scholarly journals Synthetic and Structural Study of peri-Substituted Phosphine-Arsines

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7222
Author(s):  
Brian A. Chalmers ◽  
D. M. Upulani K. Somisara ◽  
Brian A. Surgenor ◽  
Kasun S. Athukorala Arachchige ◽  
J. Derek Woollins ◽  
...  
Keyword(s):  
Decomposition Product ◽  
31P Nmr ◽  
31P Nmr Spectroscopy ◽  
Dispersion Forces ◽  
State Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Crystallography ◽  
Donor Acceptor ◽  
Tertiary Arsine

A series of phosphorus-arsenic peri-substituted acenaphthene species have been isolated and fully characterised, including single crystal X-ray diffraction. Reactions of EBr3 (E = P, As) with iPr2PAcenapLi (Acenap = acenaphthene-5,6-diyl) afforded the thermally stable peri-substitution supported donor–acceptor complexes, iPr2PAcenapEBr23 and 4. Both complexes show a strong P→E dative interaction, as observed by X-ray crystallography and 31P NMR spectroscopy. DFT calculations indicated the unusual As∙∙∙As contact (3.50 Å) observed in the solid state structure of 4 results from dispersion forces rather than metallic interactions. Incorporation of the excess AsBr3 in the crystal structure of 3 promotes the formation of the ion separated species [iPr2PAcenapAsBr]+Br− 5. A decomposition product 6 containing the rare [As6Br8]2– heterocubane dianion was isolated and characterised crystallographically. The reaction between iPr2PAcenapLi and EtAsI2 afforded tertiary arsine (BrAcenap)2AsEt 7, which was subsequently lithiated and reacted with PhPCl2 and Ph2PCl to afford cyclic PhP(Acenap)2AsEt 8 and acyclic EtAs(AcenapPPh2)2 9.

The two solid-state conformations of nefopam methiodide, a quaternary ammonium salt of the analgesic drug

1990 ◽  
Vol 68 (7) ◽  
pp. 1128-1134 ◽  
Author(s):  
Robert Glaser ◽  
André Michel ◽  
Marc Drouin
Keyword(s):  
Solid State ◽  
Ammonium Salt ◽  
Quaternary Ammonium ◽  
Quaternary Ammonium Salt ◽  
State Structure ◽  
X Ray Diffraction ◽  
Analgesic Drug ◽  
X Ray ◽  
Positional Disorder ◽  
X Ray Crystallography

The solid-state structure of nefopam methiodide, a quaternary ammonium salt of nefopam hydrochloride (a non-narcotic analgesic drug), has been determined by single crystal X-ray diffraction analysis. Nefopam methiodide gives crystals belonging to the monoclinic P21/c space group and, at 298 K, a = 10.001(1), b = 9.928(1), c = 17.598(1) Å, β = 94.41(1)°, V = 1742.2(2) Å3, Z = 4, R(F) = 0.086, and Rw(F) = 0.108. Due to disorder, the boat (flattened chair) and twist-chair (flattened chair) conformations of the 2,5-benzoxazocine eight-membered ring were both observed in the crystal with 55:45 occupancy, respectively. Positional disorder was also observed for the iodide counterion, which showed occupancies of 81:9.5:9.5. Keywords: nefopam, analgesic, X-ray crystallography, conformation.

scholarly journals Synthesis and X-ray Diffraction Study of thiosemicarbazone Palladacycles with dppm

Proceedings ◽  
2021 ◽  
Vol 62 (1) ◽  
pp. 13
Author(s):  
Marcos Rúa-Sueiro ◽  
Paula Munin-Cruz ◽  
Francisco Reigosa ◽  
José M. Vila ◽  
Juan M. Ortigueira
Keyword(s):  
Nmr Spectroscopy ◽  
31P Nmr ◽  
Antimicrobial Agents ◽  
Cross Coupling ◽  
31P Nmr Spectroscopy ◽  
Coupling Reactions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cross Coupling Reactions ◽  
Platinum Salt

Cyclometallated compounds have been extensively studied, in particular those with palladium and platinum. This is because of their possible applications in medicinal chemistry, as anticancer or antimicrobial agents; in some cases, with similar results as cisplatin, carboplatin or oxaliplatin. What is also remarkable is their use as homogeneous catalysts, for example, in cross coupling reactions such as Suzuki–Miyaura or Mizoroki–Heck. Herein, we report the synthesis of different thiosemicarbazone ligands, which will be reacted with a palladium or platinum salt, to give the corresponding cyclometallated compounds; in addition, their reactivity with bis(diphenylphosphino)methane (dppm) will be studied. Characterization has been carried out by elemental analysis, IR spectroscopy, 1H and 31P NMR spectroscopy. Additionally, 1c has been studied by X-ray diffraction.

scholarly journals Third Generation Buchwald Precatalysts with XPhos and RuPhos: Multigram Scale Synthesis, Solvent-Dependent Isomerization of XPhos Pd G3 and Quality Control by 1H- and 31P-NMR Spectroscopy

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3507
Author(s):  
Svitlana O. Sotnik ◽  
Artem M. Mishchenko ◽  
Eduard B. Rusanov ◽  
Andriy V. Kozytskiy ◽  
Konstantin S. Gavrilenko ◽  
...  
Keyword(s):  
Quality Control ◽  
Nmr Spectra ◽  
31P Nmr ◽  
Impurity Content ◽  
31P Nmr Spectroscopy ◽  
Third Generation ◽  
X Ray Diffraction ◽  
Simple Method ◽  
Spectra Analysis ◽  
X Ray

The third generation Buchwald precatalysts Pd(ABP)(Phos)(OMs) (also known as Phos Pd G3)) with XPhos and RuPhos were prepared in multigram scale by a modified procedure (ABP = fragment of C-deprotonated 2-aminobiphenyl, XPhos = 2-dicyclohexylphosphino-2′,4′,6′-triisopropylbiphenyl, RuPhos = 2-dicyclohexylphosphino-2′,6′-diisopropoxybiphenyl, OMs− = CH3SO3−). The 1H- and 31P-NMR spectra of the title complexes and some impurities, measured by various 1D and 2D techniques, were analyzed in detail. The solvent-dependent isomerization of Pd(ABP)(XPhos)(OMs) was studied by NMR, and the X-ray structures of two isomers were determined. The impurities in precatalysts, such as Pd(ABP)(HABP)(OMs) (HABP—neutral 2-aminobiphenyl coordinated to Pd2+ in N-monodentate mode) and PdCl2(XPhos)2, were identified and characterized by single crystal X-ray diffraction. A simple method for the quick quality control (QC) of the precatalysts, suitable for routine use, was proposed. The method was based on the assessment of the impurity content on the basis of the 1H-NMR spectra analysis.

scholarly journals Substituent effects in phosphine ligands

2011 ◽  
Vol 30 (1) ◽  
Author(s):  
C. Alicia Renison ◽  
D. Bradley G. Williams ◽  
Alfred J. Muller
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
Molecular Modelling ◽  
31P Nmr ◽  
Substituent Effects ◽  
Phosphine Ligands ◽  
31P Nmr Spectroscopy ◽  
Electronic Effects ◽  
X Ray ◽  
X Ray Crystallography

The study illustrates the use of the P-atom to evaluate steric and electronic effects in P-containing organic compounds. The work involves the synthesis of substituted triarylphosphines and their corresponding Rh Vaska complexes. High resolution X-ray crystallography, molecular modelling, 31P NMR spectroscopy and IR will be used to quantify substituent effects.

scholarly journals Diethylstilbestrol Modifies the Structure of Model Membranes and Is Localized Close to the First Carbons of the Fatty Acyl Chains

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 220
Author(s):  
Alessio Ausili ◽  
Inés Rodríguez-González ◽  
Alejandro Torrecillas ◽  
José A. Teruel ◽  
Juan C. Gómez-Fernández
Keyword(s):  
Membrane Surface ◽  
Water Layer ◽  
Fatty Acyl ◽  
31P Nmr Spectroscopy ◽  
Relaxation Rates ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Acyl Chains ◽  
Dynamics Simulations

The synthetic estrogen diethylstilbestrol (DES) is used to treat metastatic carcinomas and prostate cancer. We studied its interaction with membranes and its localization to understand its mechanism of action and side-effects. We used differential scanning calorimetry (DSC) showing that DES fluidized the membrane and has poor solubility in DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) in the fluid state. Using small-angle X-ray diffraction (SAXD), it was observed that DES increased the thickness of the water layer between phospholipid membranes, indicating effects on the membrane surface. DSC, X-ray diffraction, and 31P-NMR spectroscopy were used to study the effect of DES on the Lα-to-HII phase transition, and it was observed that negative curvature of the membrane is promoted by DES, and this effect may be significant to understand its action on membrane enzymes. Using the 1H-NOESY-NMR-MAS technique, cross-relaxation rates for different protons of DES with POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) protons were calculated, suggesting that the most likely location of DES in the membrane is with the main axis parallel to the surface and close to the first carbons of the fatty acyl chains of POPC. Molecular dynamics simulations were in close agreements with the experimental results regarding the location of DES in phospholipids bilayers.

scholarly journals Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3920
Author(s):  
Martin Weber ◽  
Gábor Balázs ◽  
Alexander V. Virovets ◽  
Eugenia Peresypkina ◽  
Manfred Scheer
Keyword(s):  
Diffraction Analysis ◽  
Room Temperature ◽  
31P Nmr ◽  
Spectroscopic Studies ◽  
Iron Complex ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

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