. 2023 Apr 4;13(4):645. doi: 10.3390/biom13040645

Table 1.

Logarithms of the protonation and formation constants of InsP₈ (I = 0.15 M; T = 22 °C).

Equilibrium	log K
	InsP₈	5PCP-InsP₅	InsP₆
	³¹P NMR (22 °C) ^a	³¹P NMR (22 °C) ^b	Potentiometry (37 °C) ^b
L¹⁴⁻ + H⁺ ↔ HL¹³⁻	11.21(1)	11.48(1)	10.8(1)
L¹⁴⁻ + 2 H⁺ ↔ H₂L¹²⁻	22.78(2)	22.42(2)	21.3(1)
L¹⁴⁻ + 3 H⁺ ↔ H₃L¹¹⁻	34.22(2)	32.26(2)	31.63(6)
L¹⁴⁻ + 4 H⁺ ↔ H₄L¹⁰⁻	43.96(2)	40.94(2)	40.42(6)
L¹⁴⁻ + 5 H⁺ ↔ H₅L⁹⁻	52.58(3)	47.67(2)	47.32(6)
L¹⁴⁻ + 6 H⁺ ↔ H₆L⁸⁻	59.41(8)	51.93(2)	53.04(7)
L¹⁴⁻ + 7 H⁺ ↔ H₇L⁷⁻	64.91(6)	55.64(2)	56.14(9)
L¹⁴⁻ + 8 H⁺ ↔ H₈L⁶⁻	68.79(7)	---	---
5 K⁺ + HL¹³⁻ ↔ [K₅(HL)]⁸⁻	12.47(3)	6.57(3)	---
4 K⁺ + H₂L¹²⁻ ↔ [K₄(H₂L)]⁸⁻	9.76(3)	4.61(3)	---
4 K⁺ + H₃L¹¹⁻ ↔ [K₄(H₃L)]⁷⁻	---	4.50(5)	5.42(5)
3 K⁺ + H₄L¹⁰⁻ ↔ [K₃(H₄L)]⁷⁻	5.446(5)	3.94(4)	3.36(5)
2 K⁺ + H₅L⁹⁻ ↔ [K₂(H₅L)]⁷⁻	3.820(7)	2.79(7)	---
K⁺ + H₆L⁸⁻ ↔ [K(H₆L)]⁷⁻	2.58(5)	---	---
K⁺ + H₇L⁷⁻ ↔ [K(H₇L)]⁶⁻	2.08(3)	---	---
Mg²⁺ + L¹⁴⁻ + 4 K⁺ ↔ [MgK₄L]⁸⁻	22.4(1)	---	---
Mg²⁺ + HL¹³⁻ + 4 K⁺ ↔ [MgK₄(HL)]⁷⁻	21.6(1)	11.64(5)	---
Mg²⁺ + H₂L¹²⁻ + 3 K⁺ ↔ [MgK₃(H₂L)]⁷⁻	18.1(1)	9.75(7)	---
Mg²⁺ + H₃L¹¹⁻ + 3 K⁺ ↔ [MgK₃(H₃L)]⁶⁻	15.0(1)	8.79(7)	---
Mg²⁺ + H₄L¹⁰⁻ + 2 K⁺ ↔ [MgK₂(H₄L)]⁶⁻	11.6(1)	6.96(7)	---
Mg²⁺ + H₅L⁹⁻ + K⁺ ↔ [MgK(H₅L)]⁶⁻	9.1(1)	5.26(7)	---
Mg²⁺ + H₆L⁸⁻ + K⁺ ↔ [MgK(H₆L)]⁵⁻	7.3(1)	---	---
Mg²⁺ + H₆L⁸⁻ ↔ [Mg(H₆L)]⁶⁻	---	4.71(7)	---

^a This work, σ = 0.033 (H⁺), 0.053 (K⁺) and 0.051 (Mg²⁺). ^b Thermodynamic data reported previously for similar systems are included for comparison; the equations in the left column refer to InsP₈ complexes [28,46,47]. The standard deviation on the uncertain digit is added between brackets.