112633-27-9Relevant academic research and scientific papers
Improved synthesis of a C3-symmetrical pyridinophane
Nolan, Claire,Gunnlaugsson, Thorfinnur
, p. 1993 - 1996 (2008)
The formation of the C3-symmetrical 2,11,20-triaza[3.3.3](2,6)pyridinophane 1 was undertaken with the aim of improving the synthesis of this highly desirable macrocycle, with the future aim of functionalizing 1 with amide pendent arms for the recognition of lanthanide ions. The synthesis of 1 involves the stepwise transformation of pyridine-2,6-dicarboxylic acid into two key intermediates; N,N-bis[(6-hydroxymethyl)pyridin-2-yl]-p-tosylamide 7 and 6-bis[(amino-p-tosyl)methyl]pyridine 5. The macrocyclization of these two intermediates gave 8, from which 1 was formed upon deprotection of the three tosyl groups.
Lanthanide complexes based on a diazapyridinophane platform containing picolinate pendants
Roca-Sabio, Adrian,Mato-Iglesias, Marta,Esteban-Gomez, David,Blas, Andres De,Rodriguez-Blas, Teresa,Platas-Iglesias, Carlos,Bonnet, Celia S.,Toth, Eva
, p. 10893 - 10903,11 (2012)
A new macrocyclic ligand, N,N-bis[(6-carboxy-2-pyridyl)methyl]-2,11- diaza[3.3](2,6)pyridinophane (H2BPDPA), was prepared, and its coordination properties toward the LnIII ions were investigated. The hydration numbers (q) obtained from luminescence lifetime measurements in aqueous solution of the EuIII and TbIII complexes indicate that they contain one inner-sphere water molecule. The structure of the complexes in solution has been investigated by 1H and 13C NMR spectroscopy, as well as by theoretical calculations performed at the density functional theory (B3LYP) level. The minimum-energy conformation calculated for the YbIII complex is in excellent agreement with the experimental structure in solution, as demonstrated by analysis of the Yb III-induced paramagnetic 1H shifts. Nuclear magnetic relaxation dispersion (NMRD) profiles and 17O NMR measurements recorded on solutions of the GdIII complex were used to determine the parameters governing the relaxivity. The results show that this system is endowed with a relatively fast water-exchange rate kex298 = 63 × 106 s-1. Thermodynamic stability constants were determined by pH-potentiometric titration at 25 °C in 0.1 M KCl. The stability constants, which fall within the range logKLnL = 12.5-14.2, point to a relatively low stability of the complexes primarily as a consequence of the low basicity of the ligand.
Well-defined Aryl-FeII complexes in cross-coupling and C?H activation processes
Magallón, Carla,Planas, Oriol,Roldán-Gómez, Steven,Luis, Josep M.,Company, Anna,Ribas, Xavi
, p. 1195 - 1200 (2021)
Herein we explore the intrinsic organometallic reactivity of iron embedded in a tetradentate N3C macrocyclic ligand scaffold that allows the stabilization of aryl-Fe species, which are key intermediates in Fe-catalyzed cross-coupling and C?H functionalization processes. This study covers C?H activation reactions using MeLH and FeCl2, biaryl C?C coupling product formation through reaction with Grignard reagents, and cross-coupling reactions using MeLBr or HLBr in combination with Fe0(CO)5. Synthesis under light irradiation and moderate heating (50 °C) affords the aryl-FeII complexes [FeII(Br)(MeL)(CO)] (1Me) and [FeII(HL)(CO)2]Br (1H). Exhaustive spectroscopic characterization of these rare low-spin diamagnetic species, including their crystal structures, allowed the investigation of their intrinsic reactivity.
Improved synthesis of symmetrically & asymmetrically: N -substituted pyridinophane derivatives
Wessel, Andrew J.,Schultz, Jason W.,Tang, Fengzhi,Duan, Hui,Mirica, Liviu M.
, p. 9923 - 9931 (2017/12/12)
The N,N′-di(toluenesulfonyl)-2,11-diaza[3,3](2,6)pyridinophane (TsN4) precursor was sought after as a starting point for the preparation of various symmetric and asymmetric pyridinophane-derived ligands. Various procedures to synthesize TsN4 had been published, but the crucial problem had been the purification of TsN4 from the larger 18- and 24-membered azamacrocycles. Most commonly, column chromatography or other laborious methods have been utilized for this separation, yet we have found an alternate selective dissolution method upon protonation which allows for multi-gram scale output of TsN4·HCl. This optimized synthesis of TsN4 also led to the development of symmetric RN4 derivatives as well as the asymmetric derivative N-(tosyl)-2,11-diaza[3,3](2,6)pyridinophane (TsHN4). Using this TsHN4 precursor, different N-substituents can be added to create a library of asymmetric RR′N4 macrocyclic ligands. These asymmetric RR′N4 derivatives expand the utility of the RN4 framework in coordination chemistry and the ability to study the electronic, steric, and denticity effects of these pyridinophane ligands on the metal center.
Synthesis of Polyaza Macrocyclic Ligands Incorporating Pyridine Units
Hosseini, Mir Wais,Comarmond, Jacques,Lehn, Jean-Marie
, p. 1066 - 1077 (2007/10/02)
The synthesis of nine macrocyclic polyamines 2-10 containing pyridine units is described.These compounds are 22-(9), 24-(2-4,6,8,10), or 26-(5,7) membered hexaaza (2,3,9,10) or octaaza (4-7) macrocycles in which one to four pyridine units are incorporated
STRATEGY FOR THE SYNTHESIS OF UNSYMMETRICAL N-SUBSTITUTED POLYAZAMACROCYCLES
Gu, Kunjian,Mertes, Kristin Bowman,Mertes, Mathias P.
, p. 1323 - 1326 (2007/10/02)
A covergent route is described for the preparation of unsymmetrical N-substituted polyammonium macrocycles that is potentially applicable for the synthesis of a wide variety of macrocycles of differing ring size and heteroatom substitution.
Synthesis and Characterisation of the Sodium and Lithium Cryptates of Macrobicyclic Ligands Incorporating Pyridine, Bipyridine, and Biisoquinoline Units
Alpha, Beatrice,Anklam, Elke,Deschenaux, Robert,Lehn, Jean-Marie,Pietraskiewicz, Marek
, p. 1042 - 1052 (2007/10/02)
Synthetic procedures have been developed for the preparation of sodium and lithium cryptates of the macrobicyclic ligands 1-11 containing pyridine, bipyridine, and biisoquinoline groups.They involve stepwise construction of the bicyclic system as well as direct macrobicyclisation procedures (Scheme 1) and give access to both symmetrical and dissymmetrical structures.Marked cation template effects have been found that facilitate the cyclisation processes.The ligands 1-11 were isolated as their cryptates with Na+ or Li+ cations.
