Quantum mechanical calculation of aqueuous uranium complexes: carbonate, phosphate, organic and biomolecular species

Table 2 Uranium organic complex potential energies (Hartrees/molecule), interatomic distances (in Å) and calculated ¹³C NMR chemical shifts (in ppm).

Models	G	CN	U=O	U-O(H₂)	U-O(C)	δ¹³C
Oxalate
Expt (This work)	-----	---	-----	-----	-----	174.5
HOx^-•8(H₂O)	-989.3358	---	-----	-----	-----	176.2
Ox^2-•8(H₂O)	-988.7157	---	-----	-----	-----	179.3
Uranyl-oxalate
Expt (This work)	-----	---	-----	-----	-----	169.0
[UO₂(OH₂)₄]²⁺-Ox	-885.0151	7	1.79	2.61	2.28	164.7
[UO₂(OH₂)₄]²⁺-Ox•11(H₂O)	-1725.8906	7	1.79	2.48¹	2.41	172.0
[UO₂(OH₂)₄]²⁺-Ox•30(H₂O)	-3178.3494	7	1.79	2.47	2.40	167.4
Catechol
Expt [102]	DMSO	---	-----	-----	-----	116.1, 119.8, 145.6
	Solid	---	-----	-----	-----	115.7, 121.7, 142.7
H₂Cat	-382.6927	---	-----	-----	-----	115.5, 121.1, 144.3
Uranyl-catechol
Expt (This work)	DMSO					115.7, 119.3, 145.3
	Solid					115.7, 122.3, 143.4
[UO₂(OH₂)₄]²⁺-H₂Cat	-890.0170	8	1.76	2.62	2.60	116.1, 132.4, 137.7
[UO₂(OH₂)₄]²⁺-H₂Cat (OS)	-3029.9112	7	1.79	2.45	≈5.9	115.7, 126.1
						123.2, 128.6
						138.5, 147.4
[UO₂(OH₂)₄]²⁺-H₂Cat•28(H₂O) (Singlet)
	-3029.8947	7	1.79	2.45	2.48	121.8, 128.3, 141.6
[UO(OH)(OH₂)₄]²⁺-HCat•28(H₂O) (Triplet)
	-3029.9386	7	1.91²	2.50	2.42	138.3, 179.1, 113.2, 114.2, 127.6, 128.3,
[U(OH)₂(OH₂)₄]²⁺-Cat•28(H₂O) (Quintet)
	-3029.9477	7	2.17³	2.43	2.60	192.0, 195.3
						129.4, 151.2
						123.0, 137.1
[U(OH)₂(OH₂)₄]²⁺-Cat•28(H₂O) (Singlet)⁴
	-3030.6937	--	-----	-----	-----	160.5, 181.6,
						116.7, 144.5,
						149.6, 159.4
[U(OH)₂(OH₂)₄]²⁺-Quinone•28(H₂O) (OS)
	-3029.9359	7	2.17	2.46	≈6	114.9, 194.3
						137.7, 166.3
						159.8, 202.6

δ¹³C relative to TMS HF/6-31G(d,p)//B3LYP/6-31G(d,p) chemical shielding of 201.4 and δ¹⁷O relative to water B3LYP/6-311+G(d,p)//B3LYP/6-31G(d,p) chemical shielding of 293 ppm. δ¹³C shifts listed in order as the two phenolic C atoms, the two C atoms α with respect to the phenol groups, and the two C atoms β with respect to the phenol groups. (OS = outer-sphere)
1 = One U-OH₂ deprotonated to form U-OH and a H₃O⁺ in the solvation sphere
2 = One U-O at 1.85 Å and one U-OH at 1.96 Å
3 = One U-OH at 2.14 Å and one U-OH at 2.21 Å
4 = aqueous Gibbs free energy in the quintet structure without ZPE correction

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