title: New ruthenium carbonyl clusters containing unusual  5-sulfido-,  4-benzyne-, and thianthrene-derived ligands: Insertion of ruthenium into the thianthrene ring by C-S activation

authors: Hassan, Mohammad R.

abstract: Treatment of [Ru3(CO)12] with thianthrene in refluxing toluene afforded [( 4-S)Ru4( -CO)2(CO)9( 4- 2-C6H4)] (1), [( 5-S)Ru6( -CO)2(CO)15( - 3-C12H8S)] (2), and [( 5-S)Ru5( -CO)2(CO)11( - 3-C12H8S)( 4- 2-C6H4)] (3) in 18%, 8%, and 16% yields, respectively. Thermolysis of 2 in refluxing heptane gave compounds 1 and 3. A similar thermolysis of 3 in refluxing toluene gave 1 in 90% yield. Treatment of 3 with neat MeCN afforded the labile compound [( 5-S)Ru5( -CO)2(CO)10( - 3-C12H8S)( 4- 2-C6H4)(MeCN)] (4) in 73% yield. The reaction of 4 with P(OMe)3 gave the substitution product [( 5-S)Ru5( -CO)2(CO)10( - 3-C12H8S)( 4- 2-C6H4){P(OMe)3}] (5) in 52% yield. Compounds 1-4 have been structurally characterized. Compound 1 contains a  4-capping sulfido and a  4- 2-benzyne ligand, whereas 3, 4, and 5 contain  5-sulfido and  4- 2-benzyne ligands. The latter three compounds provide rare examples of  5-sulfido and metal-assisted opening of the thianthrene ligand on polynuclear centers. In compounds 1, 3, and 4 the  4- 2-benzyne ligand is perpendicular to the Ru4 face of the clusters and represents a previously uncharacterized bonding mode for benzyne.

text: New ruthenium carbonyl clusters containing unusual  5-sulfido-,  4-benzyne-, and thianthrene-derived ligands: Insertion of ruthenium into the thianthrene ring by C-S activation Treatment of [Ru3(CO)12] with thianthrene in refluxing toluene afforded [( 4-S)Ru4( -CO)2(CO)9( 4- 2-C6H4)] (1), [( 5-S)Ru6( -CO)2(CO)15( - 3-C12H8S)] (2), and [( 5-S)Ru5( -CO)2(CO)11( - 3-C12H8S)( 4- 2-C6H4)] (3) in 18%, 8%, and 16% yields, respectively. Thermolysis of 2 in refluxing heptane gave compounds 1 and 3. A similar thermolysis of 3 in refluxing toluene gave 1 in 90% yield. Treatment of 3 with neat MeCN afforded the labile compound [( 5-S)Ru5( -CO)2(CO)10( - 3-C12H8S)( 4- 2-C6H4)(MeCN)] (4) in 73% yield. The reaction of 4 with P(OMe)3 gave the substitution product [( 5-S)Ru5( -CO)2(CO)10( - 3-C12H8S)( 4- 2-C6H4){P(OMe)3}] (5) in 52% yield. Compounds 1-4 have been structurally characterized. Compound 1 contains a  4-capping sulfido and a  4- 2-benzyne ligand, whereas 3, 4, and 5 contain  5-sulfido and  4- 2-benzyne ligands. The latter three compounds provide rare examples of  5-sulfido and metal-assisted opening of the thianthrene ligand on polynuclear centers. In compounds 1, 3, and 4 the  4- 2-benzyne ligand is perpendicular to the Ru4 face of the clusters and represents a previously uncharacterized bonding mode for benzyne.

year: 2007-07-01

title: Organomanganese compounds in organic synthesis

authors: Prasad, Narendra Jai

subjects: cyclomanganated chalcones

abstract: This thesis describes the preparation and reactions of some cyclomanganated chalcones, dienones and aryl ketones. Investigation has previously been undertaken into the reaction of cyclomanganated chalcones and dienones with alkynes to give both pyranyl and cycloheptadienyl Mn(CO)₃ complexes. In the current study, the reaction was further investigated with a cyclomanganated dienone derived from a cyclic ketone which gave only the (pyranyl)Mn(CO)₃ complex (2-6) and not the cycloheptadienyl product as consistent with a mechanism previously proposed. Also extended in the current study was previous work involving the methylmanganese pentacarbonyl-mediated transformation of enynes to cyclopropanated bicyclic compounds and cyclopentanes bearing an exocyclic double bond. In the current study, benzylmanganese pentacarbonyl was used instead of methylmanganese pentacarbonyl under similar conditions. In the current study however, the type of product that formed in diethyl ether (3-4) was the one dominant in acetonitrile in the MeMn(CO)₅ study, and that formed in acetonitrile (3-5) was the dominant product type in diethyl ether (3-4). There was no apparent explanation for this reverse reactivity. Ferrocenyl pyrylium salts of the type 5-5 have been prepared using a new route to ferrocenyl pyrylium from cyclomanganated chalcones and ferrocenylethyne. UV-visible and electrochemical properties of the pyrylium salts have been investigated. The ferrocenyl pyrylium salt (5-5) was obtained by the oxidation of [2-ferrocenyl-4,6-diphenyl-ɳ₅]-pyranyltricarbonylmanganese (5-6). The crystal structure of 5-6 was also determined.

text: Organomanganese compounds in organic synthesis This thesis describes the preparation and reactions of some cyclomanganated chalcones, dienones and aryl ketones. Investigation has previously been undertaken into the reaction of cyclomanganated chalcones and dienones with alkynes to give both pyranyl and cycloheptadienyl Mn(CO)₃ complexes. In the current study, the reaction was further investigated with a cyclomanganated dienone derived from a cyclic ketone which gave only the (pyranyl)Mn(CO)₃ complex (2-6) and not the cycloheptadienyl product as consistent with a mechanism previously proposed. Also extended in the current study was previous work involving the methylmanganese pentacarbonyl-mediated transformation of enynes to cyclopropanated bicyclic compounds and cyclopentanes bearing an exocyclic double bond. In the current study, benzylmanganese pentacarbonyl was used instead of methylmanganese pentacarbonyl under similar conditions. In the current study however, the type of product that formed in diethyl ether (3-4) was the one dominant in acetonitrile in the MeMn(CO)₅ study, and that formed in acetonitrile (3-5) was the dominant product type in diethyl ether (3-4). There was no apparent explanation for this reverse reactivity. Ferrocenyl pyrylium salts of the type 5-5 have been prepared using a new route to ferrocenyl pyrylium from cyclomanganated chalcones and ferrocenylethyne. UV-visible and electrochemical properties of the pyrylium salts have been investigated. The ferrocenyl pyrylium salt (5-5) was obtained by the oxidation of [2-ferrocenyl-4,6-diphenyl-ɳ₅]-pyranyltricarbonylmanganese (5-6). The crystal structure of 5-6 was also determined.

year: 2009

title: Materials for enhancing denitrification performance in partially saturated vertical flow wetlands for marae

authors: Liu, Lucian XiaoRan

abstract: There are upwards of 773 marae in New Zealand which are responsible for many key events for the indigenous people, Māori, many of which are located rurally and have inadequate on-site wastewater treatment mostly comprising of a septic tank followed by land application. Māori have many strong beliefs about water and subsequently criteria surround the treatment of wastewater due to the effects it can have on people and environment. One proposed solution that meets criteria are treatment wetlands, more specifically partially saturated vertical flow wetlands which require a smaller footprint and produce better effluent than traditional wetland designs. NIWA (National Institute of Water and Atmospheric Research) has experimented with mesocosm scale versions of this design and has encountered issues with denitrification in the saturated zone.

This research is therefore directed at enhancing denitrification in the saturated zone with materials that are able to supplement organic carbon for denitrification. Several woodchip materials (Eastern Cottonwood, Mahogany, Manuka, Eucalyptus, Crack Willow, Princess Tree and Pine) along with two industry by-product materials (Brewers Spent Grain and Slum gum) and Coir (Coconut derivative) were examined for denitrification capabilities and to serve in producing a leachate for dosing the proposed system to supplement organic carbon for denitrification.

The research is split into three phases; the first examines the ability of materials to release organic carbon into water over 60 days, the second examines the same but over three 10 day cycles, and the third quantifies denitrification performance of the materials at lab scale.

Results showed that producing a suitable leachate is not possible without the use of fresh material for each batch. By-product materials had great capacity for releasing organic carbon into water and denitrification (up to 85.5% nitrate removal) but had limited lifespans as media. While woodchip materials did not exhibit as great carbon release, they achieved comparable denitrification (74.2-74.5% nitrate removal) with long lifespans. Therefore, a woodchip and industry by-product mix could be the solution. Alternatively, there are many woodchip species, some which could have better denitrification capacity or suitable industry by-products with longer useful lifespans.

text: Materials for enhancing denitrification performance in partially saturated vertical flow wetlands for marae There are upwards of 773 marae in New Zealand which are responsible for many key events for the indigenous people, Māori, many of which are located rurally and have inadequate on-site wastewater treatment mostly comprising of a septic tank followed by land application. Māori have many strong beliefs about water and subsequently criteria surround the treatment of wastewater due to the effects it can have on people and environment. One proposed solution that meets criteria are treatment wetlands, more specifically partially saturated vertical flow wetlands which require a smaller footprint and produce better effluent than traditional wetland designs. NIWA (National Institute of Water and Atmospheric Research) has experimented with mesocosm scale versions of this design and has encountered issues with denitrification in the saturated zone.

This research is therefore directed at enhancing denitrification in the saturated zone with materials that are able to supplement organic carbon for denitrification. Several woodchip materials (Eastern Cottonwood, Mahogany, Manuka, Eucalyptus, Crack Willow, Princess Tree and Pine) along with two industry by-product materials (Brewers Spent Grain and Slum gum) and Coir (Coconut derivative) were examined for denitrification capabilities and to serve in producing a leachate for dosing the proposed system to supplement organic carbon for denitrification.

The research is split into three phases; the first examines the ability of materials to release organic carbon into water over 60 days, the second examines the same but over three 10 day cycles, and the third quantifies denitrification performance of the materials at lab scale.

Results showed that producing a suitable leachate is not possible without the use of fresh material for each batch. By-product materials had great capacity for releasing organic carbon into water and denitrification (up to 85.5% nitrate removal) but had limited lifespans as media. While woodchip materials did not exhibit as great carbon release, they achieved comparable denitrification (74.2-74.5% nitrate removal) with long lifespans. Therefore, a woodchip and industry by-product mix could be the solution. Alternatively, there are many woodchip species, some which could have better denitrification capacity or suitable industry by-products with longer useful lifespans.

year: 2023