title: Synthesis, photophysical properties and structures of organotin-Schiff bases utilizing aromatic amino acid from the chiral pool and evaluation of the biological perspective of a triphenyltin compound.
abstract: Five new organotin(IV) complexes of compositions [Me2SnL1] (1), [Me2SnL2]n(2), [Me2SnL3] (3), [Ph3SnL1H]n(4) and [Ph3SnL3H] (5) (where L1=(2S)-2-((E)-((Z)-4-hydroxypent-3-en-2-ylidene)amino)-3-(1H-indol-3-yl)propanoate, L2=(2S)-(E)-2-((2-hydroxybenzylidene)amino)-3-(1H-indol-3-yl)propanoate and L3=(2S)-(E)-2-((1-(2-hydroxyphenyl)ethylidene)amino)-3-(1H-indol-3-yl)propanoate were synthesized and spectroscopically characterized. The crystal structures of 1-4 were determined. For the dimethyltin derivative 2, a polymeric chain structure was observed as a result of a long Sn∙∙∙O contact involving the exocyclic carbonyl oxygen-atom from the tridentate ligand of a neighboring Sn-complex unit. The tin atom in this complex has a distorted octahedral coordination geometry, in which the long Sn-O bond is almost trans to the tridentate ligand nitrogen-atom. In contrast, the dimethyltin(IV) complexes 1 and 3 displayed discrete monomeric structures where the tin atom has distorted trigonal-bipyramidal geometry with the two coordinating L oxygen atoms defining the axial positions. On the other hand, 4 is a chain polymer in the solid state. The ligand-bridged Sn atoms adopt a trans-Ph3SnO2trigonal-bipyramidal configuration with equatorial phenyl groups. A carboxylato oxygen atom from one and the hydroxyl oxygen of the successive ligand in the chain occupy the axial positions. The solution structures were predicted by the use of119Sn NMR chemical shifts. The photophysical properties of the complexes were investigated in the solid and in solution. The triphenyltin(IV) compound 4 was tested in detail ex vivo against A375 (human melanoma) cell line, exhibiting an IC50value of 261nM to induce cell death as assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay without significant alteration of cytolysis as determined by lactate dehydrogenase (LDH) assay. Compound 4-mediated potent cell death was also determined by Live and Dead assay and caspase-mediated cleavage of poly-ADP ribose polymerase (PARP). Potent cell death activity was not observed in primary cells, like blood-derived peripheral mononuclear cells (PBMC). Compound 4 inhibited the diphenyl hexatriene (DPH) binding to cells and decreased the micro viscosity in a dose-dependent manner. Additionally, the ability of 4 and cyclodextrin (CD) to interact was determined by molecular modelling.
authors.affiliation: Centre for Advanced Studies in Chemistry, North-Eastern Hill University, NEHU Permanent Campus, Umshing, Shillong 793 022, India. Electronic address: basubaul@nehu.ac.in.
authors.forename: Tushar S
authors.initials: TS
authors.lastname: Basu Baul
authors.affiliation: Centre for Advanced Studies in Chemistry, North-Eastern Hill University, NEHU Permanent Campus, Umshing, Shillong 793 022, India.
authors.forename: Pelesakuo
authors.initials: P
authors.lastname: Kehie
authors.affiliation: School of Life & Environmental Science, Deakin University, Geelong, Victoria 3217, Australia.
authors.forename: Andrew
authors.initials: A
authors.lastname: Duthie
authors.affiliation: Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Calcutta 700009, India.
authors.forename: Nikhil
authors.initials: N
authors.lastname: Guchhait
authors.affiliation: Centre for DNA Fingerprinting & Diagnostics, Nampally, Hyderabad 500 001, India.
authors.forename: Nune
authors.initials: N
authors.lastname: Raviprakash
authors.affiliation: Centre for DNA Fingerprinting & Diagnostics, Nampally, Hyderabad 500 001, India.
authors.forename: Raveendra B
authors.initials: RB
authors.lastname: Mokhamatam
authors.affiliation: Centre for DNA Fingerprinting & Diagnostics, Nampally, Hyderabad 500 001, India. Electronic address: manna@cdfd.org.in.
authors.forename: Sunil K
authors.initials: SK
authors.lastname: Manna
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Viale delle Scienze, Parco D'Orleans II, Edificio 17, 90128 Palermo, Italy.
authors.forename: Nerina
authors.initials: N
authors.lastname: Armata
authors.affiliation: Dipartimento di Fisica e Chimica, Università degli Studi di Palermo, Viale delle Scienze, Parco D'Orleans II, Edificio 17, 90128 Palermo, Italy; CIRCMSB - Consorzio Interuniversitario di Ricerca in Chimica dei Metalli nei Sistemi Biologici, 1, Piazza Umberto I, 70121 Bari, Italy.
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Scopelliti
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
authors.forename: Ruimin
authors.initials: R
authors.lastname: Wang
authors.affiliation: Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany. Electronic address: ullrich.englert@ac.rwth-aachen.de.
authors.forename: Ulli
authors.initials: U
authors.lastname: Englert
mesh_terms: D024322:Amino Acids, Aromatic / Q000737:chemistry*; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D018360:Crystallography, X-Ray; D006801:Humans; D020128:Inhibitory Concentration 50; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D009947:Organotin Compounds / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D055668:Photochemical Processes; D012545:Schiff Bases / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D013237:Stereoisomerism
chemical_list: D024322:Amino Acids, Aromatic; D000970:Antineoplastic Agents; D009947:Organotin Compounds; D012545:Schiff Bases; C030665:triphenyltin
keywords: A375 (human melanoma) cell line; Chiral Schiff bases; Organotin(IV) compounds; Spectroscopy; Tryptophan; X-ray crystallography