The Chemical Structure of the Anti-Fungal Iodopropynyl Butylcarbamate

Chemistry, Health
Ever purchased wipes or some other product that was labeled hypoallergenic? Why did the label say that? Hypoallergenic is defined as: relatively unlikely to cause an allergic reaction. So all the ingredients in such a product must have a well-established safety record. Even if a few individuals experience difficulty, it would be mild, perhaps superficial. There is a compound that, despite being hypoallergenic, fights mold successfully. Its name? Iodopropynyl butylcarbamate. The achieved objective requires only a very slight amount of IPBC. Effective at minimal concentrations and water-soluble, IPBC is a cost-effective anti-fungal preservative. A Closer Look at IPBC Notice the chemical structure of iodopropynyl butylcarbamate in the illustration. The portion of the molecule encircled by green is the carbamate portion of the molecule. It is a derivative of carbamic acid…
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Odor Chemistry: Lady Beetle Vs. Marmorated Stink Bug

Chemistry, Nature
It was the ol' one-two. First we were attacked by Asian Lady Bird Beetles, Harmonia axyridis, then the brown marmorated stink bug, Halyomorpha halys. The Lady Bird Beetles were detected first in Louisiana in 1988. Close on its heels, the Stink bugs were detected in Pennsylvania in 1996. Both exude horrible odors when provoked or crushed, though the constituent chemicals are entirely different. Stink Bug Chemistry The stench of the Stink Bug is actually rather simple, as far as stenches go. Two organic compounds, each a "first cousin" of the other, are the culprits: trans-2-octenal and trans-2-decenal (see image). These two compounds are classified as both aldehydes (-CHO) and alkenes (-C=C-). Let's first examine how they are named. Notice both compounds have a straight chain or backbone of carbon atoms…
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Woodward cis-Hydroxylation Reaction

Chemistry, Medicine
Silver acetate, in combination with iodine, forms the initial reactant package for the Woodward reaction. This reaction, carried to completion, selectively converts an alkene into a cis-diol. The prefix cis- refers to the addition of two atoms (or groups of atoms) to the same side of a molecular double bond. Trans-, when used, refers to addition across the double bond – of one atom or group to one side, one to the other side. The Mechanism The mechanism is illustrated in the image (below) up to the point of hydrolysis. The product of that hydrolysis is pictured in the introductory image. We see, first, the iodine splits, the I atom adding to the double bond. In the next part of the reaction, the silver atom attaches to the iodine, and…
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How Does Bleach Bleach? What Removes the Color?

Chemistry
When doing the laundry, we ask, what temperature should the water be, how much detergent should I use, will I need fabric softener, will I need bleach? If I use bleach, should I use chlorine bleach or should I use oxygen bleach? Kinds of Bleach There are two kinds of bleach, based on needed strength and fabric sensitivity. Chlorine bleach, historically the older and stronger variety, is based on sodium or calcium hypochlorite, NaOCl or CaOCl. One name brand of laundry bleach is Clorox®. It contains 5.25% NaOCl. How does chlorine bleach remove color? In order to understand that, we need first to ask, what is the chemistry behind the colors used in fabrics? Color in Fabrics When we think of colors applied to fabrics, the chemist usually thinks of…
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Tetrahydrofuran or Diethyl Ether – Which to Use?

Chemistry
Tetrahydrofuran (C4H8O) is a heterocyclic hydrocarbon. One of the carbon atoms of a cyclopentane ring (along with its two hydrogen atoms) is replaced by an atom of oxygen. THF is an ether. It's frequently used for its solvent properties. In certain organometallic reactions, tetrahydrofuran replaces all or part of the standard solvent diethyl ether, (C2H5-O-C2H5), written in chemists' shorthand Et-O-Et. Tetrahydrofuran Vs. Diethyl Ether Although THF is essentially diethyl ether gone cyclic, its physical properties differ somewhat. A prime example of that relates to hydrogen bonding. Although both molecules possess an electron-rich oxygen atom, in THF, the oxygen is openly exposed. The ring can twist, but that's about it. The hydrocarbon portions of ethyl ether¹ have much greater freedom of motion. They can sweep around, making hydrogen bonding easier to…
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Organic Ozonides – How They Form, How They React

Chemistry
As you might guess, organic ozonides are derived from ozone. So let's first consider the nature of ozone. The ozone molecule is bent and unstable. It is thus polarized and quick to react with unsaturated molecules, notably alkenes. The image illustrates the result. What, however, is the mechanism producing the result in a typical case?¹ Initially, all three oxygen molecules add to the alkene on the same side of what was previously a double bond. This structure, however, is a transient intermediate, which rearranges to form the ozonide structure. Ozonides are relatively stable. However, they can be readily split to yield a pair of carbonyl compounds. Organic Ozonides in Synthesis Some ozonides are explosive, so they are seldom isolated. However, ozonides can be made to undergo a number of useful…
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Don’t Monkey Around – What is a Banana Bond?

Chemistry, Education
A banana bond is not a typical chemical bond by any stretch of the imagination. It is a 3-center, 2-electron bond. The shape of this kind of bond resembles a banana, hence its name. Perhaps the simplest example of a banana bond is demonstrated between boron and hydrogen in the diborane molecule, B2H6. Elemental Atomic Orbitals We begin with a discussion of the much simpler, more typical 2-center, 2-electron single bond. When atoms form molecules, the atomic orbitals involved transform into molecular orbitals. Let's consider a very simple example. Say we want to form one C-H bond of the molecule methane (CH4). Now hydrogen atoms only have one electron. The single electron lies in the 1s2 orbital. That type of orbital possesses spherical symmetry. Unlike hydrogen, carbon has 12 electrons…
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The Curiously Stable Dodecaborate Dianion

Chemistry
There is a lot of talk concerning the chemistry of carbon. And this is totally appropriate. The chemistry of carbon is the chemistry of life. But little is known about boron, which is right next door to carbon on the periodic table of the elements. Yet, boron is a most interesting element. For one thing, boron, like carbon, is capable of bonding to itself. Boron Bonds to Itself There are many compounds in which the element does just that, it bonds to itself. Consider a few of its combinations with hydrogen (see the image). As you advance to larger boron-hydrogen structures, however, it becomes clear the molecular bonding for boron differs considerably from the hydrocarbons. Dodecaborane Dodecaborane somewhat resembles dodecahedrane (C20H20) in outward appearance, even though in terms of bonding,…
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Ozone – The Other Oxygen: A Brief Discussion

Chemistry, Physics
Ozone (O3), a triatomic form of the ordinarily diatomic oxygen (O2), is a curious species. We will discuss some of ozone's curious physical properties. We will not include information related to health or the environment. Molecular Bonding Just as it takes two points to determine a straight line, diatomic oxygen is also linear. It's bond length is 1.208 Å (equal to 120.8 pm). Ozone is not linear; it is bent at an angle of 116.8o, which is greater than the measure of the angle for a water molecule, 104.5o. Comparing Boiling Points The third oxygen atom plus the relatively large angle suggests ozone should boil at a higher temperature than oxygen. In fact, this is the case. This is because the bent ozone molecules, as seen in the illustration, produces…
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Chemistry: What’s a Chromophore?

Chemistry
One online definition of chromophore is "an atom or group whose presence is responsible for the color of a compound." Although one may think of a chromophore that includes a metal atom such as copper, nickel, or cobalt, in organic chemistry a chromophore is more likely to consist of a collection of carbon-carbon multiple bonds, perhaps with modifying features. It is the organic variety we discuss in this article. Multiple Bonds Most organic compounds incorporate one or more of three carbon-to-carbon bond varieties: single bonds, double bonds, triple bonds. When drawing a basic organic compound, these are usually represented by: C–C, C=C, and C≡C, respectively. Although such notations are quite useful, they afford little information concerning bond nature and behavior. Bond Hybridization The best working hypothesis for bonding between atoms…
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