Table 2.

Experimental (DNP and non-DNP) and calculated ¹⁷O NMR parameters for model oxygen environments

Molecule	CQ (MHz)	η	δiso (ppm)	Ω (ppm)	κ
Water (DNP)	6.8 (2)	0.95 (5)	0 (150)	n.d.	n.d.
Water (exp.)i	6.43	0.935	n.d.	n.d.	n.d.
Water (exp.)ii	6.66	0.935	0	n.d.	n.d.
Water (GIPAW)*	−6.833	0.90	−68.24	35.59	−0.40
Urea (DNP)	7.5 (3)	0.5 (2)	150 (150)	n.d.	n.d.
Urea (exp.)iii	7.24	0.92	108	280	−0.857
Urea (GIPAW)	7.576	0.96	172.37	262.98	−0.82
Phenol (DNP)	8.3 (3)	0.95 (5)	100 (150)	n.d.	n.d.
Phenol (exp.) iv	8.3 (1)	0.95 (5)	80 (5)	n.d.	n.d.
Phenol (GIPAW)*	−8.686	0.84	81.61	71.12	0.53

ⁱ- Ba et al.¹³⁶;

ⁱⁱ- Spiess et al.¹³⁵;

ⁱⁱⁱ- Dong et al.¹⁰⁶;

^iv- ¹⁷O MAS NMR data acquired at 17.4 T (see Figure S4);

^*-Where multiple crystallographic oxygen sites existed the averages of these are presented within the table (please refer to supporting information Tables S1 to S3). Experimental uncertainties are given in parenthesis. The Herzfeld-Berger¹⁴¹ convention is used to describe the chemical shift anisotropy, with the span (Ω) and skew (κ) defined as, Ω = (δ₁₁ − δ₃₃) and κ = 3(δ₂₂−δ_iso)/ Ω, respectively.