Search

Single nanocrystal arrays were fabricated on sub-microwells of poly(ethylene glycol) (PEG) copolymer using selective wetting on the hydrophilic regions of the exposed substrate surface and subsequent drying. Templates were produced by molding a thin film of a PEG-based random copolymer on hydrophilic substrates such as glass or silicon dioxide. The polymeric microstructures provide a topographical barrier around the well, which makes it possible to create nanocrystal arrays with controlled geometrical features. The size of the nanocrystal was found to decrease with decreasing well size and also decrease with decreasing topological height. A simple empirical equation was derived to predict the size of the crystal as a function of the pattern size and height, which is in good agreement with the experimental data.

The nature of the products obtained on reacting R3SnCl (R = Me, Bu and Ph), Ph2SnCl2and Bu2SnO with amino acids having nitrogen‐containing heterocyclic rings; i.e. L‐histidine and DL‐tryptophan, is shown to depend upon the reaction conditions. Ten new organotin(IV) derivatives of these amino acids have been synthesized and characterized by elemental analyses, molar conductance and electronic spectra, and the bonding in these complexes is discussed in terms of their infrared, far‐infrared, 1H and 13C NMR, and 119Sn Mössbauer spectra. The complexes soluble in DMSO have been tested in vitroagainst a wide spectrum of bacteria and fungi and found to be active. Two complexes, Ph3SnL‐1 and Ph3SnL‐2, have been found to be slightly active in vivoagainst a multi‐infection fungal model in mice. Copyright © 1999 John Wiley & Sons, Ltd.

The nature of the products obtained on reacting R3SnCl (R = Me, Bu and Ph), Ph2SnCl2 and Bu2SnO with amino acids having nitrogen-containing heterocyclic rings; i.e. L-histidine and DL-tryptophan, is shown to depend upon the reaction conditions. Ten new organotin(IV) derivatives of these amino acids have been synthesized and characterized by elemental analyses, molar conductance and electronic spectra, and the bonding in these complexes is discussed in terms of their infrared, far-infrared, ¹H and ¹³C NMR, and ¹¹⁹Sn Mössbauer spectra. The complexes soluble in DMSO have been tested in vitro against a wide spectrum of bacteria and fungi and found to be active. Two complexes, Ph3SnL-1 and Ph3SnL-2, have been found to be slightly active in vivo against a multi-infection fungal model in mice. Copyright © 1999 John Wiley & Sons, Ltd.

Eight new diorganotin complexes formulated as R2Sn(OArCR″=NCHR′COO) were prepared and characterized by 1H and 13C NMR, IR, and elemental analysis. A single crystal X-ray diffraction study of the dibutyltin N-salicylidenevaline complex, Bu2Sn(OC6H4CH=NCH(i-Pr)COO), determines the molecular structure. The crystals are orthorhombic, space group P212121with a = 9.187(2) Å, b = 10.003(2) Å, c = 23.482(4) Å, V = 2157.8(6) Å3, Z = 4, and Dc = 1.392 g cm−3. The final discrepancy factors are RF = 0.040, and Rw = 0.021 for 1131 significant reflections. The tin atom has a distorted trigonal bipyramidal coordination, with no short intermolecular contacts. The two axial Sn—O bonds of 2.078(10) and 2.151(8) Å and the equatorial Sn—N bond of 2.158(8) Å are among the shortest found in related complexes. The fact that the closest intermolecular Sn—O distance is 4.511(8) Å indicates a nonbridging carbonyl group.

Equimolar reactions of dibutyltin(IV) oxide with Schiff bases derived from amino‐acids led to the formation of a new series of dibutyltin(IV) complexes of general formula, Bu2SnL [L=dianion of tridentate Schiff bases derived from the condensation of 2‐hydroxy‐1‐naphthaldehyde or acetyl acetone with glycine (L‐1), L‐β‐alanine (L‐2), DL‐valine (L‐3), DL‐4‐aminobutyric acid (L‐4), L‐methionine (L‐5), L‐leucine (L‐6) and phenylglycine (L‐7)]. An attempt has been made to prove the structures of the resulting complexes on the basis of elemental analyses, conductance measurements and electronic, IR, multinuclear magnetic resonance (1H, 13C and 117Sn) and 119Sn Mössbauer spectral studies. The complexes have been tested against various bacteria [Streptococcus faecalis,Klebsiella pneumoniae,Escherichia coli,Pseudomonas aeruginosa,Staphylococcus aureuspenicillin resistance (2500 units)] and fungi (Candida albicans, Cryptococcus neoformans,Sporotrichum schenckii,Trichophyton mentagrophytesand Aspergillus fumigatus). All the complexes showed moderate activity. The cytotoxicity of a few compounds has been screened in vitroagainst seven human tumour cell lines, viz. MCF‐7, EVSA‐T, WiDr, IGROV, M19 MEL, A498 and H226. The activities found experimentally were better than those obtained for cisplatin and carboplatin © 1997 John Wiley & Sons, Ltd.

New organotin(IV) complexes of the general formula R SnCl,4-n.L [where n = 3, R = CH3 or C6 H5, n = 2, R = C6 H5L = Schiff bases derived from the condensation of thiosemicarbazide with acetophenone (L-1), 4-nitrobenzaldehyde (L-2), glyoxal (L-3), 5-chlorosalicylaldehyde (L-4), cyclohexanone (L-5), 2-hydroxy-1-naphthaldehyde (L-6), 2-methoxybenzaldehyde (L-7), 4-methoxy-benzaldehyde (L-8), furfuraldehyde (L-9), salicylaldehyde (L-10) and benzylmethylketone (L-11)J have been synthesized and characterized by elemental analyses, conductance measurements, electronic, infra-red, far-infra-red, 1H NMR and Sri Mössbauer spectral studies. Thermal studies of some of the complexes have been carried out using TG, DTG, DTA techniques. Mass loss considerations at main decomposition stages indicate conversion of the complexes to tin(II) sulphide. A distorted octahedral structure has been proposed for all the complexes. The complexes have also been tested against various pathogenic bacteria and fungi. A few complexes have shown considerable activity in comparison to the ligand.

Equimolar reactions of dibutyltin(IV) oxide with Schiff bases derived from amino-acids led to the formation of a new series of dibutyltin(IV) complexes of general formula, Bu2SnL [L=dianion of tridentate Schiff bases derived from the condensation of 2-hydroxy-1-naphthaldehyde or acetyl acetone with glycine (L-1), l-β-alanine (L-2), dl-valine (L-3), dl-4-aminobutyric acid (L-4), l-methionine (L-5), l-leucine (L-6) and phenylglycine (L-7)]. An attempt has been made to prove the structures of the resulting complexes on the basis of elemental analyses, conductance measurements and electronic, IR, multinuclear magnetic resonance (¹H, ¹³C and ¹¹⁷Sn) and ¹¹⁹Sn Mössbauer spectral studies. The complexes have been tested against various bacteria [Streptococcus faecalis, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus penicillin resistance (2500 units)] and fungi (Candida albicans, Cryptococcus neoformans, Sporotrichum schenckii,Trichophyton mentagrophytes and Aspergillus fumigatus). All the complexes showed moderate activity. The cytotoxicity of a few compounds has been screened in vitro against seven human tumour cell lines, viz. MCF-7, EVSA-T, WiDr, IGROV, M19 MEL, A498 and H226. The activities found experimentally were better than those obtained for cisplatin and carboplatin © 1997 John Wiley & Sons, Ltd.

Regardless of the proportions of the ligand and triphenyltin chloride used, the new yellow, thermally stable 1:1 complexes (I) are formed (no yields given).

(IIIa) crystallizes in P21/n with Z=4.

Tri- and diorganotin(IV) complexes of L-tyrosine, DL-aspartic acid and L-glutamic acid have been found to show antimicrobial activity in vitro and slight activity in vivo against a multi-infection antifungal model in mice.