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Rocco D, Housecroft CE, Constable EC. Synthesis of Terpyridines: Simple Reactions-What Could Possibly Go Wrong? Molecules 2019; 24:molecules24091799. [PMID: 31075948 PMCID: PMC6539753 DOI: 10.3390/molecules24091799] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/07/2019] [Accepted: 05/08/2019] [Indexed: 11/25/2022] Open
Abstract
The preparation of 24-functionalized 12,22:26,32-terpyridines (4′-functionalized 3,2:6′,3″-terpyridines) by the reaction of three 4-alkoxybenzaldehydes with 3-acetylpyridine and ammonia was investigated; under identical reaction conditions, two (R =nC4H9, C2H5) gave the expected products whereas a third (R = nC3H7) gave only a cyclohexanol derivative derived from the condensation of three molecules of 3-acetylpyridine with two of 4-(n-propoxy)benzaldehyde. A comprehensive survey of “unexpected” products from reactions of ArCOCH3 derivatives with aromatic aldehydes is presented. Three different types of alternative product are identified.
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Freund S, Hinaut A, Marinakis N, Constable EC, Meyer E, Housecroft CE, Glatzel T. Comparing a porphyrin- and a coumarin-based dye adsorbed on NiO(001). BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2019; 10:874-881. [PMID: 31165014 PMCID: PMC6541355 DOI: 10.3762/bjnano.10.88] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 04/03/2019] [Indexed: 06/09/2023]
Abstract
Properties of metal oxides, such as optical absorption, can be influenced through the sensitization with molecular species that absorb visible light. Molecular/solid interfaces of this kind are particularly suited for the development and design of emerging hybrid technologies such as dye-sensitized solar cells. A key optimization parameter for such devices is the choice of the compounds in order to control the direction and the intensity of charge transfer across the interface. Here, the deposition of two different molecular dyes, porphyrin and coumarin, as single-layered islands on a NiO(001) single crystal surface have been studied by means of non-contact atomic force microscopy at room temperature. Comparison of both island types reveals different adsorption and packing of each dye, as well as an opposite charge-transfer direction, which has been quantified by Kelvin probe force microscopy measurements.
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Zaiter S, Kirk C, Taylor M, Klein YM, Housecroft CE, Sciortino NF, Clements JE, Cooper RI, Kepert CJ, Neville SM. Heteroatom substitution effects in spin crossover dinuclear complexes. Dalton Trans 2019; 48:7337-7343. [PMID: 30882806 DOI: 10.1039/c8dt05010d] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We probe the effect of heteroatom substitution on the spin crossover (SCO) properties of dinuclear materials of the type [Fe2(NCX)4(R-trz)5]·S (X = S, Se; S = solvent; R-trz = (E)-N-(furan-2-ylmethylene)-4H-1,2,4-triazol-4-amine (furtrz); (E)-N-(thiophen-2-ylmethylene)-4H-1,2,4-triazole-4-amine (thtrz)). For the furtrz family ([Fe2(NCX)4(furtrz)5]·furtrz·MeOH; X = S (furtrz-S) and X = Se (furtrz-Se)) gradual and incomplete one-step SCO transitions are observed (furtrz-S (T1/2 = 172 K) and furtrz-Se (T1/2 = 205 K)) and a structural evolution from [HS-HS] to [HS-LS] per dinuclear species. Contrasting this, within the thtrz family ([Fe2(NCX)4(thtrz)5]·4MeOH; X = S (thtrz-S) and X = Se (thtrz-Se)) more varied SCO transitions are observed, with thtrz-S being SCO-inactive (high spin) and thtrz-Se showing a rare complete two-step SCO transition (T1/2(1,2) = 170, 200 K) in which the FeII sites transition from [HS-HS] to [HS-LS] to [LS-LS] per dinuclear unit with no long range ordering of spin-states at the intermediate plateau. Detailed structure-function analyses have been conducted within this growing dinuclear family to rationalise these diverse spin-switching properties.
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Abstract
The fungus Amanita muscaria contains neurotoxins which account for its long-time use as a hallucinogen. In contrast, A. muscaria is also a bioaccumulator of high levels of vanadium, the reason for which is still obscure.
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Rudin D, Lanzilotto A, Bachmann F, Housecroft CE, Constable EC, Drewe J, Haschke M, Krähenbühl S. Non-immunological toxicological mechanisms of metamizole-associated neutropenia in HL60 cells. Biochem Pharmacol 2019; 163:345-356. [PMID: 30653950 DOI: 10.1016/j.bcp.2019.01.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/11/2019] [Indexed: 01/15/2023]
Abstract
Metamizole is an analgesic and antipyretic, but can cause neutropenia and agranulocytosis. We investigated the toxicity of the metabolites N-methyl-4-aminoantipyrine (MAA), 4-aminoantipyrine (AA), N-formyl-4-aminoantipyrine (FAA) and N-acetyl-4-aminoantipyrine (AAA) on neutrophil granulocytes and on HL60 cells (granulocyte precursor cell line). MAA, FAA, AA, and AAA (up to 100 µM) alone were not toxic for HL60 cells or granulocytes. In the presence of the myeloperoxidase substrate H2O2, MAA reduced cytotoxicity for HL60 cells at low concentrations (<50 µM), but increased cytotoxicity at 100 µM H2O2. Neutrophil granulocytes were resistant to H2O2 and MAA. Fe2+ and Fe3+ were not toxic to HL60 cells, irrespective of the presence of H2O2 and MAA. Similarly, MAA did not increase the toxicity of lactoferrin, hemoglobin or methemoglobin for HL60 cells. Hemin (hemoglobin degradation product containing a porphyrin ring and Fe3+) was toxic on HL60 cells and cytotoxicity was increased by MAA. EDTA, N-acetylcystein and glutathione prevented the toxicity of hemin and hemin/MAA. The absorption spectrum of hemin changed concentration-dependently after addition of MAA, suggesting an interaction between Fe3+ and MAA. NMR revealed the formation of a stable MAA reaction product with a reaction pathway involving the formation of an electrophilic intermediate. In conclusion, MAA, the principle metabolite of metamizole, increased cytotoxicity of hemin by a reaction involving the formation of an electrophilic metabolite. Accordingly, cytotoxicity of MAA/hemin could be prevented by the iron chelator EDTA and by the electron donors NAC and glutathione. Situations with increased production of hemin may represent a risk factor for metamizole-associated granulocytopenia.
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Housecroft CE, Thomas CM, Lim MH. The central role of the d-block metals in the periodic table. Dalton Trans 2019; 48:9405-9407. [DOI: 10.1039/c9dt90117e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Welcome to this themed issue of Dalton Transactions entitled “The central role of the d-block metals in the periodic table”
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Nohara I, Prescimone A, Häussinger D, Housecroft CE, Constable EC. [Cu(POP)(N^S)][PF6] and [Cu(xantphos)(N^S)][PF6] compounds with 2-(thiophen-2-yl)pyridines. RSC Adv 2019; 9:13646-13657. [PMID: 35519553 PMCID: PMC9063866 DOI: 10.1039/c9ra02617g] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 04/24/2019] [Indexed: 11/29/2022] Open
Abstract
A series of [Cu(POP)(N^S)][PF6] and [Cu(xantphos)(N^S)][PF6] compounds (POP = bis(2-(diphenylphosphino)phenyl)ether, xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene) in which the N^S ligand is a 2-(thiophen-2-yl)pyridine (1), 2-(thiophen-2-yl)-6-methylpyridine (2), 2-(5-methylthiophen-2-yl)pyridine (3) or 2-(5-methylthiophen-2-yl)-6-methylpyridine (4) have been prepared and characterized in solution and the solid state. Single crystal structures of [Cu(POP)(1)][PF6], [Cu(xantphos)(1)][PF6], [Cu(xantphos)(2)][PF6], [Cu(POP)(3)][PF6]·CH2Cl2, and [Cu(xantphos)(4)][PF6] confirm chelating N^S and P^P ligands, and distorted tetrahedral copper(i) centres. There is close cation⋯anion association, particularly in [Cu(xantphos)(1)][PF6]. Although the compounds are stable over days in CH2Cl2 solution, they are susceptible to the effects of competing ligands such as chloride ion and MeCN. Analysis of the NMR spectroscopic data of a solution of [Cu(POP)(3)][PF6] with added Cl−, gives a Kd value of 0.14 ± 0.03 mM, indicative of ion-pairing. [Cu(POP)(N^S)][PF6] and [Cu(xantphos)(N^S)][PF6] exhibit quasi-reversible or irreversible Cu+/Cu2+ oxidations. They are blue emitters in solution, and the presence of the 5-methyl group in the thiophene ring in 3 and 4 leads to a red-shift in the emission. The highest photoluminescence quantum yields are for [Cu(POP)(2)][PF6] (30.8%) and [Cu(POP)(4)][PF6] (33.2%), both of which have a 6-methyl-substituted pyridine ring in the N^S ligand. Excited-state lifetimes are <5 ns. On going from solution to powder samples, red-shifts of 133 to 163 nm are observed leading to yellow emitters. The brightest emitter, [Cu(xantphos)(1)][PF6], was tested in a LEC device but showed poor electroluminescence and poor charge transporting characteristics. [Cu(P^P)(N^S)][PF6] with N^S = 2-(thiophen-2-yl)pyridines show close cation⋯anion association in the solid-state; complex cation association with Cl− occurs in solution. The compounds are blue-emitters in solution with a red-shift of the emission on going to the solid.![]()
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Brunner F, Babaei A, Pertegás A, Junquera-Hernández JM, Prescimone A, Constable EC, Bolink HJ, Sessolo M, Ortí E, Housecroft CE. Phosphane tuning in heteroleptic [Cu(N^N)(P^P)]+ complexes for light-emitting electrochemical cells. Dalton Trans 2019; 48:446-460. [DOI: 10.1039/c8dt03827a] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effects on photo-and electroluminescent properties of structurally modifying the bisphosphane in [Cu(N^N)(P^P)]+ complexes (N^N = bpy, 6-Mebpy, 6,6′-Me2bpy) are described.
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Karpacheva M, Housecroft CE, Constable EC. Electrolyte tuning in dye-sensitized solar cells with N-heterocyclic carbene (NHC) iron(II) sensitizers. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:3069-3078. [PMID: 30643705 PMCID: PMC6317411 DOI: 10.3762/bjnano.9.285] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 11/29/2018] [Indexed: 06/09/2023]
Abstract
We demonstrate that the performances of dye-sensitized solar cells (DSCs) sensitized with a previously reported N-heterocyclic carbene iron(II) dye in the presence of chenodeoxycholic acid co-adsorbant, can be considerably improved by altering the composition of the electrolyte while retaining an I-/I3 - redox shuttle. Critical factors are the solvent, presence of ionic liquid, and the use of the additives 1-methylbenzimidazole (MBI) and 4-tert-butylpyridine (TBP). For the electrolyte solvent, 3-methoxypropionitrile (MPN) is preferable to acetonitrile, leading to a higher short-circuit current density (J SC) with little change in the open-circuit voltage (V OC). For electrolytes containing MPN, an ionic liquid and MBI (0.5 M), DSC performance depended on the ionic liquid with 1-ethyl-3-methylimidazolium hexafluoridophosphate (EMIMPF) > 1,2-dimethyl-3-propylimidazolium iodide (DMPII) > 1-butyl-3-methylimidazolium iodide (BMII) ≈ 1-butyl-3-methylimidazolium hexafluoridophosphate (BMIMPF). Omitting the MBI leads to a significant improvement in J SC when the ionic liquid is DMPII, BMII or BMIMPF, but with EMIMPF the removal of the MBI additive results in a dramatic decrease in V OC (542 to 42 mV). For electrolytes containing MPN and DMPII, the effects of altering the MBI concentration have also been investigated. Although the addition of TBP improves V OC, it causes significant decreases in J SC. The best performing DSCs with the NHC-iron(II) dye employ an I-/I3 --based electrolyte with MPN as solvent, DMPII ionic liquid (0.6 M) with no or 0.01 M MBI; values of J SC = 2.31 to 2.78 mA cm-2, V OC = 292 to 374 mV have been achieved giving η in the range of 0.47 to 0.57% which represents 7.8 to 9.3% relative to an N719 reference DSC set at 100%. Electrochemical impedance spectroscopy has been used to understand the role of the MBI additive in the electrolytes.
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Klein YM, Prescimone A, Karpacheva M, Constable EC, Housecroft CE. Sometimes the Same, Sometimes Different: Understanding Self-Assembly Algorithms in Coordination Networks. Polymers (Basel) 2018; 10:E1369. [PMID: 30961295 PMCID: PMC6401813 DOI: 10.3390/polym10121369] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 12/07/2018] [Accepted: 12/08/2018] [Indexed: 01/21/2023] Open
Abstract
The syntheses and characterizations of three new ligands containing two 4,2':6',4″-tpy or two 3,2':6',3″-tpy metal-binding domains are reported. The ligands possess different alkyloxy functionalities attached to the central phenylene spacer: n-pentyloxy in 3, 4-phenyl-n-butoxy in 4, benzyloxy in 5. Crystal growth under ambient conditions has led to the formation of {[Co(NCS)₂(3)]·0.8C₆H₄Cl₂}n and {[Co(NCS)₂(4)]·1.6H₂O·1.2C₆H₄Cl₂}n, with structures confirmed by single crystal X-ray diffraction. Both the cobalt(II) center and ligand 3 or 4 act as 4-connecting nodes and both {[Co(NCS)₂(3)]·0.8C₆H₄Cl₂}n and {[Co(NCS)₂(4)]·1.6H₂O·1.2C₆H₄Cl₂}n possess a 3D cds net despite the fact that 3 and 4 contain two 4,2':6',4″-tpy and two 3,2':6',3″-tpy units, respectively. Taken in conjunction with previously reported data, the results indicate that the role of the alkyloxy substituent is more significant than the choice of 4,2':6',4″- or 3,2':6',3″-tpy isomer in determining the assembly of a particular 3D net. The combination of Co(NCS)₂ with 5 resulted in the formation of the discrete molecular complex [Co(NCS)₂(MeOH)₂(5)₂]·2CHCl₃·2MeOH in which 5 acts as a monodentate ligand. The pendant phenyls and both coordinated and non-coordinated 4,2':6',4″-tpy units are involved in efficient π-stacking interactions.
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Housecroft CE. Protecting the Eggs of a Praying Mantis: Natural Biomaterials. Chimia (Aarau) 2018; 72:819-821. [PMID: 30514428 DOI: 10.2533/chimia.2018.819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Coiled-coil proteins are the basis of the biomaterial that protects the overwintering eggs of praying mantises.
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Freund S, Pawlak R, Moser L, Hinaut A, Steiner R, Marinakis N, Constable EC, Meyer E, Housecroft CE, Glatzel T. Transoid-to-Cisoid Conformation Changes of Single Molecules on Surfaces Triggered by Metal Coordination. ACS OMEGA 2018; 3:12851-12856. [PMID: 31458009 PMCID: PMC6645055 DOI: 10.1021/acsomega.8b01792] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 09/20/2018] [Indexed: 05/12/2023]
Abstract
Conformational isomers are stereoisomers that can interconvert over low potential barriers by rotation around a single bond. However, such bond rotation is hampered by geometrical constraints when molecules are adsorbed on surfaces. Here, we show that the adsorption of 4,4'-bis(4-carboxyphenyl)-6,6'-dimethyl-2,2'-bipyridine molecules on surfaces leads to the appearance of prochiral single molecules on NiO(001) and to enantiopure supramolecular domains on Au(111) surfaces containing the transoid-molecule conformation. Upon additional Fe adatom deposition, molecules undergo a controlled interconversion from a transoid-to-cisoid conformation as a result of coordination of the Fe atoms to the 2,2'-bipyridine moieties. As confirmed by atomic force microscopy images and X-ray photoelectron spectroscopy measurements, the resulting molecular structures become irreversibly achiral.
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Keller S, Prescimone A, Bolink H, Sessolo M, Longo G, Martínez-Sarti L, Junquera-Hernández JM, Constable EC, Ortí E, Housecroft CE. Luminescent copper(i) complexes with bisphosphane and halogen-substituted 2,2'-bipyridine ligands. Dalton Trans 2018. [PMID: 29790540 DOI: 10.1039/c8tc02882f] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/16/2023]
Abstract
Heteroleptic [Cu(P^P)(N^N)][PF6] complexes, where N^N is a halo-substituted 2,2'-bipyridine (bpy) and P^P is either bis(2-(diphenylphosphino)phenyl)ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos) have been synthesized and investigated. To stabilize the tetrahedral geometry of the copper(i) complexes, the steric demands of the bpy ligands have been increased by introducing 6- or 6,6'-halo-substituents in 6,6'-dichloro-2,2'-bipyridine (6,6'-Cl2bpy), 6-bromo-2,2'-bipyridine (6-Brbpy) and 6,6'-dibromo-2,2'-bipyridine (6,6'-Br2bpy). The solid-state structures of [Cu(POP)(6,6'-Cl2bpy)][PF6], [Cu(xantphos)(6,6'-Cl2bpy)][PF6]·CH2Cl2, [Cu(POP)(6-Brbpy)][PF6] and [Cu(xantphos)(6-Brbpy)][PF6]·0.7Et2O obtained from single crystal X-ray diffraction are described including the pressure dependence of the structure of [Cu(POP)(6-Brbpy)][PF6]. The copper(i) complexes with either POP or xantphos and 6,6'-Cl2bpy, 6-Brbpy and 6,6'-Br2bpy are orange-to-red emitters in solution and yellow-to-orange emitters in the solid state, and their electrochemical and photophysical properties have been evaluated with the help of density functional theory (DFT) calculations. The emission properties are strongly influenced by the substitution pattern that largely affects the geometry of the emitting triplet state. [Cu(POP)(6,6'-Cl2bpy)][PF6] and [Cu(xantphos)(6,6'-Cl2bpy)][PF6] show photoluminescence quantum yields of 15 and 17%, respectively, in the solid state, and these compounds were tested as luminophores in light-emitting electrochemical cells (LECs). The devices exhibit orange electroluminescence and very short turn-on times (<5 to 12 s). Maximum luminance values of 121 and 259 cd m-2 for [Cu(POP)(6,6'-Cl2bpy)][PF6] and [Cu(xantphos)(6,6'-Cl2bpy)][PF6], respectively, were achieved at an average current density of 100 A m-2. External quantum efficiencies of 1.2% were recorded for both complexes.
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Abstract
The replacement of hydroxy or phosphate ions in the naturally occurring inorganic material hydroxyapatite by carbonate ions leads to the properties of dental enamel and dentine that allow carnivores to cope with the stresses and forces involved in devouring their prey.
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Sciortino NF, Ragon F, Klein YM, Housecroft CE, Davies CG, Jameson GNL, Chastanet G, Neville SM. Guest-Responsive Elastic Frustration “On–Off” Switching in Flexible, Two-Dimensional Spin Crossover Frameworks. Inorg Chem 2018; 57:11068-11076. [DOI: 10.1021/acs.inorgchem.8b01651] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Housecroft CE. Geckos, Ceilings and van der Waals. Chimia (Aarau) 2018; 72:428-429. [DOI: 10.2533/chimia.2018.428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The ability of a gecko to run rapidly across ceilings and up and down vertical walls is a striking example of the application of van der Waals interactions.
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Keller S, Brunner F, Junquera-Hernández JM, Pertegás A, La-Placa MG, Prescimone A, Constable EC, Bolink HJ, Ortí E, Housecroft CE. Front Cover: CF 3
Substitution of [Cu(P^P)(bpy)][PF 6
] Complexes: Effects on Photophysical Properties and Light-Emitting Electrochemical Cell Performance (ChemPlusChem 4/2018). Chempluschem 2018. [DOI: 10.1002/cplu.201800113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Housecroft CE. Tolerating Toxins: Grasshoppers that Feast on Pyrrolizidine Alkaloids §. Chimia (Aarau) 2018; 72:156-157. [DOI: 10.2533/chimia.2018.156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The elegant grasshopper (Zonocerus elegans) and the variegated grasshopper (Z. variegatus) are among insects that deliberately consume and store pyrrolizidine alkaloids which are subsequently used in defence mechanisms.
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Keller S, Brunner F, Junquera-Hernández JM, Pertegás A, La-Placa MG, Prescimone A, Constable EC, Bolink HJ, Ortí E, Housecroft CE. CF3
Substitution of [Cu(P^P)(bpy)][PF6
] Complexes: Effects on Photophysical Properties and Light-Emitting Electrochemical Cell Performance. Chempluschem 2018; 83:143. [DOI: 10.1002/cplu.201800112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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70
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Nijs T, Klein YM, Mousavi SF, Ahsan A, Nowakowska S, Constable EC, Housecroft CE, Jung TA. The Different Faces of 4′-Pyrimidinyl-Functionalized 4,2′:6′,4′′-Terpyridines: Metal–Organic Assemblies from Solution and on Au(111) and Cu(111) Surface Platforms. J Am Chem Soc 2018; 140:2933-2939. [DOI: 10.1021/jacs.7b12624] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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71
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Keller S, Brunner F, Junquera-Hernández JM, Pertegás A, La-Placa MG, Prescimone A, Constable EC, Bolink HJ, Ortí E, Housecroft CE. CF 3 Substitution of [Cu(P^P)(bpy)][PF 6 ] Complexes: Effects on Photophysical Properties and Light-Emitting Electrochemical Cell Performance. Chempluschem 2018; 83:217-229. [PMID: 31957280 DOI: 10.1002/cplu.201700501] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/22/2017] [Indexed: 11/06/2022]
Abstract
Herein, [Cu(P^P)(N^N)][PF6 ] complexes (P^P=bis[2-(diphenylphosphino)phenyl]ether (POP) or 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (xantphos); N^N=CF3 -substituted 2,2'-bipyridines (6,6'-(CF3 )2 bpy, 6-CF3 bpy, 5,5'-(CF3 )2 bpy, 4,4'-(CF3 )2 bpy, 6,6'-Me2 -4,4'-(CF3 )2 bpy)) are reported. The effects of CF3 substitution on their structure as well as their electrochemical and photophysical properties are also presented. The HOMO-LUMO gap was tuned by the N^N ligand; the largest redshift in the metal-to-ligand charge transfer (MLCT) band was for [Cu(P^P){5,5'-(CF3 )2 bpy}][PF6 ]. In solution, the compounds are weak yellow to red emitters. The emission properties depend on the substitution pattern, but this cannot be explained by simple electronic arguments. Among powders, [Cu(xantphos){4,4'-(CF3 )2 bpy}][PF6 ] has the highest photoluminescence quantum yield (PLQY; 50.3 %) with an emission lifetime of 12 μs. Compared to 298 K solution behavior, excited-state lifetimes became longer in frozen Me-THF (77 K; THF=tetrahydrofuran), thus indicating thermally activated delayed fluorescence (TADF). Time-dependent (TD)-DFT calculations show that the energy gap between the lowest-energy singlet and triplet excited states (0.12-0.20 eV) permits TADF. Light-emitting electrochemical cells (LECs) with [Cu(POP)+(6-CF3 bpy)][PF6 ], [Cu(xantphos)(6-CF3 bpy)][PF6 ], or [Cu(xantphos){6,6'-Me2 -4,4'-(CF3 )2 bpy}][PF6 ] emit yellow electroluminescence. The LEC with [Cu(xantphos){6,6'-Me2 -4,4'-(CF3 )2 bpy}][PF6 ] had the fastest turn-on time (8 min), and the LEC with the longest lifetime (t1/2 =31 h) contained [Cu(xantphos)(6-CF3 bpy)][PF6 ]; these LECs reached maximum luminances of 131 and 109 cd m-2 , respectively.
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Housecroft CE. Integrating Chemistry: Crossing the Millennium Divide. Chimia (Aarau) 2018; 72:36-42. [PMID: 29490791 DOI: 10.2533/chimia.2018.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
A personal account of the development of two University level chemistry books is presented. The account focuses on ways to integrate the traditional branches of chemistry into a textbook that captures the imagination of students and relates chemical principles and fundamental topics to environmental, medicinal, biological and industrial applications. The ways in which teaching methods have changed over two decades and how web-based resources can be used to improve the communication of chemical (in particular structural) concepts are highlighted.
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Marinakis N, Wobill C, Constable EC, Housecroft CE. Refining the anchor: Optimizing the performance of cyclometallated ruthenium(II) dyes in p-type dye sensitized solar cells. Polyhedron 2018. [DOI: 10.1016/j.poly.2017.12.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Freund S, Hinaut A, Marinakis N, Constable EC, Meyer E, Housecroft CE, Glatzel T. Anchoring of a dye precursor on NiO(001) studied by non-contact atomic force microscopy. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:242-249. [PMID: 29441269 PMCID: PMC5789385 DOI: 10.3762/bjnano.9.26] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 12/25/2017] [Indexed: 05/26/2023]
Abstract
The properties of metal oxides, such as charge-transport mechanisms or optoelectronic characteristics, can be modified by functionalization with organic molecules. This kind of organic/inorganic surface is nowadays highly regarded, in particular, for the design of hybrid devices such as dye-sensitized solar cells. However, a key parameter for optimized interfaces is not only the choice of the compounds but also the properties of adsorption. Here, we investigated the deposition of an organic dye precursor molecule on a NiO(001) single crystal surface by means of non-contact atomic force microscopy at room temperature. Depending on the coverage, single molecules, groups of adsorbates with random or recognizable shapes, or islands of closely packed molecules were identified. Single molecules and self assemblies are resolved with submolecular resolution showing that they are lying flat on the surface in a trans-conformation. Within the limits of our Kelvin probe microscopy setup a charge transfer from NiO to the molecular layer of 0.3 electrons per molecules was observed only in the areas where the molecules are closed packed.
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Keller S, Camenzind TN, Abraham J, Prescimone A, Häussinger D, Constable EC, Housecroft CE. Self-assembly of heteroleptic dinuclear silver(i) complexes bridged by bis(diphenylphosphino)ethyne. Dalton Trans 2018; 47:946-957. [PMID: 29260149 DOI: 10.1039/c7dt03923a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a study of the self-assembling behaviour in solution of Ag[PF6] with one equivalent of an N^N ligand (N^N = 6,6'-dimethyl-2,2'-bipyridine (6,6'-Me2bpy) or 2,2':6',2''-terpyridine (tpy)), together with either 0.5 or one equivalent of the bridging ligand bis(diphenylphosphino)ethyne (dppa). Each product contains a dinuclear cation, with one or two dppa ligands bridging the two Ag+ centres; 6,6'-Me2bpy and tpy, respectively, act as chelating ligands. The compounds have been analysed in solution using NMR spectroscopic methods (1H, 1H{31P}, COSY, NOESY, 13C, HMQC and HMBC), including room and low temperature measurements. 31P{1H} NMR spectra recorded at different temperatures allow a deeper insight into the dynamic equilibrium processes. In addition, solution 31P-109Ag HSQC spectroscopic measurements were performed and show, inter alia, the ratio of the splitting in the F1 dimension and the 1J31P-109Ag coupling constant in the fully coupled HSQC. Single crystal X-ray diffraction yielded two pseudo-polymorphic structures for the doubly-bridged [Ag2(dppa)2(tpy)2][PF6]2 and one for the singly-bridged [Ag2(dppa)(6,6'-Me2bpy)2][PF6]2.
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