http://blogs.najah.edu/author/emp-2144 An-Najah Blogs :: papers work en-us Thu, 18 Apr 2024 22:00:20 IDT Thu, 18 Apr 2024 22:00:20 IDT [email protected] [email protected] http://blogs.najah.edu/staff/emp-2144/article/Polysiloxane-supported-decacarbonyldimanganese0-catalyst-for-terminal-olefin-hydrosilylation-reactions-the-effect-of-the-support-on-the-catalyst-selectivity-activity-and-stability-Published ArticlesA new class of supported carbonyl manganese catalyst was prepared by treating the dimeric decacarbonyldimanganese0 Mn2CO10 with insoluble aminated polysiloxane surface Solid state FT-IR spectra indicated that the supported catalyst is a dimeric complex that is substituted with two amine ligands one at each Mn atom The supported manganese complex was investigated as catalyst for the hydrosilylation reaction of terminal olefins Contrary to the homogeneous Mn2CO10 catalytic system the supported manganese complex was completely selective toward the hydrosilylation reaction with no detectable olefin isomerization or other side-reaction products Furthermore the catalyst was selective to produce the linear hydrosilylation product rather than the branched one No lowering in catalyst activity due to the support was observed A good proportion of the catalyst activity after separation and reuse was retained for at least four times Highly reproducible catalytic activity measurements were obtained with catalytic samples taken from same prepared batch Different prepared batches showed lower reproducibility The effect of different reaction parameters such as the solvent effect the temperature effect the concentration effect and the added-ligand effect have also been studied Laines kinetic studies indicated that the cluster remained intact during the reaction Journal of Molecular Catalysis A: Chemical Volume 144 Issue 1 22 July 1999 Pages 47-59http://blogs.najah.edu/staff/emp-2144/article/Terminal-Olefin-Isomerization-Reactions-Catalyzed-By-PolySiloxane-Supported-Ru3Co12---The-Effect-Of-The-Support-On-The-Catalyst-Selectivity-Activity-And-StabilityPublished ArticlesDodecacarbonyltriruthenium0 Ru3CO12 1 has been chemically anchored to the aminated polysiloxane surface 2 The resulting supported ruthenium complex 3 was evaluated as catalyst for the olefin isomerization reactions Contrary to its homogeneous catalyst counterpart 1 the supported catalyst 3 showed exceptionally high selectivity towards 1-octene isomerization and trans-2-octene was the sole product of the reaction mixture The olefin isomerization reaction was markedly activated by the presence of the tertiary silane EtO3SiH No hydrosilylation reaction products were detected Preliminary kinetic study indicated catalysis by lower nuclearity catalytic species where the cluster fragments during the reaction process The effects of different reaction parameters on the rate of the reaction have been investigatedhttp://blogs.najah.edu/staff/emp-2144/article/The-catalytic-activity-of-polysiloxane-supported-metalloporphyrins-in-olefin-oxidation-reactions-the-effect-of-the-support-on-the-catalytic-activity-and-selectivity-Published ArticlesSupported tetra-4-pyridylporphyrinato-manganeseIII [MnIIITPyP] and -tinIV [SnIVTPyP]2 have been prepared The solid support was iodonated polysiloxane surface prepared by condensation reactions of EtO4Si with MeO3SiCH23I The supported metalloporphyrins were employed as catalysts for the oxidation reactions of 1-octene and of cyclohexene NaBH4 was used to reduce [MnIIITPyP] and [SnIVTPyP]2 back to their catalytically active MnII and SnII forms respectively Contrary to their homogeneous counterparts both of the supported metalloporphyrins catalysed the cyclohexene oxidation reaction to yield only 2-cyclohexen-1-one with no other products over a reaction time of 10 h In addition to cyclohexene oxidation the supported [MnIIITPyP] catalysed 1-octene oxidation as well whereas the supported [SnIVTPyP]2 was inactive for the oxidation of 1-octene Journal of Molecular Catalysis A: Chemical Volume 113 Issues 1-2 25 November 1996 Pages 35-44 http://blogs.najah.edu/staff/emp-2144/article/A-role-for-decaying-leaves-in-mitigating-the-harmful-effects-of-acid-rain-Effects-of-acidity-foreign-ions-concentration-of-leaves-and-locationPublished ArticlesDecaying leaves have been found capable of resisting the effects of acid rain via their ability to buffer water In a previous study the buffering action of five common types of leaves cypress oak pine cinchona and ficus was investigated In the present study the effects of several factors on the buffering ability of these leaves have been studied These factors are acidity presence of foreign ions concentration of leaves and location The studied factors have been found not to affect the pattern of variation of pH of the leaf suspensions with time but to affect the pH value reached by these suspensions Ficus leaves have shown a distinct copability of neutralizing acidic waters Journal of Environmental Science and Health Part A Volume 29 Issue 3 April 1994 pages 467 - 475http://blogs.najah.edu/staff/emp-2144/article/The-Mechanism-of-1--Octene-Isomerization-and-Hydrosilylation-Reaction-Catalysed-by-Ru3CO12Published ArticlesIsomerization and hydrosilylation reactions of terminal olefins have been reported under thermal and photochemical conditions using Ru3 C0 12 1 and HRu3 CO 211 0 In a very recent work we reported E LI that 1 catalyses both Isomerization and hydrosilylation reactions of 1-octene eq 1 It has been found that the isomerization reaction occurs via lower nuclearity catalytic species that result from fragmentation of the mother cluster 1 Evidence in favour of concurrent cluster catalysis was also reported On the other hand the hydrosilylation reaction occurred via cluster catalysis at first and after some-time fragment catalysis occurred http://blogs.najah.edu/staff/emp-2144/article/Spectrophotometric-Determination-of-Uranium-with-Di-2-pyridyl-Ketone-BenzoylhydrazonePublished ArticlesA method for the spectrophotometric determination of uranium VI by complexation with Di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution is described Uranium VI forms a 1:2 complex with DPKBH The complex has a maximum absorbance at 377 um Beers law is obeyed over the range 0 2 - 12 ugm1 1 The effect of pH excess reagent percentage of ethanol vv stability of the complex and the tolerance limit of many metal ions and common anions have been reported The method has been applied to the determination of uranium in Egyptian monazite sandhttp://blogs.najah.edu/staff/emp-2144/article/A-role-for-decaying-leaves-in-mitigating-the-harmful-effects-of-acid-rain-Published ArticlesHarmful effects of acid rain have been considered a serious problem In this paper we have studied the ability of several common types of leaves to mitigate the effect of acid rain via the ability of these leaves to act as buffers in water The pH of leaf suspensions of cypress pine oak cinchona and ficus leaves has been determined and its variation with time has been followed The buffer capacities for these leaf suspensions have also been determined at several times over a long period of time The effect of dilution on this buffer capacity has been studied The speeds at which the various leaf suspensions adjust their pH value when disturbed have been studied The capability of the various leaves studied here to act as a buffer can be arranged in the order: Ficus cypress ~ cinchona pine ~ oak Journal of Environmental Science and Health Part A Volume 29 Issue 1 January 1994 pages 115 - 127http://blogs.najah.edu/staff/emp-2144/article/Cluster-versus-non-cluster-catalysis-in-olefin-thermal-isomerization-and-hydrosilylation-in-the-presence-of-Ru3CO12Published ArticlesThe ruthenium cluster Ru3CO12 1 has been evaluated as a catalyst precursor for the thermal reactions of 1-octene with EtO3SiH in a mixture of dioxane and benzene at temperatures of 5075C At 70C or higher olefin isomerization and hydrosilylation reactions were observed; the products trans-2-octene and C5H11CH2CH2CH2SiOEt3 2 were identified The reactions were accompanied by a side reaction that involved generation of hydrogen gas The sum of the rates of appearance of 2 and H2 equalled the rate of disappearance of EtO3SiH No significant isomerization was observed in the absence of EtO3SiH Maximum turnover number values of 750 70 and 70 were obtained for isomerization hydrosilylation and H2 production reactions respectively At 60C or lower no hydrosilylation or hydrogen production was observed and the only product was trans-2-octene No detectable disappearance of EtO3SiH was observed Acetophenone was also hydrosilated by use of cluster 1 as catalyst; the only product obtained was EtO3SiOCPhHCH3 Kinetic studies indicated that the reactions of 1-octene and the reaction of acetophenone involved a catalytically active species of lower nuclearity There was evidence of concurrent cluster catalysis especially during the first few minutes of the reaction Journal of Organometallic Chemistry Volume 452 Issues 1-2 15 June 1993 Pages 167-173 http://blogs.najah.edu/staff/emp-2144/article/Olefin-hydrogenation-and-isomerization-catalysed-by-Ru3CO12-and-its-derivatives-Cluster-vs-non-cluster-catalysisPublished ArticlesThe systems Ru3CO12nL L = PPh3 CH3CN EtO3SiCH23NH2; n = 03 15 have been employed as catalysts andor catalyst precursors for thermal hydrogenation and isomerization reactions of 1-octene under moderate reaction conditions 1 atm at 70C or below In the hydrogenation reaction the system Ru3CO1215CH3CN showed the highest activity with turnover numbers up to 1000 For this system the kinetics indicated that the hydrogenation occurs via a lower nuclearity catalytic species formed by fragmentation of the mother cluster On the other hand the isomerization reaction occurs after a 1020 min induction period by higher-nuclearity catalytic species The isomerization gave trans-2-octene only and none of the cis-isomer The effects of other factors on the rates of hydrogenation and isomerization reactions are described Journal of Organometallic Chemistry Volume 452 Issues 1-2 15 June 1993 Pages 161-165 http://blogs.najah.edu/staff/emp-2144/article/Effects-on-growth-and-uptake-of-broad-beans-Vicia-fabae-L-by-root-and-foliar-treatments-of-plant-with-lead-and-cadmiumPublished ArticlesUptake of toxic metals by plants has been of great interest to environmental scientists because this might harm the growth of plant and cause health hazard to man and animal In this study the effects of two elements lead and cadmium which cause high concern because of their cummulative nature have been studied on broad beans Both elements have been found to affect the growth of broad beans and this effect increased with the increase of concentration of metal in solutions used for root-treatment or for foliar-treatment of plant The effect of foliar-treatment was very much higher than the effect of root-treatment by lead or cadmium Cadmium was found more toxic to plant growth than lead The effect of cadmium treatment was more on the growth of fruits while the effect of lead treatment was more on the roots of broad beans The least affected part by lead or cadmium was the stem of plant Both the concentration and the whole content of metal in plants and its varoius parts roots stem leaves and fruits increased steadily with the increase of cadmium or lead concentration in solutions used for either root-treatment or foliar-treatment Concentration of metal ions was higher in roots and leaves than in fruits and stems of treated plants The uptake of metal to plant was calculated to be a very small part of the total amount of metal added during treatment Some explanations have been suggested in this study to explain the results obtained Journal of Environmental Science and Health Part A Volume 27 Issue 7 October 1992 pages 1619 - 1642http://blogs.najah.edu/staff/emp-2144/article/Spectrophotometric-Determination-of-Uranium-in-Ores-Using-Di-2-Pyridyl-Ketone-Hydrazone-DerivativesPublished ArticlesTwo methods for the spectrophotometric determination of uranium VI are described The methods are based on the formation of colored complexes for uranium VI with 1di-2-pyridyl ketone nicotinoylhydrazone DPKNH and 2di-2-pyridyl ketone thiophenoylhydrazone DPKTH in 50 vv ethanolic solution The complexes formed a uranium VI: complexing reagent mole ratio of 1:2 Maximum absorbance is at 373 nm for UVIDPKNH and at 389 nm for UVI - DPKTH Ranges of linearity effect of pH effect of excess reagent stability of the complexes and the tolerance limit for many metal ions and common anions have been reported The two methods have been applied to the determination of uranium in eygeptian monazite sand Spectroscopy Letters Volume 25 Issue 4 June 1992 pages 585 - 592http://blogs.najah.edu/staff/emp-2144/article/Spectrophotemetric-determination-of-cobalt-in-aqueous-solution-using-di-2-pyridyl-ketone-derivatives-Published ArticlesA method for the spectrophotometric determination of cobaltII is presented with a comparison of the binary complexes formed by cobaltII with di-2-pyridyl ketone nicotinoylhydrazone DPKNH di-2-pyridyl ketone 2-thiophenoylhydrazone DPKTH and di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution CobaltII forms 1:2 complexes with the three reagents Maximum absorbance is at 372 nm for CoII-DPKNH at 389 nm for CoII-DPKTH and at 370 nm for CoII-DPKBH Ranges of linearity effects of pH and excess reagent sensitivity stability of the complexes and tolerance limits of ions are reported It was concluded that the system with DPKTH is the best followed by DPKNH and then DPKBH The method was applied to the determination of cobalt in different alloys Analytica Chimica Acta Volume 259 Issue 1 5 April 1992 Pages 175-179 http://blogs.najah.edu/staff/emp-2144/article/Spectrophotometric-Determination-of-Cobalt-with-Di-2-Pyridyl-Ketone-BenzoylhydrazonePublished ArticlesA method for the spectrophotometric determination of cobalt II by complexation with di-2-pyridyl ketone benzoylhydrazone DPKBH in 50 vv ethanolic solution is described Cobalt II forms a 1:2 complex with DPKBH The complex has maximum absorbance at 370 nm Beers law is obeyed over the range 01 - 28 gml-1 The effect of pH effect of excess reagent stability of the complex and the tolerance limit of many metal ions have been reported The method is applied to the determination of cobalt in different alloys containing other metals ions Spectroscopy Letters Volume 24 Issue 9 November 1991 pages 1145 - 1152http://blogs.najah.edu/staff/emp-2144/article/Hydrosilylation-reactions-catalysed-by-decacarbonyldimanganeseOPublished ArticlesDecacarbonyldimanganeseO complex Mn2CO10 has been evaluated as a catalyst for hydrosilylation reactions of 1-hexene with tertiary silanes Et3SiH and EtO3SiH The reaction of Et3SiH appears to be first order with respect to the catalyst to the hexene and to the silane although catalyst deactivation occurs when relatively high silane concentrations are used The reaction rate is slightly affected by varying the type of the silane used The rate of disappearance of the tertiary silane is consistent with that of the 1-hexene which means that the catalyst is selective to hydrosilylation reactions This was confirmed by following the rates of disappearance of Si-H and C=C IR bands at 2210 2100 and 1650 cm1 for EtO3SiH Et3SiH and 1-hexene respectively A comparison of the behaviour of Mn2CO10 with that of Co2CO8 is reported here together with a suggested mechanism for the manganese catalyst Journal of Molecular Catalysis Volume 39 Issue 1 January 1987 Pages 1-11http://blogs.najah.edu/staff/emp-2144/article/Homogeneous-catalysis-of-the-reaction-of-silanes-with-alcohols-using-decacarbonyl-dimanganese-0Published ArticlesDimanganese decacarbonyl catalyst has been evaluated in the reactions of HSiR3 R = Et OEt with ROH R = Me Et i-Pr t-Bu and benzyl under various conditions The order of reactivity of the alcohols decreases when more bulky alkyl groups are used and that of the silanes increases if a more electron-withdrawing group OEt is used Kinetic analysis indicates that the reaction is first order with respect to the silane to the alcohol and to the catalyst The effects of varying the solvent and adding a phosphine ligand have also been investigated Journal of Molecular Catalysis Volume 35 Issue 2 May 1986 Pages 137-142