Distribution of C–O bond lengths in the anions for salts 1–3.

Complex	D C–O (Å)	ΔDC–O (Å)
Salt 1	C23–O6: 1.266(4), C23–O5: 1.256(4)	0.01
Salt 2	C23–O6: 1.272(5), C23–O7: 1.253(4)	0.019
Salt 3	C23–O7: 1.311(6), C23–O6: 1.225(6)	0.086
	C46–O17: 1.307(6), C46–O16: 1.226(6)	0.081