Theoretical Investigation of the Cooperativity in CH₃CHO·2H₂O, CH₂FCHO·2H₂O, and CH₃CFO·2H₂O Systems

Table 2

Properties of the isolated CH₂FCHO and H₂O molecules and the A and B complexes between CH₂FCHO and one and two water molecules (distances in Å, σ ^*occupation in e, hyperconjugation energies in kcal mol⁻¹, and frequencies in cm⁻¹).

	IsolatedCH2FCHO	A(1-1)	A(1-2)	B(1-1)	B(1-2)
𝑟(C1H3)	1.1096	1.1077	1.1077	1.1065	1.1053
𝜈(C1H3)	2914	2938	2938	2958	2975
𝜎^∗(C1H3)	0.068	0.063	0.062	0.060	0.056
%𝑠C1(H3)	32.1	31.8	31.7	32.5	33.7
𝑞(C1)	0.408	0.427	0.440	0.421	0.417
𝑞(H3)	0.117	0.125	0.124	0.141	0.177
𝑟(C4H5)	1.0940	1.0933	1.0962	1.0942	1.0945
𝜈(C4H5H6)	3096,3045	3106,3058	3077,3024	3094,3044	3090,3041
𝜎^∗(C4H5)	0.0199	0.0196	0.0250	0.0200	0.0200
%𝑠C4(H5)	25.74	25.97	27.46	25.70	25.61
𝑞(C4)	−0.011	−0.021	−0.038	−0.011	−0.011
𝑞(H5)	0.190	0.207	0.246	0.193	0.191
𝑟(C1=O2)	1.203	1.208	1.210	1.208	1.213
𝜈(C1=O2)	1816	1798	1793	1797	1773
LPO2→𝜎^∗(C1H3)	22.94	21.42	21.33	20.83	18.15
LPO9→𝜎^∗(C1H3)	—	—	—	—	3.4
LPO2→𝜎^∗(H8O9)	—	5.53	6.94	5.51	9.11
LPO9(O12)→𝜎^∗(C4H5)	—	0.10	4.56	—	—
	Isolated H2O	A(1-1)	A(1-2)	B(1-1)	B(1-2)
𝑟(OH)	0.9620	0.9696	0.9724^a	0.9689	0.9753^a
			0.9756^b		0.9746^b
𝜈(H2O)	3926,3820	3896,3725	3893,3676^c	3898,3720	3889,3594^c
			3892,3579^d		3892,3631^d
Σ𝑞(H2O)	—	−0.013	+0.006^e	−0.019	0.000^e
			−0.012^f		−0.014^f

^aO₉H₈ bond. ^bO₁₂H₁₁ bond. 𝑟(OH⋯) in the water dimer is 0.9700 Å. ^c𝜈(H₈O₉H₁₀). ^d𝜈(H₁₁O₁₂H₁₃). ^eΣ𝑞 on (H₈O₉H₁₀)^fΣ𝑞 on (H₁₁O₁₂H₁₃).