Tris(trimethylsilyl)‐substituted group 14‐element‐centered anion monomers [LiE(SiMe3)3·3THF] (E = Si, Ge, and Sn) can be distilled under reduced pressure to give dimeric silyllithium 4 and stannyllithium 6, and trimeric germyllithium 5 without pyrolysis products such as dilithiometallanes. The molecular structures of 4, 5, and 6 were unequivocally determined by X‐ray diffraction. Dimer 4 has a symmetrical bent four‐membered‐ring structure consisting of two anionic silicon atoms and two cationic lithium atoms with coordinated THF molecules. Dimer 6 has an unsymmetrical distorted four‐membered‐ring structure consisting of two anionic tin atoms, a bridged unsolvated lithium atom, and a bridged lithium atom solvated by a THF molecule. Interestingly, 6 aggregates to form dimers of dimers by an intermolecular CH3···Li interaction. Trimeric germyllithium 5 forms an equilateral triangular lithium cluster without solvation. Compound 5 has a crystallographic threefold axis with three anionic germanium atoms and three cationic lithium atoms lying in the same plane. The lithium atoms in 5 are stabilized by an intramolecular CH3···Li interaction. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Environmental samples are known to be contaminated with complex chemicals such as estrogens, polycyclic aromatic hydrocarbons, and retinoids. These contaminants have potentially an adverse impact on survival of aquatic animals, because we found previously that medaka (Oryzias latipes) embryos are defective in the development of blood vessels and bones in the presence of these chemicals. Thus, it is important to test whether sewage effluents contain inhibitory activities against the embryonic development. To examine for such activity, medaka embryos were exposed for 48 h to extracts or freeze-evaporated concentrates of effluent samples collected from different municipal sewage treatment plants. We used the transgenic embryos that are hypersensitive to estrogens due to a high-level expression of estrogen receptor for detecting the total (sum of estrogenic and non-estrogenic) vessel-inhibiting activity. The embryos were specifically defective in blood-vessel formation in most effluent samples, showing the activities ranging from 3 to 30 ng of 17beta-estradiol equiv per liter. Detection limit of 17beta-estradiol was 10 ng per liter. For detection of the non-estrogenic vessel-inhibiting activity, we treated the transgenic embryos in the presence of an antiestrogen, tamoxifen, or used the wild-type embryos. The non-estrogenic activities were found in some (7 out of 18) effluents, ranging from half to all of the total activities. Our findings for the first time demonstrate the utility of the vascular assay for monitoring sewage effluents.