Other Types of Caps

Dummy Group

Note

Ranganathan and Gready⁷⁸ does not call this method the “dummy group” method, but in referring to ⁷⁸, Liu et al.⁶⁴ do so (I make no claim that Liu et al.⁶⁴ coined the term either).

In the context of QM/MM method development, Ranganathan and Gready⁷⁸ noted that one usually breaks carbon-carbon bonds between \(sp^3\) hybridized carbons. Letting \(X\) be the carbon which is in the fragment, and \(Y\) be the carbon not in the fragment, the dummy-group approach replaces \(Y\) not with a single hydrogen atom, but with a methyl group. While not explicitly considered in Ranganathan and Gready⁷⁸, the presumed generalization is that \(Y\) is replaced by the monovalent functional group \(YH_{n-1}\) where \(n\) is the valency of \(Y\) in the supersystem.