Carbon−Phosphorus Bond Activation of Tri(2-thienyl)phosphine at Dirhenium and Dimanganese Centers

Reaction of [Re2(CO)9(NCMe)] with tri(2-thienyl)phosphine (PTh3) in refluxing cyclohexane affords three substituted dirhenium complexes: [Re2(CO)9(PTh3)] (1), [Re2(CO)8(NCMe)(PTh3)] (2), and [Re2(CO)8(PTh3)2] (3). Complex 2 was also obtained from the room-temperature reaction of [Re2(CO)8(NCMe)2] with PTh3 and is an unusual example in which the acetonitrile and phosphine ligands are coordinated to the same rhenium atom. Thermolysis of 1 and 3 in refluxing xylene affords [Re2(CO)8(μ-PTh2)(μ-η1:κ1-C4H3S)] (4) and [Re2(CO)7(PTh3)(μ-PTh2)(μ-H)] (5), respectively, both resulting from carbon−phosphorus bond cleavage of a coordinated PTh3 ligand. Reaction of [Re2(CO)10] and PTh3 in refluxing xylene gives a complex mixture of products. These products include 3−5, two further binuclear products, [Re2(CO)7(PTh3)(μ-PTh2)(μ-η1:κ1-C4H3S)] (6) and [Re2(CO)7(μ-κ1:κ2-Th2PC4H2SPTh)(μ-η1:κ1-C4H3S)] (7), and the mononuclear hydrides [ReH(CO)4(PTh3)] (8) and trans-[ReH(CO)3(PTh3)2] (9). Binuclear 6 is structurally similar to 4 and can be obtained from reaction of the latter with 1 equiv of PTh3. Formation of 7 involves a series of rearrangements resulting in the formation of a unique new diphosphine ligand, Th2PC4H2SPTh. Reaction of [Mn2(CO)10] with PTh3 in refluxing toluene affords the phosphine-substituted product [Mn2(CO)9(PTh3)] (10) and two carbon−phosphorus bond cleavage products, [Mn2(CO)6(μ-PTh2)(μ-η1:η5-C4H3S)] (11) and [Mn2(CO)5(PTh3)(μ-PTh2)(μ-η1:η5-C4H3S)] (12). Both 11 and 12 contain a bridging thienyl ligand that is bonded to one manganese atom in a η5-fashion. The molecular structures of eight of these new complexes were established by single-crystal X-ray diffraction studies, allowing a detailed analysis of the disposition of the coordinated ligands

Diagnosed hematological malignancies in Bangladesh - a retrospective analysis of over 5000 cases from 10 specialized hospitals

Background The global burden from cancer is rising, especially as low-income countries like Bangladesh observe rapid aging. So far, there are no comprehensive descriptions reporting diagnosed cancer group that include hematological malignancies in Bangladesh. Methods This was a multi-center hospital-based retrospective descriptive study of over 5000 confirmed hematological cancer cases in between January 2008 to December 2012. Morphological typing was carried out using the “French American British” classification system. Results A total of 5013 patients aged between 2 to 90 years had been diagnosed with malignant hematological disorders. A 69.2% were males (n = 3468) and 30.8% females (n = 1545), with a male to female ratio of 2.2:1. The overall median age at diagnosis was 42 years. Acute myeloid leukemia was most frequent (28.3%) with a median age of 35 years, followed by chronic myeloid leukemia with 18.2% (median age 40 years), non-Hodgkin lymphoma (16.9%; median age 48 years), acute lymphoblastic leukemia (14.1%; median age 27 years), multiple myeloma (10.5%; median age 55 years), myelodysplastic syndromes (4.5%; median age 57 years) and Hodgkin’s lymphoma (3.9%; median age 36 years). The least common was chronic lymphocytic leukemia (3.7%; median age 60 years). Below the age of 20 years, acute lymphoblastic leukemia was predominant (37.3%), followed by acute myeloid leukemia (34%). Chronic lymphocytic leukemia and multiple myeloma had mostly occurred among older patients, aged 50-over. Conclusions For the first time, our study presents the pattern and distribution of diagnosed hematological cancers in Bangladesh. It shows differences in population distributions as compared to other settings with possibly a lower presence of non-Hodgkin lymphoma. There might be under-reporting of affected women. Further studies are necessary on the epidemiology, genetics and potential environmental risk factors within this rapidly aging country

Chiral and achiral phosphine derivatives of alkylidyne tricobalt carbonyl clusters as catalyst precursors for (asymmetric) inter- and intramolecular Pauson-Khand reactions.

Phosphine derivatives of alkylidyne tricobalt carbonyl clusters have been tested as catalysts/catalyst precursors in intermolecular and (asymmetric) intramolecular Pauson-Khand reactions. A number of new phosphine derivatives of the tricobalt alkylidyne clusters [Co(3)(mu(3)-CR)(CO)(9)] (R = H, CO(2)Et) were prepared and characterised. The clusters [Co(3)(mu(3)-CR)(CO)(9-x)(PR'(3))(x)] (PR'(3) = achiral or chiral monodentate phosphine, x = 1-3) and [Co(3)(mu(3)-CR)(CO)(7)(P-P)] (P-P = chiral diphosphine; 1,1'- and 1,2-structural isomers) were assayed as catalysts for intermolecular and (asymmetric) intramolecular Pauson-Khand reactions. The phosphine-substituted tricobalt clusters proved to be viable catalysts/catalyst precursors that gave moderate to very good product yields (up to approximately 90%), but the enantiomeric excesses were too low for the clusters to be of practical use in the asymmetric reactions

Antioxidant and antibacterial activities of methanolic extract of BAU kul (Ziziphus mauritiana), an improved variety of fruit from Bangladesh

BAU Kul (Ziziphus mauritiana) is a new and improved variety of plum fruit from Bangladesh. This study aims to investigate the antioxidant potency and antibacterial activity of methanolic extracts of BAU Kul using Soxhlet extraction followed by complete evaporation of residual methanol. BAU Kul is a very good source of phenolics, flavonoids, ascorbic acid and tannins. The reducing sugar and protein content of BAU Kul were 1.68 and 0.81% by weight, respectively. BAU Kul was very active in 1,1-diphenyl-2- picrylhydrazyl radical (DPPH) scavenging and ferric reducing antioxidant power assay (527.289.2 [M Fe (II)]/100g), thus confirming its high antioxidant potential. Antibacterial activities were measured using the agar well-diffusion method. BAU Kul was most toxic to Pseudomonas aeruginosa, followed (in order) by Staphylococcus aureus, Salmonella paratyphi, Escherichia coli and Chromobacterium violaceum. In conclusion, BAU Kul is a nutritious fruit that provides good antioxidant and antibacterial activities (in particular toward P.aeruginosa) and a cheap source of vitamins.Practical ApplicationsBAU Kul is a new and sweet seasonal fruit which is very popular to the consumers of Bangladesh. This fruit can be a good source of nutrients as well as the antioxidants applicable in different types of diseases caused by oxidative stresses. BAU Kul can also be used as traditional medicine for different types for infectious diseases

Antioxidant and antibacterial activities of methanolic extract of BAU kul (Ziziphus mauritiana), an improved variety of fruit from Bangladesh

Journée d'étude, mardi 4 décembre 2012 Centre Pompidou - petite salle - 9h30 (accès sur inscription) La constitution d'un catalogue raisonné des expositions du Centre Pompidou s'insère également dans le mouvement plus large qui conduit différents champs disciplinaires à aborder la question de l'histoire de l'exposition : histoire de l'art, esthétique, muséologie, histoire des politiques culturelles... A chaque fois se posent des questions de choix d'objets, d'accès à l'information, d'agenceme..