Interplay of P-H and E-H (E = S, Se) bonds in Palladium derivatives: synthesis and disruption of new mixed-valence Palladium triangulo clusters mediated by proton mobility. Crystal and molecular structure of [Pd3(mu-PCy2)2(mu-SPh)(PCy2H)2(SPh)].

An excess of PhEH (E = S, Se) reacts with Pd2(PCyzH)2(mu-PCy2)(mu-eta-3-C3H5) causing, by protonation of the bridging ligands, the disruption of the dinuclear unit and the formation of the monomers trans-[Pd(EPh)2(PCy2H)2]. The isolated monomers were reacted with the same pi-allyl dimer providing a synthetic route to the clusters [Pd3-(mu-PCy2)2(mu-EPh)(PCy,H)2(EPh)]; these mixed-valence triangulo complexes exhibit high stability both in the solid state and in solution, but are reactive toward weak proton donors. Reaction with an excess of PhEH and PCy2H rapidly and quantitatively gives the monomers trans- [Pd(EPh)2(PCy2H)2]. All complexes were characterized by multinuclear NMR analyses. [Pd3(mu-PCy2)2 (mu-SPh)(PCy2H)2(SPh)] crystallizes in the Pnma space group (orthorhombic, Z = 4) with the following unit cell dimensions: a = 13.587(4), b = 25.231(8), c = 18.306(6)

Absolute nutrient concentration measurements in cell culture media: 1H q-NMR spectra and data to compare the efficiency of pH-controlled protein precipitation versus CPMG or post-processing filtering approaches

The NMR spectra and data reported in this article refer to the research article titled “A simple and accurate protocol for absolute polar metabolite quantification in cell cultures using q-NMR” [1]. We provide the 1H q-NMR spectra of cell culture media (DMEM) after removal of serum proteins, which show the different efficiency of various precipitating solvents, the solvent/DMEM ratios, and pH of the solution. We compare the data of the absolute nutrient concentrations, measured by PULCON external standard method, before and after precipitation of serum proteins and those obtained using CPMG (Carr-Purcell-Meiboom-Gill) sequence or applying post-processing filtering algorithms to remove, from the 1H q-NMR spectra, the proteins signal contribution. For each of these approaches, the percent error in the absolute value of every measurement for all the nutrients is also plotted as accuracy assessment. Keywords: 1H NMR, pH-controlled serum removal, PULCON, Accuracy, CPMG, Deconvolutio

A simple and accurate protocol for absolute polar metabolite quantification in cell cultures using quantitative nuclear magnetic resonance.

Absolute analyte quantification by nuclear magnetic resonance (NMR) spectroscopy is rarely pursued in metabolomics, even though this would allow researchers to compare results obtained using different techniques. Here we report on a new protocol that permits, after pH-controlled serum protein removal, the sensitive quantification (limit of detection [LOD] = 5-25 μM) of hydrophilic nutrients and metabolites in the extracellular medium of cells in cultures. The method does not require the use of databases and uses PULCON (pulse length-based concentration determination) quantitative NMR to obtain results that are significantly more accurate and reproducible than those obtained by CPMG (Carr-Purcell-Meiboom-Gill) sequence or post-processing filtering approaches. Three practical applications of the method highlight its flexibility under different cell culture conditions. We identified and quantified (i) metabolic differences between genetically engineered human cell lines, (ii) alterations in cellular metabolism induced by differentiation of mouse myoblasts into myotubes, and (iii) metabolic changes caused by activation of neurotransmitter receptors in mouse myoblasts. Thus, the new protocol offers an easily implementable, efficient, and versatile tool for the investigation of cellular metabolism and signal transduction

Absolute nutrient concentration measurements in cell culture media: (1)H q-NMR spectra and data to compare the efficiency of pH-controlled protein precipitation versus CPMG or post-processing filtering approaches.

The NMR spectra and data reported in this article refer to the research article titled "A simple and accurate protocol for absolute polar metabolite quantification in cell cultures using q-NMR" [1]. We provide the (1)H q-NMR spectra of cell culture media (DMEM) after removal of serum proteins, which show the different efficiency of various precipitating solvents, the solvent/DMEM ratios, and pH of the solution. We compare the data of the absolute nutrient concentrations, measured by PULCON external standard method, before and after precipitation of serum proteins and those obtained using CPMG (Carr-Purcell-Meiboom-Gill) sequence or applying post-processing filtering algorithms to remove, from the (1)H q-NMR spectra, the proteins signal contribution. For each of these approaches, the percent error in the absolute value of every measurement for all the nutrients is also plotted as accuracy assessment