Strong Closed-Shell Interactions in Inorganic Chemistry.

Synthesis, structure, and bonding in polyiodide and metal iodide-iodine systems.

Bonding and structure trends of thiosemicarbazone derivatives of metals—An overview

Recent studies suggest that the developmental toxicity associated with childhood lead poisoning may be attributable to interactions of Pb(II) with proteins containing thiol-rich structural zinc-binding sites. Here, we report detailed structural studies of Pb(II) in such sites, providing critical insights into the mechanism by which lead alters the activity of these proteins. X-ray absorption spectroscopy of Pb(II) bound to structural zinc-binding peptides reveals that Pb(II) binds in a three-coordinate Pb(II)-S3 mode, while Zn(II) is known to bind in a four-coordinate mode in these proteins. This Pb(II)-S_3 coordination in peptides is consistent with a trigonal pyramidal Pb(II)-S_3 model compound previously reported by Bridgewater and Parkin, but it differs from many other reports in the small molecule literature which have suggested Pb(II)-S_4 as a preferred coordination mode for lead. Reexamination of the published structures of these “Pb(II)-S_4” compounds reveals that, in almost all cases, the coordination number of Pb is actually 5, 6, or 8. The results reported herein combined with this new review of published structures suggest that lead prefers to avoid four-coordination in sulfur-rich sites, binding instead as trigonal pyramidal Pb(II)-S_3 or as Pb(II)-S_(5-8). In the case of structural zinc-binding protein sites, the observation that lead binds in a three-coordinate mode, and in a geometry that is fundamentally different from the natural coordination of zinc in these sites, explains why lead disrupts the structure of these peptides and thus provides the first detailed molecular understanding of the developmental toxicity of lead.

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Reexamination of lead(II) coordination preferences in sulfur-rich sites: implications for a critical mechanism of lead poisoning.

Bismuth chemistry has received much less attention in comparison with that of N, P, As, and Sb, but the last years have revealed an increasing interest in the investigation of both the inorganic and the organometallic chemistry of the heaviest element of the group 15 elements.1 There are several fields Cristian Silvestru (left) was born in Baia-Mare, Romania, in 1955 and graduated in chemistry at the Babes-Bolyai University, Cluj-Napoca, in 1979. He obtained his M.Sc. degree 1 year later. After 2 years as Chemist in a mining company, he was a Research Chemist at the Institute of Chemical and Biochemical Energetics from 1982 to 1989. He received his Ph.D. degree in the group of Professor Ionel Haiduc in Cluj in 1990, with his dissertation research on organometallic compounds with potential biologic activity. In 1990, he joined the Chemistry Department of the BabesBolyai University in Cluj-Napoca. Since 1995 he has been a Full Professor of Inorganic Chemistry and since 1996 Vice-Dean of the Faculty of Chemistry and Engineering Chemistry. He published a book, Organometallics in Cancer Chemotherapy (with I. Haiduc, 2 volumes, CRC Press: Boca Raton, FL, 1989, 1990), and in 1992 received the “Petre Spacu” award of the Romanian Academy for his contributions on the antitumor properties of organometallic compounds (with Dr. Carmen Socaciu and Dr. Adela Bara). Professor Silvestru spent several research stays in Germany (Bremen University 1993sVisiting Professor, 1996sDAAD Grant), Belgium (Vrije Universiteit Brussel 1993sEuropean Community Grant), and Mexico (Instituto de Quimica, Universidad Nacional Autonoma de Mexico 1993−95sVisiting Research Professor, CONACYT Grant). His research interests include organometallic chemistry of main group elements, coordination chemistry of thioligands (mainly organophosphorus compounds), and biological (antitumor) properties of main group organometallics.

Structural chemistry of bismuth compounds. I. Organobismuth derivatives.

Copper(II) and nickel(II) complexes of 2,3-butanedione bis(N(3)-substituted thiosemicarbazones)

Syntheses and structures of isopropyl- and [bis(trimethylsilyl)methyl]antimony rings and catena-tri- and catena-tetrastibines by reaction of organoantimony rings with distibines

Bis(diphenyldithiophosphinato)lead(II), Pb(S 2 PPh 2 ) 2 , was obtained either as a redistribution/decomposition product of Ph 2 Pb(S 2 PPh 2 ) 2 or directly as a reaction product of Pb(OCOCH 3 ) 2 .3H 2 O and NH 4 S 2 PPh 2 . Its crystal and molecular structure was determined by X-ray diffraction. The compound crystallizes in the triclinic space group P1, with cell parameters a=9.017(2) A, b=10.839(2) A, c=12.808(2) A, α=99.48(2) o , β=90.13(2) o , γ= 97.91 (2) o , and Z=2. The monomeric unit contains distorted square-pyramidal PbS 4 units

Crystal and Molecular Structure of Bis(diphenyldithiophosphinato)lead(II), .infin.1[Pb(S2PPh2)2], a New Type of Polymer Associated through Pb.cntdot..cntdot..cntdot.S Secondary Interactions

Klaus H. Ebert

Papers

Copper(II) and nickel(II) complexes of 2,3-butanedione bis(N(3)-substituted thiosemicarbazones)

Syntheses and structures of isopropyl- and [bis(trimethylsilyl)methyl]antimony rings and catena-tri- and catena-tetrastibines by reaction of organoantimony rings with distibines

Crystal and Molecular Structure of Bis(diphenyldithiophosphinato)lead(II), .infin.1[Pb(S2PPh2)2], a New Type of Polymer Associated through Pb.cntdot..cntdot..cntdot.S Secondary Interactions

Strukturen von [Me4Sb]2[MeSbI4]MeSbI2, und [Me4Sb]I. Darstellung von Me3Sb · MeSbI2 und farbwechsel bei Me4Sb2 · Me2SbBr

Syntheses and structures of dimesitylbismuth(III) bromide, Mes2BiBr, and bis(diphenyldithiophosphinato)mesitylbismuth(III), MesBi(S2PPh2)2