Table 2. Experimental and First-Principles Chemical Shift Tensor Principal Axis Components (ppm) for the Carbanionic Phenolic and PSB Forms, and their Best-Fit Two-Site Exchange.

site	comp	C-Phen	C-PSB	two-site	expt
Schiff-base N	δ11	584.8	348.4	523.0	526.8
	δ22	396.1	240.7	383.1	368.6
	δ33	–19.4	17.1	–12.3	0.3
	red. χ2	7.99	85.84	0.68
C′	δ11	216.3	215.2	216.1	209.3
	δ22	200.3	195.5	199.3	204.7
	δ33	101.9	99.8	101.5	105.2
	red. χ2	1.47	2.77	1.63