title: N- vs O-Coordination in cyclomanganation of 1,5-diaryl-3-(2-pyridyl)pentane-1,5-diones and 3-(2-pyridyl)chalcones; cyclomanganation at saturated carbon and the crystal structure of [1,5-diphenyl-κC2-3-(2-pyridyl- κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese

authors: Tully, Warren

subjects: Manganese

abstract: Reaction of 1,5-diphenyl-3-(2-pyridyl)pentane-1,5-dione (5a) with 2.5 moles of benzylpentacarbonylmanganese in petroleum spirit under reflux gives a small amount of the symmetric di-aryl-manganated product [1,5-diphenyl-κC2-3-(2-pyridyl)pentane-1,5-dione-κO1κO5]bis-(tetracarbonylmanganese) (7a), but mostly [1,5-diphenyl-κC2-3-(2-pyridyl-κN)pentan-2-yl- κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese (6a) which is manganated at only one aryl carbon [by Mn(CO)4] but also [by Mn(CO)3 with N and O coordination] at the methylene carbon adjacent to the Mn(CO)4-coordinated ketone carbonyl. The latter is a rare example of direct cyclomanganation at a saturated carbon and the only known case adjacent to a carbonyl group; the X-ray crystal structure of 6a is reported. With 3 moles of benzylpentacarbonylmanganese the yield of 6a remains unchanged but some trimanganation product [1,5-diphenyl-κC2′κC2 -3-(2-pyridyl-κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tris-(tetracarbonylmanganese) (8a) is formed, presumably from 7a. Routes to products are proposed and activating factors considered. 1,5-Di-(2-thienyl)-3-(2-pyridyl)pentane-1,5-dione (5b) and its 3-thienyl isomer (5c) similarly give 6a analogues [1,5-di-(2-thienyl-κC3)-3-(2-pyridyl-κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese (6b) and [1,5-di-(3-thienyl-κC2)-3-(2-pyridyl-κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese (6c).
Also reported are the mono-cyclomanganation product [1-(2,6-dimethoxyphenyl)-3-(2-pyridyl-κN)prop-2-en-2-yl-κC2-1-one]tetracarbonylmanganese (16) and dicyclomanganation product [1-(2,5-dimethyl-3-thienyl-κC4)-3-(2-pyridyl-κN)prop-2-en-2-yl- κC2-1-one-κO ]bis-(tetracarbonylmanganese) (17) from reaction of the respective (E)-1-aryl-3-(2-pyridyl)prop-2-en-1-ones (3-(2-pyridyl)chalcones), the first reported examples of enone metallation at the α-carbon via N-coordination by a β-2-pyridyl group.

text: N- vs O-Coordination in cyclomanganation of 1,5-diaryl-3-(2-pyridyl)pentane-1,5-diones and 3-(2-pyridyl)chalcones; cyclomanganation at saturated carbon and the crystal structure of [1,5-diphenyl-κC2-3-(2-pyridyl- κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese Reaction of 1,5-diphenyl-3-(2-pyridyl)pentane-1,5-dione (5a) with 2.5 moles of benzylpentacarbonylmanganese in petroleum spirit under reflux gives a small amount of the symmetric di-aryl-manganated product [1,5-diphenyl-κC2-3-(2-pyridyl)pentane-1,5-dione-κO1κO5]bis-(tetracarbonylmanganese) (7a), but mostly [1,5-diphenyl-κC2-3-(2-pyridyl-κN)pentan-2-yl- κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese (6a) which is manganated at only one aryl carbon [by Mn(CO)4] but also [by Mn(CO)3 with N and O coordination] at the methylene carbon adjacent to the Mn(CO)4-coordinated ketone carbonyl. The latter is a rare example of direct cyclomanganation at a saturated carbon and the only known case adjacent to a carbonyl group; the X-ray crystal structure of 6a is reported. With 3 moles of benzylpentacarbonylmanganese the yield of 6a remains unchanged but some trimanganation product [1,5-diphenyl-κC2′κC2 -3-(2-pyridyl-κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tris-(tetracarbonylmanganese) (8a) is formed, presumably from 7a. Routes to products are proposed and activating factors considered. 1,5-Di-(2-thienyl)-3-(2-pyridyl)pentane-1,5-dione (5b) and its 3-thienyl isomer (5c) similarly give 6a analogues [1,5-di-(2-thienyl-κC3)-3-(2-pyridyl-κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese (6b) and [1,5-di-(3-thienyl-κC2)-3-(2-pyridyl-κN)pentan-2-yl-κC2-1,5-dione-κO1κO5]tetracarbonylmanganesetricarbonylmanganese (6c).
Also reported are the mono-cyclomanganation product [1-(2,6-dimethoxyphenyl)-3-(2-pyridyl-κN)prop-2-en-2-yl-κC2-1-one]tetracarbonylmanganese (16) and dicyclomanganation product [1-(2,5-dimethyl-3-thienyl-κC4)-3-(2-pyridyl-κN)prop-2-en-2-yl- κC2-1-one-κO ]bis-(tetracarbonylmanganese) (17) from reaction of the respective (E)-1-aryl-3-(2-pyridyl)prop-2-en-1-ones (3-(2-pyridyl)chalcones), the first reported examples of enone metallation at the α-carbon via N-coordination by a β-2-pyridyl group.

year: 2005-07-01

title: The economic value of biodiversity in New Zealand: Results from a household survey

authors: Kaval, Pamela

subjects: native biodiversity

abstract: This paper presents the results of a national study examining the economic value of biodiversity in New Zealand. Three valuation techniques were used to collect information from respondents: the contingent valuation method, the well-being method and the choice modelling method. Results revealed that respondents were familiar with the native plants and animals in their areas and valued them highly, therefore having a strong value for native biodiversity.

text: The economic value of biodiversity in New Zealand: Results from a household survey This paper presents the results of a national study examining the economic value of biodiversity in New Zealand. Three valuation techniques were used to collect information from respondents: the contingent valuation method, the well-being method and the choice modelling method. Results revealed that respondents were familiar with the native plants and animals in their areas and valued them highly, therefore having a strong value for native biodiversity.

year: 2009-06

title: The digital divide in New Zealand: The position of Maori and Pacific peoples

authors: Gibson, John

subjects: communication

abstract: Information and communication technology plays an ever-growing role in economic, political and social life and those who are unable to access such technologies are increasingly disadvantaged. Hence, what has come to be known as the 'digital divide' is of considerable significance. Here, indicators of that divide as it affects Maori and

text: The digital divide in New Zealand: The position of Maori and Pacific peoples Information and communication technology plays an ever-growing role in economic, political and social life and those who are unable to access such technologies are increasingly disadvantaged. Hence, what has come to be known as the 'digital divide' is of considerable significance. Here, indicators of that divide as it affects Maori and

year: 2002