4-Bromo-N,N′-bis­(4-methoxy­phen­yl)benzamidine

The title compound, C21H19BrN2O2, is an amidine containing electron-donating meth­oxy groups and a bulky Br atom on the benzene rings. The solid-state structure reveals a non-centrosymmetric mol­ecule, with an E configuration around the C=N double bond. The C—N bonds show distinct amine [1.3689 (19) Å] and imine [1.285 (2) Å] characteristics. In the crystal, symmetry-related mol­ecules are linked via a very weak N—H⋯N inter­action, and C—H⋯O and C—H⋯π inter­actions

Evaluation of feeds from tropical origin for in vitro methane production potential and rumen fermentation in vitro

Enteric methane arising due to fermentation of feeds in the rumen contributes substantially to the greenhouse gas emissions. Thus, like evaluation of chemical composition and nutritive values of feeds, methane production potential of each feed should be determined. This experiment was conducted to evaluate several feeds for methane production potential and rumen fermentation using in vitro gas production technique so that low methane producing feeds could be utilized to feed ruminants. Protein- and energy-rich concentrates (n=11), cereal and grass forages (n=11), and different straws and shrubs (n=12), which are commonly fed to ruminants in India, were collected from a number of locations. Gas production kinetics, methane production, degradability and rumen fermentation greatly varied (p<0.01) among feeds depending upon the chemical composition. Methane production (mL/g of degraded organic matter) was lower (p<0.01) for concentrate than forages, and straws and shrubs. Among shrubs and straws, methane production was lower (p<0.01) for shrubs than straws. Methane production was correlated (p<0.05) with concentrations of crude protein (CP), ether extract and non-fibrous carbohydrate (NFC) negatively, and with neutral detergent (NDF) and acid detergent fiber (ADF) positively. Potential gas production was negatively correlated (p=0.04) with ADF, but positively (p<0.01) with NFC content. Rate of gas production and ammonia concentration were influenced by CP content positively (p<0.05), but by NDF and ADF negatively (p<0.05). Total volatile fatty acid concentration and organic matter degradability were correlated (p<0.05) positively with CP and NFC content, but negatively with NDF and ADF content. The results suggest that incorporation of concentrates and shrubs replacing straws and forages in the diets of ruminants may decrease methane production

Panchromatic Ru(II)-polypyridyl complexes as NIR emitters

AKP thanks the Leverhulme Trust for an early career fellowship (ECF-2017-326), ScotCHEM for a short-term Postgraduate and Early Career Researcher Exchange (PECRE) fellowship and University of St Andrews for financial support. VNKBA thanks the UGC for a fellowship.Two novel mer-Ru(II) heteroleptic complexes containing stongly donating tridendate ligands (dgpy and dgpz) were synthesised and optoelectronically characterised. These complexes exhibited quasi-reversible ligand- and metal-based redox events and panchromatic absorption with the lowest energy absorption maxima trailing up to 750 nm. These panchromatic dyes were found to be NIR emissive at λPL ~ 835 nm with associated excited-state lifetimes (τPL) of ~ 10 ns. The enhanced photophysical properties of these complexes compared to those of [Ru(tpy)2]2+ (tpy = 2,2′:6′,2′′-terpyridine; λabs < 575 nm, λPL ~ 629 nm and τPL ~ 0.25 ns) are due to the larger 3MLCT-3MC energy-gap as a combined effect of larger bite angle and strong σ-donation offered by the dgpy and dgpz ligands.PostprintPeer reviewe

Bis(2,2′-bipyridine)(5-isothio­cyanato-1,10-phenanthroline)ruthenium(II) bis­(hexa­fluoridophosphate) acetonitrile solvate

The title compound, [Ru(C10H8N2)2(C13H7N3S)](PF6)2·CH3CN, was synthesized by the reaction of thio­phosgene and bis­(2,2′-bipyridine)(1,10-phenanthrolin-5-amine)ruthenium(II) bis­(hexa­fluoridophosphate). The RuII atom adopts a slightly distorted octa­hedral RuN6 coordinaton formed by four N atoms of two bipyridine ligands and by two N atoms of the 1,10-phenantroline ligand. The isothio­cyanate group is almost linear, with an N—C—S angle of 174.4 (6)°. Two of the three hexa­fluoridophosphate counter-anions are located on inversion centres

Blue emissive cobalt(III) complexes and their use in the photocatalytic trifluoromethylation of polycyclic aromatic hydrocarbons

A.K.P and G.S.H thank Natural Sciences and Engineering Research Council of Canada. A.K.P thanks the Leverhulme Trust Early Career Fellowship (ECF-2017-326) and the University of St Andrews. The authors thank the Prof. & Mrs Purdie Bequests Scholarship and AstraZeneca support for C.L. EZ-C thanks the Engineering and Physical Sciences Research Council (EP/M02105X/1) and the University of St Andrews.The first examples of room temperature (r.t.) luminescent Co(III) complexes ( 1 and 2 ) are presented that exhibit intense ligand‐to‐metal and ligand‐to‐ligand charge transfer absorption in the low energy UV region (λabs ~ 360‐400 nm) and low‐negative quasi‐reversible reduction events (E1/2(red) = −0.58 V and −0.39 V vs. SCE for 1 and 2 , respectively). The blue emission of 1 and 2 at r.t. is due to the large bite angles and strong σ‐donation of the ligands, the combined effect of which helps to separate the emissive 3LMCT (triplet ligand‐to‐metal charge transfer) and the non‐emissive 3MC (triplet metal‐centered) states. 1 and 2 were found to be powerful photo‐oxidants (ECo(III)*/Co(II) = 2.26 V and 2.75 V vs. SCE of 1 and 2 , respectively) and were used as inexpensive photoredox catalysts for the regioselective mono(trifluoromethylation) of polycyclic aromatic hydrocarbons (PAHs) in good yields (~ 40‐58%).PostprintPeer reviewe

Near-infrared fluorescence of silicon phthalocyanine carboxylate esters

EZ-C acknowledges the University of St Andrews for financial support. We are grateful to the EPSRC for financial support from grant EP/M02105X/1 and the European Research Council for financial support from grant 321305. I.D.W.S. acknowledges a Royal Society Wolfson Research Merit Award.Seven silicon(IV) phthalocyanine carboxylate esters (SiPcs, 1–7 ) with non-, partially- and per-fluorinated aliphatic (linear or branched at the alpha-carbon) and aromatic ester groups have been synthesized, their solid-state structures determined and their optoelectronic properties characterized. The SiPcs exhibit quasi-reversible oxidation waves (vs. Fc+/Fc) at 0.58–0.75 V and reduction waves at −0.97 to −1.16 V centered on the phthalocyanine ring with a narrow redox gap range of 1.70–1.75 V. Strong absorbance in the near-infrared (NIR) region is observed for 1–7 with the lowest-energy absorption maximum (Q band) varying little as a function of ester between 682 and 691 nm. SiPcs 1–7 fluorescence in the near-infrared with emission maxima at 691–700 nm. The photoluminescence quantum yields range from 40 to 52%. As a function of esterification, the SiPcs 1–7 exhibit moderate-to-good solubility in chlorinated solvents, such as 1,2-dichlorobenzene and chloroform.Publisher PDFPeer reviewe

Controlling the emission efficiency of blue-green iridium (iii) phosphorescent emitters and applications in solution-processed organic light-emitting diodes

We show that the emission efficiency of blue-green phosphorescent emitters can be controlled through coupling of the excited state to vibrational modes. We controlled this vibrational coupling through choice of different ligands and as a result, complexes with CF3-groups on the ancillary ligand were essentially non-emissive (ΦPL 50%). Emission of the complexes can be drastically improved (30 times higher ΦPL compared to degassed solution for the CF3-containing complexes) by blending them with an inert solid host such as PMMA, which mitigates metal-ligand vibrations. Solution-processed organic light-emitting diodes made from these materials showed efficiency as high as 6.3%

Controlling the emission efficiency of blue-green iridium(III) phosphorescent emitters and applications in solution-processed organic light-emitting diodes

We are grateful to the European Research Council (grant 321305), EPSRC (grants EP/J01771X/1, EP/L017008/1 and EP/M02105X/1) for financial support. IDWS acknowledges a Royal Society Wolfson Research Merit Award. GSH thanks the Natural Sciences and Engineering Research Council (NSERC) of Canada for funding.We show that the emission efficiency of blue-green phosphorescent emitters can be controlled through coupling of the excited state to vibrational modes. We controlled this vibrational coupling through choice of different ligands and as a result, complexes with CF3-groups on the ancillary ligand were essentially non-emissive (ΦPL 50%). Emission of the complexes can be drastically improved (30 times higher ΦPL compared to degassed solution for the CF3-containing complexes) by blending them with an inert solid host such as PMMA, which mitigates metal-ligand vibrations. Solution-processed organic light-emitting diodes made from these materials showed efficiency as high as 6.3%.PostprintPeer reviewe

Synthesis, characterization and optoelectronic properties of iridium complexes bearing nonconjugated six-membered chelating ligands

The authors thank the EPSRC UK National Mass Spectrometry Facility at Swansea University for analytical services. C.H. acknowledges the Région Bretagne, France for funding. D.J. acknowledges the European Research Council and the Région des Pays de la Loire for financial support in the framework of a Starting Grant (Marches - 278845) and the LUMOMAT RFI project, respectively. This research used resources of 1) the GENCI-CINES/IDRIS, 2) the CCIPL (Centre de Calcul Intensif des Pays de Loire), 3) a local Troy cluster. E.Z.-C. acknowledges the University of St. Andrews and EPSRC (EP/M02105X/1) for financial support.We report the synthesis, characterization and the optoelectronic properties of a series of four new luminescent iridium(III) complexes 1-4 , of the form [Ir(C^N)2(N^N)]PF6 [where C^N is the nonconjugated benzylpyridinato (bnpy) and N^N is a neutral diimine ancillary ligand] with the goal of investigating the impact of the methylene spacer between the coordination moieties of the C^N ligand on the optoelectronic properties of the complexes. The crystal structures of 1-3 illustrate two possible orientations of the methylene unit of the bnpy ligand. The formation of these two separate conformers is a result of the conformational flexibility of the bnpy ligand. In complexes 3 and 4 , mixtures of the two conformers were observed by 1H-NMR spectroscopy in CDCl3 at room temperature, whereas only a single conformer is detected for 1 and 2 . Detailed DFT calculations corroborate ROESY experiments, accounting for the presence and relative populations of the two conformers. The optoelectronic properties of all four complexes, rationalized by the theoretical study, demonstrate that the interruption of conjugation in the C^N ligands results in a reduced electrochemical gap but similar triplet state energies and lower photoluminescence quantum yields compared to the reference complexes R1-R4 . Depending on the nature of the N^N ligand, we observe (1) marked variations of the ratio of the conformers at ambient temperature and (2) phosphorescence ranging from yellow to red.PostprintPeer reviewe