CHEM 125a - Lecture 16 - Recognizing Functional Groups

Lecture 16 - Recognizing Functional Groups


This lecture continues the discussion of the HOMO/LUMO view of chemical reactivity by focusing on ways of recognizing whether a particular HOMO should be unusually high in energy (basic), or a particular LUMO should be unusually low (acidic). The approach is illustrated with BH3, which is both acidic and basic and thus dimerizes by forming unusual "Y" bonds. The low LUMOs that make both HF and CH3F acidic are analyzed and compared underlining the distinction between MO nodes that derive from atomic orbitals nodes (AON) and those that are antibonding (ABN). Reaction of HF as an acid with OH- is shown to involve simultaneous bond-making and bond-breaking.


Professor McBride's website resource for CHEM 125 (Fall 2008)

This website may include third-party materials pertaining to relevant topics, provided for the user's convenience. Yale does not control or take responsibility for the content of any off-site pages or linked sites.


Reading assignments, problem sets, PowerPoint presentations, and other resources for this lecture can be accessed from Professor McBride's on-campus course website, which was developed for his Fall 2008 students. Please see Resources section below.

Course Media





Low Bandwidth Video

mov [100MB]

High Bandwidth Video

mov [500MB]