Rational design of N-heterocyclic compound classes via regenerative cyclization of diamines

Introducing unknown compound classes is the key to extent the chemical space qualitatively. Here the authors report on a concept to design heterocyclic compound classes rationally and the synthesis of unknown classes of N-heterocyclic compound

Sterically demanding iminopyridine ligands

Two sterically demanding iminopyridine ligands, (2,6-diisopropylphenyl)[6-(2,4,6-triisopropylphenyl)pyridin-2-ylmeth- ylene]amine and (2,6-diisopropylphenyl)]6-(2,6-dimethylphenyl)pyridin-2-ylmethylene]amine, were prepared by a two-step process: first, condensation of 6-bromopyridine-2-carbaldehyde with an equimolecular amount of 2,6-diisopropylaniline, and second, Kumada-type coupling of in-situ-formed Grignard compounds of 1-bromo-2,6-dimethylphenyl and 1-bromo-2,4,6-triisopropylphenyl. Dichlorido complexes of the ligands were synthesized starting from FeCl2, [PdCl2(cod)], [NiCl2(dme)], and CoCl2 (cod = 1,5-cyclooctadiene, dine = dimethoxyethane). X-ray crystal structure analyses of a Fe, Pd, and Co complex were determined. Ethylene polymerization/oligomerization behavior of the dichlorido complexes after activation with methyl duminoxane or triethylaluminum was studied. Ethylene dimerization selectivity greater than 95% was observed. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007

CCDC 639684: Experimental Crystal Structure Determination

Related Article: T.Irrgang, S.Keller, H.Maisel, W.Kretschmer, R.Kempe|2007|Eur.J.Inorg.Chem.||4221|doi:10.1002/ejic.200700322,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 639685: Experimental Crystal Structure Determination

Related Article: T.Irrgang, S.Keller, H.Maisel, W.Kretschmer, R.Kempe|2007|Eur.J.Inorg.Chem.||4221|doi:10.1002/ejic.200700322,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

CCDC 639686: Experimental Crystal Structure Determination

Related Article: T.Irrgang, S.Keller, H.Maisel, W.Kretschmer, R.Kempe|2007|Eur.J.Inorg.Chem.||4221|doi:10.1002/ejic.200700322,An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Long-Term High Resolution Sediment and Sea Surface Temperature Spatial Patterns in Arctic Nearshore Waters retrieved using 30-year Landsat Archive Imagery

The Arctic is directly impacted by climate change. The increase in air temperature drives the thawing of permafrost and an increase in coastal erosion and river discharge. This leads to a greater input of sediment and organic matter into coastal waters, which substantially impacts ecosystems and the subsistence economy of the local population. Yet, the patterns of sediment dispersal in nearshore zones are not well known, because ships do not often reach shallow waters and satellite remote sensing is traditionally focused on less dynamic environments. We use the extensive Landsat archive to investigate sediment dispersal patterns specifically on Arctic nearshore environments, where field measurements are scarce. Multiple Landsat scenes were combined to calculate means and medians of sediment dispersal and sea surface temperatures under changing seasonal wind conditions in the nearshore zone of Herschel Island Qikiqtaruk in the western Canadian Arctic since 1982. We use the Landsat red and thermal wavebands, as well as a recently published water turbidity algorithm to relate archive wind data to suspended sediment concentrations and sea surface temperature. We also map the transport pathways of water and sediment along the coast at high spatial resolution. Our results show that these pathways are clearly related to the prevailing wind conditions, being ESE and NW. During easterly wind conditions, the Mackenzie River plume expands over extensive parts of the western Canadian Beaufort Shelf and is the main explanatory variable for sediment dispersal and sea surface temperature distributions. During northwesterly wind conditions, the influence of the Mackenzie River Plume is negligible and regional currents along the coast are the main driver. Our results highlight potential of high spatial resolution Landsat imagery to detect small scale hydrodynamic features, but also show the need to specifically tune a bio-optical model for Arctic nearshore environments

Long-Term High Resolution Sediment and Sea Surface Temperature Spatial Patterns in Arctic Nearshore Waters retrieved using 30-year Landsat Archive Imagery

The Arctic is directly impacted by climate change. The increase in air temperature drives the thawing of permafrost and an increase in coastal erosion and river discharge. This leads to a greater input of sediment and organic matter into coastal waters, which substantially impacts ecosystems and the subsistence economy of the local population. Yet, the patterns of sediment dispersal in nearshore zones are not well known, because ships do not often reach shallow waters and satellite remote sensing is traditionally focused on less dynamic environments. We use the extensive Landsat archive to investigate sediment dispersal patterns specifically on Arctic nearshore environments, where field measurements are scarce. Multiple Landsat scenes were combined to calculate means and medians of sediment dispersal and sea surface temperatures under changing seasonal wind conditions in the nearshore zone of Herschel Island Qikiqtaruk in the western Canadian Arctic since 1982. We use the Landsat red and thermal wavebands, as well as a recently published water turbidity algorithm to relate archive wind data to suspended sediment concentrations and sea surface temperature. We also map the transport pathways of water and sediment along the coast at high spatial resolution. Our results show that these pathways are clearly related to the prevailing wind conditions, being ESE and NW. During easterly wind conditions, the Mackenzie River plume expands over extensive parts of the western Canadian Beaufort Shelf and is the main explanatory variable for sediment dispersal and sea surface temperature distributions. During northwesterly wind conditions, the influence of the Mackenzie River Plume is negligible and regional currents along the coast are the main driver. Our results highlight potential of high spatial resolution Landsat imagery to detect small scale hydrodynamic features, but also show the need to specifically tune a bio-optical model for Arctic nearshore environments