| 1. |
- Tunik, S P, et al.
(författare)
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Reactions of [H2OS3(CO)(10)] with conjugated diynes (RC2C2R ') containing nucleophilic oxygen in beta position of a substituent (R = Ph, R ' = CH2OH, C(O)Ph; R = R ' = CMe2(OH))
- 2003
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Ingår i: Organometallics. - : American Chemical Society (ACS). - 1520-6041 .- 0276-7333. ; 22:17, s. 3455-3465
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Tidskriftsartikel (refereegranskat)abstract
- Reactions of [H2Os3(CO)10] with a series of diynes, RC2C2R' (1: R = Ph, R' = CH2OH; 2: R = Ph, R' = C(O)Ph; 3: R = R' = C(OH)Me2), have been studied. It was found that upon coordination to the triosmium cluster, the nucleophilic oxygens of the R' substituents of 1 and 2 take part in intramolecular cyclization reactions to give [HOs3(CO)10{-1:2-PhCH2(C=CH-C=CH-O)}] (5) and [HOs3(CO)10{-1:1-Ph(C=CH-C=C-O)CPh}] (6), respectively, both of which contain furan rings coordinated to the cluster core. On heating of the latter compound, the furan moiety remains intact, but a carbonyl group dissociates from the cluster, leading to the formation of [HOs3(CO)9(3-1:3:1-Ph(C=CH-C=C-O)CPh)] (7) with a closed "C3Os3" pentagonal pyramidal structure. Reaction of [H2Os3(CO)10] with 3 does not lead to cyclization of the diyne; instead, the clusters [Os3(CO)10{3-2-(RCH=CH-C2R)}] (8) and [Os3(CO)10{3-2-(RC2C2R)}] (9) are formed. Deuterium labeling of the starting compounds has been used in the reaction of [H2Os3(CO)10] with HOCH2C2C2CH2OH in order to investigate possible mechanisms of the cyclization reaction. The crystal and molecular structures of clusters 5, 7, and 9 are presented.
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| 3. |
- Chubarenko, B., et al.
(författare)
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Converting beach wrack into a resource as a challenge for the Baltic Sea (an overview)
- 2021
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Ingår i: Ocean and Coastal Management. - : Elsevier. - 0964-5691 .- 1873-524X. ; 200, s. 1-15
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Tidskriftsartikel (refereegranskat)abstract
- The paper distinguishes beach wrack, the marine generated organic part of beach cast, as a separate management object and discusses research questions related to its management and economically viable use. Based on experiences from the Baltic Sea and existing practices from countries with different management systems clear distinction between the management of natural and anthropogenic components of cast material is seen as an essential prerequisite for developing sustainable product chains that allow beach wrack to be used as a resource of commercial value. Presenting and discussing examples from Denmark (Koge Municipality), Germany (Kuhlungsborn, Rugen and Poel Island), Poland (Gulf of Gdansk), Russia (Curonian and Vistula spits) and Sweden (Kalmar municipality and Oland), social, ecological, and economic consequences of beach wrack removal are analysed to improve the attractiveness of beaches for recreational purposes. It also includes potential contribution to Baltic Sea water restoration processes through the removal of the organic part of beach cast, where indeed more studies about the chemical (nutrients, metals) composition of beach wrack are required for reliable calculation of a depuration rate. For local economies within the Baltic Sea region, the organic part of beach cast (beach wrack and terrestrial debris) has reasonable economic prospects as a renewable natural resource, e.g. for soil improvement products, in fertilisers and bio-coal production, for landfill covers (contributing to climate change mitigation), biogas generation, and even for coastal protection by providing humus-like material for accelerated dune vegetation succession. For all these recycling options the development of cost-efficient technologies for collecting beach cast on sandy as well as stony beaches and also for separating the organic part from sand and anthropogenic litter (mainly plastic), is urgently required. Amendments of legal regulations, that better reflect the dualism of beach cast are also required. In essence, dualism results from the fact that beach wrack is a part of nature (or a natural resource) when it remains on a beach. However, beach wrack immediately becomes legally categorised as waste once humans collect it irrespective of its litter content. Another legal aspect being dealt with originates from the migration of the beach wrack between water and beach, whilst it is an object of epleagl cleaning operations only at the beach it onto the beach, but not whilst in the water.
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