7703-74-4Relevant articles and documents
Free Amino Acid Recognition: A Bisbinaphthyl-Based Fluorescent Probe with High Enantioselectivity
Zhu, Yuan-Yuan,Wu, Xue-Dan,Gu, Shuang-Xi,Pu, Lin
, p. 175 - 181 (2019)
A novel fluorescent probe based on a bisbinaphthyl structure has been designed and synthesized. This compound in combination with Zn(II) has exhibited highly enantioselective fluorescence enhancement with 13 common free amino acids. For example, its enantiomeric fluorescent enhancement ratios (ef or δIL/δID) in the presence of the following amino acids are extremely high: 177 for valine, 199 for methionine, 186 for phenylalanine, 118 for leucine, and 89 for alanine. The observed high enantioselectivity and the extent of the substrate scope are unprecedented in the fluorescent recognition of free amino acids. This fluorescent probe can be applied to determine the enantiomeric composition of the structurally diverse chiral amino acids. NMR and mass spectroscopic investigations have provided clues to elucidate the observed high enantioselectivity.
A one dimensional coordination polymer composed of antiferromagnetically coupled disk-like [Mn7] units
Yang, En-Che,Huang, Han-Sheng,Huang, Shao-Yun,Huang, Shi-Yi,Chang, Yu-Ying,Lee, Gene-Hsiang,Sheu, Hwo-Shuenn,Chang, Chung-Kai
, p. 6963 - 6969 (2018)
The synthesis, characterization by X-ray analysis and magnetic properties of a one dimensional coordination polymer {[Mn7(OH)2(dhap)2(N3)3(MeCN)4(ClO4)2]·2(MeCN)·2(ClO4)}∞ (1) are reported. The ligand dhapH4 in the complex is 2,6-bis[N,N-di(hydroxyethyl)aminomethyl]pyridine. This compound crystallizes in the monoclinic space group C2/c. Each [Mn7(OH)2(dhap)2(N3)3(MeCN)4(ClO4)2] unit (abbreviated by Mn7) is linked end-to-end by azido ligands to its neighboring units to form a one dimensional polymer. Magnetic susceptibility measurements indicate that the polymer is composed of S = 8 units with inter-Mn7-unit antiferromagnetic coupling. The Jahn-Teller axes of the Mn7 units are arranged in a zigzag manner along the polymer chain which induces spin canting at low temperatures. The slow magnetization relaxation at low temperatures was evidenced by observing out-of-phase signals in ac magnetic susceptibility measurements that give Ueff = 47.5 K and Δ0 = 2.7 × 10-13 s. This phenomenon also indicates that this one dimensional coordination polymer functions as a single-chain magnet (SCM).
Synthesis, characterization and X-ray crystal structures of cyclam derivatives. Part VI. Proton binding studies of a pyridine-strapped 5,12-dioxocyclam based macrobicycle
Meyer, Michel,Fremond, Laurent,Tabard, Alain,Espinosa, Enrique,Vollmer, Guy Yves,Guilard, Roger,Dory, Yves
, p. 99 - 108 (2005)
The 14-membered cyclic diamide 1,4,8,11-tetraazacyclotetradecane-5,12-dione (5,12-dioxocyclam) can be considered as a trans-autodiprotected tetraazamacrocycle and provides a convenient starting material for the preparation of macrobicyclic receptors. As an example, the secondary amine nitrogen atoms located at the 1 and 8 positions were cross-bridged with a 1,3-pyridyl strap, affording the constrained ansa-dioxocyclam ligand 1,9,12,18,22-pentaazatricyclo[7.6.6.13,7]docosa-3,5,7(22)-triene-13, 19-dione (L1). The proton binding properties of this cage-type compound, which possesses a hemispherical cavity, were fully investigated by spectroscopic (IR, NMR, UV, MALDI-TOF MS), quantum chemical, and potentiometric methods. While both bridgehead tertiary amines have their free lone pairs oriented inside the cavity, intramolecular hydrogen bonding was found to play a key role in determining the structural features of the free base and its protonated forms. L1 behaves as a diprotic base in water with log K011 = 8.94(1) and log K012 = 2.32(9), but most interestingly shows slow proton-transfer rates on the NMR timescale.
Phosphonated chelates for nuclear imaging
Abada, Sabah,Lecointre, Alexandre,Christine, Cline,Ehret-Sabatier, Laurence,Saupe, Falk,Orend, Gertraud,Brasse, David,Ouadi, Ali,Hussenet, Thomas,Laquerrire, Patrice,Elhabiri, Mourad,Charbonnire, Loc J.
, p. 9601 - 9620 (2014)
A series of bis-, tris- and tetra-phosphonated pyridine ligands is presented. In view of their potential use as chelates for radiopharmaceutical applications, the physico-chemical properties of the ligands and of their Co(ii), Ni(ii), Cu(ii), and Zn(ii) complexes were studied by means of potentiometry and UV-Vis absorption spectroscopy. The pKa values of the ligands and of the complexes, as well as the stability constants for the formation of the complexes, are presented. The kinetic aspects of the formation of Cu(ii) complexes and of their dissociation in acidic media were studied by means of stopped flow experiments, and the stability of the Cu(ii) complex toward reduction to Cu(i) was investigated by cyclic voltammetry and by titration with different reducing agents. The different thermodynamic and kinetic aspects of the polyphosphonated ligands were compared with regard to the impact of the number of phosphonic acid functions. Considering the very promising properties for complexation, preliminary SPECT/CT imaging experiments were carried out on mice with 99mTc using the bis- and tetra-phosphonated ligands L2 and L1. Finally, a bifunctional version of chelate L1, L, was used to label MTn12, a rat monoclonal antibody with both specificity and relatively high affinity for murine tenascin-C. The labeling was monitored by MALDI/MS spectrometry and the affinity of the labeled antibody was checked by immunostaining experiments. After chelation with 99mTc, the 99mTc-L-MTn12 antibody was injected into a transgenic mouse with breast cancer and the biodistribution of the labeled antibody was followed by SPECT/CT imaging.
Synthesis of macrocyclic inclusion complexes using olefin metathesis
Ng, Po Ling,Lambert, John N.
, p. 1749 - 1750 (1999)
The ruthenium-catalysed synthesis of a macrocyclic chelate is described. The reaction proceeds at room temperature using 5% catalyst to afford 4 in 80% isolated yield.
Coordination-driven self-assembly of palladium(II)-based metallacalixarenes as anion receptors using flexible pyridine-bridged diimidazole ligands
Du, Wutong,Tong, Jin,Deng, Wei,Wang, Mingxue,Yu, Shuyan
, p. 485 - 488 (2020/04/15)
Two types of palladium(II)-based metallacalixarenes [ML]2+ and [ML2]2+ have been synthesized through coordination-driven self-assembly from a series of flexible pyridine-bridged diimidazole ligands [2,6-bis((1H-imidazol-1-yl)methyl) pyridine (L1), 2,6-bis((1H-benzo[d]imidazol-1-yl)methyl)pyridine (L2), 2,6-bis((1H-naphtho[2, 3-d]imidazol-1-yl)methyl)pyridine (L3)], with palladium(II)-based building blocks [Pd(BF4)2(M1-BF4) and (tmeda)Pd(NO3)2 (M2-NO3) (tmeda = N,N,N′,N′-tetramethyl-ethylenediamine)]. All complexes were characterized by NMR spectroscopy (1H NMR and 13C NMR), mass spectrometry (CSI-MS, ESI-HRMS) and elemental analysis. The single crystal X-ray diffraction analysis of [M1L22](NO3)2, [M1L32](NO3)2, [M1L32](PF6)2 and [M2L3](NO3)2 further confirmed the uniquely single bowl-shape and double bowl-shape structures. The anion binding properties within the metallacalixarenes as receptors were also investigated by NMR titration experiments in DMSO.
Structural and Thermodynamics Studies on Polyaminophosphonate Ligands for Uranyl Decorporation
Ye, Gaoyang,Roques, Jérome,Solari, Pier-Lorenzo,Den Auwer, Christophe,Jeanson, Aurélie,Brandel, Jérémy,Charbonnière, Lo?c J.,Wu, Wangsuo,Simoni, éric
, p. 2149 - 2159 (2021/02/16)
The development of actinide decorporation agents with high complexation affinity, high tissue specificity, and low biological toxicity is of vital importance for the sustained and healthy development of nuclear energy. After accidental actinide intake, sequestration by chelation therapy to reduce acute damage is considered as the most effective method. In this work, a series of bis- and tetra-phosphonated pyridine ligands have been designed, synthesized, and characterized for uranyl (UO22+) decorporation. Owing to the absorption of the ligand and the luminescence of the uranyl ion, UV-vis spectroscopy and time-resolved laser-induced fluorescence spectroscopy (TRLFS) were used to probe in situ complexation and structure variation of the complexes formed by the ligands with uranyl. Density functional theory (DFT) calculations and X-ray absorption fine structure (XAFS) spectroscopy on uranyl-ligand complexes revealed the coordination geometry around the uranyl center at pH 3 and 7.4. High affinity constants (log K ～17) toward the uranyl ion were determined by displacement titration. A preliminary in vitro chelation study proves that bis-phosphonated pyridine ligands can remove uranium from calmodulin (CaM) at a low dose and in the short term, which supports further uranyl decorporation applications of these ligands.
Functionally Versatile and Highly Stable Chelator for 111In and 177Lu: Proof-of-Principle Prostate-Specific Membrane Antigen Targeting
Li, Lily,Jaraquemada-Peláez, María De Guadalupe,Kuo, Hsiou-Ting,Merkens, Helen,Choudhary, Neha,Gitschtaler, Katrin,Jermilova, Una,Colpo, Nadine,Uribe-Munoz, Carlos,Radchenko, Valery,Schaffer, Paul,Lin, Kuo-Shyan,Bénard, Fran?ois,Orvig, Chris
, p. 1539 - 1553 (2019/05/22)
Here, we present the synthesis and characterization of a new potentially nonadentate chelator H4pypa and its bifunctional analogue tBu4pypa-C7-NHS conjugated to prostate-specific membrane antigen (PSMA)-targeting peptidomimetic (Glu-urea-Lys). H4pypa is very functionally versatile and biologically stable. Compared to the conventional chelators (e.g., DOTA, DTPA), H4pypa has outstanding affinities for both 111In (EC, t1/2 ≈ 2.8 days) and 177Lu (β-,?, t1/2 ≈ 6.64 days). Its radiolabeled complexes were achieved at >98% radiochemical yield, RT within 10 min, at a ligand concentration as low as 10-6 M, with excellent stability in human serum over at least 5-7 days (- complexes (M3+ = In3+, Lu3+, La3+) were dependent on the ionic radii, where the smaller In3+ has the highest pM value (30.5), followed by Lu3+ (22.6) and La3+ (19.9). All pM values are remarkably higher than those with DOTA, DTPA, H4octapa, H4octox, and H4neunpa. Moreover, the facile and versatile bifunctionalization enabled by the p-OH group in the central pyridyl bridge of the pypa scaffold (compound 14) allows incorporation of a variety of linkers for bioconjugation through easy nucleophilic substitution. In this work, an alkyl linker was selected to couple H4pypa to a PSMA-targeting pharmacophore, proving that the bioconjugation sacrifices neither the tumor-targeting nor the chelation properties. The biodistribution profiles of 111In- and 177Lu-labeled tracers are different, but promising, with the 177Lu analogue particularly outstanding.
