15862-19-8Relevant articles and documents
Terpyridine-based heteroditopic ligand for RuIILn3III metallostar architectures (Ln = Gd, Eu, Nd, Yb) with MRI/optical or dual-optical responses
Boulay, Alexandre,Deraeve, Cline,Vander Elst, Luce,Leygue, Nadine,Maury, Olivier,Laurent, Sophie,Muller, Robert N.,Mestre-Voegtl, Batrice,Picard, Claude
, p. 1414 - 1425 (2015)
A new ditopic ligand (L) based on a 2,2′:5′,4″-terpyridine unit substituted in the 2″,6″ positions with iminodiacetate arms has been designed and synthesized for the construction of RuIIL3Ln3III supramolecular architectures. The two components of this system, a 2,2′-bipyridine unit for RuII coordination and a pyridine-bis(iminodiacetate) core for LnIII coordination, are tightly connected via a covalent Carom(py)-Carom(py) bond. The paramagnetic and photophysical properties of the corresponding tetrametallic RuIIL3Gd3III complex have been evaluated, highlighting the potential of this metallostar structure to act as a bimodal MRI/optical imaging agent. Variable-temperature 17O NMR and proton nuclear magnetic relaxation dispersion (NMRD) measurements showed that this complex exhibits (i) a remarkable relaxivity per metallostar molecule, particularly at clinical and high magnetic fields (r1310K = 51.0 and 36.0 mM-1 s-1 at 20 and 300 MHz, respectively) and (ii) a near-optimal residence lifetime of GdIII coordinated water molecule (τM310K = 77.5 ns). This is the result of the presence of two inner-sphere water molecules in the GdIII components of the metallostar and a slow tumbling rate of the molecule (τR310K = 252 ps). Upon excitation in the visible domain (λexc = 472 nm), the RuII component of the complex exhibits a bright-red luminescence centered at 660 nm with a quantum yield of 2.6% in aqueous solutions at pH 7.4. Moreover, this RuIIL3Gd3III assembly is also characterized by a high kinetic inertness in biological media (PBS and human serum solutions) and a high photostability (photobleaching). Finally, preliminary photophysical studies on RuL3Nd3 and RuL3Yb3 assemblies revealed that the RuII center acts as an effective sensitizer for LnIII-based luminescence in the near-IR region. The NdIII species was found to be the most effective at quenching the 3MLCT luminescence of the Ru center.
Single-molecule white-light of tris-pyrazolonate-Dy3+ complexes
Liu, Jiaxiang,Shi, Qi,He, Yani,Fu, Guorui,Li, Wentao,Miao, Tiezheng,Lü, Xingqiang
, (2019)
Based on the self-assembly of the pyrazolone ligand HPMIP (1-phenyl-3-methyl-4-(isobutyryl)-5-pyrazolone), DyCl3·6H2O and/or the 5-Br-2,2′-bpy (5-bromo-2,2′-bipyridine), two tris-pyrazolonate-Dy3+-complexes [Dy(PMIP)3(H2O)2] (2) and [Dy(PMIP)3(5-Br-2,2′-bpy)] (5) characteristic of dual-emissive emissions toward single-molecule white-light are obtained, respectively, and in dependence on the effective suppression from the oscillator-induced quenching by the involved 5-Br-2,2′-bpy, the color-compensation of the residual ligands-based strong emission and the Dy3+-centered (4F9/2 → 6HJ/2 transitions) multiple emissions renders its Dy3+-complex 5 an efficient (Φem = 4.2%) single-molecule white-light.
Fullerene receptor based on calix[5]arene through metal-assisted self-assembly
Haino, Takeharu,Araki, Hiromi,Yamanaka, Yuko,Fukazawa, Yoshimasa
, p. 3203 - 3206 (2001)
A self-assembled fullerene receptor based on calix[5]arene has been developed. Silver cation complexation held together the two calix[5]arenes with bipyridine units providing a large enough cavity to take up C60 or C70. The formation of the supramolecular complex with C60 or C70 was established by using the electrospray mass spectrometry.
A Paramagnetic NMR Spectroscopy Toolbox for the Characterisation of Paramagnetic/Spin-Crossover Coordination Complexes and Metal–Organic Cages
Lehr, Marc,McConnell, Anna J.,N?ther, Christian,Paschelke, Tobias,S?nnichsen, Frank D.,Trumpf, Eicke,Vogt, Anna-Marlene
, p. 19344 - 19351 (2020)
The large paramagnetic shifts and short relaxation times resulting from the presence of a paramagnetic centre complicate NMR data acquisition and interpretation in solution. As a result, NMR analysis of paramagnetic complexes is limited in comparison to diamagnetic compounds and often relies on theoretical models. We report a toolbox of 1D (1H, proton-coupled 13C, selective 1H-decoupling 13C, steady-state NOE) and 2D (COSY, NOESY, HMQC) paramagnetic NMR methods that enables unprecedented structural characterisation and in some cases, provides more structural information than would be observable for a diamagnetic analogue. We demonstrate the toolbox's broad versatility for fields from coordination chemistry and spin-crossover complexes to supramolecular chemistry through the characterisation of CoII and high-spin FeII mononuclear complexes as well as a Co4L6 cage.
Electrochemiluminescent dinuclear Ru(II) complexes assembled with 1,1′-(1,2-ethynediyl)- or dimethlyene-bridged bis(bipyridine) ligands: Synthesis and photophysical and electrochemical properties
Kim, Minki,Kang, Chang Hoon,Hong, Subong,Lee, Won-Yong,Kim, Byeong Hyo
, p. 145 - 150 (2013)
1,2-Di(2,2′-bipyridin-5-yl)ethane (BL1) and 1,2-di(2,2′- bipyridin-5-yl)ethyne (BL2) were synthesized as new bridging ligands and coordinated to (RuL2(acetone)2)(PF6) 2 for the preparation of various [Ru(L)2(BL)Ru(L) 2](PF6)4-type dinuclear ruthenium complexes (where BL = BL1, BL2 and L = bpy, o-phen, DTDP). The electrochemical redox potentials, spectroscopic properties, and relative electrochemiluminescence intensity of BL1 and BL2 were characterized and compared to those of well-known tris(1,10-phenanthroline)rutheniun(II) [Ru(o-phen)3](PF 6)2] complex as a reference. Dinuclear Ru(II) complexes containing the conjugated bridging ligand (BL2) showed much more intense electrochemiluminescent responses than dinuclear Ru(II) complexes with the non-conjugated bridging ligand (BL1). Among the complexes with conjugated bridging ligands, [(DTDP)2Ru(bpy-CC-bpy)Ru(DTDP)2](PF 6)4 exhibited enhanced ECL intensities as high as 3.6 times greater than that of the reference, [Ru(o-phen)3](PF 6)2.
Redox-switchable π-conjugated systems bearing terminal ruthenium(II) complexes
Shen, Xiuliang,Moriuchi, Toshiyuki,Hirao, Toshikazu
, p. 7711 - 7714 (2003)
p-Phenylenediamine bearing terminal bipyridyl moieties was synthesized by palladium-catalyzed amination. The corresponding ruthenium(II) complex was formed and characterized, providing a redox-switchable photoinduced electron-transfer system.
Metallosupramolecular Architectures Formed with Ferrocene-Linked Bis-Bidentate Ligands: Synthesis, Structures, and Electrochemical Studies
Findlay, James A.,McAdam, C. John,Sutton, Joshua J.,Preston, Dan,Gordon, Keith C.,Crowley, James D.
, p. 3602 - 3614 (2018)
The self-assembly of ligands of different geometries with metal ions gives rise to metallosupramolecular architectures of differing structural types. The rotational flexibility of ferrocene allows for conformational diversity, and, as such, self-assembly processes with 1,1′-disubstituted ferrocene ligands could lead to a variety of interesting architectures. Herein, we report a small family of three bis-bidentate 1,1′-disubstituted ferrocene ligands, functionalized with either 2,2′-bipyridine or 2-pyridyl-1,2,3-triazole chelating units. The self-assembly of these ligands with the (usually) four-coordinate, diamagnetic metal ions Cu(I), Ag(I), and Pd(II) was examined using a range of techniques including 1H and DOSY NMR spectroscopies, high-resolution electrospray ionization mass spectrometry, X-ray crystallography, and density functional theory calculations. Additionally, the electrochemical properties of these redox-active metallosupramolecular assemblies were examined using cyclic voltammetry and differential pulse voltammetry. The copper(I) complexes of the 1,1′-disubstituted ferrocene ligands were found to be coordination polymers, while the silver(I) and palladium(II) complexes formed discrete [1 + 1] or [2 + 2] metallomacrocyclic architectures.
A tris-diketonate-Eu(III) complex with the brominated 2,2′-bpy ancillary ligand doped in PMMA for high color-purity red luminescence
He, Yani,Liu, Lin,Zhang, Zhao,Fu, Guorui,Lü, Xingqiang,Wong, Wai-Kwok,Jones, Richard A.
, p. 13 - 15 (2016)
Through the physical doping of a new red-emitting (ΦEuL = 34.9%) tris-β-diketonate Eu3 +-complex [Eu(DBM)3(5-Br-2,2′-bpy)] (1; DBM = dibenzoylmethane) with the brominated 2,2′-bpy ancillary ligand 5-Br-2,2′-bpy (5-bromo-2-(pyridin-2-yl)pyridine) in PMMA (poly(methyl methacrylate), the obtained hybrid material 1@PMMA exhibits significantly improved physical properties including the enhanced Eu3 +-based color-purity red luminescence (ΦEuL = 53.7%).
Dynamer and Metallodynamer Interconversion: An Alternative View to Metal Ion Complexation
Brzechwa-Chodzyńska, Anna,Gilski, Miros?aw,Harrowfield, Jack M.,Stefankiewicz, Artur R.,Zieliński, Micha?
, p. 8552 - 8561 (2020)
A bifunctional molecule containing both a bidentate binding site for metal ions and an aminopyrimidine H-bond donor-acceptor site has been synthesized, and its properties, in its free and coordinated forms, have been established in solution and in the solid state by analytical and spectroscopic methods as well as by X-ray structure determinations. Structural characterization has shown that it forms a one-dimensional H-bonded polymeric assembly in the solid state, while spectroscopic measurements indicate that it also aggregates in solution. The reaction of a simple Fe(II) salt with this assembly results in the emergence of two geometrical isomers of the complex: [FeL3](BF4)2·9H2O - C1 (meridional, mer) and [FeL3]2(SiF6)(BF4)2·12H2O - C2 (facial, fac). While, complex C1 in the solid state generates a one-dimensional H-bonded polymer involving just two ligands on each Fe center, with the chirality of the complex units alternating along the polymer chain, the structure of complex C2 shows NH···N interactions seen in both the ligand and mer complex (C1) structures to be completely absent. Physicochemical properties of the free and complexed ligand differ substantially.
Spontaneous resolution of an electron-deficient tetrahedral Fe4L4 cage
Bonakdarzadeh, Pia,Pan, Fangfang,Kalenius, Elina,Jur?ek, Ond?ej,Rissanen, Kari
, p. 14890 - 14893 (2015)
A highly electron-deficient C3-symmetric tris(bipyridyl) ligand was prepared in four steps and used for the coordination of Fe(OTf)2, thereby resulting in the homochiral assembly of a new family of robust tetrahedral M4L4 cages. This homochiral T-symmetric cage containing a relatively large cavity of 330 ?3 is capable of encapsulating an anionic guest, as was determined by mass spectrometry, 19F NMR spectroscopy, and finally shown from its crystal structure. Moreover, crystallization of the cage from CH3CN led to crystals containing both (ΔΔΔΔ and ΛΛΛΛ) enantiomers, while crystallization from CH3OH resulted in crystals containing only the right-handed (ΔΔΔΔ) cage. The difference in the crystal packing of the two crystal structures is discussed and a feasible explanation for the unique phenomenon among supramolecular cages - spontaneous resolution - is given. Supramolecular chiral resolution: A highly electron-deficient tetrahedral cage was formed from a stable tris(bipyridyl) ligand and a FeII salt. Crystallization of the racemic CH3OH solution leads to spontaneous resolution of the cages, whereas crystallization from CH3CN does not. The encapsulation of an anionic guest was observed in CH3CN.
Synthesis of Nitrile-Functionalized Polydentate N-Heterocycles as Building Blocks for Covalent Triazine Frameworks
Debruyne, Maarten,Everaert, Jonas,Heugebaert, Thomas S. A.,Stevens, Christian V.,Van Der Voort, Pascal,Van Hecke, Kristof,Van Speybroeck, Veronique,Vanden Bussche, Flore
, (2021/10/21)
Covalent triazine frameworks (CTFs) based on polydentate ligands are highly promising supports to anchor catalytic metal complexes. The modular nature of CTFs allows to tailor the composition, structure, and function to its specific application. Access to a broad range of chelating building blocks is therefore essential. In this respect, we extended the current available set of CTF building blocks with new nitrile-functionalized N-heterocyclic ligands. This paper presents the synthesis of the six ligands which vary in the extent of the aromatic system and the denticity. The new building blocks may help in a rational design of enhanced support materials in catalysis.
Luminescence Tunable Europium and Samarium Complexes: Reversible On/Off Switching and White-Light Emission
Chen, Jing,Xie, Ziyu,Meng, Lingyi,Hu, Ziying,Kuang, Xiaofei,Xie, Yiming,Lu, Can-Zhong
supporting information, p. 6963 - 6977 (2020/05/18)
Single-molecule functional materials with luminescence tunable by external stimuli are of increasing interest due to their application in sensors, display devices, biomarkers, and switches. Herein, new europium and samarium complexes with ligands having triphenylamine (TPA) groups as the redox center and 2,2′-bipyridine (bpy) as the coordinating groups and diketonate (tta) as the second ligand have been constructed. The complexes show white-light emission in selected solvents for proper mixtures of the emission from Ln3+ ions and the ligands. Meanwhile, they exhibit reversible luminescence switching on/off properties by controlling the external potential owing to intramolecular energy transfer from the Ln3+ ions to the electrochemically generated radical cation of TPA+. Time-dependent density functional theory (TD-DFT) calculations have been performed to study the electronic spectra. The proposed intramolecular energy transfer processes have been verified by density functional theory (DFT) studies.
