Table 2.

Experimental and calculated enthalpies of adduct formation (−ΔH, kJ·mol⁻¹ at 298 K)) between BF₃ and Lewis bases in dichloromethane (DCM) and nitrobenzene (NB) solutions (reaction (2a) and (2b)); kJ·mol⁻¹). The signification of uncertainties on experimental enthalpies is discussed in the text. G4*-calculated gas-phase enthalpies are listed in the last column.

	Solvent CH2Cl2 (DCM)			Solvent PhNO2 (NB)			Gas Phase
Lewis Base	Experimental in DCM a	G4* + Discrete Solvation Model b	Δ = Calc − Exp	Experimental in NB a	G4* + Continuous Solvation Model c	Δ = Calc − Exp	G4*
Trimethylamine	139.5 ± 1.8	145.7	6.2				126.4e
N-Methylpyrrolidine	139.5 ± 0.8	143.8	4.3				125.2
Quinuclidine	150.01 ± 3.48 [153.4 ± 0.9] d	162.9	12.9 [9.5]	160.5 ± 0.9	171.2	10.7	139.1
Pyridine	128.1 ± 0.5	126.3	−1.8	137.9 ± 0.7	137.4	−0.5	100.4e
Acetonitrile	60.4 ±0.5	60.7	−0.3				32.3
Dimethyl ether	83.6 ± 0.2	78.0	−5.6				62.4
Tetrahydrofuran	90.4 ± 0.3	96.2	5.8	93.0 ± 0.3	103.9	10.9	74.8
Tetrahydropyran	85.4 ± 0.5	81.2	−4.2				69.0e
Acetone	76.0 ± 0.2	74.3	−1.7	78.1 ± 0.3	82.7	4.6	54.2
Ethyl acetate	75.6 ± 0.3	73.2	−2.4				55.9
γ-Butyrolactone	75.1 ± 1.2	71.7	−3.4				53.1
Dimethyl carbonate	67.6 ± 0.4	62.8	−4.8				30.8
Nitrobenzene	[35.8 ± 1.4] d,f	39.3	[3.5]	37.7 ± 1.4 g	45.3	7.6	21.0e
Hexamethyl-phosphoramide (HMPA)	117.5 ± 0.5	127.7	10.2	123.1 ± 0.5	135.2 (121.9) i	12.1 (−1.2)	101.3 h
Trimethylphosphine	97.4 ± 0.3	97.5	0.1				66.1
Tetrahydrothiophene	51.6 ± 0.2	54.8	3.2				37.9

^a Experimental values corresponding to the reaction: BF_3(gas) + LB_(solution) → [LB-BF₃]_(solution). ^b Solvation effects are calculated using a model combining specific interactions (SSM) and a continuum model; see text. ^c Solvation effects are calculated using a continuum model, including geometry optimization at the B3LYP/6-31+g(d,p) level of theory. ^d Secondary value calculated from measurements in NB [25]. The assigned uncertainty corresponds to the repeatability, see text, but additional uncertainties are expected by converting to a value in DCM as solvent. ^e In these particular cases, the standard G4 yields a higher value than the one obtained with the non-standard G4* procedure; see Table S2. ^f Value for the Lewis base PhNO₂ in CH₂Cl₂ solution, estimated using Equation (4), see text. ^g Value measured for the dissolution of BF₃ in pure PhNO₂, corresponding to the adduct formation with the Lewis base PhNO₂ in PhNO₂ solution. ^h Published value obtained by extrapolation of the G4MP2 results [31]. ⁱ Solvation effects do not include geometry optimization. The previously reported value (119.3 kJ·mol⁻¹) [31] is very close but not strictly equal because the basis set used in the calculation of the solvation effects was different from the one used here.