38 research outputs found
Metallo-cryptophane cages from cis-linked and trans-linked strategies.
Data supporting study of Pd(II) metallo-cage species from cyclotriguaiacylene derived ligands
The effect of carboxylate position on the structure of a metal organic framework derived from cyclotriveratrylene
Two cyclotriveratrylene-based ligands H3L1 and H3L2 have been synthesised using microwave heating and used in the formation of 1 [Zn2(L1)(DMA)2(CH3COO)] and 2 [Zn6(L2)4(DMA)6(H2O)5] (DMA = N,N-dimethylacetamide). 1 displays an unusual trigonal paddlewheel node geometry, while Zn(II) paddlewheels are observed in 2. However the stacking of CTV molecules in 1 is replaced by an uncommon molecular capsule structure in 2
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Energy and Electron Transfer Dynamics within a Series of Perylene Diimide/Cyclophane Systems.
Artificial photosynthetic systems for solar energy conversion exploit both covalent and supramolecular chemistry to produce favorable arrangements of light-harvesting and redox-active chromophores in space. An understanding of the interplay between key processes for photosynthesis, namely light-harvesting, energy transfer, and photoinduced charge separation and the design of novel, self-assembling components capable of these processes are imperative for the realization of multifunctional integrated systems. We report our investigations on the potential of extended tetracationic cyclophane/perylene diimide systems as components for artificial photosynthetic applications. We show how the selection of appropriate heterocycles, as extending units, allows for tuning of the electron accumulation and photophysical properties of the extended tetracationic cyclophanes. Spectroscopic techniques confirm energy transfer between the extended tetracationic cyclophanes and perylene diimide is ultrafast and quantitative, while the heterocycle specifically influences the energy transfer related parameters and the acceptor excited state.S.T.J.R. thanks the Cambridge Home and European Scholarship Scheme and the Robert Gardiner memorial scholarship. S.T.J.R., A.F. and O.A.S. thank the ERC starting investigator grant ASPiRe (project no. 240629) and the EPSRC (reference no. EP/G060649/1). Femtosecond and nanosecond spectroscopy (R.M.Y.), EPR spectroscopy (M.D.K.) and phosphorescence spectroscopy (Y.W.) were supported as part of the ANSER Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under award no. DE-SC0001059. J.F.S., J.J.H., N.H., N.A.V. and E.D.J. acknowledge the Joint Center of Excellence in Integrated Nano-Systems (JCIN) between KACST and Northwestern University (Project 34-946) for their continued financial support. E.J.D. acknowledges NSF and Ryan fellowships. A.H. and W.M.N. thank the COST Action CM1005 “Supramolecular Chemistry in Water” and the DFG (grant NA-686/5) for financial support.This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/jacs.5b1032
Controlling the assembly of cyclotriveratrylene-derived coordination cages
A review of the emerging field of cyclotriveratrylene-derived coordination cages is presented. Ligand-functionalised cyclotriveratrylene (CTV) derivatives self-assemble with a range of metal cations to afford coordination cages, polymers and topologically non-trivial constructs, such as [2]catenanes and a self-entangled cube. Increased control over their self-assembly allows for the controlled and predictable formation of well-defined coordination cages for application in host-guest and recognition chemistry, with surfactant binding and single-crystal-to-single-crystal (SCTSC) uptake of small-molecule guests being observed
Tuning the coordination chemistry of cyclotriveratrylene ligand pairs through alkyl chain aggregation
Propylated cyclotriveratrylene (CTV) ligands display different coordination chemistry over their methylated congeners as a result of increased solubility, an affinity for alkyl chain aggregation and steric factors. The propylated ligand tris(isonicotinoyl)-tris(propoxy)-cyclotricatechylene (L1p) forms a 1D coordination polymer within complex {[Ag(L1p)[Co(C2B 9H11)2]](DMF)}∞ (complex 1p), and a 2D sheet of 4·82 topology in {[Cd(L1p)(ONO 2)2(H2O)]·(DMF)·0.5(Et 2O)}∞ (complex 2p), neither of which are formed with the analogous methylated ligand tris(isonicotinoyl)-cyclotriguaiacylene (L1m). Both complexes 1p and 2p display multiple sites of aggregation of hydrophobic groups. The new propylated ligand tris(2-quinolylmethyl)-tris(propoxy)- cyclotricatechylene (L2p) forms a 1D coordination polymer with Ag(i) in complex{[Ag2(L2p)2][Co(C2B9H 11)2]2·1.5(MeNO2)} ∞ (complex 3p) and a novel, compressed octahedral structure with palladium(ii) cations, [Pd6(L2p)4(CF 3CO2)12] (complex 4p). Neither complex was accessible with the methylated congener tris(2-quinolylmethyl)- cyclotriguaiacylene (L2m)
Metallo-cryptophane cages from cis-linked and trans-linked strategies
Trigonal bipyramidal metallo-cage species [Pd₃(dppp)₃(L)₂]∙6OTf (where dppp = bis(diphenylphosphino)propane, OTf = triflate and L is tris(iso-nicotinoyl)cyclotriguaiacylene (L1) or tris(fluoro-iso-nicotinoyl)cyclotriguaiacylene (FL1)) have been characterised in solution to exist predominantly as the anti-isomers. The crystal structure of [Pd₃(dppp)₃(FL1)₂]∙6OTf, however, was found to be the achiral syn-isomer. The complex [Pd₃Cl₃(L2)₂] (where L2 = tris(methylbenzimidazolyl)cyclotriguaiacylene) is a trans-linked M₃L₂ cage, observed by mass spectrometry and in the solid state as the anti-isomer. Ligand L2 also forms a 1:1 co-crystal with cyclotriguaiacylene
Lanthanide coordination polymers with pyridyl-N-oxide or carboxylate functionalised host ligands
Metallo-cryptophanes decorated with Bis-N-heterocyclic carbene ligands: self-assembly and guest uptake into a nonporous crystalline lattice
Pd3L2 metallo-cryptophane cages with cyclotriveratrylene-type L ligands can be stabilized by use of a bis-N-heterocyclic carbene as an auxiliary cis-protecting ligand, while use of more common protecting chelating ligands such as ethylenediamine saw a Pd3L2 to Pd6L8 rearrangement occur in solution. The crystalline Pd3L2 complexes act as sponges, taking up 1,2-dichorobenzene or iodine in a single-crystal-to-single-crystal fashion despite not exhibiting conventional porosity
Spin state behavior of iron(II)/dipyrazolylpyridine complexes. New insights from crystallographic and solution measurements
The isomeric complexes [Fe(1-bpp)2]2+ and [Fe(3-bpp)2]2+ (1-bpp=2,6-di[pyrazol-1-yl]pyridine; 3-bpp=2,6-di[1H-pyrazol-3-yl]pyridine) and their derivatives are some of the most widely investigated complexes in spin-crossover research. This article addresses two unique aspects of their spin-state chemistry. First, is an unusual structural distortion in the high-spin form that can inhibit spin-crossover in the solid state. A new analysis of these structures using continuous shape measures has explained this distortion in terms of its effect on the metal coordination geometry, and has shown that the most highly distorted structures are a consequence of crystal packing effects. Second, solution studies have quantified the influence of second-sphere hydrogen bonding on spin-crossover in [Fe(3-bpp)2]2+, which responds to the presence of different anions and solvents (especially water). Previously unpublished data from the unsymmetric isomer [Fe(1,3-bpp)2]2+ (1,3-bpp=2-[pyrazol-1-yl]-6-[1H-pyrazol-3-yl]pyridine) are presented for comparison. Modifications to the structure of [Fe(3-bpp)2]2+, intended to augment these supramolecular effects, are also described