Metal Chelate Complexes

So here we're gonna talk about the different complexes that are metal and a licking conform once they combined. First we're gonna say that a ligand can be thought of as a lewis base because it bonds to a central metal cat ion in a complex ion by using its lone pair. When you talked about general lewis acid based theories in general chemistry, remember the lewis base was the electron pair donor and the lewis acid was the electron pair. Except er a common example that we would see is for example a metal ion reacting with a compound or element with lone pairs. Here the water would serve as the lewis base or the ligand and attach itself to the lewis acid which is the calcium ion. In this example together you would add them and when you add them to create a product we call that product and add duct because you added them together. Now typically these lewis acids or metal ions, they form six connections with Liggins. Now we're gonna say here Liggins can be characterized by the number of elements in the molecule that can donate a lone pair. So there's different number of ligand atoms within any given compound that can donate a lone pair. We're gonna say that they are referred to as key leading compounds or agents because they use their lone pairs to grab onto metal cat ions. And in fact kayla just refers to as greek for crab claw because they kind of form a vise grip around the metal ion itself. Now first we can talk about Liggins that have only one leg in atom within them to donate a lone pair, we're gonna say Liggins that possess only one element able to donate a lone pair referred to as mono dented Liggins. So mono dent, it just means one tooth. Common examples here we have our water, so x minus here. Just represents a typical halogen, like your chloride ion or your fluoride ion, your bromide ion. Next we have our cyanide ion. Now your cyanide ion, technically there's a lone pair on the carbon and on the nitrogen, but it is the carbon itself that acts as the ligand adam. It is the one using its lone pair to connect to a metal ion and it is the one with the negative charge that gives the whole compound a negative charge. Overall, Next we have our hydroxide ion where the oxygen serves at donating a lone pair to connect to a metal ion. We have ammonia here. Next we have our thio sign eight ion. We're gonna stay here, technically it can be either sulfur or nitrogen that donates a lone pair to form a connection with a metal ion, but it's only one or the other, Not both at the same time, that's why it's still characterized as a mono dented Ligon. Then finally, here we have our nitrite ion and in this example it's the oxygen making a single bond that can donate a lone pair to make that connection. And here with our nitrite ion, it has resonance involved. So we could also draw it this way and in this case it would be this oxygen here that's making the single bond now that can form a connection with the metal ion. So just remember we have our ligand, which serves as a lewis base, where donates a lone pair to a lewis acid, which in this case is a metal ion. Now click onto the next video and see as we go and deeper into the different types of Liggins, where we can donate more than one just looking at them.

now we take a look at Liggins that possess more than one atom that can donate a lone pair. Now here we're gonna say, Liggins that possess two elements able to donate a lone pair referred to as by identity Liggins now, bye bye Dent it we mean to tooth. So it has two atoms within the structure that can each donate a lone pair to a metal ion. Now here we're going to have the two most common examples of by dental Liggins as our oxalate ion. And then here this one goes by two different names. We can call it um ethylene dia mean now by ethylene ethylene just refers to two CH 2 groups connected to one another. A mean just refers to the fact that each one is connected to a nitrogen. Now nitrogen in Group five ace which traditionally traditionally wants to make three bonds. Each nitrogen right now is making a bond to one carbon. They both still need two more bonds to get to that sweet spot of three elected three bonds to get to three bonds, they each have to connect to two hydrogen. So that's why here in this example our means are NH two. Now we're gonna say that by identity and Polident, It Liggins usually form more stable complexes with metal ions. That's because when by Dent it Liggins and Polident. It Liggins connect with the metal ion, they form cyclic structures and we're going to say that this increase in stability is called our key late effect. Now, for example here if we had a metal ion so commonly shown as cadmium here, we could have cadmium forming a connection with ethylene dia. Me now here we have this nitrogen using a lone pair to connect to the cadmium And it's still connected to its two hydrogen. And then that's connected to a CH two which is connected to another CH two. And then the other nitrogen forms a connection. Again, the nitrogen czar using their lone pairs to connect to the academy. Um And typically we're gonna say that metal ions wanna form six connections um with Liggins. So we can have three of these ethylene dia means forming cyclic structures around this cadmium ion. So here we have another nitrogen forming a connection and then finally this last one here. Okay, so here we have one of the Ethylene Diamond Liggins makes a cyclic structure. Then we have the second one here makes a cyclic structure. And then finally this last one here which makes another cyclic structure. So again by dental Liggins and Polident Liggins through the key leading effect or kill a defect for more stable complex ion structures like this because they can make cyclic structures as a result, mono dental Liggins can't do this because there's only one atom involved in donating a lone pair so they can make these cyclic structures. Now also remember when it comes to the metal ions, they typically want to form six bonds when connecting to Liggins. Okay, that helps to make a stable structure for them. Now that we've seen this continue onward to the last video, where we take a look at polly dented Liggins.

So here we're gonna say that Liggins that possess more than two elements that are able to donate a lone pair referred to as our Polident. It Liggins. So here we have the most common of the Polident. It Liggins uh remember Polident? It in this case means many tooth. So here we have first our tri phosphate ion in this one. Although there are five negative charges. It is these three oxygen's here that are able to form the league in connection with our metal ion. Next we have diethylene trying I mean so di ethylene refers to our two ch two groups and then try a mean refers to our three main groups. Remember nitrogen wants to make three bonds ideally. So the ones on the ends are making one bond apiece, two carbons. So to complete their three bonds needed they each form two more bonds to hydrogen. The nitrogen in the center though was making two bonds to carbon. So it only needs one more. So that's why it's. NH out of the Polident Liggins, E. D. T. A. Or ethylene. Di Amin. Tetra acetate ion is the most common one that we're going to refer to. This one has numerous forms and it's all based around the fact of the oxygen's either having hydrogen or not. When they don't possess a hydrogen they'll be negatively charged and when they do they'll be neutral. It's also based on the nitrogen possessing hydrogen or not. Okay so there are numerous forms of E. D. T. A. That will be talking about. This is just one of the forms that we're seeing here. And then we have these lesser known ones here. D C T A N T A. And E G T A. For the most part, we're going to say that the ratio of Ligon two metal is 1-1, The only one that is not a 1-1 ratio with the Ligand and the metal is NTANT actually does a 2-1 ratio. So that means that we'd have to Liggins for every one medal and the effect that this has is in terms of storage geometry. So you would say that you have to N A N T A for every one medal for example, we could talk about calcium ion for all the other ones. We have a ratio of 1 to 1. So for E. D. T. A, we could say that we have one E D T. A Reacting with one metal ion. So again, remember normally the leg into metal ratio is 1-1. The only exception is NTANTA has a 2-1 ratio instead. So just remember legends are just really lewis bases. They use their lone pairs to form a connection with a lewis acid which is in this in these examples. Typically a metal ion. Keep this in mind as we delve deeper and deeper and the different types of complexes that can form the different types of filtration as well as calculations dealing with uh concentration of ions.