Cengiz Arici

Synthesis of a water-soluble carbene complex and its use as catalyst for the synthesis of 2,3-dimethylfuran

Abstract 1,1′,3,3′-Tetrakis(p-dimethylaminobenzyl)-2,2′-biimidazolidinylidene, L2R (R=CH2C6H4NMe2-p) which contains four peripheral NMe2 substituents, was obtained from 4-dimethylaminobenzaldehyde by a three-step reaction sequence, and was used for the preparation of imidazolidin-2-ylidene Ru(II) and Rh(I) complexes 1 and 2. Etherial HCl readily protonates the NMe2 functionality on the carbene ligand of 1 to give the corresponding salt, 1′; whereas the reaction of 2 with HCl gave a hygroscopic and ill-defined rhodium species. In aqueous solution the salt 1′ is an efficient and active catalyst for intramolecular cyclisation of (Z)-3-methylpent-2-en-4-yn-1-ol into 2,3-dimethylfuran. The catalyst 1′ could be recovered by simple phase separation and the catalytic reaction was maintained for five different runs. All of the new compounds were characterised by elemental analyses, IR and NMR spectroscopy and the molecular structure of 1 was determined by X-ray crystallography.

Some new NiZn heterodinuclear complexes: square-pyramidal nickel(II) coordination

A new series of heterodinuclear nickel(II)zinc(II) complexes, [NiL·ZnCl 2 ·4-picoline] ( 1 ), [NiLDM·ZnCl 2 ·4-picoline] ( 2 ), [NiL·ZnBr 2 ·4-picoline] ( 3 ), [NiLDM·ZnBr 2 ·4-picoline] ( 4 ), [NiLDM·ZnBr 2 ·3-picoline] ( 5 ), [NiLDM·ZnBr 2 ·3,5-lutidine] ( 6 ) and [NiL·ZnI 2 ·4-picoline] ( 7 ), where L is N , N ′-bis(salicylidene)-1,3-diaminopropane dianion and LDM is N , N ′-bis(salicylidene)-2,2′-dimethyl-1,3-diaminopropane dianion, were prepared. The complexes were characterized by elemental analysis, thermogravimetric analysis and IR spectroscopy. X-ray crystallographic analysis of complexes 1 , 2 and 4 revealed that nickel(II) ion in heteronuclear complexes had a square-pyramidal coordination sphere. It is concluded that formation of square-pyramidal nickel(II) coordination depends strongly on the concentration of methyl pyridine present in the medium and occurs when methyl pyridine/Ni ratio is below 1.5.

Synthesis, spectroscopy, thermal behaviour and molecular structure of orotatotriethanolaminecopper(II) monohydrate

Abstract The orotatotriethanolaminecopper(II) monohydrate, [Cu(C5H2N2O4)(C6H15NO3)] · H2O, has been synthesized and characterized with physico-chemical methods (IR and UV-Vis spectroscopy, magnetic susceptibility, conductivity and thermoanalytical measurements) and X-ray diffraction. The structure derived from physico-chemical methods is consistent with that of the X-ray diffraction. The compound crystallizes in the monoclinic system, space group P21/n, with a = 8.6282(12), b = 16.9919(18), c = 10.6985(15) Å, β = 110.08(3)°, V = 1473.1(3) Å3, Z = 4. The copper atom is chelated by the deprotonated nitrogen pyrimidine atom and by the carboxylate oxygen atom of the orotate dianion ligand, and by the nitrogen and oxygen atoms of the triethanolamine ligand. The title compound has a distorted octahedral coordination geometry.

Synthesis and Crystal Structure of Linear Chain Homotetranuclear Complexes with N3

Mononuclear copper(II) complexes, Cu(L) [N,N′‐bis(salicylidene)‐1,3‐propanediaminato]copper(II), and Cu(LDM) [N,N′‐bis(salicylidene)‐2,2′‐dimethyl‐1,3‐propanediaminato]copper(II), were prepared from the ONNO type ligands N,N′‐bis(salicylidene)‐1,3‐diaminopropane (H2L) and N,N′‐bis(salicylidene)‐2,2′‐dimethyl‐1,3‐diaminopropane (H2LDM). These mononuclear complexes were transformed into tetranuclear complexes, [(S)Cu(L)Cu(N3)2]2 and [(S)Cu(LDM)Cu(N3)2]2 (S are solvent molecules, DMSO, DMF, THF, dioxan), with N3 ‐ and Cu(II) ions. All complexes were characterized by elemental analyses and IR spectroscopy. A molecular model of the complex [(DMSO)Cu(L)Cu(N3)2] was obtained by single crystal x‐ray diffraction methods.

The first examples of di- and cis triaryl-3a,4,5,6-tetrahydroimidazo[1,5-b]isoxazoles and their ring-opening reactions

Abstract The Δ 3 -imidazoline 3-oxides 1 undergo diastereoselective cycloaddition with dimethyl acetylenedicarboxylate 2 to give 3a,4,5,6-tetrahydroimidazo[1,5- b ]isoxazoles 3 . Thermal and base induced ring-opening reactions of compounds 3 were demonstrated.

Synthesis and crystal structure of two dimeric cadmium(II) complexes bonded with pseudohalides, 1.1 and 1.3 bonding

Abstract Two different complexes were obtained from (dmpp) and Cd(II) ions with the aid of pseudohalide ions in non-aqueous solvents. The dinuclear complex formed with thiocyanate ions show, using XRD, to posses two 1.3 bond μ bridges [CdL(SCN)2]2. The other dinuclear complex was also seen to form with cyanate ions but with the μ-bridge in a 1.1 position [CdL(OCN)2]. All Cd atoms are located in a distorted octahedral environment in 1 and 2 complexes. The Cd…Cda distances are 6.032(4) Å in 1 and 3.704(3) Å in 2, respectively. The N—C—S and O—C—N angles are approximately linear as 178.1(3) and 178.6(3)° in 1 and 177.2(5) and 176.9(7)° in 2, respectively. The Cd—(μN,S-NCS)2—Cda bonds form a zig-zag structure in 1 and the Cd—(μO,N-OCN)2—Cda bonds form a distorted square planar in 2.

INVESTIGATIONS ON SOME HETERO-TRINUCLEAR COMPLEXES OF NICKEL(II) AND COPPER(II)

Ni(II) and Cu(II) complexes of N,N′-bis(salicylidene-1,3-diaminopropane) were prepared and found to form linear and non-linear trinuclear complexes. Elemental analyses, IR spectroscopy, thermogravimetry and X-ray diffraction techniques applied to the complexes yielded valuable information about their moleculer structures. It was observed that μ-bridges in these trinuclear complexes form through the phenolic oxygens of the ligand or through anions present in the medium. In the presence of acetate, nitrate or nitrite, μ-bridges form between a pair of atoms resulting in linear trinuclear complexes. However, the presence of chloride or bromide results in μ-bridges involving the phenolic oxygens of N,N′-Bis(salicylidene)-1,3-diaminopropane.

Synthesis, crystal structure and electrochemical behaviour of [2,6-bis(3,5-dimethylpyrazolyl)pyridine](dithiocyanato)cobalt(II)

Abstract A mononuclear cobalt(II) complex, [Co(dmpp)(SCN)2], was synthesized using 2,6-bis (3,5-dimethylpyrazolyl)pyridine (dmpp) and thiocyanate anion (SCN), and characterized by IR spectroscopy and single-crystal X-ray diffraction. In addition, cyclic voltammetric studies have been performed. The complex crystalizes in monoclinic space group C 2/c, with unit cell dimensions a = 15.2469(15), b = 9.1120(9), c = 14.0302(11) Å, β = 95.823(3)°. The cell containes 4 molecules.

4-Chloro-2-(4-oxopent-2-en-2-ylamino)-phenol

In the title compound, C 11 H 12 ClNO 2 , there is an intramolecular hydrogen bond between the amino group and the carbonyl O atom [N...O 2.686 (3) A]. Additional intermolecular hydrogen bonds between the phenol O atom and the carbonyl groups of neighbouring molecules [O...O 2.634 (2) A] form a polymeric chain. The molecule is not planar. The dihedral angle between the aromatic ring and the bidentate Schiff base moiety is 44.51 (7)°. The characteristic Schiff base N-C bond length is 1.339 (3) A.

Synthesis, crystal structure and thermoanalysis of bis{[μ-bis-N,N′-(2-hydroxybenzoyl)-1,3-propandiaminato](N,N′-dimethyl formamide) (μ-benzoato)nickel(II)}nickel(II)

The title compound is a centrosymmetric, linear, homotrinuclear nickel(II) complex and has been characterized by elemental and thermogravimetric analysis, IR spectroscopy and single-crystal X-ray diffraction. The complex is monoclinic, space group P21/n, with a = 13.707(4), b = 13.455(2), c = 14.620(3) Å, β = 101.300(2)°, V = 2644.1(10) Å3 and Z = 2. The central and terminal nickel(II) ions have distorted octahedral geometry with a Ni ··· Ni distance of 3.047(1) Å.