294-80-4Relevant articles and documents
The synthesis of 1,2-bis(1,5,9-triazacyclododecyl)ethane: A showcase for the importance of the linker length within bis(alkylating) reagents
Medina-Molner, Alfredo,Blacque, Olivier,Spingler, Bernhard
, p. 4829 - 4831 (2007)
(Chemical Equation Presented) The synthesis of 1,2-bis(1,5,9- triazacyclododecyl)ethane (1) showcases how different bis(alkylating) reagents change the reaction from an intra- to an intermolecular pathway. The isolation of the intermediate hexahydro-3a,6a-ethano-1H,4H,7H,9bH-9a-aza-3a,6a- diazoniaphenalene-3a,6a-diium (2) explained why initially the synthesis of 1 was not possible. Both isomers of 2 were found in solution. DFT calculations revealed that isomer 2a is 4.6 kcal/mol lower in energy than 2b. Synthesis of 1 was finally achieved by using oxalyl chloride.
SYNTHESIS AND COPPPER(I) COMPLEXES OF A SERIES OF 9- TO 13-MEMBERED N3 MACROCYCLES
Briellmann, Markus,Kaderli, Susan,Meyer, Charles J.,Zuberbuehler, Andreas D.
, p. 680 - 689 (1987)
Eight cyclic triamines with ring sizes between 9 and 13 were synthesized by the p-toluenesulfonate method.The open-chain triamines bis(2-aminoethyl)amine (dien) and bis(3-aminopropyl)amine (diprop) were used as starting materials.In some cases, the corresponding dimeric cyclic hexaamines have been isolated and characterized as major by-products.The complexation of Cu(I) by the triamines has been studied potenciometrically in CH3CN/H2O.All ligands L form ternary complexes .The corresponding association constants vary between 1E11 and 1E7, decreasing with increasing ring size.In addition , complexes yLH>(2+), y= 1 or 2, are found as less important species with maximum concentrations of 7 to 50 percent.
Computational and experimental studies on the effect of conformational flexibility on bonding and photophysics of a triaza-macrocycle tripod
Verma, Rohini,Baral, Minati,Kanungo
, p. 253 - 273 (2021/06/30)
The effect of conformational flexibility on coordination and bonding of a chelator, [12N3Me5Ox], on the macrocyclic ring 1,5,9-tris(-5-methylene)-1,5,9-triazadodecane and its lanthanide complexes is depicted by synthesis, characterization, and theoretical techniques. The chelator and its complexes were prepared and characterized by physicochemical methods. Each lanthanide complex was eight coordinated with a pseudo-C3 symmetric distorted dodecahedron geometry. Density functional theory (DFT) studies suggest that Ln3+ ions can be easily incorporated into the chelator cavity without changing the basic geometry. Natural bonding orbitals (NBO) and energy decomposition analysis (EDA) indicate that M–L bonds have ~ 70% ionic character. Exciting and diverse behavior was observed when the results of 12N3Me5Ox were compared with 9N3Me5Ox; with the increase in the size of the macrocyclic ring, the covalency of the metal–ligand bond was increased. The luminescence properties of these complexes were different in the solid and solution state. The f–f transitions of the lanthanide were not observed for the complexes. The theoretical results are in good agreement with the experiments.
Syntheses, conformations, and basicities of bicyclic triamines
Bell, Thomas W.,Choi, Heung-Jin,Harte, William,Drew, Michael G. B.
, p. 12196 - 12210 (2007/10/03)
The multistep syntheses of several bicyclic triamines are described, all of which have an imbedded 1,5,9-triazacyclododecane ring. In 1,5,9-triazabicyclo[7.3.3]pentadecanes 12, 13, 15, and 16, two nitrogens are bridged by three carbons. The monoprotonated forms of these triamines are highly stabilized by a hydrogen-bonded network involving the bridge and both bridgehead nitrogens, producing a difference of more than 8 pKa units in acidities of their monoprotonated and diprotonated forms. The one- and zero-carbon bridges in 1,5,9-triazabicyclo[9.1.1]tridecane (23) and 7-methyl-1,5,9-triazabicyclo[5.5.0]dodecane (39) do not enhance the stabilities of their monoprotonated forms. X-ray crystal structures and computational studies of 12·HI and 16·HI reveal similar, but somewhat weaker, hydrogen-bonded networks, relative to 15·HI. The activation free energies for conformational inversion of 13·HI (14.4 ± 0.2 kcal/mol), 16·HI (15.0 ± 0.1 kcal/mol) and 16 (8.8 ± 0.3 kcal/mol) were measured by variable-temperature 1H and 13C NMR spectroscopy. These experimental barriers give an estimate of 6.2 kcal/mol for the strength of the bifurcated hydrogen bond between the bridge nitrogen and cavity proton in 16·HI. Computational studies support the hypothesis that N-inversion occurs in an open conformation, leading to an estimate of 10.32 kcal/mol for the enthalpy of the bifurcated hydrogen bond in 16·HI in the gas phase.
