Synthesis, spectroscopy, and structures of the seven-coordinate complexes (CH3)2AsC(CF3)== C(CF3)As(CH3)2W(CO)2I2P(OC6H5)3 and [(CH3)2AsC(CF3)== C(CF3)As(CH3)2]2W(CO)Br2 and spectroscopy of related seven-coordinate complexes

1998 ◽  
Vol 76 (3) ◽  
pp. 245-253
Author(s):  
Richard J Barton ◽  
Sushil K Manocha ◽  
Beverly E Robertson ◽  
Lynn M Mihichuk
Keyword(s):  
Chemical Shifts ◽  
Spectroscopic Properties ◽  
Intramolecular Rearrangement ◽  
X Ray Diffraction ◽  
Tungsten Atom ◽  
X Ray ◽  
Nmr Data ◽  
Octahedral Environment ◽  
Rearrangement Process ◽  
Coordinate Geometry

(L-L)W(CO)3I2 (L-L = (CH3)2AsC(CF3)== C(CF3)As(CH3)2) reacts with the monodentate phosphite P(OC6H5)3 and (L-L)W(CO)3Br2 reacts with L-L to form new seven-coordinate complexes (L-L)W(CO)2I2P(OC6H5)3 and (L-L)2W(CO)Br2. Low-temperature X-ray diffraction analyses show the tungsten atom to be seven coordinate in both complexes, with the geometry most closely approximated by a monocapped octahedral environment, the capping group being a carbonyl in the dicarbonyl complex; the geometry is most closely approximated by a pentagonal bipyramidal environment in the monocarbonyl complex. The 1H, 13C, and 19F NMR data indicate that the dicarbonyl complex is stereochemically nonrigid at 298 K and rigid at lower temperatures, while the monocarbonyl is nonrigid both at 298 K and at lower temperatures. ΔG not equal values calculated at coalescence temperatures are consistent with an intramolecular rearrangement process for both complexes. The 13C chemical shifts and 2J(13C-31P) values provide important structural considerations in the assignment of a seven-coordinate geometry. Spectroscopic properties for the related seven-coordinate dicarbonyl complexes (L-L)W(CO)2PX2 (P = P(OC6H5)3; X = Br; P = P(OCH3)3, P(C6H5)3; X = Br, I) and monocarbonyl complexes (L-L)2W(CO)I2 and (L-L)W(CO)X2[P(OCH3)3]2 (X = Br, I) are presented and compared to those of the two title complexes.Key words: seven-coordination, X-ray, NMR analysis.

scholarly journals Structural and Spectroscopic Properties of Two New Isostructural Complexes of Lapacholate with Cobalt and Copper

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
R. A. Farfán ◽  
J. A. Espíndola ◽  
M. I. Gomez ◽  
M. C. L. de Jiménez ◽  
M. A. Martínez ◽  
...  
Keyword(s):  
Electronic Absorption Spectra ◽  
Spectroscopic Properties ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Octahedral Environment ◽  
Distorted Octahedral ◽  
Phenol Oxygen ◽  
Oxygen Atoms

The molecular structures of two isostructural complexes of lapacholate (Lap) anion and dimethylformamide (DMF), M(Lap)2(DMF)2 with M: Co Cu, were determined by X-ray diffraction methods. The substances crystallize in the triclinic space group P1¯ with one molecule per unit cell and cell constants a=7.7591(3), b=10.3560(3), c=11.2224(4) Å, α=95.110(2), β=94.310(2), and γ=107.704(2)° for the Co complex and a=7.9308(2), b=10.0033(4), c=10.7508(4), α=97.387(2), β=93.621(2), and γ=103.980(2)° for the Cu complex. The structures were solved from 2933 (Co) and 2888 (Cu) reflections with I>2σ (I) and refined by full matrix least squares to agreement R1-factors of 0.041 (Co) and 0.033 (Cu). The metal M(II) ion is sited on a crystallographic inversion center in a MO6 distorted octahedral environment. This ion is coordinated equatorially to two lapacholate anions through their adjacent carbonyl and phenol oxygen atoms [M–O bond distances of 2.134(1) and 2.008(1) Å (Co) and 2.301(1) and 1.914(1) Å (Cu)] and axially to two DMF molecules through oxygen atoms [M–O bond lengths of 2.143(1) Å (Co) and 2.069(1) Å (Cu)]. The solid state IR transmittance and solution electronic absorption spectra of both Co and Cu compounds are also reported and compared to each other and to the corresponding spectra of other members of the lapacholate metal family of complexes.

scholarly journals Studies of Dihydropyridines by X-Ray Diffraction and Solid State 13C NMR

2007 ◽  
Vol 62 (4) ◽  
pp. 549-555 ◽  
Author(s):  
Martha S. Morales-Ríos ◽  
Antonio Martínez-Richa ◽  
Zurisaddai Hernández-Gallegos ◽  
Angelina Hernández-Barragán ◽  
Ricardo Vera-Graziano ◽  
...  
Keyword(s):  
Solid State ◽  
Phenyl Ring ◽  
Chemical Shifts ◽  
Carbonyl Groups ◽  
X Ray Diffraction ◽  
Substitution Pattern ◽  
Trans Orientation ◽  
X Ray ◽  
Nmr Data ◽  
C Nmr

Fourteen dimethyl 4-aryl-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylates (DHPs) were evaluated by means of single crystal X-ray diffraction in order to investigate the effects of the structure in the crystals on the solid state 13C NMR chemical shifts. These include the analysis of three DHPs containing two molecules per asymmetric unit. The chiral rotamer unit generated by the s-cis/s-trans orientation of the carbonyl groups, as well as by rotation of the 4-phenyl ring out of the bisecting plane containing the N1, C4, C7 atoms, resulted in a significant magnetic non-equivalence for the C2-CH3/C6-CH3 and the COOCH3 pairs of signals. The solid state 13C NMR data reveal that the substitution pattern of the phenyl ring has a marked effect on the extent to which the signals of the carbonyl carbon atoms and those of C-2/C-6 peaks are split.

1,2-Hydroboration of Alkyn-1-yldichlorosilanes using Triethylborane

2008 ◽  
Vol 63 (11) ◽  
pp. 1267-1275 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Ezzat Khan ◽  
Wolfgang Milius
Keyword(s):  
Molecular Structure ◽  
Single Crystal ◽  
Hydrogen Transfer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ethyl Group ◽  
Nmr Data

Abstract Triethylborane, BEt3, can act as a 1,2-hydroborating reagent towards alkyn-1-ylsilanes, depending on the nature of the silane. A mechanism is proposed invoking hydrogen transfer from the β -carbon of one ethyl group, quite different from the 1,2-hydroboration mechanism using tri-n-propylborane, BnPr3. The structure of the products has been confirmed by comparison with that obtained using 9-borabicyclo[3.3.1]nonane, 9-BBN, as a well established 1,2-hydroborating reagent. All products have been characterized by a consistent set of NMR data (1H, 11B, 13C and 29Si NMR). The molecular structure of (Z)-1-dichlorosilyl-1-[9-(9-borabicyclo[3.3.1]nonyl)]-2-phenylethene has been determined by single crystal X-ray diffraction.

A 4′-(4-carboxyphenyl)-3,2′:6′,3′′-terpyridine-based luminescent cadmium(II) coordination polymer for the detection of 2,4,6-trinitrophenol

2019 ◽  
Vol 75 (5) ◽  
pp. 508-513 ◽  
Author(s):  
Bin Xu ◽  
Fuming Luo ◽  
Guodong Tang ◽  
Jinfang Zhang
Keyword(s):  
Coordination Polymer ◽  
Layer Structure ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Quenching Effect ◽  
Good Thermal Stability ◽  
Octahedral Environment ◽  
Strong Luminescence ◽  
Thermal Stability Of

The title coordination polymer, poly[bis[μ3-4-(3,2′:6′,3′′-terpyridin-4′-yl)benzoato]cadmium(II)], [Cd(C22H14N3O2)2] n or [Cd(3-cptpy)2] n , (I), has been synthesized solvothermally and characterized by IR spectroscopy, thermogravimetric analysis, and single-crystal and powder X-ray diffraction. The structure is composed of 3-cptpy− ligands bridging Cd atoms, with each Cd atom coordinated by six ligands and each ligand coordinating to three Cd atoms. Each Cd atom is in a slightly distorted trans-N2O4 octahedral environment, forming a two-dimensional layer structure with a (3,6)-connected topology. Layers are linked to each other by π–π stacking, resulting in a three-dimensional supramolecular framework. The strong luminescence and good thermal stability of (I) indicate that it can potentially be used as a luminescence sensor. The compound also shows a highly selective and sensitive response to 2,4,6-trinitrophenol through the luminescence quenching effect.

scholarly journals Spin State Behavior of A Spin-Crossover Iron(II) Complex with N,N′-Disubstituted 2,6-bis(pyrazol-3-yl)pyridine: A Combined Study by X-ray Diffraction and NMR Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 793
Author(s):  
Elizaveta K. Melnikova ◽  
Dmitry Yu. Aleshin ◽  
Igor A. Nikovskiy ◽  
Gleb L. Denisov ◽  
Yulia V. Nelyubina
Keyword(s):  
Nmr Spectroscopy ◽  
Spin State ◽  
Metal Ion ◽  
Spin Crossover ◽  
Molecular Design ◽  
Chemical Shifts ◽  
Variable Temperature ◽  
High Spin State ◽  
X Ray Diffraction ◽  
X Ray

A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing ‘molecular’ design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand.

O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate: structural evidence of the decomposition product and its oxalate salt

2019 ◽  
Vol 234 (9) ◽  
pp. 613-621
Author(s):  
Marc André Althoff ◽  
Jörn Frederik Martens ◽  
Marco Reichel ◽  
Manfred Metzulat ◽  
Thomas Matthias Klapötke ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Title Compound ◽  
Analytical Methods ◽  
Decomposition Product ◽  
X Ray Diffraction ◽  
X Ray ◽  
Rearrangement Process ◽  
Study Support ◽  
First Time

Abstract The molecular and single crystal structure of O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate oxalate, as determined by single crystal X-ray diffraction studies, is described for the first time; although this compound is well-known by industry and research from the mid-20th century. The known decomposition product of pure O,O-diethyl O-[2-(dimethylamino)ethyl] phosphorothioate could also be structurally characterized. Additionally, the compounds are characterized by recent analytical methods e.g. NMR. The findings of our study support the thesis that the isolated decomposition product must be a by-product of the thiono-thiolo rearrangement process of the title compound.

Synthese und Eigenschaften einiger Silylethinylsilane; Molekülstruktur von Tetrakis(trimethylsilylethinyl)silan / Synthesis and Properties of Some Silylethynylsilane; Molecular Structure of Tetrakis(trimethylsilylethynyl)silane

1988 ◽  
Vol 43 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Hubert Schmidbaur ◽  
Jan Ebenhöch
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Single Crystal ◽  
Silicon Atom ◽  
Grignard Reagent ◽  
X Ray Diffraction ◽  
Tetrahedral Geometry ◽  
X Ray ◽  
Nmr Data

Abstract Trimethylsilylethine (1) has been prepared from C2H2, sodium and Me3SiCl in anisole. The product can be converted into a Grignard reagent Me3SiC≡CMgCl using iPrMgCl. This reagent yields the compounds Me3SiC≡CSiH3, (Me3SiC≡C)2SiH2, (Me3SiC≡C)3SiH, and (Me3SiC≡C)4Si (2-5) when treated with equivalent amounts of H3SiBr, H2SiBr2, HSiCl3, or SiCl4. respectively. The new silanes have been characterized by NMR data. The crystal structure of (Me3SiC≡C)4Si has been determined by single crystal X-ray diffraction. It shows the expected tetrahedral geometry at he central silicon atom with four linear SiC≡CSi linkages.

Darstellung und Struktur eines zweikernigen Vanadium(V)-Komplexes mit den terminal gebundenen Stickstoffliganden NtC4H9, NHtC4H9 und NH2tC4H9: [ VCl(μ-Cl)(NtC4H9)(NHtC4H9) (NH2tC4H9) ]2 / Synthesis and Molecular Structure of a Binuclear Vanadium(V) Complex Containing the Terminal Nitrogen Ligands NtC4H9, NHtC4H9, NH2tC4H9: [VCl(μ-Cl)(NtC4H9)(NHtC4H9)(NH2tC4H9)]2

1985 ◽  
Vol 40 (3) ◽  
pp. 363-367 ◽  
Author(s):  
Fritz Preuss ◽  
Edith Fuchslocher ◽  
William S. Sheldrick
Keyword(s):  
Molecular Structure ◽  
Diffraction Analysis ◽  
Vanadium Complex ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nitrogen Ligands ◽  
Nmr Data ◽  
Distorted Octahedral ◽  
Tert Butylamine ◽  
Cl Atoms

tC4H9N = VCl2(NHtC4H9) and the tert-butylamine complex [tC4H9N=VCl2(NHtC4H9)(NH2tC4H9)] have been prepared by reaction of tC4H9N=VCl3 with NH2tC4H9. 1H and 51V NMR data of these compounds are reported. The complex was investigated by X-ray diffraction analysis; the structure has been found to be a binuclear vanadium complex bridged by two Cl-atoms with a distorted octahedral arrangement of the ligands.

The crystal structure of a dithiophosphate-bridged binuclear cobalt(II) complex of a macrocyclic ligand

1981 ◽  
Vol 34 (1) ◽  
pp. 65 ◽  
Author(s):  
GA Williams ◽  
R Robson
Keyword(s):  
Crystal And Molecular Structure ◽  
Macrocyclic Ligand ◽  
Cobalt Atom ◽  
X Ray Diffraction ◽  
Triclinic Space Group ◽  
X Ray ◽  
Axial Ligands ◽  
Octahedral Environment ◽  
Metal Atoms ◽  
A Cell

The crystal and molecular structure of LCO2 [S2P(OEt)2]2 (where L is a binucleating ligand derived from the macrocycle LH2 formed by condensation of two molecules each of propane-1,3-diamine and 2-hydroxy-5-methylisophthalaldehyde) has been determined by single-crystal X-ray diffraction techniques at 295 K. The compound crystallizes in the triclinic space group Pī with two molecules in a cell of dimensions a 18.644(6), b 11.694(4), c 9.487(4) �, α 84.99(3), β 82.61(3), γ 73.48(2)�. Automatic diffractometry has provided significant Bragg intensities for 2799 independent reflections and the structure has been refined by least-squares methods to R 0.054. The structure is molecular, consisting of discrete binuclear units LCo2[S2P(OEt)2]2. The two centrosymmetric molecules in the unit cell are crystallographically unique but essentially chemically similar. The two cobalt(11) atoms in each molecule are separated by 3.075(2) and 3.072(2) �. Each cobalt atom is in an octahedral environment, with an N2O2 equatorial plane and two sulfur atoms of bridging dithiophosphate ligands in the axial positions. The Co-S bonds are the longest yet observed [2,680(3), 2.652(3), 2.642(3), 2.623(3) �]. The cobalt(11) centres are high spin, with �eff 4.53 BM per cobalt atom. The macrocyclic ligand deviates slightly from planarity. The forces exerted both by the ligand L on associated metal atoms, and by axial ligands on the macrocycle, are discussed.

Copper(II) Complexes of a Tripyridyl Ligand: Anion-Dependent Metallosupramolecular Structures

2013 ◽  
Vol 66 (11) ◽  
pp. 1447 ◽  
Author(s):  
James E. M. Lewis ◽  
James D. Crowley
Keyword(s):  
Mass Spectrometry ◽  
Solid State ◽  
Coordination Polymer ◽  
Elemental Analysis ◽  
Spectroscopic Properties ◽  
Nitrate Salt ◽  
X Ray Diffraction ◽  
X Ray ◽  
Salt Structure ◽  
Solid State Structures

A series of copper(ii) complexes of the ligand 2,6-bis(pyridin-3-ylethynyl)pyridine have been synthesised and characterised by 1H and DOSY NMR, IR and UV-Vis spectroscopies, mass spectrometry, elemental analysis and single crystal X-ray diffraction. In solution these systems display almost identical spectroscopic properties, however the solid state structures are shown to vary widely, depending upon the choice of anion. The tetrafluoroborate salt was revealed to be a discrete Cu2L4 cage-like helicate. The tosylate salt, whilst of the same Cu2L4 stoichiometry, was shown to be a coordination polymer. Finally the nitrate salt structure was observed to be a discrete Cu2L2 metallocycle.

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