The syntheses of five homoleptic copper(I) complexes [CuL2][PF6] are described in which L is a 4,4'-di(4-bromophenyl)-6,6'-dialkyl-2,2'-bipyridine ligand (compounds 1-4 with methyl, (n)butyl, (iso)butyl and hexyl substituents, respectively) or 4,4'-di(4-bromophenyl)-6,6'-diphenyl-2,2'-bipyridine (5). The new ligands 2-5 and copper(I) complexes [CuL2][PF6] (L = 1-5) have been fully characterized. The single crystal structures of 2{[Cu(1)2][PF6]}·3Me2CO, [Cu(2)2][PF6], 2{[Cu(3)2][PF6]}·Et2O and [Cu(5)2][PF6]·CH2Cl2 have been determined. The first three structures show similar distorted tetrahedral environments for the Cu(+) ions with angles between the least squares planes of the bpy domains of 85.6, 86.4 and 82.9°, respectively; in contrast, the Cu(+) ion in [Cu(5)2][PF6]·CH2Cl2 is in a flattened coordinate environment due to intra-cation face-to-face π-interactions. The solution absorption spectra of the complexes with ligands 1-4 are virtually identical with an MLCT band with values of λmax = 481-488 nm. In contrast, the absorption spectrum of [Cu(5)2][PF6] shows two broad bands in the visible region. Cyclic voltammetric data show that oxidation of the copper(I) centre occurs at a more positive potential in [Cu(2)2][PF6], [Cu(3)2][PF6] and [Cu(4)2][PF6] than in [Cu(1)2][PF6] or [Cu(5)2][PF6] with the latter being oxidized at the lowest potential. The complexes have been used to prepare dye-sensitized solar cells (DSCs) incorporating heteroleptic dyes of type [Cu(L)(Lanchor)](+) where L is 1-5 and Lanchor is a 6,6'-dimethyl-2,2'-bipyridine functionalized in the 4- and 4'-positions with phosphonic acid groups with (Lanchor = 7) and without (Lanchor = 6) a spacer between the metal-binding and anchoring domains. The presence of the spacer results in enhanced performances of the dyes, and the highest energy conversion efficiencies are observed for the dyes [Cu(3)(7)](+) (η = 2.43% compared to 5.96% for standard dye N719) and [Cu(5)(7)](+) (η = 2.89% compared to 5.96% for N719). Measurements taken periodically over the course of a week indicate that the cells undergo a ripening process (most clearly seen for [Cu(5)(6)](+) and [Cu(5)(7)](+)) before their optimum performances are achieved. IPCE (EQE) data are presented and confirm that, although the photo-to-current conversions are promising (37-49% for λmax≈ 480 nm), the copper(I) dyes do not realize the broad spectral response exhibited by N719.

Ion-sensitive field-effect transistors based on silicon nanowires with high dielectric constant gate oxide layers (e.g., Al2O3 or HfO2) display hydroxyl groups which are known to be sensitive to pH variations but also to other ions present in the electrolyte at high concentration. This intrinsically nonselective sensitivity of the oxide surface greatly complicates the selective sensing of ionic species other than protons. Here, we modify individual nanowires with thin gold films as a novel approach to surface functionalization for the detection of specific analytes. We demonstrate sodium ion (Na(+)) sensing by a self-assembled monolayer (SAM) of thiol-modified crown ethers in a differential measurement setup. A selective Na(+) response of ≈-44 mV per decade in a NaCl solution is achieved and tested in the presence of protons (H(+)), potassium (K(+)), and chloride (Cl(-)) ions, by measuring the difference between a nanowire with a gold surface functionalized by the SAM (active) and a nanowire with a bare gold surface (control). We find that the functional SAM does not affect the unspecific response of gold to pH and background ionic species. This represents a clear advantage of gold compared to oxide surfaces and makes it an ideal candidate for differential measurements.

The construction of carboxylic acid compounds in a selective fashion from low value materials such as alkenes remains a long-standing challenge to synthetic chemists. In particular, β-addition to styrenes is underdeveloped. Herein we report a new electrosynthetic approach to the selective hydrocarboxylation of alkenes that overcomes the limitations of current transition metal and photochemical approaches. The reported method allows unprecedented direct access to carboxylic acids derived from β,βtrisubstituted alkenes, in a highly regioselective manner.

Ligands containing first and second generation hole-transport triphenylamino-dendrons have been evaluated as ancillary ligands in copper(I) DSCs yielding an optimal efficiency of 3.77% in unmasked cells. The effects of masking the DSCs on measured parameters are discussed.

The spaiial patiern.-i of while clover atid sward hurt'iicc height (SSH) lh;il developed in established perennial ryegrus.s {LoUuin pereiinf)/wWne clover {Trijohiim repens) pastures under culling (cul every 4 wcek.s to 5 cm) and gracing (continuously grazed with sheep to 5 cm) were nieu.sured. While clover cover wLis recorded in 1000 contiguous 5 X 5-cni quadrats down 50-ni permanent transects from early spring to late autumn. Measurements of SSH were made at lO-cm intervals clown the same transect. Spatial pattern wa.s analysed using two-lerm local quadrat variance and patch-gap analysis. At least two scales of .spatial pattern existed for white clover when defoliation ireaimcnLs hegim. While clover was not distrihuted at random but found in patche.s (mean size = 1 i m) where it was finely intermixed with grass. Patches, separated by gaps (regions of no clover) (mean size = 2-3 m), were iti turn aggregated into 'patches of patches', separaled by larger gaps {mean size = 4-1 m). Under grazing the pattern of patches and gaps did not aller. Under cutting, patch size increased and gap size decreased, explaming in pan the greater mass and cover of white clover that arose in cut than grazed swards during the experiment. No new patches of white §PreEern address; Berks SL5 7PY.UK. clover due to seedling establishment or clonal growth were observed in either cui or grazed swards. The intensity of pattern increa.sed in both cut and griized swards, but the increase was greater in cut swards. The initial single scale of spatial pattern of SSH ot" tall patches (mean size = 1-2 m) separated by shorl patches (mean size = 2-7 m) did not change under grazing. SSH became uniform under cutting. It is suggesied ihat the response of plants to selective (spatially heterogeneous) gracing is a crucial factor in the developmeni and maintenance of spatial pattern in grxsslands. The importance of spalial pattern to our understanding and interpretation of plant-plant and plant-anitiial interactions and 10 the composition of temperate gras.slands is considered.

A hybrid tetrathiafulvalene-oligothiophene compound has been synthesised, in which the fulvalene unit is fused on both sides to an end-capped septithiophene oligomer. The compound (1) has been studied by cyclic voltammetry, UV-vis spectroelectrochemistry and X-ray crystallography. The properties of this material are compared to the half-unit (9), which lacks the TTF core and contains only one septithiophene chain. In the case of the larger molecule, there are multiple and complex redox processes leading to the loss of 6-8 electrons per molecule. Charge generation layer time-of-flight measurements give maximum hole mobilities of ca. 1 Â 10 À5 cm 2 V À1 s À1 .

Seasonal and spatial fluctuations in forage quality, accessibility and output provide strong incentives for migratory stock keeping in Central Asia. Over the past century, mobile livestock husbandry has either been suppressed or collapsed and a fragmented pattern of rangeland use has ensued. Policy shifts underlying these processes in Kazakstan are traced. New patterns are evident whereby some flocks are again being moved by season to different pastures. In the market economy, individual families now decide on the costs and benefits of moving their animals. Results are reported from a multidisciplinary study of two rangeland areas in Kazakstan, including a survey of 46 households interviewed quarterly during 2001-2002 and community-level analyses of grazing patterns. Flock mobility is considered in terms of flock size and household assets of labour and capital. For most households in the study sites, movement is neither economically attractive nor absolutely necessary. Having enough resources is not a sufficient condition for moving. Other factors that bear uponthe decision to move include the degree of grazing pressure around the shepherds' home base. In heavily stocked areas, even small-scale producers are finding ways of moving their animals. In isolated or abandoned areas where forage is plentiful, movement can be minimised even for large flocks.

Complex multi-redox-active organic semiconductors have been made incorporating tetrathiafulvalene as a fused bridge between oligothiophene chains.