162318-34-5Relevant articles and documents
Immobilization of bis(bipyridine) BINOL ligands and their use in chiral resolution
Bunzen, Jens,Kiehne, Ulf,Benkhaeuser-Schunk, Christian,Luetzen, Arne
, p. 4786 - 4789 (2009)
An enantlomerlcally pure bls(blpyrldlne) BINOL ligand was synthesized which was functionalized with an Iodine substituent In Its periphery. Using this halogen function, the ligand was Immobilized on a commercially available polystyrene gel via Suzuki cross-coupling. The functlonallzed gel was found to be effective In the chiral resolution of similar bis(blpyrldlne) ligands based on a Troeger's base core.
The influence of different spacer lengths on the selectivity of self-assembly processes of bis(bipyridine)-BINOL helicates
Bunzen, Jens,Hapke, Marko,Luetzen, Arne
, p. 3885 - 3894 (2009)
The synthesis and self-assembly behaviour of a series of en-antiomerically pure bis(chelating) ligands is reported. The li-gands differ in the spacer unit between a BINOL core and. two bipyridyl groups as the chelating entities and were found to undergo completely diastereoselective self-assembly to di-nuclear double-stranded helicates with silver(I) salts, as dem-onstrated by NMR and CD spectroscopy and ESI mass spec-trometry. Upon coordination to iron(II) or zinc(II) ions, however, a dramatic loss in the diastereoselectivity of the self-assembly of dinuclear triple-stranded helicates was observed, as a result: of increasing spacer length. In the case of zinc(II), the self-assembly processes were even found, to be nonselec-tive with regard to the composition of the helicates.
Cross-π-conjugated enediyne with multitopic metal binding sites
Nauroozi, Djawed,Wurster, Benjamin,Faust, Rüdiger
, p. 38612 - 38616 (2020)
The synthesis of an enediyne molecule functionlized with different metal coordination sites in a cross-π-conjugated fashion is reported. Using Pd-mediated cross-coupling reactions, 2,2′-bipyridine units were attached at the periphery of diazafluorenemethylidene to obtain a multitopic ligand. UV-vis spectrosopic investigations along with electrochemical analyses reveal electronic communication along the conjugated path reflected in red-shifted absorption spectra and shifts of reduction potentials. The properties of the ligand could be manipulated by coordinating [Ru(bpy)2]2+ fragments at all three coordination spheres of the molecule while the different complexing imine moieties serve as possible coordination sites for various metal centres. This journal is
Self-assembly of heteroleptic dinuclear metallosupramolecular kites from multivalent ligands via social self-sorting
Benkh?user, Christian,Lützen, Arne
, p. 693 - 700 (2015)
A Tr?ger's base-derived racemic bis(1,10-phenanthroline) ligand (rac)-1 and a bis(2,2′-bipyridine) ligand with a central 1,3-diethynylbenzene unit 2 were synthesized. Each of these ligands acts as a multivalent entity for the binding of two copper(I) ions. Upon coordination to the metal ions these two ligands undergo selective self-assembly into heteroleptic dinuclear metallosupramolecular kites in a high-fidelity social self-sorting manner as evidenced by NMR spectroscopy and mass spectrometry.
Lowering Electrocatalytic CO2Reduction Overpotential Using N-Annulated Perylene Diimide Rhenium Bipyridine Dyads with Variable Tether Length
Dubrawski, Zachary S.,Gelfand, Benjamin S.,Koenig, Josh D. B.,Piers, Warren E.,Rao, Keerthan R.,Risko, Chad,Welch, Gregory C.,Willkomm, Janina
supporting information, p. 16849 - 16864 (2021/10/20)
We report the design, synthesis, and characterization of four N-annulated perylene diimide (NPDI) functionalized rhenium bipyridine [Re(bpy)] supramolecular dyads. The Re(bpy) scaffold was connected to the NPDI chromophore either directly [Re(py-C0-NPDI)] or via an ethyl [Re(bpy-C2-NPDI)], butyl [Re(bpy-C4-NPDI)], or hexyl [Re(bpy-C6-NPDI)] alkyl-chain spacer. Upon electrochemical reduction in the presence of CO2 and a proton source, Re(bpy-C2/4/6-NPDI) all exhibited significant current enhancement effects, while Re(py-C0-NPDI) did not. During controlled potential electrolysis (CPE) experiments at Eappl = -1.8 V vs Fc+/0, Re(bpy-C2/4/6-NPDI) all achieved comparable activity (TONco ～25) and Faradaic efficiency (FEco ～94%). Under identical CPE conditions, the standard catalyst Re(dmbpy) was inactive for electrocatalytic CO2 reduction; only at Eappl = -2.1 V vs Fc+/0 could Re(dmbpy) achieve the same catalytic performance, representing a 300 mV lowering in overpotential for Re(bpy-C2/4/6-NPDI). At higher overpotentials, Re(bpy-C4/6-NPDI) both outperformed Re(bpy-C2-NPDI), indicating the possibility of coinciding electrocatalytic CO2 reduction mechanisms that are dictated by tether-length and overpotential. Using UV-vis-nearIR spectroelectrochemistry (SEC), FTIR SEC, and chemical reduction experiments, it was shown that the NPDI-moiety served as an electron-reservoir for Re(bpy), thereby allowing catalytic activity at lower overpotentials. Density functional theory studies probing the optimized geometries and frontier molecular orbitals of various catalytic intermediates revealed that the geometric configuration of NPDI relative to the Re(bpy)-moiety plays a critical role in accessing electrons from the electron-reservoir. The improved performance of Re(bpy-C2/4/6-NPDI)dyads at lower overpotentials, relative to Re(dmbpy), highlights the utility of chromophore electron-reservoirs as a method for lowering the overpotential for CO2 conversion.
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
supporting information, p. 19344 - 19351 (2020/09/01)
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.
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.
supporting information, p. 3602 - 3614 (2018/04/06)
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.
Synthesis and photophysical properties of ruthenium(ii) polyimine complexes decorated with flavin
Guo, Huimin,Zhu, Lijuan,Dang, Can,Zhao, Jianzhang,Dick, Bernhard
, p. 17504 - 17516 (2018/07/06)
A bipyridine ruthenium(ii) complex (Ru-1) with a flavin moiety connected to one of the bipyridine ligands via an acetylene bond was designed and synthesized, and its photophysical properties were investigated. Compared with the tris(bipyridine) Ru(ii) com
Reversible Self-Assembly of Water-Soluble Gold(I) Complexes
Aguiló, Elisabet,Moro, Artur J.,Gavara, Raquel,Alfonso, Ignacio,Pérez, Yolanda,Zaccaria, Francesco,Guerra, Célia Fonseca,Malfois, Marc,Baucells, Clara,Ferrer, Montserrat,Lima, Jo?o Carlos,Rodríguez, Laura
supporting information, p. 1017 - 1028 (2018/02/14)
The reaction of the gold polymers containing bipyridyl and terpyridyl units, [Au(C≡CC15H10N3)]n and [Au(C≡CC10H7N2)]n, with the water-soluble phosphines 1,3,5-triaza-7-phosphatricyclo[3.3.1.13.7]decane and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane gives rise to the formation of four gold(I) alkynyl complexes that self-assemble in water (H2O) and dimethyl sulfoxide (DMSO), through different intermolecular interactions, with an impact on the observed luminescence displayed by the supramolecular assemblies. A detailed analysis carried out by NMR studies performed in different DMSO/deuterated H2O mixtures indicates the presence of two different assembly modes in the aggregates: (i) chain assemblies, which are based mainly on aurophilic interactions, and (ii) stacked assemblies, which are based on Au···π and π···π interactions. These different supramolecular environments can also be detected by their intrinsic optical properties (differences in absorption and emission spectra) and are predicted by the changes in the relative binding energy from density functional theory calculations carried out in DMSO and H2O. Small-angle X-ray scattering (SAXS) experiments performed in the same mixture of solvents are in agreement with the formation of aggregates in all cases. The aromatic units chosen, bipyridine and terpyridine, allow the use of external stimuli to reversibly change the aggregation state of the supramolecular assemblies. Interaction with the Zn2+ cation is observed to disassemble the aggregates, while encapsulating agents competing for Zn2+ complexation revert the process to the aggregation stage, as verified by SAXS and NMR. The adaptive nature of the supramolecular assemblies to the metal-ion content is accompanied by significant changes in the absorption and emission spectra, signaling the aggregation state and also the content on Zn2+.
Catalysis of Michael Additions by Covalently Modified G-Quadruplex DNA
Dey, Surjendu,Rühl, Carmen L.,J?schke, Andres
supporting information, p. 12162 - 12170 (2017/09/14)
Enantioselective catalysis utilizing G-quadruplex DNA-based artificial metalloenzymes has emerged as a new approach in the field of aqueous-phase homogeneous catalysis. Recently, a catalytic asymmetric Michael addition employing a covalently modified G-quadruplex in combination with CuII ions has been reported. Here we assess, by systematic chemical variation and using various spectrometric techniques, a variety of parameters that govern rate acceleration and stereoselectivity of the reaction, such as the position of modification, the topology of the quadruplex, the nature of the ligand, the length of the linker between ligand and DNA, the chemical identity of monovalent ions and transition metal complexes. The DNA quadruplex modified at position 10 (dU10) with hexynyl-linked bpy ligand showed twice the initial reaction rate as compared with the DNA strand derivatized at position 12 (dU12). The strikingly different dependence of the stereoselectivity on the linker length, and their different spectroscopic properties indicate large differences in the architecture of the catalytic centers between the dU10-derivatized and the dU12-modified quadruplexes. Upon addition of CuII, both types of bpy-derivatized DNA strands form defined 1:1 Cu–DNA complexes stable enough for mass spectrometric analysis, while the underivatized strands exhibit weak and unspecific binding, correlated with much lower catalytic rate acceleration. Both dU10- and dU12-derivatized quadruplexes could be reused ten times without reduction of stereoselectivity.
