ORG-12

Swain–Lupton

log(k/k0) = f F + r R. Field and resonance dual parameters.

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Physical organicSwain–Lupton

Governing equation

\log(k/k_0)=fF+rR

where

f: Field weight (—)
F: Field F (—)
r: Resonance weight (—)
R: Resonance R (—)
k_0: Reference rate (1/s)
k: Rate (1/s)

Lecture brief

Historical brief

Hammett (1937) and Taft linear free-energy, E-factor green metrics, Woodward–Fieser UV and Claisen equilibria are how organic chemistry became predictive. The lab is substituent, waste and tautomer. This sheet (ORG-12 — Swain–Lupton) is the form associated with Swain–Lupton. Working symbols: $f$ , $F$ , $r$ , $R$ , $k_0$ $\rightarrow$ $k$ . F is through-bond/field, R is resonance. A dual-parameter upgrade of Hammett for mixed positions.

Purpose

Purpose: compute

k

from

f

F

r

R

k_0

in Organic chemistry via

\log(k/k_0)=fF+rR

log(k/k0) = f F + r R. Field and resonance dual parameters. Use it when a real organic chemistry question must be answered in SI before a code check.

Live realistic example

In symbols

Live case. Given

f = 0.600\,\mathrm{—}

F = 0.400\,\mathrm{—}

r = 0.400\,\mathrm{—}

R = 0.100\,\mathrm{—}

k_0 = 1.000\,\mathrm{1/s}

, the governing relation

\log(k/k_0)=fF+rR

yields

k = 1.9055\,\mathrm{1/s}

. Enter tabulated F, R and reaction weights f, r. Move a slider: the numbers are this situation, not a canned story.

Calculator

Inputs

Field weight f0.6 —Field F F0.4 —Resonance weight r0.4 —Resonance R R0.1 —Reference rate k_01 1/s

Outputs

Rate k1.9055 1/s

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Narration of this film

Enter tabulated F, R and reaction weights f, r.

F is through-bond/field, R is resonance. A dual-parameter upgrade of Hammett for mixed positions.

Reading speed

Watch on YouTube