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71.
Functionalized, hydrogen-bonding ionic liquids have been successfully evaluated as media for the performance of cofactor-dependent enzyme catalysed oxidations; the effects of incorporating hydroxyl groups into both the cation and anion have been studied and the dependence of activity upon water content has been evaluated. 相似文献
72.
Cronin L McGregor PA Parsons S Teat S Gould RO White VA Long NJ Robertson N 《Inorganic chemistry》2004,43(25):8023-8029
The "one-pot" synthesis and characterization of a large 28-mer macrocycle (H(4)L(2)) with oxamido units capable of complexing guest ions through oxygen or nitrogen donor atoms is reported. Single-crystal structure determination of H(8)L(2)(NO(3))(4) and (Cu(2)[H(2)L(2)](H(2)O)(2))(NO(3))(2) demonstrated that the macrocycle contains two sites capable of complexing two nitrate anions or two copper(II) ions, involving a large structural reorganization in the conformation of the macrocyclic framework on coordination of the copper(II) ions when compared to the nitrate. Electrochemical and magnetic susceptibility measurements on the dinuclear Cu(II) complex and the related mononuclear and trinuclear Cu(II) complexes derived from the related 14-mer macrocycle were carried out and illustrate the role of the oxamido groups in mediating metal-metal interaction and delocalization. 相似文献
73.
Carbery DR Reignier S Miller ND Adams H Harrity JP 《The Journal of organic chemistry》2003,68(11):4392-4399
A stereocontrolled approach to alpha-alkyl beta-alkynyl cyclohexanones is reported through a Lewis acid mediated rearrangement reaction of enol ethers bearing an Co-alkyne moiety. The reaction proceeds with high levels of stereoselectivity in the presence of Ti- and B-Lewis acids to provide a range of alpha,beta-disubstituted cyclohexanones in high yield although the products are prone to epimerization at the alpha-position in the presence of the B-promoter system. The potential for an enantioselective variant of this process is outlined, and a rationale for the observed stereochemical trends and detailed structural analyses of the ketone products are described. 相似文献
74.
75.
Branscombe ND Atkins AJ Marin-Becerra A McInnes EJ Mabbs FE McMaster J Schröder M 《Chemical communications (Cambridge, England)》2003,(9):1098-1099
Multi-frequency EPR spectroscopy on 61Ni-labelled samples of [Ni2(L)]3+ confirms extensive charge-delocalisation between the Ni(III) centre and thiolate donors in the Ni(II)Ni(III) complex. 相似文献
76.
Alexander J. Blake Binod B. De Wan‐Sheung Li Neil R. Thomas 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):m570-m574
In the title compounds, [N‐(phenyl{2‐[N‐(S)‐(2‐picolyl)prolylamino]phenyl}methylene)‐(S)‐phenylalaninato]nickel(II), [Ni(C33H30N4O3)], (I), [N‐(phenyl{2‐[N‐(S)‐(3‐picolyl)prolylamino]phenyl}methylene)‐(S)‐phenylalaninato]nickel(II) hemihydrate, [Ni(C33H30N4O3)]·0.5H2O, (II), and [N‐({2‐[N‐(S)‐ethylprolylamino]phenyl}phenylmethylene)‐(S)‐phenylalaninato]nickel(II), [Ni(C29H29N3O3)], (III), the NiII centres have approximate square‐planar coordination geometries from N3O donor sets. The picolyl N atoms in (I) and (II) are too remote from the metal centres to interact significantly, but the metal coordination geometries experience tetrahedral distortion and/or displacement of the metal centre from the N3O plane. These are linked to conformational differences between the ligands of the symmetry‐independent complexes (Z′ = 2), which in turn are related to molecular packing. In (III), where a less sterically demanding ethyl group replaces the picolyl substituents, there are none of the distortions or displacements seen in (I) and (II). 相似文献
77.
A review of the chemical and physical properties of MnRe(CO)10 and its derivatives has been undertaken. This heterobimetallic complex is one of the simplest complexes known which contains a bond between two different metals and does not contain bridging groups. The review has revealed that high yield synthetic strategies are known for this complex and the synthetic strategies have bearing for the synthesis of other bimetallic complexes. Kinetic data suggest that information available on monometallic fragments can provide information on the reactivity trends expected for the dimer. However, the second metal is not a neutral spectator and provides a site forsecondary reactions eg for CO substitution. Data on the physical properties of the dimer are sparse and definitive statements ond
Mn-Re·v
Mn-Re, HMn-Re etc. cannot be made. This has significant implications for studies on related simple and complex dimer and cluster complexes. 相似文献
78.
Nolde F Qu J Kohl C Pschirer NG Reuther E Müllen K 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(13):3959-3967
Two new synthetic approaches to terrylenediimides, highly photostable fluorescent dyes, are described. For the first time terrylenediimide has been synthesised in a straightforward procedure that makes large quantities available. The second route includes an efficient cross-coupling reaction followed by a cyclodehydrogenation. Monofunctionalisation of the imide structure allows terrylenediimides now to be coupled with a variety of compounds, for example, by Suzuki cross-coupling, which can lead to an array of terrylenediimides with new functional groups such as hydroxy, amino, or carboxy groups needed to link up with other molecules. The functionalisation in the bay region is used to tune the properties of terrylenediimides and extend the range of applications, for example, by introducing water solubility. These tetrasubstituted terrylenediimides offer, depending on the substituents used, exciting features such as good solubility in common organic solvents, water solubility, or NIR absorption. 相似文献
79.
Day TM Unwin PR Wilson NR Macpherson JV 《Journal of the American Chemical Society》2005,127(30):10639-10647
The use of single-walled carbon nanotube (SWNT) networks as templates for the electrodeposition of metal (Ag and Pt) nanostructures is described. Pristine SWNTs, grown on insulating SiO2 surfaces using catalyzed chemical vapor deposition, served as the working electrode. In the simplest case, electrical contact was made by depositing a gold strip on the SWNT substrate (device 1). Deposition of Ag and Pt over extensive periods (30 s) resulted in a high density of particles on the SWNTs, with almost contiguous nanowire formation from the Au/SWNT boundary moving to isolated nanoparticles at further distances from the contact. For direct electrochemical studies of Ag and Pt nucleation, the assembly was coated in a resist layer and a small window opened up to expose only the electrically connected SWNTs to solution (device 2). In this case, the electrochemical signature in voltammetric and amperometric studies of metal deposition was due solely to processes at the SWNTs. Coupled with high-resolution microscopy measurements (atomic force microscopy and field emission scanning electron microscopy), this approach provided detail on the nucleation and growth mechanisms of Ag and Pt on SWNTs under electrochemical control. In particular, Ag growth was found to be rapid and progressive with an increasing nanoparticle density with time, whereas Pt deposition was characterized by lower nucleation densities and slower growth rates with a tendency for larger particles to be produced over long times. 相似文献
80.
Neil Bricklebank Simon J. Coles Michael B. Hursthouse Peter J. Skabara 《Journal of organometallic chemistry》2005,690(2):328-332
The title compound, Fc2(Ph)PS · I2, has been prepared and characterised in both the solid state and solution. Single crystal X-ray crystallography reveals that the adduct adopts a molecular charge-transfer structure in the solid state. Mössbauer spectroscopy confirms the presence of low spin Fe2+ but also indicates the presence of ca. 24% of an Fe3+ species. The electrochemistry of Fc2(Ph)PS · I2, Fc2(Ph)PS and Fc2(Ph)P has been studied using a combination of cyclic voltammetry and differential pulse voltammetry. The data for Fc2(Ph)PS · I2 show two redox processes, consistent with the sequential oxidation of the ferrocenyl groups to ferrocenium species. 相似文献