Elimination of HX from Haloalkanes

One way to synthesize alkenes is to remove hydrogen halide (HX) from a haloalkane (alkyl halide) in an elimination reaction.

Learn how in AUS-e-TUTE's new tutorial Dehydrohalogenation of Haloalkanes

AUS-e-TUTE Members should log-in to play the game and take the test (with immediate feedback and worked solutions).

Classification of Haloalkanes

Question: How do you classify haloalkanes (alkyl halides) as primary, secondary or tertiary?

Answers at https://www.ausetute.com.au/rxclassify.html

Test your knowledge of how to classify haloalkanes with AUS-e-TUTE's games and tests (with instant feedback and worked solutions!). Find out more at https://www.ausetute.com.au/register.html

Alkanol + HX

What happens when you add a concentrated hydrohalic acid, like hydrobromic acid or hydrochloric acid or hydroiodic acid, to an alkanol?
A substitution reaction!
Find out more in AUS-e-TUTE's new tutorial at https://www.ausetute.com.au/alkanolhx.html

AUS-e-TUTE Members should log-in to use the new tutorial, game and test (with worked solutions!).

Saturation

What does it mean when a Chemist refers to a molecule as saturated or unsaturated?
How do you test a compound to see if it is saturated or unsaturated?
The answers to these questions, with examples, are given in AUS-e-TUTE's new tutorial Saturated and Unsaturated Organic Compounds

AUS-e-TUTE Members should log-in to access the game, test and exam (with worked solutions) on this topic.

Homologous Series

What is a homologous series in organic chemistry?
Homologous series refers to a group of compounds that have:

1. the same functional group
2. constant successive differences in composition

The individual molecules making up a homologous series  are referred to as homologues (or homologs).

Find out more about homologous series and homologues at https://www.ausetute.com.au/homologous.html

AUS-e-TUTE Members should log-in to use the new Members Only tutorial, game, test and exam (with worked solutions ofcourse).

Classification of Organic Reactions

Organic reactions are reactions in which the reactants and products are carbon-containing compounds, or organic compounds.
The chemical reactions that organic compounds take part in can be classified as:

• substitution reactions
• addition reactions
• elimination reactions
• oxidation reactions
• reduction reactions
• polymerisation reactions
• rearrangement reactions

AUS-e-TUTE has just added new resources including  a tutorial, game and test with worked solutions to help you identify and classify these types of organic reactions. AUS-e-TUTE Members should log-in to use these new resources.

If you are not an AUS-e-TUTE, a free-to-view tutorial is currently available at https://www.ausetute.com.au/organicrxn.html

Properties of Nitriles

Why are the physical properties, such boiling point and solubility, of an alkanenitrile so similar to that of a primary alkanol with the same number of carbon atoms in the hydrocarbon chain?
Why do alkanenitriles react with so many different reactants?
AUS-e-TUTE has just added new resources to help you understand the physical and chemical properties or alkanenitriles.
AUS-e-TUTE Members should log-in to use the new tutorial, game and test (with worked solutions).
If you are not an AUS-e-TUTE Member you can access a "free-to-view" tutorial at https://www.ausetute.com.au/nitriles.html

Properties of Aldehydes and Ketones

Aldehydes and ketones contain the same functional group, for example, butanal and butanone both contain the same carbonyl functional group (C=O). So how would you tell if a substance was butanal or butanone?
AUS-e-TUTE has just added new resources to help you understand the similarities and differences in the chemical and physical properties of aldehydes and ketones (as represented by alkanals and alkanones). AUS-e-TUTE Members should log-in to use the new tutorial, game, test and exam with worked solutions.
If you are not an AUS-e-TUTE member there is currently a "free-to-view" tutorial on this topic at https://www.ausetute.com.au/ketones.html

Naming Nitriles

How do you name a molecule like H-C≡N?
If you are an inorganic chemist you might call it:

• hydrogen cyanide (hydrogen name)
• hydridonitridocarbon (additive name)
• methylidyneazane (substitutive name)

If you are an organic chemist you might call it:

• hydrogen cyanide (functional class name)
• formonitrile (preferred IUPAC name)
• methanenitrile (substitutive name) 

The CN functional group at the end of a hydrocarbon chain results in a molecule that belongs to a class of organic compounds called nitriles. All nitriles contain a terminal CN group known as the cyano functional group.
AUS-e-TUTE has a new tutorial, game and test to help our members understand and apply IUPAC naming rules to nitriles. Members should log-in to use these new resources.

If you are not a member of AUS-e-TUTE you can access a "free-to-view" tutorial on naming nitriles at https://www.ausetute.com.au/namnitrile.html

Breaking Triglycerides up into Fatty Acids

Triglycerides are found in the fats and oils you eat. They are produced in a condensation reaction between a glycerol and 3 fatty acids. So, is it possible to reverse this reaction? Can we add water to a triglyceride to break it up into glycerol and 3 fatty acids?
Good question!
AUS-e-TUTE has new resources to help you understand the hydrolysis of triglycerides.
Members should log in to access the new tutorial, game, test and exam (with worked solutions).
If you are not an AUS-e-TUTE Member, you can access the "free-to-view" tutorial at
https://www.ausetute.com.au/hydrolysistg.html

Omega Fatty Acids

"Health Food" companies are always trying to sell us something new.
Instead of eating tasty fish they recommend we consume fish oil wrapped in plastic as a pill. Apparently this is because we are suddenly deficient in "omega-3 fatty acids".
So what are omega-3 fatty acids?
Where do they come from?
Do we really need them?

AUS-e-TUTE Members should log-in to access the new omega fatty acid resources (tutorial, game, test, exam).

If you are not an AUS-e-TUTE Member you can access a free-to-view tutorial at
https://www.ausetute.com.au/omegafat.html

Hydroxyacid or Carboxyalkanol?

So, you've learnt how to name organic molecules containing the OH (hydroxy) functional group, and, you can name molecules that have the COOH (carboxyl) functional group, the carbonyl functional group (C=O), and the NH₂ (amine) functional group.
Excellent!
But what happens when there are 2 or more different functional groups on the same molecule?
Can you still name it?
We can help!
AUS-e-TUTE has just added a new tutorial, game, test and exam to help you learn the IUPAC rules and confidently apply them to these sorts of molecules.
AUS-e-TUTE Members should log-in to use the new resources (under Organic Nomenclature).
If you are not an AUS-e-TUTE Member you can view the tutorial for free at
https://www.ausetute.com.au/nam2fung.html

Rosalind Franklin and the Structure of DNA

Three men, James Dewey Watson,  Francis Harry Compton Crick and Maurice Hugh Frederick Wilkins, shared the The Nobel Prize in Physiology or Medicine 1962 "for their discoveries concerning the molecular structure of nucleic acids and its significance for information transfer in living material.", that is, they  modeled DNA as a double helix, each strand of the helix has a backbone of  sugar molecules held together by phosphate groups. The two strands are twisted together and held together by hydrogen bonds. But how did they learn what DNA was made up of?

 This is where Rosalind Elsie Franklin enters the story of DNA. In 1951 she was a Research Associate at Kings College London where she worked on  X-ray diffraction studies with her colleague Maurice Wilkins. Her x-ray diffraction images of DNA led to the discovery of the DNA helix. The image on the left is known as "photograph 51" and was an x-ray diffraction image of DNA obtained by Franklin's Ph.D student Raymond Gosling.

X-ray diffraction is an instrumental technique used to elucidate the structure of crystals of chemical compounds. Incoming x-rays are diffracted by the crystal lattice and they exit the crystal at different angles. An x-ray crystallographer like Franklin can measure the angles and intensities of these diffracted x-rays to produce a 3-dimensional picture of the density of electrons in the crystal lattice. The electron density can then be used to determine the locations of atoms within the crystal lattice.

Without Franklin's knowledge, Maurice Wilkins showed this image to James Watson who used it, along with other evidence, to develop a model of DNA. Science historians still debate whether Franklin would have determined the structure of DNA on her own had her images not been shared with Watson.

Rosalind Franklin made important scientific contributions, not only to the discovery of the structure of DNA and RNA, but also in helping us to understand the structure of viruses, coal and graphite.
Unfortunately, Rosalind Franklin died of ovarian cancer in 1958. Nobel Prizes are not generally awarded posthumously so her contribution to the elucidation of the structure of DNA is not well-known.


Further Reading:
Chemistry of DNA
Intramolecular Forces
Intermolecular Forces

Suggested Study Questions:

1. Explain the terms crystalline and amorphous.
2. Give an example of a crystalline substance and an example of an amorphous substance.
3. Explain why DNA had to be crystallised before useful information could be obtained using x-ray diffraction.
4. What does the abbreviation DNA stand for?
5. What are the 4 principle bases that make up DNA?
6. These principle bases occur in pairs; what are these 2 pairs?
7. What kind of chemical bonds act between the atoms making up each base in a strand of DNA?
8. What kind of chemical forces join one of the bases on one strand of DNA to its corresponding pair on the other strand of DNA?
9. If you wanted to separate the 2 strands of a DNA double helix, what sort of chemical bonds would you need to break?
10. If you wanted to separated each base from the backbone of sugar molecules, what sort of chemical bonds would you need to break?

Short Chain Fatty Acids?

I came across this story in the Sydney Morning Herald this morning, "A make-or-break moment for what may be a new molecule". Sounds exciting doesn't it. A hint of uncertainty, is it or isn't it a new molecule? What will it "make or break"?

It appears that Charles Mackay, a Professor of Microbiology at Monash Biomedicine Discovery Institute has, "demonstrated that dietary fibre and its breakdown fermented products, the short chain fatty acids (SCFAs) influence gut homeostasis, the composition of the gut microbiota, immune tolerance, and inflammatory responses."  I must apologize, I've never been particularly interested in biology, so I actually have no idea what any of that means, but from the story in the newspaper it appears that Professor Mackay thinks we should be eating more "short chain fatty acids" as are present in fermented foods such as vinegars and hence vegetables pickled in vinegars, and this will help regulate our blood pressure and immune system, keeping us healthy. Good news for me, I love pickled onions and gherkins, and have been known to indulge in sauerkraut and kimchi.

But what on earth is a "short chain fatty acid"?

Now, a fatty acid is a long chain carboxylic acid.
A carboxylic acid is a molecule with a carboxylic acid functional group (COOH) at the end of a hydrocarbon chain.
For example, formic acid is the carboxylic acid which is present in an ant's sting. It has only one carbon atom in the chain, its formula is HCOOH (CH₂O₂)
Acetic acid is the carboxylic acid that gives vinegar it's tang. It has 2 carbon atoms in its chain,

CH₃-COOH (C₂H₄O₂)

But fatty acids have lots of carbon atoms in the chain, common fatty acids have 12 or 14 or 16, or 18 carbon atoms in the chain. These fatty acids (long chain carboxylic acids) are found naturally in the oils and fats of plants and animals. If the long hydrocarbon chain is saturated (contains only single bonds between the carbon atoms in the chain) it is called a saturated fatty acid. If there is one, or more, double bonds between carbon atoms in the long chain then it is referred to as an unsaturated fatty acid.

So a "short chain fatty acid" would be what? A short long chain carboxylic acid? Sounds like nonsense doesn't it? Maybe it's a medium length chain carboxylic acid?

According to wikipedia (which may or may not be a reliable source of information),  a "short chain fatty acid" is a fatty acid with 2 to 6 carbon atoms. Included in wikipedia's list of "short chain fatty acids" are the two carboxylic acids we used as examples above, formic acid (which has only 1 carbon atom in its chain and hence does not actually fit within wikipedia's own definition and hence my concern about the reliability of the information it provides), and, acetic acid. So, a "short chain fatty acid" is in fact NOT a short chain "fatty acid", it is simply a short chain carboxylic acid!

Is the "molecule" new, as claimed by the headline? Most unlikely because:

• "short chain fatty acids" is just a poor description of a group of molecules sharing a carboxylic acid functional group, not just 1 molecule
• we've known about these short chain carboxylic acids for a very, very long time

References:
http://www.smh.com.au/national/a-make-or-break-moment-for-what-may-be-a-new-miracle-molecule-20180216-p4z0ky.html
https://research.monash.edu/en/persons/charles-mackay 
https://en.wikipedia.org/wiki/Short-chain_fatty_acid 

Suggested Study Questions:

1.  Draw the 2-dimensional structure formula for each of the following carboxylic acids:
   • formic acid
   • acetic acid
   • propanoic acid
   • butanoic acid
   • pentanoic acid
   • hexanoic acid
2. Draw a condensed structural formula for each of the carboxylic acids in question 1.
3. Draw a skeletal structural formula for each of the carboxylic acids in question 1.
4. Give the molecular formula for each of the carboxylic acids in question 1.
5. Give the empirical formula for each of the carboxylic acids in question 1
6. Are the carboxylic acids in question best described as saturated or unsaturated? Explain your answer.
7. On each 2-dimensional structural formula, identify, circle and name the functional group common to all the molecules.
8. Draw at least 2 structural isomers with the molecular formula C₅H₁₀O₂
9. Circle the functional groups in the molecules you draw in question 8. Name these functional groups.
10. Choose 2 of the structural isomers drawn in question 8. Would you expect these 2 molecules to have very similar, or very different, physical and chemical properties. Explain your answer.

Omega-3 Acids Fight Cancer

Scientists at the University of Guelph have found that omega-3s from fish are better at preventing cancer than omega-3s from plants.

"Omega-3s" refer to omega-3 fatty acids which are a type of long-chain, polyunsaturated carboxylic  acid. Long-chain carboxylic acids are referred to as "fatty acids".
The three omega-3 fatty acids studied were: 

• α-linolenic acid (ALA) which is found in plant seeds and oils

• eicosapentaenoic acid (EPA) which is found in fish, algae and phytoplankton

• docosahexaenoic acid (DHA) which is found in fish, algae and phytoplankton

 The skeletal structural formula for α-linolenic acid is shown below:

 The IUPAC name of α-linolenic acid is (9Z,12Z,15Z)-9,12,15-octadecatrienoic acid. 
The carbon atom of the carboxyl functional group (COOH) is labelled as 1, the next carbon atom in the chain is 2, then 3, etc, up until we reach the last carbon in the chain, carbon 18. The parent hydrocarbon for this molecule is therefore octadecane, with a suffix added for the carboxyl functional group, so we have octadecanoic acid. 
Along the way we find 3 (tri) double bonds (en) at carbons numbered 9, 12 and 15, so we modify the name of the carboxylic acid in one of two ways:

• 9,12,15-octadecatrienoic acid

• octadeca-9,12,15-trienoic acid

The "Z" indicates the 3-dimensional geometry,  in this case the "Z" geometry equates to a "cis" geometry.
So why would  (9Z,12Z,15Z)-9,12,15-octadecatrienoic acid be called an omega-3 acid?
There is an alternative naming "system" (not IUPAC)  in which the first carbon atom is not labelled 1, but instead it is called "alpha" (α), and, the carbon atom at the end of the long hydrocarbon chain is called "omega" (ω). Then, the last carbon atom in the chain (omega) is labelled 1, and you start counting back towards the carboxyl functional group. If you do this, you will find that carbon 3 has a double on it, hence, (9Z,12Z,15Z)-9,12,15-octadecatrienoic acid is called an omega-3 fatty acid. The 3 indicates the position of the first double bond from the omega carbon atom.

The skeletal structural formula of eicosapentaenoic acid is shown below:

The IUPAC name for this molecule is (5Z,8Z,11Z,14Z,17Z)-5,8,11,14,17-Icosapentaenoic acid. 
There are 20 carbon atoms in the chain so the parent hydrocarbon chain is icosane, which is modified with a suffix because there is a carboxyl functional group, icosanoic acid.
There are 5 (pent) double bonds (en) located on carbons 5, 8, 11, 14 and 17, so the name of this molecule is either:

• 5,8,11,14,17-icosapentenoic acid

• icosa-5,8,11,14,17-pentenoic acid

Once again, the Zs in the name refer to the geometry (same as a "cis" geometry in this case).
Notice that, in the alternative naming "system" in which the last carbon atom in the chain is labelled "omega" and then you count backwards from this, we see that the first double bond encountered is on carbon 3, so this molecule is also referred to as an omega-3 fatty acid.

The skeletal structural formula below is that of docosahexaenoic acid:

This molecule has the IUPAC name (4Z,7Z,10Z,13Z,16Z,19Z)-4,7,10,13,16,19-Docosahexaenoic acid. 22 carbon atoms in the chain (docosa), 6 (hexa) double bonds on carbons 4, 7, 10, 13, 16, 19 and a carboxyl functional group: 4,7,10,13,16,19-docosahexaenoic acid or docosa-4,7,10,13,16,19-hexenoic acid. Zs indicate geometry (same as "cis" in this case).
Using the alternative numbering system, the first double bond occurs of the third carbon atom from the omega carbon atom (last carbon in the chain) so it is also classified as an omega-3 fatty acid.

While all three of these omega-3 fatty acids were shown to be effective in reducing the size of tumours in mice, however, higher doses of the plant-based α-linolenic acid was required to deliver the same impact as the omega-3 fatty acids found in fish (icosapentaenoic acid and docosahexaenoic acid)



Reference:

Jiajie Liu, Salma A. Abdelmagid, Christopher J. Pinelli, Jennifer M. Monk, Danyelle M. Liddle, Lyn M. Hillyer, Barbora Hucik, Anjali Silva, Sanjeena Subedi, Geoffrey A. Wood, Lindsay E. Robinson, William J. Muller, David W.L. Ma. Marine fish oil is more potent than plant based n-3 polyunsaturated fatty acids in the prevention of mammary tumours. The Journal of Nutritional Biochemistry, 2017; DOI: 10.1016/j.jnutbio.2017.12.011

Further Reading:
Introduction to naming organic molecules: http://www.ausetute.com.au/namctut1.html
Introduction to functional groups: http://www.ausetute.com.au/fungroup.html
Fatty acids: http://www.ausetute.com.au/fattyacid.html 
Structure and properties of carboxylic acids: http://www.ausetute.com.au/carboxyl.html
Molecular formula: http://www.ausetute.com.au/molecularformula.html
2-Dimensional structural formula: http://www.ausetute.com.au/structural2D.html
Condensed structural formula: http://www.ausetute.com.au/condensedsf.html
Skeletal structural formula: http://www.ausetute.com.au/skeletal.html
Cis-trans isomers: http://www.ausetute.com.au/cistranso.html 


Suggested Study Questions:

1. What functional group is common to all fatty acids? 
2. Define the following terms as they are used in chemistry:
   • saturated
   • unsaturated
   • monounsaturated
   • polyunsaturated
3.  Give the molecular formula for each of the three omega-3 acids in the article
4. The structural formula given in the article are referred to as "skeletal". What does this mean in chemistry?
5. Draw a 2-dimensional (full display) structural formula for each of the omega-3 acids in the article.
6. On the structural formula of each of the three omega-3 acids circle the:
   
   • carboxyl functional group in red
   • double bonds in blue
7. What features are common to three omega-3 acids in the article?
8.  In what ways do the the three omega-3 acids in the article differ?
9. You have probable heard about omega-6 acids. How do you think an omega-6 acid will be similar to an omega-3 acid?
10. How will an omega-6 acid be different from an omega-3 acid?
11. What is meant by a cis isomer and a trans isomer?
12. All the omega-3 fatty acids in the article are the cis isomers. Build a model, and draw, a trans isomer of one of the fatty acids.

Triclosan

Triclosan is an organic compound used as an antibacterial and antifungal agent in some products. The structure of triclosan is given below

Triclosan has the systematic IUPAC name of 5-chloro-2-(2,4-dichlorophenoxy)phenol.
Since its development in the 1960s, it has been used as a hospital scrub. Its use spread beyond our hospitals and into our homes where it can be found as an additive in toothpaste, soaps and detergents.
In 2007, University of Michigan School of Public Health undertook a study which found that consumer-grade antibacterial soaps containing Triclosan are just as effective as plain soap for removing bacteria from your hands.
University of Cambridge researchers may have found a new use for Triclosan; as an anti-malarial agent.
Malaria kills more than 500,000 people every year. Unfortunately, malaria parasites are becoming more resistant to the drugs we have been using to treat malaria.. It appears that Triclosan inhibits an enzyme in the malaria parasite and works even in drug-resistant parasites! It is hoped a new anti-malarial drug based on Triclosan can be developed in the future.

Reference:
Elizabeth Bilsland, Liisa van Vliet, Kevin Williams, Jack Feltham, Marta P. Carrasco, Wesley L. Fotoran, Eliana F. G. Cubillos, Gerhard Wunderlich, Morten Grøtli, Florian Hollfelder, Victoria Jackson, Ross D. King, Stephen G. Oliver. Plasmodium dihydrofolate reductase is a second enzyme target for the antimalarial action of triclosan. Scientific Reports, 2018; 8 (1) DOI: 10.1038/s41598-018-19549-x

Further Reading:
IUPAC Nomenclature (organic): http://www.ausetute.com.au/namctut1.html
Introduction to functional groups: http://www.ausetute.com.au/fungroup.html
Benzene: http://www.ausetute.com.au/benzene.html
Molecular Formula: http://www.ausetute.com.au/molecularformula.html
2-dimensional structural formula: http://www.ausetute.com.au/structural2D.html
Condensed structural formula: http://www.ausetute.com.au/condensedsf.html
Skeletal structural formula: http://www.ausetute.com.au/skeletal.html 
Pure substances and mixtures: http://www.ausetute.com.au/puresubs.html
Solutions concepts: http://www.ausetute.com.au/solutions.html
Percentage composition: http://www.ausetute.com.au/percentc.html
Mass-mole calculations:  http://www.ausetute.com.au/massmole.html
Concentration (molarity): http://www.ausetute.com.au/concsols.html
Parts per million (ppm): http://www.ausetute.com.au/partspm.html
weight/weight (mass/mass) concentration: http://www.ausetute.com.au/weightpc.html

Suggested Study Questions:

1.  Use the skeletal structural formula for Triclosan to draw a 2-dimensional structural formula.
2. On your structural formula, identify each halogen.
3. On your structural formula, identify a hydroxyl functional group
4.  On your structural formula, identify an ether link
5. On your structural formula, identify a benzene ring
6. Give the molecular formula for Triclosan
7.  An antibacterial handwash contains 0.5% by mass Triclosan. For 250 g of this handwash, calculate:
   • mass in grams of Triclosan present
   • moles of Triclosan present
8. Calculate the concentration of Triclosan in the same 250 g of handwash in units of:
   • mol L^-1
   • g/100g
   • parts per million (ppm)
9. Is toothpaste a pure substance or a mixture? Explain your answer.
10. Is Triclosan a pure substance or a mixture? Explain your answer.

 

Bee Killing Chemicals?

This morning I read a story in the Sydney Morning Herald, "Bunnings to pull pesticide allegedly linked to bee deaths".  According to the story, cans of Yates "Confidor" which have been stocked by the homewares and hardware giant Bunnings, contains neonicotinoid, a class of compounds used as an insecticide that some studies have suggested affects bee's navigation and immune systems and ultimately leads to the death of the bee colony. Indeed, a story on this appeared in New Scientist in July 2017 in which Dave Goulson at the University of Sussex, UK, is quoted as saying, "Although the field trial results varied between countries, the overall evidence points to harmful effects for bees. I think you’d have to be pretty unreasonable at this point not to accept that, at least some of the time, these chemicals harm bees when used in normal farming practice.”  The same story quoted Richard Schmuck of Bayer, one of the makers of this class of insecticides, as saying, "We remain confident that neonicotinoids are safe when used and applied responsibly."

As the name neonicotinoids suggests, these are "new" molecules based on the molecular structure of nicotine shown below:

 Nicotine has been used as a pesticide for over 200 years. It is found lots of plants.  Up to 3% of the mass of the tobacco plant is nicotine, and trace amounts of nicotine are found in vegetables like eggplants, potatoes and tomatoes. When used as a pesticide,  it degrades rapidly in the environment and is not very selective so it is not really a good pesticide. For instance, a dose of 1mg per kg of body mas can kill a human.
Development of neonicotinoids began in the 1980s by Shell and1990s by Bayer. Neonicotinoids are generally less toxic to birds and mammals than they are to insects, and, some of the breakdown products are also toxic to insects, this is why they can be used as insecticides.
Consider the structural formula of imidacloprid, an example of a neonicotinoid and one of the most widely used insecticides:

 Imidacloprid was patented by Bayer in 1985 as the first commercial neonicotinoid. Traditionally insecticides were coated onto plants, "crop dusting", but neonicotinoids like  imidacloprid are water soluble and break down slowly in the environment so they are absorbed by plants. Bees are exposed to these compounds in the plant's pollen.
The early 2000s saw the introduction of two other neonicotinoid compounds;  clothianidin and thiamethoxam. 

clothianidin	thiamethoxam

Clothianidin can be used as a spray, dust or injectable liquid, depending on which plants it is being to protect.
In 2013 the European Union restricted the use of imidacloprid, clothianidin and thiamethoxam on crops that attract bees.

References:
http://www.smh.com.au/national/bunnings-to-pull-pesticide-allegedly-linked-to-bee-deaths-20180113-h0htzq.html
https://www.newscientist.com/article/2139197-strongest-evidence-yet-that-neonicotinoids-are-killing-bees/

Suggested Further Reading
IUPAC Nomenclature:  http://www.ausetute.com.au/namctut1.html
Introduction to Functional Groups: http://www.ausetute.com.au/fungroup.html
Molecular Formula: http://www.ausetute.com.au/molecularformula.html
2-Dimensional Structural Formula: http://www.ausetute.com.au/structural2D.html
Skeletal Structural Formula: http://www.ausetute.com.au/skeletal.html
 Introduction to Polarity of Molecules: http://www.ausetute.com.au/molpolar.html
Intermolecular Forces and Solubility:  http://www.ausetute.com.au/intermof.html
Aqueous Solutions (water as a solvent): http://www.ausetute.com.au/aqueous.html

Suggested Study Questions:

1. Use molecular model kits to build models of  the following molecules:
   • nicotine
   • imidacloprid
   • clothianidin
   • thiamethoxam
2. Draw a 2-dimensional (full display) structural formula for each of the following molecules:
   • nicotine
   • imidacloprid
   • clothianidin
   • thiamethoxam
3. Write the molecular formula for each of the following molecules:
   • nicotine
   • imidacloprid
   • clothianidin
   • thiamethoxam
4. Consider the nicotine molecule. Do you expect it to be soluble in water? Explain your answer.
5. Consider a molecule of imidacloprid. Do you expect it to be soluble in water? Explain your answer.
6. What property of clothianidin enables it to be used as a spray? Explain this property in chemical terms.
7.  What alteration to the structure of a nicotine molecule could you make so that it would become more soluble in water?
8. Carefully compare the structure of clothianidin and thiamethoxam (the molecular models you built could be useful here). In what ways are the molecules:
   • similar
   • different
9. Considering only the structure of nicotine and the neonicotinoids in this article, explain why nicotine might be more toxic to humans than the neonicotinoids.
10. Compare the quotes from Dave Goulson and Richard Schmuck in the article. In what ways are the two quotes:
    • similar
    • different
11. Imagine you have been asked by your government to decide whether or not to ban the use of neonicotinoids in agriculture. What would you advise? Explain why.

Betaines

Betaines are found in plants, animals and microorganisms. Rich sources of betaines in the human diet are seafood, spinach and wheat germ or bran. Research is beginning to indicate that betaines are important nutrients for the prevention of chronic disease. Researchers are also interested in incorporating betaines into polymer brushes used for antifouling and lubrication.

Betaines are compounds with a positively charged functional group linked to a negatively charged functional group with an alkyl chain in between. The alkyl chain is often referred to as an alkyl chain spacer.  The general structure of an N-alkyl betaine is shown below:

The first betaine discovered was found in sugar beets in the nineteenth century. This betaine is (trimethylammonio)acetate, also known as trimethylglycine, and its skeletal structure is shown below:

Another example of a betaine is 2-(trimethylammonio)octadecanoate (also known as hexadecylbetaine) with the skeletal structure shown below:

2-(Trimethylammonio)tetradecanoate, or dodecylbutaine or laurylbutaine, is also a butaine and its skeletal structure is shown below:

Betaines are strongly attracted to water molecules because of these two charged functional groups.
The solubility of betaines in water is dependent on the length of the carbon chain, as well as on temperature and pH. 
In acidic solution, betaines acquire a net positive charge and act like a cationic surfactant. In anionic solutions, betaines acquire a net negative charge and act like an anionic surfactant.

Betaines can also be used in polymer brushes which are polymers bound to a surface. Polymer brushes can be used for antifouling and lubrication because the hydration of the ionic groups reduces the ability of other materials to adhere to the surface. 

Researchers at Kyushu University recently investigated a series of alkly chain spacers of different lengths bound to a silicon surface. They found that the polymer brushes swelled in humid air and water. It is believed that this is due to electrostatic repulsion between charged groups, and not dependent on the length of the alkyl chain.
In deionised water, net positive cations and net negative anions are repelled because of the  electrostatic force which causes the chain dimension to expand, whereas they shrink under high ionic strength by a charge screening effect of the bound ions.

Reference:
https://www.sciencedaily.com/releases/2017/08/170821094302.htm

Further Reading
Introduction to Functional Groups
2-Dimensional Structural Formula
Condensed Structural Formula
Molecular Formula
Amino Acids
Surfactants ( as found in synthetic detergents)
Intermolecular Forces and Solubility

Suggested Study Questions

1. Locate and identify each functional group on the skeletal structural formula of
• general formula N-alkyl betaine 
• (trimethylammonio)acetate
• 2-(trimethylammonio)octadecanoate
• 2-(trimethylammonio)tetradecanoate
2. Draw a 2-dimensional structural formula for each of the following molecules:
• (trimethylammonio)acetate
• 2-(trimethylammonio)octadecanoate
• 2-(trimethylammonio)tetradecanoate
3. Write the condensed structural formula for each of the following molecules:
• (trimethylammonio)acetate
• 2-(trimethylammonio)octadecanoate
• 2-(trimethylammonio)tetradecanoate
4. Write the molecular formula for each of the following molecules:
• (trimethylammonio)acetate
• 2-(trimethylammonio)octadecanoate
• 2-(trimethylammonio)tetradecanoate
5. Compare the structure of betaines to that of 2-amino acids. Can N-alkyl betaines be classified as alpha amino acids (2-amino acids) ? Justify your answer.
6. Write chemical equations to describe what happens to an N-alkyl betaine in:
• acidic aqueous solution
• basic aqueous solution
7. Compare the structure of N-alkyl betaines to the surfactants found in synthetic detergents. In what ways are surfactant molecules 
• similar to N-alkyl betaines
• different from N-alkyl betaines
8. Explain how N-alkyl betaines act like 
• a cationic surfactant in acidic aqueous solution
• an anionic surfactant in basic aqueous solution
9. Consider the structure of (trimethylammonio)acetate and 2-(trimethylammonio)octadecanoate. Which molecule do you expect to be more soluble in water? Justify your answer.
10. Consider the structure of (trimethylammonio)acetate and 2-(trimethylammonio)octadecanoate. Which molecule do you expect to be more soluble in paraffin oil? Justify your answer.