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Treatment of cytosine with tris(2-aminoethyl)amine (tren) and Cu(ClO 4 ) 2 ·6H 2 O under alkaline conditions gave a ternary tren–Cu 2+ –cytosine complex, [{Cu(tren)} 2 (cytosinato)]·(ClO 4 ) 3 ·0.5H 2 O, whose crystal structure was determined by X-ray diffraction. In the structure of the [{Cu(tren)} 2 (cytosinato)] 3+ cation, two tren-capped square-pyramidal Cu 2+ ions bind to a cytosinate anion, one through the deprotonated N(1) of cytosine with the formation of an intra-molecular interligand hydrogen bond between the keto substituent O(2) of the base and the amino group of tren and the other through both the ring nitrogen N(3) and the exocyclic O(2) of the base, forming a four-membered chelate-ring. An overview on metal bonding properties of N(1)-unsubstituted cytosine observed in so far reported crystal structures is given, emphasizing the significance of intra-molecular interligand interaction as a factor that affects metal-binding sites of cytosine. [ABSTRACT FROM AUTHOR]

Abstract: Novel liquid crystal (LC) trimers with a flexible tris(2-aminoethyl)amine (TREN) core and cyanobiphenyl arms have been designed. These non-traditional mesogens form nematic mesophase over a broad temperature range depending on the alkyl chain length. Their chemical structures were confirmed by the combination of 1H NMR, 13C NMR, APT, COSY and FT-IR spectra. The mesophases were characterized by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). Thermogravimetric analysis showed that LC trimers are highly thermal stable both in the range of the mesophase and above the clearing point. [Copyright &y& Elsevier]

Abstract: A dimeric complex of [(tren)Ni(μ-Cl)2Ni(tren)](ClO4)2 (1) and a polymeric complex of {[Fe(CN)6][Ni(tren)]2[Ni(tren)(H2O)]2}Cl2(ClO4)2·4H2O (2), are isolated from the reaction of potassium ferricyanide, nickel chloride and tren and their X-ray structures and magnetic properties were characterized. Two [Ni(tren)]2+ units are linked through bis μ-Cl ligands forming dimeric structure of 1. In complex 2, there are two kinds of Ni(II) unit, terminal ([Ni(tren)(H2O)]2+) and bridged ([Ni(tren)]2+), and this bridged [Ni(tren)]2+ units are linked with two different Fe(II) ions through μ-NC ligands forming one-dimensional polymeric rectangular chain. 1 shows a weak ferromagnetic coupling between two Ni(II) ions and 2 shows spin crossover in Fe(II) ion. [Copyright &y& Elsevier]

Abstract: Mesoporous SBA-15 was synthesized using rice husk ash (RHA) as the silica source and their defective Si–OH groups were grafted with tris(2-aminoethyl) amine (TREN) dendrimers generation through step-wise growth technique. The X-ray diffraction (XRD) and nitrogen adsorption/desorption results of parent SBA-15 obtained from RHA, suggests its resemblance with SBA-15 synthesized using conventional silica sources. Furthermore, the nitrogen adsorption/desorption results of SBA-15/TREN dendrimer generations (G1–G3) illustrates the growth of dendrimer inside the mesopores of SBA-15 and their CO2 adsorption capacity was determined at 25°C. The maximum CO2 adsorption capacity of 5–6 and 7–8wt% over second and third dendrimer generation was observed which is discernibly higher than the reported melamine and PAMAM dendrimers. The experimental CO2 adsorption capacity was found to be less than theoretically calculated CO2 adsorption capacity due to inter and intra molecular amidation as result of steric hindrance during the dendrimer growth. These SBA-15/TREN dendrimer generations also exhibit thermal stability up to 350°C and CO2 adsorption capacity remains unaltered upon seven consecutive runs. [Copyright &y& Elsevier]

Abstract: Mesoporous MCM-41, MCM-48 and SBA-15 were synthesized using Rice husk ash (RHA) as the silica source and their defective Si–OH sites were functionalized by 3-cholropropyltrimethoxysilane (CPTMS) which was subsequently grafted with amine compounds, Tris(2-aminoethyl)amine (TREN) and Tetraethylenepentamine (TEPA). X-ray powder diffraction (XRD) and BET results of the parent mesoporous silica suggested their closeness of structural properties to those obtained from conventional silica sources. CO2 adsorption of branched amine TREN and straight chain amine TEPA at 25, 50 and 75°C was obtained by Thermogravimetric Analyser (TGA) at atmospheric pressure. TREN grafted mesoporous silica showed 7% of CO2 adsorption while TEPA grafted mesoporous silicas showed less CO2 adsorption, which is due to the presence of isolated amine groups in TREN. TREN grafted mesoporous silicas were also observed to be selective towards CO2, thermally stable and recyclable. The order of CO2 adsorption with respect to amount of amine grafting was observed to be MCM-48/TREN>MCM-41/TREN>SBA-15/TREN. [Copyright &y& Elsevier]

Abstract: Using tris(2-aminoethyl)amine [(C 2 H 4 NH 2 ) 3 N] (tren) as a template, two new tantalum fluorides are obtained by slow evaporation of solutions: [H4 tren](TaF7)2 ·H2O (I) and [H4 tren](TaF7)2 (II). The structure determinations are performed by single crystal X-ray technique. Structures of I and II are built up from isolated TaF7 distorted monocapped trigonal prisms or pentagonal bipyramids; charge balance is achieved by tetraprotonated [H4 tren]4+ cations which possess a “scorpion” configuration. In I and II, TaF7 polyhedra, connected by hydrogen bonds with water molecules in I, lie in corrugated layers; hydrogen bond networks ensure the cohesion between these layers and [H4 tren]4+cations. [Copyright &y& Elsevier]

[Display omitted] • ESI MS, DFT, ITC and NMR show that CB n (n = 6–8) bind polydent tripodal ligand TREN. • TREN-CB n adducts with 1:1 stoichiometry have two different charges. • CB6 and CB7 favors the diprotonated complex with TREN. • Intramolecular N–H...N hydrogen bond stabilized TREN inside CB6 and CB7. • CB8 favors the triprotonated complex with TREN. • In solution the TREN forms the most stable complex with CB7. Binding interactions between a tripodal ligand tris(2-aminoethyl)amine (TREN) and a series of cucurbit[n]urils (n = 6–8) in aqueous (H 2 O or D 2 O) formic acid solutions were investigated by electrospray mass spectrometry (ESI MS), isothermal titration calorimetry (ITC) and NMR titration. DFT calculations were also performed to rationalize the experimental findings. ESI MS data indicate that the studied cucurbiturils bind TREN amine forming two types of adducts of a 1:1 stoichiometry. Dipositive adducts are formed by CB6 and CB7 homologues, while tripositive adducts are formed by CB7 and CB8 homologues. DFT calculations show that the type of the formed adduct is connected with the dimensions of the cucurbituril portal. The results of NMR and ITC measurements confirm that all three CB n homologues (n = 6–8) bind TREN ligands spontaneously in the liquid phase. According ITC results the CB7 homologue binds this amine more strongly than the CB6 and CB8 homologues. [ABSTRACT FROM AUTHOR]