Dalton Transactions

doi: 10.1039/c0dt90084bpmid: N/A

doi: 10.1039/c0dt90085kpmid: N/A

Martin, Lane W.

doi: 10.1039/c0dt00576bpmid: 20820616

An in-depth look at the complex materials chemistry of multiferroics is undertaken. In the last decade, considerable attention has been focused on the search for and characterization of new multiferroic materials as scientists and researchers have been driven by the promise of exotic materials functionality (i.e., electric field control of ferromagnetism). In this manuscript we develop a picture of multiferroic materials, including details on the nature of order parameters and coupling in these materials, the scarcity of such materials, routes to create and control the properties in these materials, and we finish by investigating such effects in the model multiferroic BiFeO3.

Zheng, Yan-Zhen; Speldrich, Manfred; Schilder, Helmut; Chen, Xiao-Ming; Kögerler, Paul

doi: 10.1039/c0dt00935kpmid: 20953520

A solvothermally derived tetranuclear cobalt(ii) complex, [Co4(phen)4Cl8] (phen = phenanthroline), featuring a zig-zag backbone of {Co(μ2-Cl)2Co} planes, exhibits ferromagnetic exchange and slow relaxation of the magnetization and represents the first Co SMM with a linear core structure.

Mohammadnezhad, Gholamhossein; Amini, Mostafa M.; Khavasi, Hamid Reza

doi: 10.1039/c0dt00983kpmid: 20953475

A novel polynuclear single-source precursor was prepared and characterized by single-crystal X-ray diffraction and multinuclear NMR spectroscopy. Nano-crystalline MgAl2O4 spinel was synthesized via sol–gel processing of [MgAl2(μ3-O)(μ2-OiPr)4(OiPr)2]4. XRD, TGA-DSC and HRTEM confirmed the formation of a spinel phase at 475 °C, a temperature lower than any known processing temperature for MgAl2O4.

McMullin, Claire L.; Jover, Jesús; Harvey, Jeremy N.; Fey, Natalie

doi: 10.1039/c0dt00778apmid: 20963224

We have used dispersion-corrected DFT (DFT-D) together with solvation to examine possible mechanisms for reaction of PhX (X = Cl, Br, I) with Pd(PtBu3)2 and compare our results to recently published kinetic data (F. Barrios-Landeros, B. P. Carrow and J. F. Hartwig, J. Am. Chem. Soc., 2009, 131, 8141–8154).1 The calculated activation free energies agree near-quantitatively with experimentally observed rate constants.

Natrajan, Louise S.; Toulmin, Anita; Chew, Alex; Magennis, Steven W.

doi: 10.1039/c0dt00750apmid: 20941434

Four structurally related iridium(iii) and ruthenium(ii) complexes bearing two polar terpyridyl–stilbene derived chromophores 4-(4-{2-[4-(methoxy)phenyl]ethenyl}phenyl)-2,2′-6′,2′′-terpyridine (ttpyeneanisole) and 4-(4-{2-[phenyl]ethenyl}phenyl)-2,2′-6′,2′′-terpyridine (tpystilbene) have been synthesised and characterised in the solid state and in solution. In the solid state, the dihedral angle subtending the pyridyl and tolyl groups of 27.1° in the Ir(iii) complex [Ir(ttpyeneanisole)2]·3PF6 is more acute than in the Ru(ii) derivative [Ru(tpystilbene)2]·2PF6 (35.5°), indicating the presence of a greater degree of π-delocalisation across the terpyridine unit in the former compound. Their luminescence properties in fluid solution have been investigated following both resonant and non-resonant excitation. We have shown that each of the complexes undergoes two-photon excitation when excited in the near infrared (740 to 820 nm), with two-photon absorption cross sections in the range 11–67 × 10−50 cm4 s photon−1. The larger cross sections for the Ir(iii) complexes reflect the differences observed in the solid state. This work therefore demonstrates that such complexes are promising as luminescent markers for 3D imaging and illustrates that simple functionalisation of the chromophores and the choice of metal can lead to marked enhancements in the two-photon cross sections (σ2) compared to those of simpler heteroleptic polypyridyl based derivatives.

Sciacca, Beniamino; Alvarez, Sara D.; Geobaldo, Francesco; Sailor, Michael J.

doi: 10.1039/c0dt00936apmid: 20967329

The high stability of Salonen's thermally carbonized porous silicon (TCPSi) has attracted attention for environmental and biochemical sensing applications, where corrosion-induced zero point drift of porous silicon-based sensor elements has historically been a significant problem. Prepared by the high temperature reaction of porous silicon with acetylene gas, the stability of this silicon carbide-like material also poses a challenge—many sensor applications require a functionalized surface, and the low reactivity of TCPSi has limited the ability to chemically modify its surface. This work presents a simple reaction to modify the surface of TCPSi with an alkyl carboxylate. The method involves radical coupling of a dicarboxylic acid (sebacic acid) to the TCPSi surface using a benzoyl peroxide initiator. The grafted carboxylic acid species provides a route for bioconjugate chemical modification, demonstrated in this work by coupling propylamine to the surface carboxylic acid group through the intermediacy of pentafluorophenol and 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC). The stability of the carbonized porous Si surface, both before and after chemical modification, is tested in phosphate buffered saline solution and found to be superior to either hydrosilylated (with undecylenic acid) or thermally oxidized porous Si surfaces.

Creaven, Bernadette Sarah; Czeglédi, Eszter; Devereux, Michael; Enyedy, Éva Anna; Foltyn-Arfa Kia, Agnieszka; Karcz, Dariusz; Kellett, Andrew; McClean, Siobhán; Nagy, Nóra Veronika; Noble, Andy; Rockenbauer, Antal; Szabó-Plánka, Terézia; Walsh, Maureen

Boni, Adriano; Marchetti, Fabio; Pampaloni, Guido; Zacchini, Stefano

doi: 10.1039/c0dt00697apmid: 20953481

The novel cationic diiron μ-allenyl complexes [Fe2Cp2(CO)2(μ-CO){μ-η1:η2α,β-Cα(H)CβCγ(R)2}]+ (R = Me, 4a; R = Ph, 4b) have been obtained in good yields by a two-step reaction starting from [Fe2Cp2(CO)4]. The solid state structures of [4a][CF3SO3] and of the diruthenium analogues [Ru2Cp2(CO)2(μ-CO){μ-η1:η2α,β-Cα(H)CβCγ(R)2}][BPh4] (R = Me, [2a][BPh4]; R = Ph, [2c][BPh4]) have been ascertained by X-ray diffraction studies. The reactions of 2c and 4a with Brønsted bases result in formation of the μ-allenylidene compound [Ru2Cp2(CO)2(μ-CO){μ-η1:η1-CαCβCγ(Ph)2}] (5) and of the dimetallacyclopentenone [Fe2Cp2(CO)(μ-CO){μ-η1:η3-Cα(H)Cβ(Cγ(Me)CH2)C(O)}] (6), respectively. The nitrile adducts [Ru2Cp2(CO)(NCMe)(μ-CO){μ-η1:η2-Cα(H)CβCγ(R)2}]+ (R = Me, 7a; R = Ph, 7b), prepared by treatment of 2a,c with MeCN/Me3NO, react with N2CHCO2Et/NEt3 at room temperature, affording the butenolide-substituted carbene complexes [Ru2Cp2(CO)(μ-CO){μ-η1:η3-Cα(H)CβCγ(R)2OC(O)C(H)] (R = Me, 10a; R = Ph, 10b). The intermediate cationic compound [Ru2Cp2(CO)(μ-CO){μ-η1:η3-Cα(H)CβCγ(Me)2OC(OEt)C(H)]+ (9) has been detected in the course of the reaction leading to 10a. The addition of N2CHCO2Et/NHEt2 to 7a gives the 2-furaniminium-carbene [Ru2Cp2(CO)(μ-CO){μ-η1:η3-Cα(H)CβCγ(Me)2OC(OEt)C(H)]+ (11). The X-ray structures of 10a, 10b and [11][BF4] have been determined. The reactions of 4a,b with MeCN/Me3NO result in prevalent decomposition to mononuclear iron species.