Intermolecular O—H⃛O and C—H⃛π(C5H5), and intramolecular C—H⃛O interactions in 2-(ferrocenyl)thiophene-3-carboxylic acid

The title compound, [Fe(C₅H₅)(C₁₀H₇O₂S)], an important precursor en route to organometallic donor–π–acceptor systems, forms dimers in the solid state through cyclic intermolecular carboxyl­ic acid O—H⃛O hydrogen bonds, graph set R(8) [O⃛O 2.661 (2) Å and O—H⃛O 175°]. Intermolecular C_Cp—H⃛π_Cp interactions between the unsubstituted cyclo­penta­dienyl (Cp) rings and C_thiazole—H⃛π_Cp interactions link neighbouring mol­ecules into a three-dimensional network [C⃛Cg 3.753 (7) Å and C—H⃛Cg 156°, and C⃛Cg 3.687 (3) Å and C—H⃛Cg 129°; Cg is the ring centroid]. Intramolecular C—H⃛O inter­actions are present, graph set S(7) [C⃛O 2.925 (3) Å and C—H⃛O 120°, and the closest C—H⃛S_thienyl contact has a C⃛S distance of 3.058 (2) Å].     

Determination of the Protonation Constants of Gadolinium(Iii) Diethyltriaminepentaacetic Acid by Solvent Extraction and Icp-Aes

Abstract

The first and second protonation constant (logβ₁₁₁,logβ₁₂₁ ) of the metal-ligand complex Gadolinium(III)-diethyltriamine-pentaacetic acid (DTPA) have been determined to be 2.27 and 1.52 at 25 °C and I = 0.1. A technique in which the three complexes (H₂Gd-DTPA, HGd-DTPA^?1, Gd-DTPA^?2) are separated according to their relative polarity is utilized. An inductively coupled plasma-atomic emission spectrometer (ICP-AES) is used to determine the relative concentrations of each species by monitoring the gadolinium concentration.     

Impact of environmental conditions on the marine natural product bryostatin 1

Marine Natural Products (MNPs), such as bryostatin 1, are exposed to a range of physical and chemical conditions through the life cycle of the host organism. These include exposure to sunlight, oxidizing and reducing agents, cation binding, and adsorption to reactive metal oxide surfaces. Using Fourier Transform-Ion Cyclotron Resonance (FT-ICR), Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS), UV/Vis absorbance spectroscopy, and molecular modeling, we studied the impact of UV light, TiO2, I2, and reaction with FeCl3 on the structure of bryostatin 1. Our results demonstrate that natural conditions transform bryostatin to a number of structures, including one with a molar mass of 806 Da, which we have previously identified in the sediment collected from the Gulf of Mexico. To date, at least 20 different structures of bryostatin have been reported in the literature. This work suggests that these variations may be products of the chemical environment in which the bryozoa Bugula neritina resides and are not the result of genetic variations within Bugula.     

Kohlenwasserstoffe

Analytical and Bioanalytical Chemistry -