The compound [Ph2Sn(2-OC6H4C(CH3)NCH2COO)], 1, shows a distorted trigonal-bipyramidal geometry in the solid state. Reaction of 1 with Ph3SnCl yields a 1:1 adduct in which the two tin atoms are joined via the carbonyl atom of the ligand in 1 to form a mixed diorgano/triorgano species. NMR data indicate that the 1:1 adduct dissociates in noncoordinating solvent. Similarly, [ t Bu2Sn(2-OC6H4C(CH3)NCH2COO)· t Bu2SnCl2], which has been characterized crystallographically in the solid state, is dissociated in solution. In contrast to the above behavior, monomeric [Vin2Sn(2-OC6H4C(CH3)NCH2COO)] forms an adduct with a water molecule to yield [Vin2Sn(2-OC6H4C(CH3)NCH2COO)OH2] in the solid state.

A series of R 3 SnO 2 CR′ compounds, where R) Me (1), Et (2), n Bu (3), Ph (4), and cHex (5) and R′CO 2 is the carboxylate residue of 2-[(E)-2-(2-hydroxy-5-methylphenyl)-1-diazenyl]benzoic acid, has been shown by multinuclear magnetic resonance studies to be monomeric in solution. Crystallography shows that monomeric four-coordinate species are found in the solid state for 4 and 5 but polymeric structures with five-coordinate tin atoms are found for 1-3. The different behavior is ascribed to the steric demands of the tin-bound substituents. A fair correlation is found between the difference in 117 Sn chemical shift between the solution and solid states and the carbonyl oxygen-tin distance of the compounds 1-5, only when the data of 4, R) Ph, are omitted. This indicates that the mesomeric effect of the phenyl group does not express its influence to the same extent in the solid and solution states, unlike the inductive effects. By contrast, a good correlation including 4 is found between the Mössbauer quadrupole splitting and the difference in 117 Sn chemical shift between the solution and solid states. This shows that the nature of the organic group on the tin atom contributes to similar extents to the values of the 117 Sn chemical shifts in solution and solid state, independently of the existence or not of mesomeric effects, and that the parallel behavior of QS and 117 Sn chemical shifts is geometry independent.

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Potassium 2-{[(2Z)-(3-hydroxy-1-methyl 2-butenylidene)]amino}-4-methyl-pentanoate (L1HK) and potassium 2-{[(E)-1-(2-hydroxyphenyl)alkylidene]amino}-4-methyl-pentanoates (L2HK-L3HK) underwent reactions with PhnSnCl4-n (n = 2 and 3) to give the amino acetate functionalized Schiff base organotin(IV) complexes [Ph3SnLH]n (1-3) and [Ph2SnL] (4), respectively. These complexes have been characterized by 1H, 13C, 119Sn NMR, IR spectroscopic techniques in combination with elemental analyses. The crystal structures of 1 and 3 were determined. The crystal structures reveal that the complexes exist as polymeric chains in which the L-bridged Sn-atoms adopt a trans-R3SnO2 trigonal bipyramidal configuration with the Ph groups in the equatorial positions and the axial locations occupied by a carboxylate oxygen atom from one carboxylate ligand and the alcoholic or phenolic oxygen atom of the next carboxylate ligand in the chain. The carboxylate ligands coordinate in the zwitterionic form with the alcoholic/phenolic proton moved to the nearby nitrogen atom. The solution structures were predicted by 119Sn NMR spectroscopy. When these organotin(IV) complexes were tested against A498, EVSA-T, H226, IGROV, M19 MEL, MCF7 and WIDR human tumor cell lines, the average ID50 values obtained were 55, 80 and 35 ng/ml for triphenyltin(IV) compounds 1-3, respectively. The most cytotoxic triphenyltin(IV) compound in the present report (3) with an average ID50 value of around 35 ng/ml is found to be morer cytotoxic for all the cell lines studied than doxorubicin, cisplatin, 5-fluorouracil and etoposide. (3) with an average ID 50 value of around 35 ng/ml is found to be morer cytotoxic for all the cell lines studied than doxorubicin, cisplatin, 5-fluorouracil and etoposide.

SUMMARY A new rapid air‐drying technique which gives results comparable to critical point‐drying is described for scanning electron microscopy, using a trematode parasite, Homalogaster paloniae, as a test specimen.

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