts of the energy landscape where the structural configurations are able to modify the local potential energy function of the probe.Chemical reactions in biology can be controlled by the fluctuations in the energies of the reactant states. When the reactions involve charge translocations, the motions of the charges in the surrounding medium cause changes in the electric fields in the neighborhood of the reacting species, which in turn cause fluctuations of the reactant energies. These fluctuations occur on the time scale of the nuclear motions of the medium. For chemical processes occurring in a protein environment, such as in enzyme catalysis, the dynamics of the protein nuclei can control the reaction. Therefore, it is very important to determine experimentally the essential properties of the fluctuations associated with various observables, such as their mean values, time-correlation functions, and structural origins.The experimental approaches to determining time-correlation functions include spectroscopic line shape measurements and time-domain responses. In the vibrational frequency regime the line-shape approach is a common one (1), although it does not always expose the underlying physical origins of the fluctuations. Time-domain techniques were also developed some time ago that enabled investigations of the various contributions to the line width such as pure dephasing and population relaxation (2). The dephasing times of vibrational transitions having static inhomogeneous distributions can be measured by means of two-pulse photon echoes (3-5). Silvestri et al. (6) have shown that for optical transitions, a photon echo with three pulses can also yield the dynamics of the inhomogeneous distribution. There were many applications of this nonlinear technique in the electronic spectroscopy of dye molecules (refs. 6-8, and see ref. 9 for a review) and of cofactors in biological systems [light-harvesting complex II (10), reaction center (11...

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Section: Discussionmentioning

confidence: 99%

Protein fluctuations are sensed by stimulated infrared echoes of the vibrations of carbon monoxide and azide probes

Lim

Hamm²,

Hochstrasser³

1998

Proc. Natl. Acad. Sci. U.S.A.

143

181

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“…However, NaN3 is not already a purely ionic compound since the valence states are hybridized with the cation states in the range of 40,lx,30,, the maximum hybridization occurring in 4ag. This results in the reconstruction of the isolated N; spectrum [19] and in lowering the 4ag band energy with respect to lxu. It should be noted that similar data were also obtained for LiN3 [S] where one notes that lithium azide is not a purely ionic compound.…”

Section: Band Structuresmentioning

confidence: 99%

Electronic Structure of Metal Azides

Gordienko

Zhuravlev

Поплавной

1996

Physica Status Solidi (b)

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Calculations of energy band structure, density of states, electronic density, and chemical bond parameters for a series of MeN3, where Me = Na, K, Rb, Cs, Ag, T1 have been given. The density functional theory and pseudopotential technique in mixed basis have been used. The valence band has been shown to be essentially formed from azideion states for alkali metal azides. The conduction band contains two subbands separated by a band gap. The first band is responsible for the anion states, while the second one is responsible for the cation ones. Silver d-states and thallium s-states have been seen to change greatly the structure of both the valence and conduction bands for AgN3 and TINS, viz. the upper valence bands are of a mixed anion-cation nature, the conduction band bottom consists of cation states, but the anion contributions increase when the energy grows. IIJIOTHOCTU, MeTOAOM I I C e B~O n O T e H~a . J I a , B CMeIlIaHHOM 6 a s a c e . HOKaCaHO, 9 T O B a 3 w a X Il&3lOSHbIX MeTanJIOB BaJIeHTHaX 3 0 H a Cf$OpMUpOBaHa IIpeUMyQeCTBeHHO U 3 COCTOXHEIfi a3wn e p B W 3 0 H a O T B e q a e T SLHIIOHHbIM, BTOpaX KaTUOHHbIM COCTOXHUIIM. d-COCTOIIHIlrr Ag S-COC-TOIIHMX T1 CyQeCTBeHHO MeHXHlT KaK BZUIeHTHyIO 30HY, TaK M 30HY IIpOBOAUMOCTEI. B AgN3 U T1N3 BepXHUe B m e H T H b I e 30HbI UMeIOT aHUOH-KaTUOHHYHl IIpUpOgy, HHO 30HbI IIpOBOAUMOCTH OTBeYaeT KaTUOHHbIM COCTOXHUXM C HapaCTaHUeM BKnaAOB OT aHUOHHbIX n p U BO3paCTaHUU WoHa. 3 o~a II~OBOAI~MOCTU COCTOMT 113 R B~X nogio~, p a 3~e n e~~b 1 x s a n p e~~e~~b r~ V a c r K o M .3 H e p r a u .

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“…As a classical example of a strong nucleophile, the azide anion is of considerable importance in organic and inorganic chemistry. − The structure and properties of N 3 - have been well studied by various spectroscopic methods in the gas phase, − solution, − and crystal and solid matrixes. − Theoretical calculations have also been carried out on the electronic structure of the azide anion and its behavior in solution. − Despite all the experimental and theoretical investigations in bulk solution, little information has been obtained about the microsolvation of the azide anion in water clusters, which can provide molecular level understanding about the azide-water interactions. The large values of the quadruple moment and polarizability 22 make N 3 - a very special solute.…”

Section: Introductionmentioning

confidence: 99%

Solvation of the Azide Anion (N₃^-) in Water Clusters and Aqueous Interfaces: A Combined Investigation by Photoelectron Spectroscopy, Density Functional Calculations, and Molecular Dynamics Simulations

Yang¹,

Kiran²,

Wang³

et al. 2004

J. Phys. Chem. A

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We report a photoelectron spectroscopy and computational study of hydrated N 3anion clusters, N 3 -(H 2 O) n (n ) 0-16), in the gas phase. Photoelectron spectra of the solvated azide anions were observed to consist of a single peak, similar to that of the bare N 3 -, but the spectral width was observed to broaden as a function of cluster size due to solvent relaxation upon electron detachment. The adiabatic and vertical electron detachment energies were measured as a function of solvent number. The measured electron binding energies indicate that the first four solvent molecules have much stronger interactions with the solute anion, forming the first solvation shell. The spectral width levels off at n ) 7, suggesting that three waters in the second solvation shell are sufficient to capture the second shell effect in the solvent relaxation. Density functional calculations were carried out for N 3solvated by one to five waters and showed that the first four waters interact directly with N 3and form the first solvation shell on one side of the solute. The fifth water does not directly solvate N 3and begins the second solvation shell, consistent with the observed photoelectron data. Molecular dynamics simulations on both solvated clusters and bulk interface revealed that the asymmetric solvation state in small clusters persist for larger systems and that N 3prefers interfacial solvation on water clusters and at the extended vacuum/water interface.

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Charge Distribution of the Azide Ion

Abstract: Vibrational relaxation of azide ion in water: The role of intramolecular charge fluctuation and solventinduced vibrational coupling

Cited by 34 publications

References 12 publications

Protein fluctuations are sensed by stimulated infrared echoes of the vibrations of carbon monoxide and azide probes

Protein fluctuations are sensed by stimulated infrared echoes of the vibrations of carbon monoxide and azide probes

Electronic Structure of Metal Azides

Solvation of the Azide Anion (N₃^-) in Water Clusters and Aqueous Interfaces: A Combined Investigation by Photoelectron Spectroscopy, Density Functional Calculations, and Molecular Dynamics Simulations

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Charge Distribution of the Azide Ion

Abstract: Vibrational relaxation of azide ion in water: The role of intramolecular charge fluctuation and solventinduced vibrational coupling

Cited by 34 publications

References 12 publications

Protein fluctuations are sensed by stimulated infrared echoes of the vibrations of carbon monoxide and azide probes

Protein fluctuations are sensed by stimulated infrared echoes of the vibrations of carbon monoxide and azide probes

Electronic Structure of Metal Azides

Solvation of the Azide Anion (N3-) in Water Clusters and Aqueous Interfaces: A Combined Investigation by Photoelectron Spectroscopy, Density Functional Calculations, and Molecular Dynamics Simulations

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Product

Resources

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Solvation of the Azide Anion (N₃^-) in Water Clusters and Aqueous Interfaces: A Combined Investigation by Photoelectron Spectroscopy, Density Functional Calculations, and Molecular Dynamics Simulations