Band 35, Heft 3-4

Two trinuclear stannaindoxanes (2,6-Mes 2 C 6 H 3 In)( t -Bu 2 Sn) 2 (μ 3 -O)(μ-OH) 2 (μ-Cl)Cl ( 1 ) and (2,6-Mes 2 C 6 H 3 In) 2 ( t -Bu 2 Sn)(μ 3 -O)O(μ-OH) 2 ( 2 ) were obtained by the reaction of ( t -Bu 2 SnO) 3 with [2,6-Mes 2 C 6 H 3 In(μ-Cl)Cl] 2 and [2,6-Mes 2 C 6 H 3 In(μ-OH) 2 ] 4 , respectively. Attempts at crystallizing 2 by slow evaporation of a CHCl 3 solution proceeded with the advantageous absorption of CO 2 from the air and yielded the trinuclear indium hydrogen carbonate cluster (2,6-Mes 2 C 6 H 3 In) 3 (CO 3 H) 2 (μ-OH) 4 ( 3 ). More rationally, 3 was prepared when a CHCl 3 solution of [2,6-Mes 2 C 6 H 3 In(μ-OH) 2 ] 4 was purged with gaseous CO 2 .

The first series of building blocks for metal-organic frameworks (MOFs) utilizing the ( S )-2,2′-diethoxy-1,1′-binaphthyl-6,6′-dicarboxylic acid ligand linked with a number of α,ω-bis(chlorodiorganostannyl) alkane spacers and α,ω-bis(dichloroorganostannyl) alkane spacers has been synthesized and characterized. The new compounds have been shown to form monomeric chiral rings with the potential to generate large coordination networks. The potential formation of chiral supramolecular and polymeric materials from the chiral precursors was explored by investigating the structures that form as a result of the hypervalency available at metal centers. These chiral compounds were built using the concept that stemmed from the construction of MOFs. The ‘pre-organized’ chiral rings synthesized here can potentially find use in chiral catalysis, enantioselective synthesis and in designing chiral polymers.

A new asymmetric bis-benzimidazole ligand, 1,3-bis(1 H -benzimidazol-2-yl)-propan-1-one (L), was synthesized by known methods. ZnX 2 (X=Cl, Br, I, ClO 4 , NO 3 , OAc) complexes of the ligand were synthesized and characterized by elemental analysis, molar conductivity, TGA, ESI-MS, FT-IR, NMR and fluorescence spectroscopy. According to the spectral data, the ligand exhibits a keto-enol equilibrium in polar solvents. The ligand gave complexes with eight-membered chelate ring coordinating through both of the C=N nitrogen atoms, whereas the C=O oxygen atom does not bind to the Zn(II) ion. Fluorescence properties of the ligand and the complexes were investigated. Considerable red shift is observed in ZnBr 2 , ZnI 2 and Zn(OAc) 2 complexes according to the ligand. By contrast, the Zn(OAc) 2 complex differs from the other Zn(II) complexes by thermal composition, molar conductivity and fluorescence characteristics, probably due to the coordination of the acetate oxygen atom.

Novel hydroxyester disiloxanes (1,3-bis(6-hydroxyhexanoylmethyl)-1,1,3,3-tetramethyl disiloxane and 3-bis(2-hydroxypropanoylmethyl)tetramethyl disiloxane) were synthesized, and preparation of other known monomers, namely 1,3-bis(hydroxypropyl)-1,1,3,3-tetramethyl disiloxane, 1,3-bis(hydroxyethoxypropyl)-1,1,3,3-tetramethyl disiloxane and 1,3-bis(hydroxymethyl)-1,1,3,3-tetramethyl disiloxane was developed to obtain better yields and reduce production time and expense. All compounds were characterized by infrared spectroscopy, using 1 H NMR, 13 C NMR, and 29 Si NMR and were reacted with diisocyanates, resulting in poly(siloxane-urethane) copolymers with unique properties.

The title compound, [(CH 3 ) 2 CH] 2 NH 2+ ·[(PhPO 3 H) 2 SnPh 3 ]-, has been synthesised and its structure determined by spectroscopies (IR, RMN and Mössbauer) and single crystal X-ray crystallography. The Mössbauer spectroscopy data for the title compound (QS=3.50 mm s -1 ) are in accordance with the trans O 2 SnC 3 geometry at tin atom. The SnPh 3 residue is axially coordinated by two monodentate [PhPO 3 H]- anions, leading to a trigonal-bipyramidal geometry around the tin atom. The anions [(PhPO 3 H) 2 SnPh 3 ]- are linked by pairs of O-H…O interaction, forming an infinite chain. In the crystal, neighbouring chains are linked by hydrogen bonds N-H…O via the cation [(CH 3 ) 2 CH] 2 NH 2+ forming a three-dimensional network.

Quercetin-germanium (Ge) (IV) complex was synthesized in the laboratory. The structure and physicochemical properties of the complex were characterized utilizing thermal and spectroscopic (UV-vis, IR and 1 H NMR) analysis. The antitumor activity of quercetin-Ge (IV) compound was evaluated by the MTT method. The complex was subjected to biological tests in vitro using four tumor cell lines (PC-3, Hela, EC9706 and SPC-A-1). The quercetin-Ge (IV) complex showed significant cytotoxicity against four tumor cell lines.

Direct aldol addition of ketones with aromatic aldehydes and vinyl aldehyde was carried out efficiently in the presence of MgI 2 etherate and Et 3 N using untreated reagent grade CH 2 Cl 2 under atmospheric conditions in a mild, efficient and highly chemoselective manner. Iodide counterion and non-coordinating reaction media (i.e., CH 2 Cl 2 ) are among the critical factors for the unique reactivity of this reaction system.