Supporting Information. Toshiyuki Takamuku a,*, Yasuhito Higuma a, Masaru Matsugami b, Takahiro To a, and. Tatsuya Umecky a

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1 Supporting Information Solvation Structure of,3-butanediol in Aqueous Binary Solvents with Acetonitrile,,4-Dioxane, and Dimethyl Sulfoxide Studied by IR, NMR, and Molecular Dynamics Simulation Toshiyuki Takamuku a,*, Yasuhito Higuma a, Masaru Matsugami b, Takahiro To a, and Tatsuya Umecky a a Department of Chemistry and Applied Chemistry, Graduate School of Science and Engineering, Saga University, Honjo-machi, Saga , Japan b Faculty of Liberal Studies, National Institute of Technology, Kumamoto College, Suya, Koshi, Kumamoto 86-2, Japan Corresponding Author Tel: * takamut@cc.saga-u.ac.jp S

2 TABLE S. Intramolecular Atom Atom Bond Lengths for (S)-,3-BD, AN, and Water, and the Potential Parameters Employed for the MD Simulations. Intramolecular atom atom bond lengths Bond r(å),3-bd C T-H.9 C T-H 2.9 C T-O H.4 O H-H O.96 C T-C T2.526 C T2-H 2.9 C T2-H 22.9 C T2-C T3.526 C T3-H 3.9 C T3-O H3.4 O H3-H O3.96 C T3-C T4.526 C T4-H 4.9 C T4-H 42.9 C T4-H 43.9 AN C TA-H A.9 C TA-H 2A.9 C TA-H 3A.9 C TA-C NA.458 C NA-N CA.57 Water OW-HW.957 HW LP LP OW HW Bond angle potentials Angle θ(degree) K(kcal/(mol - rad -2 )),3-BD H O-O H-C T O H-C T-H O H-C T-H O H-C T-C T C T-C T2-H C T-C T2-H C T-C T2-C T H -C T-H H -C T-C T H 2-C T-C T C T2-C T3-H C T2-C T3-C T C T2-C T3-O H H 2-C T2-H H 2-C T2-C T S2

3 Cont. AN H 22-C T2-C T C T3-C T4-H C T3-C T4-H C T3-C T4-H C T3-O H3-H O H 3-C T3-O H H 3-C T3-C T O H3-C T3-C T H 4-C T4-H H 42-C T4-H H 43-C T4-H N CA-C NA-C TA 8. 8 C NA-C TA-H A. 35 C NA-C TA-H 2A. 35 C NA-C TA-H 3A. 35 H A-C TA-H 2A H 2A-C TA-H 3A H 3A-C TA-H A Torsion potentials torsion φ(degree) V (kcal mol - ) V 2 (kcal mol - ) V 3 (kcal mol - ),3-BD H O-O H-C T-H...45 H O-O H-C T-C T O H-C T-C T-H O H-C T-C T-C T C T-C T-C T-H C T-C T-C T-C T H-C T-C T-H...38 van der Waals parameters and point charges σ(å) ε(kcal mol - ) q,3-bd C T H H O H H O...48 C T H H C T H O H H O S3

4 Cont. C T H H H AN C TA H A H 2A H 3A C NA N CA Water HW.24 OW LP -.24 S4

5 OH3 OH x AN H 2 O H3 H AN H2 HMDS H4 4 3 δ/ppm 2 Figure S. H NMR spectra of,3-bd in AN H 2 O mixtures as a function of x AN from to. S5

6 x AN AN-CN. AN-CH 3 C3 C C2 C4 HMDS 8 6 δ/ppm 4 2 Figure S2. 3 C NMR spectra of,3-bd in AN H 2 O mixtures as a function of x AN from to. S6

7 OH3 OH x DIO HMDS. H 2 O H3 H DIO H2 H4 4 3 δ/ppm 2 Figure S3. H NMR spectra of,3-bd in DIO H 2 O mixtures as a function of x DIO from to. S7

8 OH3 x DIO-d8.5 H3 H 2 O H OH DIO H2 H4 HMDS 4 3 δ/ppm 2 Figure S4. H NMR spectra of,3-bd in DIO-d 8 D 2 O mixtures at x DIO-d8 =.5 and. S8

9 x DIO DIO C3 C C2 C4 HMDS 8 6 δ/ppm 4 2 Figure S5. 3 C NMR spectra of,3-bd in DIO H 2 O mixtures as a function of x DIO from to. S9

10 x DMSO BD-OH HMDS.2. H 2 O DMSO H3 H H2 H4 4 3 δ/ppm 2 Figure S6. H NMR spectra of,3-bd in DMSO H 2 O mixtures as a function of x DMSO from to. S

11 x DMSO DMSO C3 C C2 C4 HMDS 8 6 δ/ppm 4 2 Figure S7. 3 C NMR spectra of,3-bd in DMSO H 2 O mixtures as a function of x DMSO from to. S

12 S3.2. H and 3 C NMR Chemical Shifts for the,3-bd Hydrocarbons. Figure S8 displays the chemical shifts of the H and 3 C atoms of the hydrocarbons at the positons and 3 of,3-bd, at which the hydroxyl groups are bound to the carbon atoms, as a function of x OS. Despite the H NMR measurements on the deuterated solutions, several values for the DIO system are lacked in Figure S8. A few values for the AN system are also absent from the figure. Nevertheless, the changes in the chemical shifts for the H, H3, C, and C3 atoms against the x OS can be well discussed as follows. The H and H3 atoms in all of the systems are shielded with increasing x OS. The shielding of the atoms may be related to the disruption of the hydrogen bonding of the hydroxyl hydrogen atoms with water molecules. As the water concentration decreases (the x OS increases), both types of the hydrogen bonds, OH OH 2 and HO HOH, between the hydroxyl groups and water are gradually disrupted in the solutions. The breaking of the hydrogen bonds, especially the latter, leads to the decrease in the electron density of the,3-bd oxygen atoms. The electron density of the oxygen atoms may move to the hydrogen atoms of the alkyl groups that the hydroxyl groups are bound. Thus, the H and H3 atoms are shielded with increasing x OS. The shielding of both atoms is more significant in the sequence of the DMSO > DIO > AN systems. The organic solvent molecules can be hydrogen-bonded with the hydroxyl hydrogen atoms of,3-bd as water molecules are eliminated from the hydroxyl groups. DMSO molecules are most strongly hydrogen-bonded with the hydroxyl groups among the organic solvents. Due to the strong hydrogen bonding, the electron density of the hydroxyl hydrogen atoms moves to the alkyl hydrogen atoms. The two factors of the disruption of the HO HOH hydrogen bonds and the formation of the bond of OH organic solvent mainly contribute to the chemical shifts of the H and H3 atoms. S2

13 The C and C3 atoms in the AN system are moderately deshielded with the increase in the x OS (Figure S8). As discussed above, the electron density may move from the hydroxyl oxygen to the alkyl hydrogen atoms through the C and C3 atoms by the disruption of the HO HOH hydrogen bonds with decreasing water content (increasing x OS ). The part of electron density for the C and C3 atoms may simultaneously decrease by the breaking of the hydrogen bonds. On the contrary, the C and C3 atoms are shielded in the DMSO water solutions with increasing x OS. This arises from the strong hydrogen bonds of OH DMSO. Hence, the electron density of the C and C3 atoms in the DMSO system increases against the increase in x OS. For the DIO system the C atom is deshielded with increasing x OS as well as the AN system. However, the variation of the chemical shift of the C3 atom against x OS is in the middle feature between those of the AN and DMSO systems. In Figure S9, the chemical shifts of the other hydrocarbons of,3-bd, the H2, H4, C2, and C4 atoms, in the three systems are plotted against the x OS. The C2 and C4 atoms are more significantly deshielded with increasing x OS in the sequence of DMSO > DIO > AN. This agrees with the sequence of the stronger hydrogen bonds of the organic solvent molecules with the,3- BD. Figures S8 and S9 suggest that the stronger the hydrogen bonds of the,3-bd hydroxyl groups with the organic solvent molecules, the more the electron density significantly moves from the C2 and C4 to the H, H3, C, and C3 atoms. On the other hand, the H2 and H4 atoms are more remarkably shielded with increasing x OS in the sequence of DIO > DMSO AN. This order does not agree with that of the strength of the hydrogen bonds between the,3-bd hydroxyl hydrogen atoms and the organic solvents. The chemical shifts of the H2 and H4 atoms may reflect the hydrophobic interaction between the hydrophobic alkyl moieties of,3-bd and the organic solvent molecules. The hydrophobic interaction like a dispersion force of DIO S3

14 molecule with the,3-bd hydrophobic moieties may be the strongest among the three organic solvents because of the largest hydrophobic moiety. For the AN and DMSO systems, the H2 and H4 atoms are first deshielded as the x OS increases from to.2 and then shielded with further increasing x OS. In the water solvent (x OS = ), the hydrogen atoms of the C H bonds within,3- BD may be pushed toward the carbon atoms by approaching of the water oxygen atoms, resulting in the shortening of the bonds. S,S2 However, water molecules are removed from the alkyl moieties of,3-bd with increasing x OS. The length of the C H bonds may be recovered with the increase in the x OS. In such manner, the H2 and H4 atoms are deshielded with increasing x OS by removing water molecules around the alkyl moieties. S-S3 Then, the hydrophobic interaction between the,3-bd alkyl moieties and AN or DMSO is strengthened with increasing x OS. Thus, the C H bonds may be shortened again. This leads to the shielding of the H2 and H4 atoms. For the DIO system, the hydrophobic interaction between the alkyl moieties of,3-bd and DIO is enough strong to hide the effect of the removing water molecules at the low x OS. References (S) Takamuku, T.; Tanaka, M.; Sako, T.; Shimomura, T.; Fujii, K.; Kanzaki, R.; Takeuchi, M. Solvation of the Amphiphilic Diol Molecule in Aliphatic Alcohol-Water and Fluorinated Alcohol-Water Solutions. J. Phys. Chem. B 2, 4, (S2) Takamuku, T.; Hatomoto, Y.; Tonegawa, J.; Tsutsumi, Y.; Umecky, T. A Study of the Solvation Structure of L-Leucine in Alcohol-Water Binary Solvents through Molecular Dynamics Simulations and FTIR and NMR Spectroscopy. ChemPhysChem 25, 6, (S3) Takamuku, T.; Tobiishi, M.; Saito, H. Solvation Properties of Aliphatic Alcohol Water and Fluorinated Alcohol Water Solutions for Amide Molecules Studied by IR and NMR Techniques. J. Solution Chem. 2, 4, S4

15 Chemical Shift / ppm AN DIO DMSO C x OS H C x OS H Figure S8. Variations of H and 3 C chemical shifts for the H, H3, C and C3 atoms of,3-bd in aqueous binary solvents with AN, DIO, and DMSO against x OS. S5

16 .7 H2.2 H4 Chemical Shift / ppm AN DIO DMSO C x OS C x OS Figure S9. Variations of H and 3 C chemical shifts for the H2, H4, C2 and C4 atoms of,3-bd in aqueous binary solvents with AN, DIO, and DMSO against x OS. S6

17 3 O,3-OW 2 x AN =.75 g(r) r / Å 6 8 Figure S. Intermolecular atom atom pair correlation functions g(r) for O,3 OW interactions between the,3-bd hydroxyl oxygen and water oxygen atoms in,3-bd AN water system at various x AN obtained from MD simulations. S7

18 OH-N OH3-N 8 x AN = 8 x AN = g(r) g(r) r / Å r / Å Figure S. Intermolecular atom atom pair correlation functions g(r) for OH N (left panel) and OH3 N (right panel) interactions between the,3-bd hydroxyl hydrogen and AN nitrogen atoms in,3-bd AN water system at various x AN obtained from MD simulations. S8

19 Mixing time / ms H3 H H2 H δ/ppm 2.5 Figure S2. NOE spectra of,3-bd in D 2 O (x AN = ) at various mixing times from to 3 ms. S9

20 Mixing time / ms H3 H H2 H δ/ppm 2.5 Figure S3. NOE spectra of,3-bd in in AN-d 3 D 2 O mixtures at x AN =.5 and various mixing times from to 3 ms. S2

21 Mixing time / ms H3 H OH H 2 O H2 H δ/ppm 2.5 Figure S4. NOE spectra of,3-bd in AN-d 3 (x AN = ) at various mixing times from to 3 ms. Despite the use of dried AN-d 3, the H peak for H 2 O is observed in the NOE spectra, particularly at the long mixing times, as a contamination. However, the very weak intensity of the peak in the NOE spectrum at the null mixing time shows the trivial content of H 2 O. Thus, the AN mole fraction of x AN for the,3-bd AN-d 3 solution can be regarded as the unity. S2