Photocrystallography and IR spectroscopy of light-induced linkage NO isomers in [RuBr(NO)2(PCyp3)2]BF4

2015 ◽  
Vol 71 (6) ◽  
pp. 788-797 ◽  
Author(s):  
Nicolas Casaretto ◽  
Sébastien Pillet ◽  
El-Eulmi Bendeif ◽  
Dominik Schaniel ◽  
Anna K. E. Gallien ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Ground State ◽  
Vibration Mode ◽  
Structural Parameters ◽  
Energy Minimum ◽  
Coupled Vibration ◽  
Trigonal Bipyramidal ◽  
Bipyramidal Structure ◽  
Ir Analysis ◽  
Optimal Wavelength

One single photo-induced linkage NO isomer (PLI) is detected and characterized in the dinitrosyl pentacoordinated compound [RuBr(NO)2(PCyp3)2]BF4 by a combination of photocrystallographic and IR analysis. In the ground state, the molecule adopts a trigonal–bipyramidal structure with the two NO ligands almost linear with angles Ru—N1—O1 = 168.92 (16), Ru—N2—O2 = 166.64 (16)°, and exactly equal distances of Ru—N = 1.7838 (17) and O—N = 1.158 (2) Å. After light irradiation of 405 nm at T = 10 K, the angle of Ru—N2—O2 changes to 114.2 (6)° by rotation of the O atom towards the Br ligand with increased distances of Ru—N2 = 1.992 (6) and N2—O2 = 1.184 (8) Å, forming a bent κN bonded configuration. Using IR spectroscopy, the optimal wavelength and maximum population of 39 (1)% of the PLI is determined. In the ground state (GS), the two symmetric νs(NO) and asymmetric νas(NO) vibrations are measured at 1820 and 1778 cm−1, respectively. Upon photo-irradiation, the detection of only one new vibrational ν(NO) stretching band at 1655 cm−1, assigned to the antisymmetric coupled vibration mode and shifted to lower wavenumbers by −123 cm−1, supports the photocrystallographic result. These experimental results are supported by additional DFT calculations, which reproduce the structural parameters and vibrational properties of both the ground state and the photo-induced linkage isomer well. Especially the experimentally characterized molecular structure of the PLI state corresponds to an energy minimum in the calculations; the stabilization of the bent κN bonded configuration of the PLI state originates from specific intramolecular orbital overlap.

Notizen: Kristallstruktur von [Et4N][PBr4]. Strukturkorrelation für Halogenophosphate(III) / Crystal Structure of [Et4N][PBr4]. Structural Correlation for Halogenophosphates(III)

1989 ◽  
Vol 44 (5) ◽  
pp. 609-611 ◽  
Author(s):  
W. S. Sheldrick ◽  
J. Kiefer
Keyword(s):  
Crystal Structure ◽  
Energy Minimum ◽  
Trigonal Bipyramidal ◽  
Structural Correlation ◽  
Bipyramidal Structure

The tetrabromophosphate(III) anion in [Et4N][PBr4] displays an extremely distorted Ψ-trigonal bipyramidal structure with axial P-Br distances of 2.970(2) and 2.305(2) Å. A structural correlation of bond distances in characterized halogenophosphates(III) indicates that such an asymmetric three-centre Br-P ··· Br interaction represents an energy minimum for isolated anions.

scholarly journals [Ph–C(NSiMe3)2]2FeCl; ein Amidinatokomplex von Eisen(III) mit verzerrt trigonal-bipyramidaler Struktur / [Ph–C(NSiMe3)2]2FeCl; an Amidinato Complex of Iron(III) with a Distorted Trigonal-Bipyramidal Structure

1991 ◽  
Vol 46 (10) ◽  
pp. 1300-1304 ◽  
Author(s):  
Alfred Zinn ◽  
Henning von Arnim ◽  
Werner Massa ◽  
Michael Schäfer ◽  
Jürgen Pebler ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Ir Spectroscopy ◽  
Single Crystals ◽  
Structure Determination ◽  
Iron Atom ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Bipyramidal Structure ◽  
Moisture Sensitive ◽  
Distorted Trigonal Bipyramidal

The amidinato complex [Ph—C(NSiMe3)2]2FeCl has been prepared by the reaction of FeOCl with the amidine Ph—C(NSiMe3)[N(SiMe3)2] in acetonitrile/THF in the form of dark red moisture sensitive single crystals. The complex was characterized by IR spectroscopy, by its 57Fe-Mössbauer spectra, as well as by an X-ray structure determination. Space group PI, Z = 2, 3180 observed unique reflections, R = 0.068. Lattice dimensions at —80°C: a = 1210.4(2), b = 1272.7(3), c = 1316.0(3) pm; α = 67.81(3)°, β = 76.14(3)°, γ = 67.19(3)°. The complex has a molecular structure in which the iron atom is surrounded in a distorted trigonal-bipyramidal fashion with the chlorine ligand and two nitrogen atoms of different amidinato chelates in equatorial positions. The remaining nitrogen atoms occupy the apical positions.

On the structural diversity anions coordinate to the butterfly-shaped [(R2Sn)3O(OH)2]2+ cations and vice versa

2014 ◽  
Vol 92 (6) ◽  
pp. 496-507 ◽  
Author(s):  
Hans Reuter ◽  
Hilko Wilberts
Keyword(s):  
Hydrogen Bonds ◽  
Iodine Atom ◽  
Structural Parameters ◽  
Structural Diversity ◽  
Hydroxyl Groups ◽  
Equatorial Position ◽  
Chelating Ligands ◽  
Trigonal Bipyramidal Coordination ◽  
Trigonal Bipyramidal ◽  
Oxygen Framework

The syntheses and crystal structures of [(t-Bu2Sn)3O(OH)2]CO3·3MeOH, 1a, [(t-Bu2Sn)3O(OH)2]CO3·3H2O·acetone, 1b, [(t-Bu2Sn)3O(OH)2][I]2·[(t-Bu2Sn(OH)I]2·2DMSO, 1c, and [(Cy2Sn)3O(OH)2][I]2·2DMSO, 2a, all containing the trinuclear [(R2Sn)3O(OH)2]2+ ion have been described. The butterfly shape of this cation is derived from two annulated, four-membered tin–oxygen rings with a central μ3-oxygen atom and trigonal-bipyramidally coordinated tin atom both belonging to both rings and two μ2-hydroxyl groups and two outer, four-fold coordinated tin atoms. In 1a and 1b, the carbonate anions interact with the outer tin atoms of the cations as bidentate chelating ligands in the classical syn–syn coordination mode, and vice versa. In this way, both outer tin atoms expand their coordination sphere from four to five, with the consequence that bond angles and lengths within the cation are determined by the axial and equatorial position of the oxygen atoms within the trigonal-bipyramidal coordination on all three tin atoms. 1c consists of two different building units, an up to now unknown hydroxide iodide of composition [(t-Bu2Sn(OH)I]2 with hydrogen-bonded DMSO molecules and a [(t-Bu2Sn)3O(OH)2]2+ cation with one coordinated and one isolated, via hydrogen bonds connected iodine ion. The hydroxide iodine is built up of two five-fold coordinated tin atoms linked via two hydroxyl groups with exocyclic iodine atoms occupying axial positions at the trigonal-biypramidally coordinated tin atoms. The unprecedented coordination of the iodine ion to the [(t-Bu2Sn)3O(OH)2]2+ cation takes place between both outer tin atoms, resulting in a five-fold, trigonal-bipyramidal coordination at these tin atoms, too. Structural parameters within the so-formed [(t-Bu2Sn)3O(OH)2I]+ complex are very similar to those of 1a and 1b, with the exception of a significant lengthening of the tin–oxygen bonds opposite to the bridging iodine atom. 2a represents the first example of the [(R2Sn)3O(OH)2]2+ cation without R = t-butyl, so far. In the solid, it consists of two crystallographic independent [(Cy2Sn)3O(OH)2][I]2 building units, each connected to two DMSO molecules via hydrogen bonds. Both building units are very similar with respect to their conformation. Each of the iodine anions coordinates with only one of the two outer tin atoms, one in an inwards, one in an outwards to the tin-oxygen framework directed position. These tin atoms are therefore also trigonal-bipyramidally coordinated as in 1a−1c, but because of steric reasons one of the trigonal-bipyramids has changed its orientation within the tin–oxygen framework, accompanied by enormous changes of bond lengths and angles therein.

scholarly journals The maximum surface area polyhedron with five vertices inscribed in the sphere {\bb S}^{2}

2021 ◽  
Vol 77 (1) ◽  
pp. 67-74
Author(s):  
Jessica Donahue ◽  
Steven Hoehner ◽  
Ben Li
Keyword(s):  
Convex Hull ◽  
Surface Area ◽  
Coordination Polyhedron ◽  
Unit Sphere ◽  
The Other ◽  
Optimal Placement ◽  
The North ◽  
Trigonal Bipyramidal ◽  
Bipyramidal Structure ◽  
North And South

This article focuses on the problem of analytically determining the optimal placement of five points on the unit sphere {\bb S}^{2} so that the surface area of the convex hull of the points is maximized. It is shown that the optimal polyhedron has a trigonal bipyramidal structure with two vertices placed at the north and south poles and the other three vertices forming an equilateral triangle inscribed in the equator. This result confirms a conjecture of Akkiraju, who conducted a numerical search for the maximizer. As an application to crystallography, the surface area discrepancy is considered as a measure of distortion between an observed coordination polyhedron and an ideal one. The main result yields a formula for the surface area discrepancy of any coordination polyhedron with five vertices.

Sulfamoyl nitrenes: singlet or triplet ground state?

2018 ◽  
Vol 54 (48) ◽  
pp. 6136-6139 ◽  
Author(s):  
Yan Lu ◽  
Hongmin Li ◽  
Manabu Abe ◽  
Didier Bégué ◽  
Huabin Wan ◽  
...  
Keyword(s):  
Triplet State ◽  
Ground State ◽  
Singlet State ◽  
Minimum Energy ◽  
Closed Shell ◽  
Low Energy ◽  
Energy Minimum ◽  
Triplet Ground State ◽  
Crossing Point

Two prototypical sulfamoyl nitrenes R2NS(O)2–N (R = H and Me) in the triplet state were generated via the closed-shell singlet state by passing a low-energy minimum energy crossing point (MECP).

Investigation of Mass Sensitivity for the Piezoelectric Diaphragm Biosensor

2011 ◽  
Vol 411 ◽  
pp. 245-249
Author(s):  
Shao Kang Li ◽  
Wei Ren ◽  
Xiao Feng Chen ◽  
Xi Yao
Keyword(s):  
Software Package ◽  
Material Parameter ◽  
Analytic Solution ◽  
Vibration Mode ◽  
Structural Parameters ◽  
Flexural Vibration ◽  
Mass Sensitivity ◽  
Rayleigh Method ◽  
Acoustic Wave Device ◽  
Wave Device

The mass sensitivity of a piezoelectric diaphragm biosensor has been investigated. The piezoelectric diaphragm utilizing a flexural vibration mode is an acoustic wave device which can be immobilized with a bio-molecular recognition layer on its surface. The mass sensitivity of the sensor was analyzed by the approximately theoretical and FEM methods, respectively. The sensitivity formula expressed by the structural parameters and the material parameter was educed for easy computing. The procedure utilizing Rayleigh method for the analytic solution of the sensitivity was introduced. The expression was verified by using a commercial FEM software package, ANSYS. The simulations are well consistent with the theory.

35Cl NQR Spectra of SnCl4 Complexes with Methylaryl Ethers

1986 ◽  
Vol 41 (1-2) ◽  
pp. 211-214 ◽  
Author(s):  
Igor M. Lazarev ◽  
Gennadii V. Dolgushin ◽  
Valentin P. Feshin ◽  
Michail G. Voronkov
Keyword(s):  
Octahedral Structure ◽  
Trigonal Bipyramidal ◽  
Distorted Octahedral ◽  
35Cl Nqr ◽  
Bipyramidal Structure ◽  
35Cl Nqr Spectra ◽  
Oxygen Atoms

SnCl4 Complexes with methylaryl ethers and their 35Cl NQR spectra have been obtained. All these complexes, except SnCl4 · 1,2-(CH3O)2C6H4, have a trigonal-bipyramidal structure. The latter compound has an essentially distorted octahedral structure. One of the ligand oxygen atoms takes part in the formation of the SnCl4 complex with 1,3-, 1,4-(CH3O)2C6H4 and RNO2. These complexes have a trigonal-bipyramidal structure too.

An amino–imino resonance study of 2-amino-4-methylpyridinium nitrate and 2-amino-5-methylpyridinium nitrate

2012 ◽  
Vol 69 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Xing-Chen Yan ◽  
Yu-Hua Fan ◽  
Cai-Feng Bi ◽  
Xia Zhang ◽  
Zhong-Yu Zhang
Keyword(s):  
Density Functional Theory ◽  
Ir Spectroscopy ◽  
Ground State ◽  
Density Functional ◽  
Acta Cryst ◽  
Functional Theory ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ground State Structures

The contributions of the amino and imino resonance forms to the ground-state structures of 2-amino-4-methylpyridinium nitrate, C6H9N2+·NO3−, and the previously reported 2-amino-5-methylpyridinium nitrate [Yan, Fan, Bi, Zuo & Zhang (2012).Acta Cryst.E68, o2084], were studied using a combination of IR spectroscopy, X-ray crystallography and density functional theory (DFT). The results show that the structures of 2-amino-4-methylpyridine and 2-amino-5-methylpyridine obtained upon protonation are best described as existing largely in the imino resonance forms.

Structural Properties of High Electronic Quality a-Si1-xCx:H by Infrared Spectroscopy

1992 ◽  
Vol 258 ◽  
Author(s):  
K. Eberhardt ◽  
E. Lotter ◽  
M. Heintze ◽  
H.-D. Mohring ◽  
G.H. Bauer
Keyword(s):  
Infrared Spectroscopy ◽  
Ir Spectroscopy ◽  
Structural Properties ◽  
Hydrogen Content ◽  
Low Carbon ◽  
Absorption Data ◽  
Experimental Transmission ◽  
Wide Compositional Range ◽  
Ir Analysis ◽  
Thickness Independent

ABSTRACTInfrared (ir) spectroscopy is used to investigate the structural properties of a-SiC:H in a wide compositional range and as a function of film thickness. Hydrogen content NH increases considerably with increasing carbon fraction. For low carbon alloys this is mainly due to an increase of hydrogen bonded to silicon, incorporated in a mono- or dihydride form. Above Eg=2.3eV the proportion of hydrogen incorporated in C-H bonds increases considerably. Oxidation of high C alloys is observed. Converting experimental transmission exactly into absorption data yields thickness independent NH values. It is shown that the previously reported discrepancy between the hydrogen content calculated from ir and nuclear reaction techniques is an artifact of the ir analysis.

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