Communication: Synthesis of a Novel Triphenyltin(IV) Derivative of 2- Mercaptonicotinic Acid with Potent Cytotoxicity in vitro

A novel triphenyltin(IV) derivative of 2-mercaptonicotinic acid (H2mna) of formula {[(C6H5)3Sn]2(mna).[(CH3)2CO]} (1) has been synthesized and characterized by elemental analysis and 1H, 13C-NMR, and FT-IR spectroscopic techniques. The crystal structure of complex (1) has been determined by single crystal X-ray diffraction analysis at 173(1) K. Compound (1) contains two triphenyltin moieties linked by a doubly de-protonated 2,mercaptonicotinic acid (H>2mna). It is an example of a pentacoordinated Ph3SnXY system with an axial-equatorial arrangement of the phenyl groups at Sn(1). Compound (1), exhibits potent, in vitro, cytotoxicity against sarcoma cancer cells (mesenchymal tissue) from the Wistar rat, polycyclic aromatic hydrocarbons (PAH, benzo[a]pyrene) carcinogenesis

Metal transfer to sediments, invertebrates and fish following waterborne exposure to silver nitrate or silver sulfide nanoparticles in an indoor stream mesocosm.

The fate of engineered nanomaterials in ecosystems is unclear. An aquatic stream mesocosm was explored the fate and bioaccumulation of silver sulfide nanoparticles (Ag2S NPs) compared to silver nitrate (AgNO3). The aims were to determine the total Ag in water, sediment and biota, and to evaluate the bioavailable fractions of silver in the sediment using a serial extraction method. The total Ag in the water column from a nominal daily dose of 10 μg L-1 of Ag for the AgNO3 or Ag2S NP treatments reached a plateau of around 13 and 12 μg L-1, respectively, by the end of the study. Similarly, the sediment of both Ag-treatments reached ~380 μg Ag kg-1, and with most of it being acid-extractable/labile. The biota accumulated 4-59 μg Ag g-1 dw, depending on the type of Ag-treatment and organism. The oligochaete worm, Lumbriculus variegatus, accumulated Ag from the Ag2S exposure over time, which was similar to the AgNO3 treatment by the end of the experiment. The planarian, Girardia tigrina, and the chironomid larva, Chironomus riparius, showed much higher Ag concentrations than the oligochaete worms; and with a clearer time-dependent statistically significant Ag accumulation relative to the untreated controls. For the pulmonated snail, Physa acuta, bioaccumulation of Ag from AgNO3 and Ag2S NP exposures was observed, but was lower from the nano treatment. The AgNO3 exposure caused appreciable Ag accumulation in the water flea, Daphnia magna, but accumulation was higher in the Ag2S NP treatment (reaching 59 μg g-1 dw). In the rainbow trout, Oncorhynchus mykiss, AgNO3, but not Ag2S NPs, caused total Ag concentrations to increase in the tissues. Overall, the study showed transfer of total Ag from the water column to the sediment, and Ag bioaccumulation in the biota, with Ag from Ag2S NP exposure generally being less bioavailable than that from AgNO3

NMR investigations on stannabicycloundecanes of the type RSn(CH2CH2CH2)3N

The 1H, 13C, and 119Sn NMR data of seven stannabicycloundecanes of the type RSn(CH2CH2CH2)3N (1, R = Cl; 2, R = Br; 3, R = I; 4, R = OH; 5, R = SPh; 6, R = Me; 7, R = Sn(CH2CH2CH2)3N) are reported. From 1H NMR coalescence data at low temperature the free activation enthalpies for the racemisation of the bicyclo[3.3.3]skeleton were estimated to be 37 ± 1 kJ/mol. They are independent of the substituent R. However, it decreases when the tin atom is replaced by silicon for R = Me.FLWNAinfo:eu-repo/semantics/publishe

Synthesis and spectroscopic investigations of bis(organostannyl)methanes

info:eu-repo/semantics/publishe

Bis(stannyl)methanes as building blocks for stannacycloalkanes

info:eu-repo/semantics/publishe

Complexes of bis(stannyl)methanes, -propanes and -butanes with HMPA

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Suppression of dislocation activity in strained epilayers

A new technique where a stress opposing the misfit stress is applied to the strained layers allows study of the conditions under which dislocations nucleate and propagate. Using this technique it is possible to suppress dislocation nucleation and reduce dislocation velocities at different stress levels without changing the epilayer thickness or the composition of the layer. The activation energy for the nucleation of dislocations at "natural" heterogeneous dislocation sources was determined to E-n=0.6 - 0.7 eV

Reduction of dislocation mobility in GexSi1-x epilayers

A new method is presented that allows reduction in the dislocation mobility in GexSi1-x layers on Si by application of a load opposing the misfit stress in the layers. Results are given for layers with a Ge mole fraction x=0·016 and x = 0·022 and layer thicknesses of 0·42-0·9 μm