Main Group Chemistry - Volume 10, issue 2

Authors: Brege, Jonathan J. | Barron, Andrew R.

Article Type: Research Article

Abstract: The treatment of SDS-SWNTs with the Group 2 metal ions Mg2+ , Ca2+ , Sr2+ , and Ba2+ causes quenching of the SWNT's fluorescence in the same manner but to a lesser extent (lower Ksv ) as they quench SDBS surfacted nanotubes. In contrast, the quenching with the Group 12 metal ions Zn2+ , Cd2+ and Hg2+ does not follow a simple Stern-Volmer behavior. Instead, two effects are observed. First, the different chirality nanotube's emission wavelengths are shifted by all Group 12 metals but to varying degrees. Second, the corrected decreases in fluorescence intensity is only affected …above a critical concentration of metal ion, [M2+ ]c , at which there is a steep change in fluorescence intensity, then above this concentration there is no significant further reduction in fluorescence intensity. There is a distinct relationship between the identity of the metal ion and the critical concentration: [Zn2+ ]c > [Cd2+ ]c > [Hg2+ ]c . The differentiation between SDBS- and SDS-surfacted SWNTs can be rationalized by a consideration of the relative hardness of the metal ions and the sulfonate and sulfate “ligands”, in particular, the structure of the SDS-SWNT conjugate is overcome by the addition of the Group 12 metal but not by Group 2 metals. Show more

Keywords: Single walled carbon nanotube, Group 2, Group 12, surfactant, fluorescence

DOI: 10.3233/MGC-2011-0040

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 89-104, 2011

Authors: Hashemian, Saeedeh

Article Type: Research Article

Abstract: The adsorption of Acid Red 151 (AR151) from water was determined for kaolin, MnFe2 O4 and MnFe2 O4 /kaolin magnetic nano-composite. MnFe2 O4 and MnFe2 O4 /kaolin were prepared using a simple chemical co-precipitation procedure. The MnFe2 O4 /kaolin composite was prepared with Mn : Fe : kaolin mass ratios of 1 : 1 : 10, 1 : 1.5 : 10 and 1 : 2 : 10. The adsorption capacity increased in 1 : 2 : 10 Mn : Fe : kaolin. Powder XRD and SEM were used to characterize the sorbents. The spinel magnetic phase is present …in the MnFe2 O4 . The AR151 adsorption is strongly dependent on pH and increases with increasing acidity with a maximum at pH 2. The adsorption capacity of the composite is greater than that of natural kaolin and MnFe2 O4 . The adsorption was not affected by the presence of chloride, but was significantly affected by sulfate. The adsorption kinetics of AR151 on kaolin and ferrite powder are similar, but the adsorption of AR151 on the MnFe2 O4 /kaolin composite is much more rapid and occurs within 2–5 min of contact. The adsorption process follows pseudo-second order kinetics. The solid magnetic composite could be conveniently recovered after adsorption. Show more

Keywords: AR151, MnFe2O4 composite, adsorption, kaolin

DOI: 10.3233/MGC-2011-0041

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 105-114, 2011

Authors: Ioannou, P.V. | Tsivgoulis, G.M.

Article Type: Research Article

Abstract: The use of dibutylstannylene ketals of two polyhydric alcohols is explored with the aim at the regiospecific preparation of partially esterified glycerol and meso-erythritol. The mono-dibutylstannylene ketal of glycerol with palmitoyl chloride gave both 1,3-diglyceride and 1-monoglyceride. The mono- and the bis-dibutylstannylene ketals of meso-erythritol with palmitoyl chloride under 1 : 1 and 1 : 2 mole ratios, respectively, gave the same product, 1,2,4-tripalmitoyl-meso-erythritol, while the bis-dibutylstannylene ketal of meso-erythritol and palmitoyl chloride (1 : 1 mole ratio) gave tri- and di-esters of meso-erythritol. The probable paths to these products are discussed.

Keywords: Glycerol, meso-erythritol, dibutyltin oxide, dibutylstannylene ketals, esterification

DOI: 10.3233/MGC-2011-0042

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 115-125, 2011

Authors: Azpeitia, Hugo F. Saucedo | Cortes-Llamas, Sara A. | Vengoechea-Gómez, Fabio A. | Rufino-Felipe, Ernesto | Crespo-Velasco, Natalie T. | Muñoz-Hernández, Miguel-Ángel

Article Type: Research Article

Abstract: The reaction of 1,2-Ethylendiamine-N,N′-bis(1H-pyrrol-2-yl)methylene (L1 H), 1,2-benzenediamine-N,N′-bis(1H-pyrrol-2-yl)methylene (L2 H) and 3,4-Dimethyl-1,2-benzenediamine-N,N′-bis(1 H-pyrrol-2-yl)methylene (L3 H) with one equivalent of AlR2 R′ (R = alkyl, R′ = alkyl, Cl) in toluene afforded the monometallic complexes [LAlR′] (1–12). All the complexes were characterized by analytical and spectroscopic methods. Compounds 1, 3, 4, 6, 7, and 11 were characterized bya single-crystal X-ray structural analyses. Due to the rigidity imposed by the ligand, 1, 3 and 4, with an ethylene “backbone” connecting the two nitrogens, adopt a severely distorted tbp geometry (av. χ = 0.68). On the other hand 6, 7 and 11, with a …phenylene backbone, adopt an intermediate tbp-sqp geometry (av. χ = 0.43). The study of the X-ray crystal structures suggests that, like group 13 Salen complexes, flexible bridges between the two imine groups favor a tbp geometry while more rigid backbones, like phenylene rings, lead to an intermediate sqp and tbp geometry. Based on the χ geometrical parameter for previously reported aluminum complexes with Schiff base ligands and those presented herein, it is possible to propose that upon the coordination geometries of five coordinated aluminum complexes are less tbp distorted (χ ≈ 1) the catalytic activity on ROP increases. Show more

Keywords: Catalysis, aluminum complexes, ring opening polymerization

DOI: 10.3233/MGC-2011-0043

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 127-140, 2011

Authors: Selvakumar, K. | Singh, Vijay Pal | Shah, Poonam | Singh, Harkesh B.

Article Type: Research Article

Abstract: The contrasting structure and reactivity of the mono ortho-coordinated aryl- and alkyl-selenium derivatives and 2,6-dibsubstituted aryl- and alkyl-selenium derivatives are described. The 2,6-disubstituted diaryl diselenides with Se$\ctdot$O intramolecular coordination and steric congestion around selenium undergo intramolecular cyclization to give the corresponding Se-O/Se-N heterocycles. The aliphatic analogue, 2-chlorocyclohex-1-ene-1,3-dicarbaldehyde (13), undergoes intramolecular cyclization upon reaction with disodium diselenide to form a resonance stabilized cyclic diselenide (15). However, 2-chlorocyclohex-1-enecarbaldehyde (16), with one coordinating formyl group, does not undergo an intramolecular cyclization under similar reaction conditions. Diselenides, 2,2′-bis(5-tert-butyl-benzene-1,3-dimethanol)diselenide (22) and bis(5-tert-butyl-isophthaladehyde) diselenide (23), with cissoid conformations are orange in color and show absorbances at …longer wavelengths (368 and 380 nm respectively, n → σ* ). The diselenides, bis(5-tert-butyl-isophthalic acid dimethyl ester)diselenide (24) and bis(5-tert-butyl-isophthalic acid diisopropyl ester)diselenide (25), with transoid conformations, are pale yellow in color with absorbances at shorter wavelengths (324 and 323 nm respectively, n → σ* ). The intramolecularly stabilized arylselenenyl bromides with 2,6-disubstitution underwent interesting cyclization reactions to afford novel cyclic selenenate esters (with Se-O bond) and selenenamides and benzisoselenazoline (with Se-N bond) derivatives depending upon the orthofunctions. Show more

Keywords: Selenium, heterocycles, glutathione peroxidase, intramolecular cyclization

DOI: 10.3233/MGC-2011-044

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 141-152, 2011

Authors: Dopke, Joel A. | Hugdahl, Jeffrey D. | Klausmeyer, Kevin K. | Brill, Matthew P. | Jaremkoĩ, Daniel S.

Article Type: Research Article

Abstract: The heterocycle 1-aza-4-oxa-7-thiacyclononane ([9]aneNOS, 5) was prepared from the intermediate N-p-toluenesulfonyl-1-aza-4-oxa-7-thiacyclononane (3) upon its deprotection via Na/Hg amalgam. The byproduct, N,N′-bis-(p-tolylsulfonyl)-1,13-diaza-7,16-dioxa-4,10-dithiacylododecane (4), was also isolated from the pot mixture of 3. Compound 5 was characterized by 1 H and 13 C NMR, and IR spectroscopy. Compounds 3 and 4 were characterized by 1 H and 13 C NMR, and IR spectroscopy, elemental analysis, and X-ray crystallography. The reaction of 5 with Ni(BF4 )2 ·6 H2 O in methanol produced the sandwich complex ([9]aneNOS)2 Ni(BF4 )2 , 6, which was characterized by UV-visible and IR spectroscopy, elemental analysis, and X-ray crystallography.

Keywords: Heterocycle, azacrown, thioether, cyclononane

DOI: 10.3233/MGC-2011-0045

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 153-163, 2011

Authors: Kattimani, Pramod P. | Raikar, Shraddha V. | Kamble, Ravindra R. | Kariduraganavar, Mahadevappa Y. | Hunnur, Raveendra K.

Article Type: Research Article

Abstract: A convenient and high yielding method was developed for the ring transformation of 1,3,4-oxadiazolinones (2a–e) from 3-arylsydnones (1a–e) to 1,2,4-triazolinones (3a–e) using zinc triflate as catalyst and then appended to 1,3-thiazoles via an imino bridge in one-pot reaction with excellent yields. The novel compounds were further scored for c logP values, drug likeliness, drug score and toxicity rates using molecular OSIRIS property explorer. Selective compounds were also screened for antimicrobial studies.

Keywords: Ring transformation, 1,2,4-triazolinones, 1,2,4-triazoles, 1,3-thiazoles, zinc triflate, OSIRIS property explorer

DOI: 10.3233/MGC-2011-0046

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 165-175, 2011

Authors: Ioannou, P.V. | Tsivgoulis, G.M.

Article Type: Research Article

Abstract: The reaction of P(SPh)3 , As(SPh)3 , Ph-As(SPh)2 and 2-O2 N-C6 H4 -As(SPh)2 with palmitoyl chloride was studied. In dichloromethane at room temperature these reactions did not give the thiol ester RCOSPh, but diphenyl disulfide PhSSPh instead, with yields that were depended on the absence or the presence of an activator [pyridine or 4-dimethylaminopyridine (DMAP)]. At 90°C P(SPh)3 and palmitoyl chloride gave RCOSPh but not PhSSPh either in the absence or in the presence of pyridine or DMAP. On the other hand, As(SPh)3 , Ph-As(SPh)2 and 2-O2 N-C6 H4 -As(SPh)2 with palmitoyl chloride at 90°C …gave mixtures of RCOSPh and PhSSPh in proportions depending on the absence or the presence of pyridine or DMAP. Probable mechanistic paths to these products are proposed. Show more

Keywords: Triphenyl trithiophosphite, triphenyl trithioarsenite, diphenyl phenyldithioarsonite, diphenyl 2-nitrophenyldithioarsonite, acyl chlorides, nucleophilicity, alpha effect

DOI: 10.3233/MGC-2011-0047

Citation: Main Group Chemistry, vol. 10, no. 2, pp. 177-185, 2011