When organic molecules are coloured, this is typically due to conjugation. Conjugation refers to the path available to electron movement created through neighbouring pi orbitals with delocalised electrons, such as the alternate double bonds in aromatic rings. Electrons can move through the connected pi orbitals, after first being excited by ambient electromagnetic radiation. The longer the available path/conjugation, the higher the energy of light absorbed by the electrons. Thus, conjugation can cause the colour of the molecule to vary depending on the energy of the light being absorbed. The parent molecule (shown below) is yellow in colour due to the conjugation between the alternate double bonds. Generally speaking, conjugation can only exist in molecules that are planar – i.e. they exist in a flat conformation. In the case of the above structure (1), there is the potential to increase the conjugation by forcing the central section to remain planar by placing a hydrocarbon tether/ring at that site (shown below). Figure 1 - Ball-and-stick models of the geometry-optimized structures of 1, 5-7 showing the change in overall planarity caused by the additional hydrocarbon ring. (1) Considering the need for planarity over the molecule, rank the systems 5, 6 and 7 from the least to the most conjugated. 5 is Blank 1 Question 8[select: , the most conjugated, neither most nor least conjugated, least conjugated] . 6 is Blank 2 Question 8[select: , the most conjugated, neither most nor least conjugated, least conjugated] . 7 is Blank 3 Question 8[select: , the most conjugated, neither most nor least conjugated, least conjugated] . (1) Huck, L. A.; Leigh, W. J. Journal of Chemical Education 2010, 87 (12), 1384-1387.多重下拉选择题
登录即可查看完整答案
我们收录了全球超50000道真实原题与详细解析,现在登录,立即获得答案。
类似问题
When organic molecules are coloured, this is typically due to conjugation. Conjugation refers to the path available to electron movement created through neighbouring pi orbitals with delocalised electrons, such as the alternate double bonds in aromatic rings. Electrons can move through the connected pi orbitals, after first being excited by ambient electromagnetic radiation. The longer the available path/conjugation, the higher the energy of light absorbed by the electrons. Thus, conjugation can cause the colour of the molecule to vary depending on the energy of the light being absorbed. The parent molecule (shown below) is yellow in colour due to the conjugation between the alternate double bonds. Generally speaking, conjugation can only exist in molecules that are planar – i.e. they exist in a flat conformation. In the case of the above structure (1), there is the potential to increase the conjugation by forcing the central section to remain planar by placing a hydrocarbon tether/ring at that site (shown below). Figure 1 - Ball-and-stick models of the geometry-optimized structures of 1, 5-7 showing the change in overall planarity caused by the additional hydrocarbon ring. (1) Considering the need for planarity over the molecule, rank the systems 5, 6 and 7 from the least to the most conjugated. 5 is Blank 1 Question 8[select: , the most conjugated, neither most nor least conjugated, least conjugated] . 6 is Blank 2 Question 8[select: , the most conjugated, neither most nor least conjugated, least conjugated] . 7 is Blank 3 Question 8[select: , the most conjugated, neither most nor least conjugated, least conjugated] . (1) Huck, L. A.; Leigh, W. J. Journal of Chemical Education 2010, 87 (12), 1384-1387.
A project has a required return of 12.6 percent, an initial cash outflow of $42,100, and cash inflows of $16,500 in Year 1, $11,700 in Year 2, and $10,400 in Year 4. What is the net present value?
Question8 The unicorn is the national animal of ScotlandSelect an alternative False True The Atlantic Ocean is the biggest ocean on Earth.Select an alternative False True Spiders have six legs.Select an alternative True False There are five different blood groupsSelect an alternative False True The human skeleton is made up of less than 100 bones.Select an alternative False True ResetMaximum marks: 5 Flag question undefined Select an alternative False True
Question8 The unicorn is the national animal of ScotlandSelect an alternative False True The Atlantic Ocean is the biggest ocean on Earth.Select an alternative False True Spiders have six legs.Select an alternative True False There are five different blood groupsSelect an alternative False True The human skeleton is made up of less than 100 bones.Select an alternative False True ResetMaximum marks: 5 Flag question undefined Select an alternative False True
更多留学生实用工具
希望你的学习变得更简单
加入我们，立即解锁 海量真题 与 独家解析，让复习快人一步！