Arsenic Compounds in Zoo- and Phyto-plankton of Marine Origin

Major water-soluble arsenic compounds accumulated in some zoo- and phyto-plankton were identified. Zooplankton were collected at sampling stations in the Sea of Japan by a Norpac net towed from 600 m depth to the surface. Phytoplankton were cultivated under axenic conditions. Water-soluble arsenic compounds were extracted repeatedly from plankton tissues by aqueous methanol. The arsenic compounds in the extracts were analyzed by HPLC–ICP/MS. Among zooplankton analyzed in the present study, two carnivorous species, i.e. Amphipoda ( Themisto sp.) and Sagittoidea ( Sagitta sp.), contained arsenobetaine as the dominant arsenic species. Arsenobetaine was the major species in Euphausiacea ( Euphausia sp.), also. The most abundant arsenic compound in the herbivorous Copepoda species ( Calanus sp.), on the other hand, was an arsenic-containing ribofuranoside with a sulfate ester group, and arsenobetaine was only a minor component. Phytoplankton contained arsenic-containing ribofuranosides apparently in a species-speific manner. The arsenic compounds in zooplankton seem to reflect their feeding habit; i.e. carnivorous species eating zooplankton or other small animals accumulate arsenobetaine, while herbivorous ones eating phytoplankton accumulate arsenic-containing ribofuranosides as major arsenic compounds.     

Selective synthesis of organic sulfides and disulfides by the reduction of elemental sulfur with samarium diiodide

Elemental sulfur can be reduced to the corresponding thiolate anion species (S²⁻ and S²⁻₂) selectively by samarium diiodide in the presence and absence of HMPA, respectively. The subsequent alkylation of the thiolate anion species provides a useful synthetic route to dialkyl sulfides and disulfides. © 1998 John Wiley & Sons, Inc. Heteroatom Chem 9: 581–584, 1998     

A stable silagermene (tBu3Si)2Si=Ge(mes)2 (mes = 2,4,6‐trimethylphenyl): Synthesis,X‐ray crystal structure,and thermal isomerization

A stable silagermene, 1,1‐bis(tri‐tert‐butylsilyl)‐2,2‐bis(2,4,6‐trimethylphenyl)silagermene, was synthesized by the reaction of dilithiosilane (^tBu₃Si)₂SiLi₂ with dichlorodimesitylgermane. Its structure was determined by spectroscopic data and X‐ray crystallography, which showed the SiGe length to be 2.2769(8) Å. The silagermene underwent isomerization at 100ˆC to form the corresponding symmetrically substituted isomer (E)‐1,2‐bis(tri‐tert‐butylsilyl)‐1,2‐bis(2,4,6‐trimethylphenyl)silagermene. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:649–653, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20503