Ligand Properties of Tri(2-thienyl)- and Tri(2-furyl)phosphine and -arsine (2-C4H3E)3P/As (E = O, S) in Gold(I) Complexes

2003 ◽  
Vol 58 (8) ◽  
pp. 751-758 ◽  
Author(s):  
Uwe Monkowius ◽  
Stefan Nogai ◽  
Hubert Schmidbaur
Keyword(s):  
Methyl Iodide ◽  
Mass Spectra ◽  
High Stability ◽  
Reference Data ◽  
Structural Studies ◽  
Phosphonium Salts ◽  
Chloride Complexes ◽  
Acetate Complex ◽  
Metal Atoms ◽  
Gold Acetate

Tri(2-thienyl)- and tri(2-furyl)phosphine and -arsine (L) have been introduced as ligands to gold(I) chloride and acetate (AuX). Structural studies have shown that in the 1:1 complexes of the type L-Au-X the gold atoms are bound exclusively to the phosphorus/arsenic centers without any intraor intermolecular approach of the donor atoms of the three heterocycles towards the metal atoms. Intermolecular aurophilic bonding is found in the crystals of the [tri(thienyl)phosphine]gold acetate complex, but is absent in crystals of the chloride complexes. The phosphines L have been quaternized with methyl iodide and the resulting phosphonium salts [LMe]I structurally characterized to provide reference data as to the preferred configurational and conformational motifs. The mass spectra of the gold complexes indicate a high stability of the dinuclear cationic species [(LAu)2X]+ with X = Cl, OAc for all ligands L.

Synthese von vier- und achtgliedrigen Heterocyclen, die Schwefel, Stickstoff und Phosphor enthalten, und die Röntgenstrukturanalyse eines phosphorhaltigen achtgliedrigen SN-Ringes / Synthesis of Four- and Eight-Membered Heterocycles Containing Sulfur, Nitrogen and Phosphorus and the X-ray Structure of a Phosphorus-Containing Eight-Membered SN-Ring

1980 ◽  
Vol 35 (9) ◽  
pp. 1130-1136 ◽  
Author(s):  
Herbert W. Roesky ◽  
Sushil K. Mehrotra ◽  
Christoph Platte ◽  
Djamrnschid Amirzadeh-Asl ◽  
Bernhard Roth
Keyword(s):  
Tertiary Amine ◽  
Phosphorus Atom ◽  
Mass Spectra ◽  
Phosphorus Pentachloride ◽  
Membered Ring ◽  
Phosphonium Salts ◽  
Nitrogen And Phosphorus ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
Phosphorus Containing

Eight-membered rings of the composition [SO2(NR)2PR′]2 3a-d with R = CH3, C2H5, and R′ = CH3, C6H5, were prepared from substituted sulfamides and dichlorophosphanes in the presence of a tertiary amine. These molecules were characterized on the basis of 1H and 31P NMR investigations and of mass spectra. 3 a reacts with phosphorus pentachloride to yield the spirocyclic derivative 4 with the phosphorus atom in the center of two four-membered rings. Methyliodide reacts with 3 a and 3 b under opening of the eight- membered ring and formation of phosphonium salts. The structure of 3 b is discussed in detail. 8b crystallizes in the orthorhombic space group Pna 21 with a = 12.60(0), b = 13.27(1), c = 12.62(4) Å.

scholarly journals Chemical Modification of Microcin J25 Reveals New Insights on the Stereospecific Requirements for Antimicrobial Activity

2019 ◽  
Vol 20 (20) ◽  
pp. 5152
Author(s):  
Helena Martin-Gómez ◽  
Marta Jorba ◽  
Fernando Albericio ◽  
Miguel Viñas ◽  
Judit Tulla-Puche
Keyword(s):  
Antimicrobial Activity ◽  
High Stability ◽  
New Product ◽  
Gram Negative Bacteria ◽  
Structural Studies ◽  
Gram Negative ◽  
Lasso Peptide ◽  
Structure Activity ◽  
Microbiological Assays ◽  
Microcin J25

In this study, microcin J25, a potent antimicrobial lasso peptide that acts on Gram-negative bacteria, was subjected to a harsh treatment with a base in order to interrogate its stability and mechanism of action and explore its structure-activity relationship. Despite the high stability reported for this lasso peptide, the chemical treatment led to the detection of a new product. Structural studies revealed that this product retained the lasso topology, but showed no antimicrobial activity due to the epimerization of a key residue for the activity. Further microbiological assays also demonstrated that it showed a high synergistic effect with colistin.

Mass spectra and proton magnetic resonance spectra of some tetrahydroprotoberberine alkaloids

1968 ◽  
Vol 46 (15) ◽  
pp. 2501-2506 ◽  
Author(s):  
C.-Y. Chen ◽  
D. B. MacLean
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Mass Spectra ◽  
Structural Studies ◽  
New Members ◽  
Magnetic Resonance Spectra

The mass spectra and the proton magnetic resonance spectra of tetrahydroprotoberberine alkaloids, oxygenated at the 9- and 10-positions, show marked differences from the spectra of those oxygenated at the 10- and 11-positions. These differences may be useful in structural studies on new members of this group of alkaloids.

Selective Si–O–Si Bond Cleavage as Synthetic Access to Functionalized, Hydrolysis-stable Zinc Silanolates

2009 ◽  
Vol 64 (11-12) ◽  
pp. 1558-s1579 ◽  
Author(s):  
Christian Däschlein ◽  
Carsten Strohmann
Keyword(s):  
Solid State ◽  
High Stability ◽  
Bond Cleavage ◽  
Structural Studies ◽  
Nmr Studies ◽  
Molecular Systems ◽  
Simple Treatment ◽  
Mild Conditions ◽  
Long Time ◽  
Hydrolysis Of

The selective cleavage of the strong and poorly reactive Si-O-Si bond in functionalized siloxanes under mild conditions is a decisive task for modern synthetic chemistry. Simple treatment of the aminomethyl-functionalized disiloxanes 1, 6, (R,R)-7 and 8 ([R2(CH2NR')SiO]2, R =Me or Ph, NR'= NC5H10, NC5H8(CH3)2 or NC4H7(CH3)) with zinc(II) bromide and zinc(II) chloride, respectively, results in the formation of highly hydrolysis-stable, molecular zinc silanolates which were long time supposed to be unstable in the presence of water. Both, the selective cleavage of the Si-O-Si bond as well as the formation of the molecular zinc silanolates are independent of the substituents at silicon, the used zinc(II) salt or the aminomethyl side arm. Detailed structural studies showed that zwitterionic interactions are the reason for the high stability towards hydrolysis of the formed zinc silanolates 9, 10, (R,R)-11 and 12. NMR studies are indicative of the same structure of these molecular systems in solution as in the solid state

New cluster ions in the FD- and FAB-mass spectra of π-allylpalladium chloride complexes

1990 ◽  
Vol 385 (1) ◽  
pp. C17-C20 ◽  
Author(s):  
C.Akira Horiuchi ◽  
Eiichi Miki ◽  
Takeo Takada ◽  
J.Yasuo Satoh ◽  
Mikio Tanaka ◽  
...  
Keyword(s):  
Mass Spectra ◽  
Cluster Ions ◽  
Chloride Complexes ◽  
Fab Mass Spectra

scholarly journals ANTHOCYANINS OF BASIL LEAVES: DETERMINATION AND PREPARATION OF DRIED ENCAPSULATED FORMS

2017 ◽  
pp. 129-135 ◽  
Author(s):  
Виктор (Viktor) Иванович (Ivanovich) Дейнека (Deineka) ◽  
Ярослава (Iaroslava) Юрьевна (Iur'evna) Кульченко (Kul'chenko) ◽  
Ирина (Irina) Петровна (Petrovna) Блинова (Blinova) ◽  
Андрей (Andrei) Николаевич (Nikolaevich) Чулков (Chulkov) ◽  
Людмила (Liudmila) Александровна (Aleksandrovna) Дейнека (Deineka)
Keyword(s):  
Mass Spectra ◽  
High Stability ◽  
Reversed Phase ◽  
Ocimum Basilicum ◽  
Mass Spectrometric ◽  
Reversed Phase Hplc ◽  
Cinnamic Acids ◽  
Spectra Analysis ◽  
Red Color ◽  
High Level

Anthocyanins composition of five purple leaves cultivars of Ocimum basilicum L. was investigated by reversed-phase HPLC with mass-spectrometric detection in the conditions of ions partial fragmentation as well as preparation of dried differently colored forms of anthocyanins encapsulated into maltodextrin matrix. Mass-spectra analysis revealed that according to anthocyanin set basil cultivars under investigation may be divided onto two groups with common feature being high level of acylation with (mainly) p-coumaric, ferulic and malonic acids of the same base – cyanidin-3-dihexoside-5-hexoside. The presence of acylation with substituted cinnamic acids permits to obtain solutions not only with red color (the property of the flavylium form) but also with blue shades coloration due to quinoid and negatively charged quinoid forms. All forms exept of flavylium are not stable in solution but stable enough to prepare dried encapsulated forms by lyophilization. And thou the loss of anthocyanins at drying is not negligible the final product is characterized with high stability at storage in refrigerator.

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