Zeynel Kılıç

Intramolecular hydrogen bonding and tautomerism in Schiff bases. Part I. Structure of 1,8-di[N-2-oxyphenyl-salicylidene]-3,6-dioxaoctane

Abstract 1,8-Di[N-2-oxyphenyl-salicylidene]-3,6-dioxaoctane (1) and 1,8-di[N-2-oxyphenyl-2-oxo-1-naphthylidenemethylamino]-3,6-dioxaoctane (2) are obtained from the reaction of triethylene glycol bis(2-aminophenyl ether) with salicylaldehyde and 2-hydroxy-1-naphthaldehyde. Compounds (1) and (2) have been characterized by elemental analysis, IR, 1H-NMR and UV-visible techniques and the structure of compound (1) has been examined crystallographically. The UV-visible spectra of 2-hydroxy Schiff bases are studied in different solvents and acidic media. Compound (2) is in tautomeric equilibria (phenolimine, OH…N ⇌ keto-amine, O…HN forms) in polar and non-polar solvents. These tautomers are not observed in polar and non-polar solvents for (1) as supported by 1H-NMR and UV-visible data. The keto-amine form is observed in acidic solutions of chloroform and benzene, but it is not observed in solutions DMSO and EtOH for compounds (1) and (2). Compound (1) is in the form of phenol-imine in solid state and a crystallographically centrosymmetric multidentate Schiff base ligand, containing two imine nitrogen, two hydroxy and four etheric O atoms. There is a strong intramolecular [ OH ⋯ N = 1.488(3) A ] hydrogen bond. The C  N imine bond and CNC bond angle are 1.270(3)A and 123.5(2)°. It crystallizes in the monoclinic space group P2 1 n with a = 6.301(1), b = 13.624(1), c = 16.189(1) A , β = 100.28(1)°, V = 1367.4(3) A 3 , Z = 2 and Dx = 1.313 g cm−3.

Phosphorus–nitrogen compounds part 27. Syntheses, structural characterizations, antimicrobial and cytotoxic activities, and DNA interactions of new phosphazenes bearing secondary amino and pendant (4-fluorobenzyl)spiro groups

A number of partly (7-9) and fully (10a-12d, Scheme 1) substituted mono(4-fluorobenzyl)spiro cyclotriphosphazenes was prepared. The structures of the compounds were determined by MS, FTIR, 1D and 2D NMR techniques. The crystal structures of 9, 11b and 12b were verified by X-ray diffraction analysis. In vitro cytotoxic activity of the phosphazenes (10a-12d) against HeLa cervical cancer cell lines was evaluated. Compound 12c was found to be the most effective, as it is a cytotoxic reagent that might activate apoptosis by altering mitochondrial membrane potential. Compounds 10b, 11b and 12b showed very good activity against yeast strains Candida tropicalis and Candida albicans. BamHI and HindIII digestion results demonstrate that the compounds (10a-12a, 10b-12b, 10d-12d), and (9, 10c-12c) bind with G/G and A/A nucleotides, respectively.

Phosphorus–nitrogen compounds. Part 50. Further studies on the formation of bicyclic cyclotetraphosphazatetraene derivatives

The reactions of hexachloro-2,6-bis(ethylamino)cyclotetraphosphazatetraene, N4P4Cl6(NHEt)2, with pyrrolidine, piperidine, morpholine, diethylamine, or cyclopropylamine give bicyclic N4P4(NRR′)5(NHEt)(NEt), as well as monocyclic derivatives N4P4(NRR′)6(NHEt)2(NRR′= pyrrolidino, piperidino, morpholino, diethylamino, or cyclopropylamino). The reactions of N4P4Cl8 with cyclopropylamine give the bicyclic, N4P4(NHC3H5)6(NC3H5), and monocyclic, N4P4(NHC3H5)8, products, the former being the first structure of its kind with an α-branched alkyl group at the bridgehead to be isolated. Salient features of the 1H and 31P n.m.r. spectra of these bicyclic phosphazenes are discussed and related to their structures. Likely reaction mechanisms are considered.

Schiff bases and their complexes with metal ions. Part II. Structures of N-n-butyl-2-hydroxy-1-naphthaldimine and bis[N-n-pentyl-2-hydroxy-1-naphthaldiminato]nickel(II)

AbstractThe Schiff base ligand (1), [C15H17NO] crystallizes in the monoclinic space group P21/c witha=10.054(3),b=10.313(3), c=13.173(4)Å, β=107.42(4)°,V=1303.2(7)Å3,Z=4,Dx=1.159 g cm−3, and μ(MoKα)=0.674 cm−1. The C2-O[1.23(1)Å] and C3−C4 [1.33(2)Å] bond lengths are short, due to its quinoidal structure. In the Schiff base nickel complex (2), [Ni(C16H18NO)2] the asymmetric unit is comprised of two half-complexes. It crystallizes in the triclinic space group

Phosphorus-nitrogen compounds. Part 23: syntheses, structural investigations, biological activities, and DNA interactions of new N/O spirocyclotriphosphazenes.

P\bar 1

Phosphorus–nitrogen compounds. Part 35. Syntheses, spectroscopic and electrochemical properties, and antituberculosis, antimicrobial and cytotoxic activities of mono-ferrocenyl-spirocyclotetraphosphazenes

witha=5.124(3),b=16.227(3),c=16.886(4)Å, α=95.47(8), β=96.00(1), γ=90.71(4)°,V=1389.6(9) Å3,Z=2,Dx=1.289 g cm−3, and μ(MoKα) =12.1 cm−1. The coordination of the Ni(II) ions are square planar with bond angles between 87.9(1) and 92.1(1)°. The Ni−O and Ni−N distances are 1.819(2), 1.922(2) and 1.823(2), 1.914(3)Å in these two complexes.

Phosphorus-nitrogen compounds Part 17: The synthesis, spectral and electrochemical investigations of porphyrino-phosphazenes

The replacement reactions of the Cl-atoms in partly substituted spiro-ansa-spiro-cyclotriphosphazenes (7 and 8) with excess pyrrolidine, 4-(2-aminoethyl)morpholine, and 1,4-dioxa-8-azaspiro[4,5]decane in dry THF led to the formation of heterocyclic amine substituted cyclotriphosphazenes (9a–c and 10a–c). All cyclotriphosphazene derivatives were characterized by elemental analysis, FTIR, MS, 1D 1H, 13C and 31P NMR and 2D HSQC, and HMBC techniques, and the crystal structure of partly substituted cyclotriphosphazene 8 was verified by X-ray diffraction analysis. Cyclotriphosphazene derivatives (5–8, 9a–c, and 10a–c) were subjected to antimicrobial activity against seven clinic bacteria and one yeast strain, and the interactions of the phosphazenes with plasmid pBR322 DNA were investigated. Phosphazene derivatives [(5, 7, 8, 9b and 9c) and (10a and 10b)] caused a slight increase and substantial decrease in the mobility of form I DNA, respectively, while 9a caused retardation on gel. Cytotoxic, apoptotic and necrotic effects against L929 fibroblast and A549 lung cancer cells were also evaluated. While the highest toxic effect was obtained for 9a in L929 fibroblast cells and for 9c in A549 lung cancer cells at 100 μg mL−1 concentration, the highest apoptotic effect was determined for 10a in L929 fibroblast cells and for 9a in A549 lung cancer cells at the same concentration. It was found that 9a and 10b exhibited the most necrotic effects against L929 fibroblast and A549 lung cancer cells, respectively. The toxic and necrotic effects of the phosphazenes against A549 lung cancer cells were greater than those against L929 fibroblast cells, whereas, the apoptotic effect of the compounds was greater in L929 fibroblast cells than in A549 lung cancer cells.

Schiff Bases and Their Complexes with Metal Ions. I. 2‐Hydroxy‐N‐n‐propyl‐1‐naphthaldimine (1) and Bis(2‐hydroxy‐κO‐N‐n‐propyl‐1‐naphthaldiminato‐κN)nickel(II) (2)

The Schiff base compounds (1 and 2) are synthesized by the condensation reactions of 2-furan-2-yl-methylamine with 2-hydroxy-3-methoxy- and 2-hydroxy-5-methoxy-benzaldehydes and reduced with NaBH(4) to give the new N/O-donor-type ligands (3 and 4). The monospirocyclotriphosphazenes containing 1,3,2-oxazaphosphorine rings (5 and 6) are prepared from the reactions of N(3)P(3)Cl(6) with 3 and 4, respectively. The reactions of 5 and 6 with excess pyrrolidine, morpholine, and 1,4-dioxa-8-azaspiro [4,5] decane (DASD) produce tetrapyrrolidino (5a and 6a), morpholino (5b and 6b), and 1,4-dioxa-8-azaspiro [4,5] deca (5c and 6c) spirocyclotriphosphazenes. The structural investigations of the compounds are examined by (1)H, (13)C, (31)P NMR, DEPT, HSQC, and HMBC techniques. The solid-state structures of 5, 5a, and 6 are determined using X-ray crystallography. The compounds 5a, 5b, 5c, 6a, 6b, and 6c are subjected to antimicrobial activity against six patojen bacteria and two yeast strains. In addition, interactions between these compounds and pBR322 plasmid DNA are presented by agarose gel electrophoresis.