Nucleophillic Strength?

[ravupadh]

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Hi,

I'm trying to memorize the trends for nucleophillic strength. I know for aprotic solvents nucleophillicity more closely relates to basicity. So for the compound's nucleophillicity do you use the rules that you did for acidity/basicity (i.e. same column acids get stronger as you go down and same family acids get stronger as you go from right to left)? The reason why I'm asking this is because in my TBR book it says: "The big difference in nucleophillicity is that size of the anion is not as important as it is with bascity". So what rules do you then use to determine the bascitiy in this case?

And how do you determine nucleophillicity in protic solvents, since hydrogen bonding can dampen strength? Thanks.

 

[LeonVCU]

To me it became mostly as a matter of instincts... From doing tons of problems. I have this memorized: b) HCl -10, Conjugate acid of ethanol -2, Hydronium -1.7, Nitric acid -1.5, COOH 5, Ammonium ion 9.3, phenol 10, OH 15, proton alpha to carbonyl 20: pKa, methane 60. Those are pKa values. The passages for the most part don't ask for extreme memorization, just seeing trends that you've just mentioned.