The first discrete hexanuclear metal clusters with cores adopting the M6(μ-O)12 cubo-octahedral topology have been synthesized in the course of a simple one-pot reaction. We present a new class of rhenium clusters which are the first hexanuclear rhenium complexes with 12 bridging ligands and the first clusters with octahedrally arranged Re atoms bridged only by O atoms forming a unique cube-like Re6(μ-O)12 unit. Our synthetic strategy demonstrates a new approach to the syntheses of polynuclear rhenium complexes under mild conditions. We discovered that the [Re6(μ-O)12(3-Mepy)6]BPh4 cluster compound has the ability to undergo reversible or/and quasireversible redox reactions without changing spatial structure and overall geometry. Subsequently, a reduction reaction of [Re6(μ-O)12(3-Mepy)6]BPh4 was performed successfully and almost quantitatively resulting in the formation of the molecular [Re6(μ-O)12(3-Mepy)6] complex.
We analysed phenological observations of first flowering and peak flowering dates of 7 species of woodland herbs in the Bia8owie · za National Park (Poland), Europe's last remaining lowland primeval forest and a World Heritage Site, during 1964-2007. There was substantial evidence for an advance in both first and peak flowering dates and flowering was closely related to temperature, which had risen substantially in this area. Similar advances have been reported from elsewhere, but typically from human-modified habitats. A comparison with contemporary data from the UK suggests that flowering was both later and less responsive in Poland. Examination of the data from the 2 countries over a wide range of temperatures hints at possible non-linear temperature responses; thus estimates of phenological change from linear regression may seriously underestimate changes which may occur in Bia8owie · za in the future.KEY WORDS: Flowering · Temperature response · Phenology · Poland · Primeval forest · Climate changeResale or republication not permitted without written consent of the publisher
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