Hamza Yilmaz

Manganese(III) Complexes of Some Amino Acid (L‐Serine, L‐Methionine, L‐Cystein) Schiff Bases Derived From 2‐Hydroxy‐1‐Naphthaldehyde

A new series of manganese(III) complexes of amino acid Schiff bases synthesized from 2‐hydroxy‐1‐naphthaldehyde and L‐serine, L‐methionine and L‐cystein. The structure of their metal complexes was investigated by elemental analyses, IR, TGA, magnetic susceptibility, and mass spectra. The structure of the N‐naphthylidene amino acid Schiff bases were determined by IR, UV, 1H NMR and mass spectra for a comparison with those of the complexes.

SOME PHYSICOCHEMICAL PROPERTIES OF THE WHITE SEPIOLITE KNOWN AS PIPESTONE FROM ESKIŞEHİR, TURKEY

Various physicochemical characteristics of a sepiolite sample from the Eskişehir area, Turkey, were investigated to help in making predictions about possible uses of the material. The sample was examined by chemical analysis (CA), thermal analysis (DTA/TGA), X-ray diffraction (XRD) analysis, particle-size analysis (PSA), linear dilatometry (LD), scanning electron microscopy (SEM), mercury porosimetry (Hg-Por.), and low-temperature nitrogen adsorption/desorption (N2-AD) techniques. The CA and XRD data indicated that the sepiolite contains only 6% dolomite by mass. The XRD patterns showed that sepiolite anhydride, enstatite, diopside, and opal-CT form upon heating the sepiolite above 600, 800, 900, and 1200°C, respectively. The maximum rate of endothermic changes in the DTA and TGA curves were observed at 82, 287, and 491°C, corresponding to the loss of external, zeolitic, and bound water from the sepiolite, respectively. Dehydroxylation and recrystallization of the sepiolite were fastest at 845°C and 862°C, respectively. The LD curve indicated that the shrinkage began at 800°C and reached 4.0% at 1000°C. The proportion of particles with diameters of <2 µm, and the external surface area of the long-term (24 h) water-treated sepiolite were determined by PSA as 79% by volume, and 8 m2g−1, respectively. The SEM view revealed discrete bundles of sepiolite fibers of various lengths. The specific surface area found from adsorption data was 316 m2g−1. The specific micro-, meso-, macro-, and total-pore volumes obtained from the combination of Hg-Por. and N2-AD results were 0.16, 0.21, 0.45, and 0.82 cm3g−1, respectively. The average macropore and micro-mesopore radii in the sepiolite were estimated (using the Hg-Por. and N2-AD data) tobe 35 and 2.4 nm, respectively.

Synthesis and characterization of Ni(II), Zn(II), and Cd(II) complexes with dithiophosphonate derivatives

Ammonium salts of p-methoxyphenyldithiophosphonic acid O-alkyl esters (H3CO-C6H4-(RO)P(S)S−NH4+; R = C2H5,-CH2CH2CH2CH2-, and cyclopentyl) and their complexes with Ni2+, Cd2+, and Zn2+ were prepared. 2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide, the so-called Lawesson reagent, was treated with the corresponding alcohol to give the O-alkyl ester of the acid. Dry NH3 was then purged through the solution of this ester to form the ammonium salt of the O-alkyl dithiophosphonic acids. Nickel complexes of these ligands were formed in acetic acid, while zinc and cadmium complexes were formed in water and an ethanol medium, respectively. The geometry of the coordinated atoms was square planar with Ni2+ and tetrahedral with Zn2+ and Cd2+. Using an alkanediol, two dithiophosphonic acids were bridged, thus forming a ligand with four S atoms for coordination. The zinc and cadmium complexes of these tetradentate ligands were also synthesized.

Synthesis and Spectroscopic Characterizations of Novel Ni(II) and Co(II) Dithiophosphinate Complexes, and X-Ray Studies on the Ni(II) Complex

Abstract The reaction of 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide (Lawessons Reagent) with two different Grignard reagents gave the corresponding dithiophos-phinic acids (DTPA), CH3OC6H4-(R)P(S)SH; [R = iso-butyl (HL1) and sec-butyl (HL2)]. HL1 and HL2 were treated with dry ammonia to convert them to the ammonium salts, NH4L1 and NH4L2. Ni(II) and Co(II) complexes of L1 and L2 – [Ni(L1)2], [Ni(L2)2]; [Co(L1)2]2 and [Co(L2)2]2—were obtained by the reaction of NH4L1 and NH4L2 with NiCl2.6H2O and CoCl2.6H2O, respectively, in ethanol. Square-planar nickel complexes [Ni(L1)2] and [Ni(L2)2] were further reacted with pyridine (Py) to obtain the octahedral complexes, [Ni(Py)2(L1)2] and [Ni(Py)2(L2)2]. The compounds were characterized by elemental analysis, FTIR, APCI/ESI-MS and 1H, 13C, and 31P NMR spectroscopies. The novel nickel(II) complex [Ni(L2)2] was characterized by X-ray crystallography. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental resource: Figures S1-S5. GRAPHICAL ABSTRACT

Dimethyl [hydr­oxy(2-nitro­phen­yl)meth­yl]phospho­nate

In the title compound, C9H12NO6P, intramolecular C—H⋯O hydrogen bonds form five- and six-membered rings. In the crystal, inversion dimers lined by pairs of C—H⋯O hydrogen bonds occur with ring motifs R 2 2(10). The O atom of the hydroxy group behaves as an accepter and the benzene ring as donor. Adjacent dimers are connected through O—H⋯O links.

Dimethyl (1-hydr­oxy-1,2-diphenyl­ethyl)phospho­nate

In the molecule of the title compound, C16H19O4P, the coordination around the P atom is distorted tetrahedral. The aromatic rings are oriented at a dihedral angle of 72.28 (11)°. Intramolecular C—H⋯O hydrogen bonding result in the formation of five- and six-membered rings. In the crystal structure, intermolecular C—H⋯O hydrogen bonds link the molecules. There is also a weak C—H⋯π interaction.

Synthesis and Spectroscopic Characterization of Novel Aryl-Dithiofluorophosphonate Derivatives and X-Ray Studies of [(4-CH3OC6H4)(F)P(S)S−][PH4P+]

Abstract Potassium and tetraphenylphosphonium salts of novel aryldithiofluorophosphonic acids were synthesized. Lawessons Reagent was allowed to react with KF in acetonitrile to yield the potassium salt of p-methoxyphenyldithiofluorophosphonic acid. Treatment of the latter with tetraphenylphosphonium chloride resulted in the formation of the tetraphenylphosphonium salt. The structures of the compounds were elucidated by FTIR, 1H, 13C, 19F, and 31P NMR spectroscopy as well as by ESI-mass spectrometry. The molecular and crystal structure of the tetraphenylphosphonium salt, determined by single crystal X-ray diffraction, is also presented. Supplemental materials are available for this article. Go to the publishers online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file. GRAPHICAL ABSTRACT

Diethyl (1-hydr­oxy-1-phenyl­ethyl)phospho­nate

The title compound, C12H19O4P, has a distorted tetrahedral geometry around the P atom. The molecules form dimers with R 2 2(10) ring motifs due to intermolecular O—H⋯O hydrogen bonds. The double-bonded O atom of the phosphonate group behaves as an acceptor and the hydroxy group acts as a donor. Both of the ethyl groups are disordered with occupancies of 0.55:0.45 and 0.725:0.275.

Diethyl (1-hydroxy-1,2-diphenylethyl)phosphonate

In the title compound, C18H23O4P, the dihedral angle between the aromatic ring planes is 69.94 (14)°. Both ethyl side chains are disordered over two sets of sites, with occupancy ratios of 80:20 and 70:30. In the crystal, inversion dimers linked by pairs of O—H⋯O hydrogen bonds occur, leading to R 2 1(8) loops, and C—H⋯O and weak C—H⋯π interactions are also seen.

(2,3-Bis(salicylideneamino-O,N)pyridinato)- nickel(II)

The coordination around the Ni atom in the title compound, {2,2′-[2,3-pyridindiylbis(iminomethyl)]diphenolato}nickel(II), [Ni(C19H13N3O2)], is slightly distorted from square planar. Within the coordination square the bond angles are in the range 83.8 (1)–94.8 (2)°. The Ni—N and Ni—O distances are equal within experimental error with average values of 1.854 (2) and 1.835 (2) A, respectively. Comparisons of bond lengths in free and Ni-coordinated ligands indicate shortening of the C—O bonds due to the packing effect. On complex formation, the whole molecule assumes a more planar form, which brings the Ni atoms from neighbouring molecules as close as 3.1908 (10) A to each other.