ESI-MS Identification of the Cationic Phosphine-Ligated Gold Clusters Au1–22: Insight into the Gold–Ligand Ratio and Abundance of Larger Clusters

2020 ◽  
Vol 32 (1) ◽  
pp. 237-246
Author(s):  
Michael A. Hewitt ◽  
Heriberto Hernández ◽  
Grant E. Johnson
Keyword(s):  
Gold Clusters ◽  
Esi Ms ◽  
Ligand Ratio ◽  
Insight Into

Role of sterics in phosphine-ligated gold clusters

2019 ◽  
Vol 21 (4) ◽  
pp. 1689-1699 ◽  
Author(s):  
Katherine A. Parrish ◽  
Mary King ◽  
Marshall R. Ligare ◽  
Grant E. Johnson ◽  
Heriberto Hernández
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Ligand Exchange ◽  
Gold Clusters ◽  
Solution Phase ◽  
Ionization Mass ◽  
Exchange Reactions ◽  
The Stability ◽  
Insight Into

This study examined the solution-phase exchange reactions of triphenylphosphine (PPh3) ligands on Au8L72+ (L = PPh3) gold clusters with three different tolyl ligands using electrospray ionization mass spectrometry to provide insight into how steric differences in the phosphines influence the extent of ligand exchange and the stability of the resulting mixed-phosphine clusters.

scholarly journals Development of validated UHPLC–PDA with ESI–MS-MS method for concurrent estimation of magnoflorine, berbamine, columbamine, jatrorrhizine, palmatine and berberine in Berberis aristata

2021 ◽  
Author(s):  
Ishita A. Basera ◽  
Aboli Girme ◽  
Vijay P. Bhatt ◽  
Ganesh Saste ◽  
Sandeep Pawar ◽  
...  
Keyword(s):  
Research Literature ◽  
Simultaneous Estimation ◽  
Therapeutic Effects ◽  
Isoquinoline Alkaloids ◽  
Esi Ms ◽  
Fragment Ions ◽  
Ich Guidelines ◽  
Negative Ionization ◽  
Concurrent Estimation ◽  
Insight Into

Abstract A validated UHPLC-PDA with an ESI-MS/MS method has been developed for simultaneous estimation of six bioactive alkaloids (magnoflorine, berbamine, columbamine, jatrorrhizine, palmatine and berberine) in the different extracts of the roots of Berberis aristata DC (Family:Berberdiaceae). It is an important medicinal herb native to Northern Himalaya and commonly known as ‘daruharidra’, ‘daruhaldi’, ‘Indian barberry’ or ‘tree turmeric’. An insight into the research literature uncovered reports on isoquinoline alkaloids like magnoflorine, berbamine, columbamine, jatrorrhizine, palmatine, and berberine as major bioactives in B. aristata roots, possessing different pharmacological and therapeutic effects. In the present study, these aforementioned alkaloids were separated on Phenomenex Luna®, 5 µm-C8 analytical column. The HPLC-MS analysis was performed at a flow rate of 0.90 mL min−1. Each alkaloid that is resolved was characterized by precursor ions and fragment ions with electrospray ionization (ESI) source in both positive and negative ionization using scan mode. The limit of detections (LODs) were 0.087, 0.727, 0.035, 0.124, 0.782 and 0.794 μg mL−1 for magnoflorine, berbamine, columbamine, jatrorrhizine, palmatine and berberine, respectively. The proposed UHPLC-PDA method was fully validated according to international (ICH) guidelines and was found to be selective, sensitive and highly accurate for the concomitant estimation of the aforementioned symbolic bio-markers of B. aristata roots.

scholarly journals Aryl bis-sulfonamides bind to the active site of a homotrimeric isoprenoid biosynthesis enzyme IspF and extract the essential divalent metal cation cofactor

2018 ◽  
Vol 9 (27) ◽  
pp. 5976-5986 ◽  
Author(s):  
Katharina Root ◽  
Konstantin Barylyuk ◽  
Anatol Schwab ◽  
Jonas Thelemann ◽  
Boris Illarionov ◽  
...  
Keyword(s):  
Protein Binding ◽  
Metal Cation ◽  
Active Site ◽  
Divalent Metal ◽  
Isoprenoid Biosynthesis ◽  
Divalent Metal Cation ◽  
Esi Ms ◽  
Binding Mechanisms ◽  
Insight Into

Native ESI-MS delivers unprecedented insight into unknown homomeric protein binding mechanisms involving complex, multistage binding equilibria with cofactors and ligands.

scholarly journals Real-time analysis of Pd2(dba)3 activation by phosphine ligands

2017 ◽  
Vol 53 (5) ◽  
pp. 854-856 ◽  
Author(s):  
Eric Janusson ◽  
Harmen S. Zijlstra ◽  
Peter P. T. Nguyen ◽  
Landon MacGillivray ◽  
Julio Martelino ◽  
...  
Keyword(s):  
Real Time ◽  
Active Species ◽  
Phosphine Ligands ◽  
Time Analysis ◽  
Esi Ms ◽  
Real Time Analysis ◽  
Insight Into

Real-time UV-Vis/ESI-MS monitoring of Pd2(dba)3 activation provides insight into active species and the effect of activation protocol on their formation.

scholarly journals New Evidence of the Bidentate Binding Mode in 3-MBA Protected Gold Clusters: Analysis of Aqueous 13–18 kDa Gold-Thiolate Clusters by HPLC-ESI-MS Reveals Special Compositions Aun(3-MBA)p, (n = 48 – 67, p = 26-30)

2019 ◽  
Author(s):  
David M. Black ◽  
M. Mozammel Hoque ◽  
Germán Plascencia-Villa ◽  
Robert L. Whetten
Keyword(s):  
Ligand Exchange ◽  
Size Range ◽  
Binding Mode ◽  
Gold Clusters ◽  
Esi Ms ◽  
Recent Interest ◽  
Mobile Phases ◽  
First Results ◽  
Gold Thiolate ◽  
New Evidence

Gold clusters protected by 3-MBA ligands (MBA = mercaptobenzoic acid, -SPhCO2H) have attracted recent interest for their unusual structures and advantageous ligand-exchange and bioconjugation properties. Azubel et al. first determined the core structure of an Au68-complex, which was estimated to have 32 ligands (3-MBA groups). To explain the exceptional structure-composition and reaction properties of this complex, and its larger homologs, Tero et al. proposed a “dynamic stabilization” via carboxyl O-H--Au interactions. Herein, we report the first results of an integrated LC/MS analysis of unfractionated samples of gold / 3-MBA clusters, spanning the narrow size range 13.4 to 18.1 kDa. Using high-throughput procedures adapted from bio-macromolecule analyses, we show that integrated capillary HPLC-ESI-MS, based upon aqueous-methanol mobile phases and ion-pairing reverse-phase chromatography, can separate several major components from the nanoclusters mixture that may be difficult to resolve by standard native gel electrophoresis due to their similar size and charge. For each component, one obtains a well-resolved mass spectrum, nearly free of adducts or signs of fragmentation. A consistent set of molecular mass determinations is calculated from detected charge-states tunable from 3- (or lower), to 2+ (or higher). One thus arrives at a series of new compositions (n, p) specific to the Au/3-MBA system. The smallest major component is assigned to the previously unknown (48, 26); the largest one is evidently (67, 30), vs. the anticipated (68, 32). Various explanations for this discrepancy are considered. A prospective is given for the several members of this novel series, along with a summary of the advantages and present limitations of the micro-scale integrated LC/MS approach to characterize such metallic-core macro-molecules, and their derivatives.

Au54(Et3P)18Cl12: a structurally related cluster to Au32(Et3P)12Cl8 gives insight into the formation process

2020 ◽  
Vol 49 (31) ◽  
pp. 10765-10771
Author(s):  
Sebastian Kenzler ◽  
Claudio Schrenk ◽  
Andreas Schnepf
Keyword(s):  
Formation Mechanism ◽  
Formation Process ◽  
Gold Cluster ◽  
Gold Clusters ◽  
Structural Motifs ◽  
Synthetic Procedure ◽  
Insight Into

Cluster fusion? A slight change in the synthetic procedure of Au32(Et3P)12Cl8 leads to the metalloid gold cluster Au54(Et3P)18Cl12, giving further insight into the formation mechanism, showing new structural motifs within metalloid gold clusters

An insight into the mechanism of the aerobic oxidation of aldehydes catalyzed by N-heterocyclic carbenes

2014 ◽  
Vol 50 (16) ◽  
pp. 2008-2011 ◽  
Author(s):  
O. Bortolini ◽  
C. Chiappe ◽  
M. Fogagnolo ◽  
P. P. Giovannini ◽  
A. Massi ◽  
...  
Keyword(s):  
Aerobic Oxidation ◽  
Heterocyclic Carbenes ◽  
Esi Ms ◽  
Insight Into

The existence of the key intermediates hypothesized for the N-heterocyclic carbene-catalyzed aerobic oxidation of aldehydes has been proven by ESI-MS (MS) experiments.

Insight into Signal Response of Protein Ions in Native ESI-MS from the Analysis of Model Mixtures of Covalently Linked Protein Oligomers

2017 ◽  
Vol 28 (9) ◽  
pp. 1863-1875 ◽  
Author(s):  
Katharina Root ◽  
Yves Wittwer ◽  
Konstantin Barylyuk ◽  
Ulrike Anders ◽  
Renato Zenobi
Keyword(s):  
Esi Ms ◽  
Protein Ions ◽  
Signal Response ◽  
Covalently Linked ◽  
Insight Into
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