Di[(hydroxyalkyl)dimethylammonium] tris[benzene-1,2-diolato(2–)]silicates and their germanium analogs: syntheses, crystal structure analyses, and NMR studies

2000 ◽  
Vol 78 (11) ◽  
pp. 1380-1387
Author(s):  
Reinhold Tacke ◽  
Alistair Stewart ◽  
Joachim Becht ◽  
Christian Burschka ◽  
Ingo Richter
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Aqueous Solutions ◽  
Room Temperature ◽  
Model Systems ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
X Ray ◽  
Germanium Silicon ◽  
And Storage

Treatment of Si(OMe)4 with three molar equivalents of 1,2-C6H4(OH)2 (= 1,2-dihydroxybenzene) and two molar equivalents of HO(CH2)nNMe2 (n = 2, 3) in acetonitrile at room temperature yields the λ6Si-silicates (HO(CH2)nNMe2H)2(SiL3) (5: n = 2; 6: n = 3; L2– = 1,2-C6H4(O)22– (= benzene-1,2-diolato(2–))). The analogous λ6Ge-germanates (HO(CH2)nNMe2H)2(GeL3) (7: n = 2; 8: n = 3) were synthesized analogously starting from Ge(OMe)4. Compounds 5·2CH3CN and 6-8 were structurally characterized by single-crystal X-ray diffraction. In addition, aqueous solutions of the Si/Ge analogs 5/7 and 6/8 were studied by NMR spectroscopy. The title compounds may be regarded as model systems for the transport and storage of silicon in biological systems and as tools to investigate biosilification.Key words: hexacoordinate silicon, hexacoordinate germanium, silicon biochemistry

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

scholarly journals Spectral Characterization and Crystal Structure of 1,2-Bis-(1H-benzimidazol-2-yl)-ethane Dihydrochloride

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Aydin Tavman ◽  
Cigdem Sayil
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
Nmr Spectra ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Triclinic System ◽  
Ir And Nmr Spectroscopy ◽  
Ft Ir ◽  
System Characteristics

The crystal structure of 1,2-bis-(1H-benzimidazol-2-yl)-ethane dihydrochloride (1) was determined by X-ray diffraction at room temperature. The structure of1was also characterized by mass, elemental analysis, FT-IR, and NMR spectroscopy techniques. The title compound crystallizes in triclinic system and space group P-1,a=7.1350,b=9.6299(1),c=15.3340(7)Å,α=80.67(2),β=79.66(2),γ=68.395(11)∘,V=958.33(10)Å3,Z=2. Owing to theanticonformations of –CH2– groups, the entire molecule is relatively flat.H1-NMR spectra of1show AA′XX′system characteristics.

Evolution of crystal structure of dual layered molecular conductor (ET)4ZnBr4(C6H4Cl2) with temperature

CrystEngComm ◽  
2021 ◽  
Author(s):  
Gennady V. Shilov ◽  
Elena I. Zhilyaeva ◽  
Sergey M. Aldoshin ◽  
Alexandra M Flakina ◽  
Rustem B. Lyubovskii ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Resistivity ◽  
Single Crystal ◽  
Room Temperature ◽  
Organic Conductor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
Molecular Conductor ◽  
Abrupt Changes

Electrical resistivity measurements of a dual layered organic conductor (ET)4ZnBr4(1,2-C6H4Cl2) above room temperature show abrupt changes in resistivity at 320 K. Single-crystal X-ray diffraction studies in the 100-350 K range...

CRYSTAL STRUCTURE OF ZIRCONIUM TRICHLORIDE

1964 ◽  
Vol 42 (10) ◽  
pp. 1886-1889 ◽  
Author(s):  
B. Swaroop ◽  
S. N. Flengas
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Main Cell ◽  
Diffraction Patterns

The crystal structure of zirconium trichloride was determined from X-ray diffraction patterns. Zirconium trichloride belongs to the [Formula: see text]space group. The dimensions of the main cell at room temperature are: a = 5.961 ± 0.005 Å and c = 9.669 ± 0.005 Å.The density of zirconium trichloride was measured and gave the value of 2.281 ± 0.075 g/cm3 while, from the X-ray calculations, the value was found to be 2.205 g/cm3.

Study of thermal properties of Ga0.5In1.5Se3 by differential scanning calorimetry

2021 ◽  
pp. 2150407
Author(s):  
S. I. Ibrahimova
Keyword(s):  
Crystal Structure ◽  
Differential Scanning Calorimetry ◽  
Thermal Properties ◽  
Thermal Effects ◽  
Room Temperature ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
Hexagonal Symmetry ◽  
Scanning Calorimetry ◽  
X Ray

The crystal structure and thermal properties of the [Formula: see text] compound have been investigated. Structural studies were performed by X-ray diffraction at room temperature. The crystal structure of this compound was found to correspond to the hexagonal symmetry of the space group P61. Thermal properties were studied using a differential scanning calorimetry (DSC). It was found in the temperature range [Formula: see text] that thermal effects occur at temperatures [Formula: see text] and [Formula: see text]. The thermodynamic parameters of these effects are calculated.

Ein tricyclisches Tetraboradisiladodecan aus Dimethyl-di-1-propinylsilan und Ethyldiboranen(6) / A Tricyclic Tetraboradisiladodecane from Dimethyl-di-1-propynylsilane and Ethyldiboranes(6)

1995 ◽  
Vol 50 (3) ◽  
pp. 439-447 ◽  
Author(s):  
Roland Köster ◽  
Günter Seidel ◽  
Roland Boese ◽  
Bernd Wrackmeyer
Keyword(s):  
Crystal Structure ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray ◽  
Structure Space ◽  
Thermal Elimination

The exhaustive hydroboration of the (C ≡ C )-groups in Me2Si(C ≡ CMe)2 (A ) by adding ethyldiboranes(6) at room temperature is presumed to lead initially to the formation of a mixture of the threo- and erythro-3,3,5,6-tetrakis(diethylboryl)-4,4-dimethyl-4-silaheptanes (1a , b). The threo-1a reacts further by borane catalysed intermolecular condensation to the substituted disilatetraboratricyclo[6.2.1.16.9]dodecane 2 with the formula , whose crystal structure [space group C2/c, a = 19.696(2), b = 10.371(1), c = 16.580(2) Å; β = 125.90(1)°; at 122 K] has been established by X -ray diffraction. In contrast, the erythro-1b undergoes intramolecular, thermal elimination of Et3B to give the 1,2-diethyl-2,4-bis(diethylboryl)- 3,3,5-trim ethyl-3-silaborolane (4). If A is added to an excess of undiluted B (“hydridebath”), then the two substituted diastereomers of the 1-carba-arachno-pentaboranes(10) (endo/exo-Et,SiH Me2) (3a, b), are formed preferentially as the result of an initial Si-C ≡-c le a v e d hydroboration.

X-ray Diffraction Studies of Solid Solutions of Pentaglycerine-Neopentylglycol

1988 ◽  
Vol 32 ◽  
pp. 609-616 ◽  
Author(s):  
D. Chandra ◽  
C. S. Barrett ◽  
D. K. Benson
Keyword(s):  
Crystal Structure ◽  
Energy Storage ◽  
Hydrogen Bonds ◽  
Solid Solutions ◽  
Room Temperature ◽  
Energy Storage Materials ◽  
Anisotropic Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cubic Structure

AbstractAn array of molecules that is anisotropic in the extreme has been discovered in certain thermal-energy storage materials and is reported here: neopentylglycol (NPG) and NPG-rich solid solutions with pentaglycerine (PG) have a crystal structure, stable at room temperature, that consists of bimolecular chains of molecules that are all unidirectionally aligned throughout a crystal. There are hydrogen bonds between every molecule in one chain and its neighbors in that chain, but none between molecules of one chain and any molecules of the neighboring parallel chains. Thus there are strong intermolecular bonds along each chain and only weaker bonds between the chains. The structure has been determined by using modern single crystal techniques with 529 independent reflections from a crystal of NPG (C5H12O2). The structure is monoclinic with space group P21/c - C2h5. This anisotropic structure transforms to a cubic structure at higher temperatures.

scholarly journals The characterisation and X-ray crystal structure of pentabromodiselenium hexafluoroarsenate, Se2Br5AsF6; some thermodynamic considerations and the nonexistence of Se2I5AsF6

1987 ◽  
Vol 65 (7) ◽  
pp. 1584-1593 ◽  
Author(s):  
Michael P. Murchie ◽  
Jack Passmore ◽  
Peter S. White
Keyword(s):  
Crystal Structure ◽  
Bond Order ◽  
Room Temperature ◽  
Bromine Atom ◽  
Elemental Selenium ◽  
Analogous Reaction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Final Agreement ◽  
Anion Interaction

The crystal structure of Se2Br5AsF6 was determined by low-temperature X-ray diffraction methods. Single crystals of Se2Br5AsF6 are rhombohedral, space group R3 with a = 13.367(4) Å, c = 19.000(6) Å, V = 2940 Å3, and Z = 9. The structure was refined to final agreement indices of R = 0.087, Rw = 0.093 for 604 observed (I > 3σ(I)) reflections and 71 parameters. The structure consists of essentially discrete Se2Br5+ cations and AsF6− anions with some cation–anion interaction. The Se2Br5+ cation, of essentially C2h symmetry contains two trans SeBr2 units, linked by a bridging bromine atom. The two terminal selenium–bromine bond distances are 2.291(7) and 2.268(6) Å, of bond order 1, and the angle between them is 100.0(3)°. The bridging bromine atom lies at the inversion centre of the Se2Br5+ cation, with an Se—Br distance of 2.582(3) Å, corresponding to a bond order of about 0.5. The two angles between the bridging Se—Br and terminal Se—Br bonds are 97.4(1)° and 98.9(2)°. Se2Br5AsF6 decomposes slowly at room temperature and rapidly at 100 °C leading to the formation of SeBr3AsF6, SeBr4, and elemental selenium. It reacts with Br2 to give SeBr3AsF6 and SeBr4. Se2Br5AsF6 is prepared by the reaction of Se4(AsF6)2 and the appropriate quantity of Br2. The analogous reaction with I2 leads to I2SeSeSeSeI2(AsF6)2 and not Se2I5AsF6. These differences have been accounted for on the basis of estimates of the appropriate bond and crystal lattice energies. The 77Se nmr of SeBr3+ and Se2Br5+ in SO2 solution, and the Raman spectrum of SeBr4 are reported.

3-Hexyne Complexes of M olybdenum(II) and Tungsten(II) Containing 2, 2 '-Bipyridine. X-Ray Crystal Structure of [MoI2(CO)(bipy)(η2-EtC2Et)]

2000 ◽  
Vol 55 (11) ◽  
pp. 1095-1098
Author(s):  
Mutlaq Al-Jahdali ◽  
Paul K. Baker ◽  
Michael B. Hursthouse ◽  
Simon J. Coles
Keyword(s):  
Crystal Structure ◽  
Carbon Monoxide ◽  
Room Temperature ◽  
Octahedral Geometry ◽  
Cationic Complex ◽  
Molybdenum Complex ◽  
Neutral Complex ◽  
Nmr Studies ◽  
X Ray ◽  
C Nmr

Reaction of [MI2(CO)(NCMe)(η2-EtC2Et)2] (M = Mo,W) with one equivalent of 2,2' -bipyridine (bipy) in CH2C12 at room temperature gives either the neutral complex, [MoI2(CO)(bipy)- (η2-EtC2Et)] (1) or the cationic complex, [WI(CO)(bipy)(η2-EtC2Et)2]I (2). The neutral molybdenum complex 1, has been crystallographically characterised, and has a pseudo-octahedral geometry with the iodo-ligand trans to the 3-hexyne, and with the bipy, carbon monoxide and other iodo-ligand occupying the equatorial face. 13C NMR studies show the 3-hexyne is donating four electrons to the molybdenum in 1.

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