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

Nutrition-related factors and binge eating behaviour in a sample of Malaysian University students

Binge eating (BE) behaviour is associated with obesity and eating disorders. This cross-sectional study investigates BE behaviour and its relationship with nutrition-related factors among university students. A total of 170 (69% females) university students in Malaysia aged 19 to 24 years participated in this study. BE behaviour was assessed with the use of Binge Eating Scale (BES) questionnaire. Socio-demographic background and nutritional status (anthropometric measurements, body mass index (BMI) and dietary intake) were also measured. BE behaviour reported by 10% percent of the participants. BE behaviour was associated with increased energy intake, elevated BMI and sex (Adjusted R2 = 0.116, p < 0.001). Differences in sex-specific factors in predicting the risk of BE behaviour were evident. In male participants, an increased in energy intake, elevated BMI and had a higher waist circumference associated with the risk of BE behaviour (Adjusted R2 = 0.411, p < 0.001). In female participants, only a higher waist circumference associated with BE behaviour (Adjusted R2 = 0.028, p < 0.05). The finding suggests that understanding sex-specific factors are necessary to prevent BE. These are the potential targets for tailored eating behaviour intervention among university students

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 diphosphine derivatives of alkylidyne tricobalt carbonyl clusters - A comparative study of different cobalt carbonyl (pre)catalysts for (asymmetric) intermolecular Pauson-Khand reactions

Reaction of the tricobalt carbyne cluster [Co-3(mu(3)-CH)(CO)(9)] with chiral diphosphines of the Josiphos and Walphos families affords the new clusters [Co-3(mu(3)-CH)(CO)(7)(P-P*)] in good yield (P-P* = J004 (1), J005 (2), J007 (3), W001 (4), W003 (5)). The new alkylidyne tricobalt clusters, and the previously known [Co-3(mu(3)-CH)(CO)(7)(mu-J003)], have been tested as catalysts/catalyst precursors for intermolecular Pauson-Khand cyclization, using norbornene and phenylacetylene as substrate. The diphosphine-substituted tricobalt carbonyl clusters proved to be viable catalysts/catalyst precursors that gave products in moderate to good yields, but the enantiomeric excesses were low. When the chiral diphosphine ligands were used as promoters/auxiliary ligands for the same Pauson-Khand reaction, using either [Co-2(CO)(8)] or [Co-4(CO)(12)] as catalyst precursors, both the overall yields and the selectivities with respect to cyclopentenone formation were significantly improved. The best results were obtained for ligands J007 and W001, with [Co-4(CO)12] as pre-catalyst, where yields of 96%, and virtually 100% selectivity were obtained. However, the enantioselectivity of product formation was low or non-existent. The crystal structure of [Co-3(mu(3)-CH)(CO)(7)(mu-J004)] is described. [J003 = [(R)-1-{(S)-2-(dicyclohexylphosphino)-ferrocenyl} ethyldicyclohexylphosphine], J004 = [(R)-1-{(S)-2-(dicyclohexylphosphino)-ferrocenyl} ethyldiphenylphosphine], J005 = [(R)-1-{(S)-2-(diphenylphosphino)ferrocenyl}ethyl-di-3,5-xylylphosphine], J007 = [(R)-1-{(S)-2-di-(4-methoxy-3,5-dimethylphenyl)phosphino)ferrocenyl) ethyldicyclohexylphosphine], W001 = [(R)-1-{(R)-2-(2'-diphenyl phosphinophenyl)ferrocenyl} ethyldi(bis-3,5-trifluoromethylphenyl) phosphine], W003 [(R)-1-{(R)-2-(2'-diphenylphosphino-phenyl)ferrocenyl}ethyldi(3,5-xylyl)phosphine]. (C) 2015 Elsevier Ltd. All rights reserved

Recovery and Reuse of Chromium from Tan Yard Solid Waste in Leather Manufacturing

Chrome tanning is the most popular and widely used method utilizing basic chromium salts in leather processing. Only 60-70% of these salts react with collagen to form leather. The rest remains unreacted being released as toxic waste and causing severe environmental pollution in many developing countries. In the current study, a significant approach was made to utilize solid waste with a clean environment perspective. The chromium was extracted as basic chromium sulfate using H2SO4 from tannery waste and reused in the leather manufacturing procedure. Extracted solid sludge was examined by Atomic Absorption Spectrometry and elemental analysis before and after the separation of chromium (III). It revealed that 97% of chromium was extracted from tan yard sludge. Recovered chromium sulfate was reused in goat skin processing. Batch experiments were carried out by applying recovered basic chromium sulfate, and a combination of fresh and recovered basic chromium sulfate solutions separately. Fresh basic chromium sulfate was used as the control method. The structure and morphology of the final processed leather were characterized by Field Emission Scanning Electron Microscope (FESEM) and Thermogravimetric analysis (TGA). The identical structural morphologies of all processed leather were confirmed in the FESEM study. The physical and chemical characteristics of all finished leather were found very similar. The TGA analysis data proved that raw leather processed by recovered chromium is thermally more stable than others. These research findings signify a new potential effort of separating important chemicals from solid sludge and reusing them. This technique is simple, cost-effective, eco-friendly, and sustainable as it reduces environmental pollution from tannery chromium waste

Reduction of Water Consumption in Leather Processing and an Investigation of the Leather Quality

Extensive use of water in different industries particularly leather tanning has drawn attention in recent years. In this research, a new approach has been developed to reduce water consumption in the tanning industry. Four different experiments were carried out on raw goat skins by using various quantities of water which were much lower than the influx of water consumed in the conventional leather tanning processes. One control experiment was conducted in which the volume of water was used as 100% of the conventional method (37 m3/ton) in every step of leather processing. The experiments showed a reduction of 15%, 25%, 35%, and 50% in water consumption respectively from the control method used in the processing of raw leathers. The resulting goat leathers were examined with various physical tests such as tensile strength, percentage of elongation, stitch, tongue tear strengths etc. The results showed the presence of all significant qualities. The processed leathers were thermally stable and exhibited percentages of elongations in the range of 40.94% to 50.85% which were considerably higher than those (38.1%) observed with the conventional method. Scanning Electron Microscopy (SEM), Thermal Gravimetric Analysis (TGA), and Fourier transform infrared (FT-IR) studies confirmed identical morphological and structural characteristics of all processed leathers. These methods of leather processing are environmentally friendly and suitable for large-scale industrial production. Efficient reduction of water use in raw leather processing may significantly decrease the toxic liquid waste and tannery pollution