p-tert-Butylcalixarene hexacarboxylic acid initially binds with low symmetry, to later adopt a highly symmetric up-down alternating conformation in the presence of Pb, Sr or Ba. The conformational dynamics for the three ions are distinct, from 15 hours, to 20 days, to 38 days, respectively.

Pb(2+) complexes can attain several different topologies, depending of the shape of the Pb 6s6p lone pair. In this paper, we study structures with a bisdirected Pb lone pair with quantum mechanics (DFT) and QM/MM calculations. We study small symmetric Pb(2+) models to see what factors are needed to get a bisdirected lone pair. Two important mechanisms have been found: First, the repulsion of th...

The asymmetric unit of the title Pb-based coordination polymer, [Pb2(C24H16N2O8)(H2O)2] n , consists of one Pb(II) cation, half of a 4,4'-(1,4-phenyl-ene)bis-(2,6-dimethyl-pyridine-3,5-di-carb-oxyl-ate (L (4-)) ligand and one coordinating water mol-ecule. The centers of the benzene ring of the ligand and the four-membered Pb/O/Pb/O ring are located on centers of inversion. The Pb(II) ion is coo...

Addition of 2 mg of Pb2+/g of soil concident with or after amendment with starch or maltose resulted in 75 and 50% decreases in net synthesis of amylase and alpha-glucosidase, respectively. Invertase synthesis in sucrose-amended soil was transiently reduced after Pb2+ addition. Amylase activity was several times less sensitive to Pb2+ inhibition than was enzyme synthesis. In most cases, the rat...

Mono- and diplatinum plumbylene complexes are prepared in which the bonding comprises synergic σ donation between the Pt and Pb atoms. The bonding distinguishes the complexes from both the classical Fischer carbene bonding model and M→Pb dative-only bonding. The Pt-Pb bond of the monoplatinum complex is stable, while the diplatinum complex reversibly loses one Pt fragment.

The Pb atom in the polymeric title compound, {[Pb(C(13)H(9)N(3)O(2))]·CH(3)OH}(n), is five-coordinated within an N(2)O(2) donor set and a lone pair of electrons, as the N-isonicotinamido-salicylaldiminate ligand coordinates the Pb(II) atom via the O,N,O'-donors and simultaneously bridges a neighbouring Pb atom via the pyridine N atom; the coordination geometry is based on a trigonal bipyramid w...

The lead(II) complexes of 2,2'-iminodiethanol (H2Dea)Pb2(Dea)(N03)2(DMF), Pb2(HDea)2Cl2 and [Pb2Br6](H3Dea)2(DM F = N,N-dimethylformamide) have been synthesized from the com­ ponents and characterized by X-ray crystallography. Both mono(HDea) and doubly (Dea) deprotonated HN (CH2CH2OH)2 are coordinated via oxygen and nitrogen atoms in Pb2(D ea)(N 03)2(DM F) and Pb2(HDea)2Cl2. The nitrate comple...

In this report, we present a new method for visual detection of Pb2+. Gold nanoparticles (Au-NPs) were synthesized in one step at room temperature, using gallic acid (GA) as reducer and stabilizer. Pb2+ is added during the gold nanoparticle formation. Analysis of Pb2+ is conducted by a dual strategy, namely, colorimetry and spectrometry. During Au-NPs synthesis, addition of Pb2+ would lead to f...

1. The binding of lead to human blood serum, and components of serum, was studied by titration with the addition of Pb(NO3)2 solution, monitoring the free Pb2+ concentration with a Pb2+ electrode, and by equilibrium dialysis. 2. In fresh serum, about 4999 out of 5000 parts of added lead were bound. This suggests that the free Pb2+ concentration is around 1/5000th of the total lead concentration...

Lead (Pb2+) poisoning causes hypertension, but little is known regarding its acute effects on cardiac contractility. To evaluate these effects, force was measured in right ventricular strips that were contracting isometrically in 45 male Wistar rats (250-300 g) before and after the addition of increasing concentrations of lead acetate (3, 7, 10, 30, 70, 100, and 300 microM) to the bath. Changes...