Inclusion Complexation of Tetrabutylammonium Iodide by Cyclodextrins

SUPPLEMENTARY INFORMATION (SI)

Inclusion complexation of tetrabutylammonium iodide by cyclodextrins

BISWAJIT DATTA, ADITI ROY and MAHENDRA NATH ROY*

Department of Chemistry, University of North Bengal, Darjeeling, West Bengal, 734 013 India

Email:

*For Correspondence

Contents

Theory and Equations……………………………….. 3-5

List of Tables

Table S1. 1H NMR data of (but4NI), α-CD, β-CD and inclusion complexes……………………….6

Table S2. Experimental values of density (ρ), viscosity (η) and refractive index (nD) of different mass fractions of aqueous α and β-cyclodextrin mixtures at298.15 Ka………………..7

Table S3. Experimental values of density (ρ), viscosity (η) and refractive index (nD) of selected Ionic solid in different mass fractions of aqueous α and β-cyclodextrinmixtures at 298.15 Ka………………………………………………………………………………………………………………………..8

Table S4. Data for surface tension and conductivity study of aqueous but4NI-α-CD system at 298.15Ka………………………………………………………………………………………………………………….....9

Table S5. Data for surface tension and conductivity of aqueous but4NI-β-CD system at 298.15Ka…………………………………………………………………………………………………………………….. 10

Table S6. Apparent molar volume (ϕV), (ηr-1)/√m and molar refraction (RM) of selected ionic solid in different mass fractions of aqueous α and β-cyclodextrin mixtures at298.15 Ka…………………………………………………………………………………………………………………………… 11

Table S7. Limiting apparent molar volume (ϕVo), experimental slope (SV*), viscosity A and B-coefficient and limiting molar refraction (RMo) of but4NI indifferent mass fractions of aqueous α and β-cyclodextrin mixtures at 298.15 Ka………………………………………………. 12

Table S8. Frequencies at FTIR spectra of α-CD, β-CD, but4NI and solid inclusion complexes………………………………………………………………………………………………………...…….. 13

List of Schemes Page No.

Scheme S1. Feasible and restricted inclusionsof the guest into the host molecule…………14

Scheme S2. Different stoichiometries of host-guest inclusion complexes………………………14

Theory:

Surface tension

The calculation of concentration of cyclodextrin at the break point of the curve and corresponding surface tension at which maximum inclusion took place have been calculated by solving the equations of two intercepting straight lines and represented in table 1. For example, in case of the ionic solid (but4NI)and β-cyclodextrin system

γ = 1.165x + 67.05(1)

γ = 2.663x + 59.90(2)

Solving equation (1) and (2),

γ = 73.52mN·m-1 and c = 4.77mM

Concentration of ionic liquid at the break point has been estimated from the mutual concentration chart of table S4-S7.

Conductivity

The concentration and corresponding conductivity at which maximum inclusion took place (break point at the curve) have been calculated by solving the equations of two intercepting straight lines and represented in table 2. For instance, in case of the ionic solid(but4NI)and α-cyclodextrin system

κ = -0.131x + 1.226 (3)

κ = -0.085x + 0.954(4)

Solving equation (3) and (4),

κ = 0.40mS·m-1 and c = 5.91 mM

Concentration of ionic liquid at the break point has been estimated from the mutual concentration chart of table S4-S7.

Table S2 refers the physical properties of binary aqueous mixtures in different mass fractions (wn=0.001, 0.003, 0.005, where n =1, 2 for α and β-CD respectively) of α and β-CD at 298.15K. The experimental measured values of density, viscosity and refractive index of the selected ionic solid(but4NI)in different mass fractions of aqueous α and β-CD mixture have been listed in table S3 as a function of concentration (molality).

Apparent molar volume

The apparent molar volumes ϕVwere determined from the solutions densities using the equation and given in table S8.

ϕV M /  1000/ m (5)

where M is the molar mass of the ionic liquids, m is the molality of the solution,  and o are the density of the solution and aqueousα and β-CD mixture respectively.

The limiting apparent molar volumes ϕ0V were obtained by a least-square treatment to the plots of ϕV versus √m using the Masson equationand shown in table S9.1

ϕV ϕ0V  SV*m (6)

The standard deviations (σ) were determined using the following equation:

 [ (Yexp Yobs) 2 / (N 1)] (7)

where N is the number of data points.

Viscosity

The experimental viscosity data for the studied systems are listed in table S3. The relative viscosity (ηr) has been analyzed using the Jones-Dole equation.2

(/o - 1)/ √m = (ηr - 1)/ √m = A + B √m (8)

where ηr = /o,  and o are the relative viscosities, the viscosities of the ternary solutions (ionic liquid + aq. CD) and binary aqueous mixture (aq. CD) and m is the molality of the ionic liquids in ternary solutions. A and B are empirical constants known as viscosity A and B-coefficients, which are specific to solute-solute and solute-solvent interactions respectively and have been estimated by least-square method by plotting (r1 ) / magainst m and reported in table S8.

Refractive index

The molar refraction, RMcan be evaluated from the Lorentz-Lorenz relation,3

RM = (nD2-1)/(nD2+ 2)(M/) (9)

where RM, nD, M and  are the molar refraction, the refractive index, the molar mass and the density of solution respectively. The Limiting molar refraction (RMo) have been estimated from the following relation and reported in table S9,4

RM  RMoRSm (10)

Tables:

Table S1. 1H NMR data of (but4NI), α-CD, β-CD and inclusion complexes

(but4NI) (300MHz, Solv: D2O) δ /ppm
0.83-0.88 (12H, t), 1.23-1.31 (8H, m), 1.53-1.59 (8H, m), 3.08-3.13 (8H, m)
α-Cyclodextrin (500 MHz, Solv: D2O)
δ /ppm / β-Cyclodextrin (400 MHz, Solv: D2O)
δ /ppm
3.48-3.51 (6H, t, J= 9.00 Hz), 3.53-3.56 (6H, dd, J= 10.00, 3.00 Hz), 3.74-3.83 (18H, m), 3.87-3.91 (6H, t, J= 9 Hz), 4.96-4.97 (6H, d, J= 3 Hz) / 3.49-3.54 (6H, t, J= 9.2 Hz), 3.57-3.60 (6H, dd, J= 9.6, 3.2 Hz), 3.79-3.84 (18H, m), 3.87-3.92 (6H,t, J= 9.2 Hz), 5.00-5.01 (6H, d, J= 3.6 Hz)
(but4NI)-α-CD
(1:1 molar ratio, 300 MHz, Solv: D2O)
δ /ppm / (but4NI)-α-CD
(1:1 molar ratio, 300 MHz, Solv: D2O)
δ /ppm
0.84-0.89 (12H, t), 1.25-1.32 (8H, m), 1.55-1.57 (8H, m), 3.09-3.15 (8H, m), 3.50-3.57 (18H, m), 3.75-3.78 (6H, t), 4.96-4.97 (6H, d) / 0.83-0.87 (12H, t), 1.23-1.30 (8H, m), 1.56-1.59 (8H, m), 3.07-3.13 (4H, m), 3.79-3.84 (18H, m), 3.87-3.92 (6H, t), 5.00-5.01 (6H, d)

Table S2. Experimental values of density (ρ), viscosity (η) and refractive index (nD) of different mass fractions of aqueous α and β-cyclodextrin mixtures at298.15 Ka

Aqueous solvent mixture / ρ×10-3
/kg∙m-3 / η
/mP∙s / nD
aq. α-CD
w1 = 0.001 / 0.99735 / 1.29 / 1.3329
w1 = 0.003 / 0.99802 / 1.30 / 1.3332
w1 = 0.005 / 0.99868 / 1.31 / 1.3335
aq. β-CD
w2 = 0.001 / 0.99755 / 1.30 / 1.3328
w2 = 0.003 / 0.99819 / 1.31 / 1.3331
w2 = 0.005 / 0.99895 / 1.32 / 1.3334

a Standard uncertainties u are: u(ρ) = 5×10-5 g∙cm-3, u(η) = 0.003 mP∙s, u(nD) =0.0002, and u(T) = ±0.01K.

Table S3. Experimental values of density (ρ), viscosity (η) and refractive index (nD)of selected Ionic solidin different mass fractions of aqueous α and β-cyclodextrinmixtures at 298.15 Ka

molality / ρ×10-3 / η / nD / molality / ρ×10-3 / η / nD
/mol∙kg-1 / /kg∙m-3 / /mP∙s / /mol∙kg-1 / /kg∙m-3 / /mP∙s
but4NI
w1 = 0.001b / w2 = 0.001b
0.010034 / 0.99836 / 1.36 / 1.3330 / 0.010032 / 0.99858 / 1.38 / 1.3330
0.025113 / 0.99988 / 1.41 / 1.3331 / 0.025106 / 1.00014 / 1.43 / 1.3331
0.040225 / 1.00140 / 1.44 / 1.3332 / 0.040212 / 1.00171 / 1.47 / 1.3333
0.055370 / 1.00293 / 1.47 / 1.3333 / 0.055350 / 1.00329 / 1.49 / 1.3334
0.070548 / 1.00446 / 1.50 / 1.3334 / 0.070518 / 1.00488 / 1.53 / 1.3336
0.085760 / 1.00599 / 1.52 / 1.3335 / 0.085717 / 1.00648 / 1.56 / 1.3338
w1 = 0.003b / w2 = 0.003b
0.010027 / 0.99901 / 1.39 / 1.3334 / 0.010025 / 0.99924 / 1.40 / 1.3334
0.025096 / 1.00053 / 1.45 / 1.3335 / 0.025088 / 1.00087 / 1.46 / 1.3335
0.040198 / 1.00207 / 1.49 / 1.3336 / 0.040178 / 1.00255 / 1.50 / 1.3337
0.055332 / 1.00361 / 1.54 / 1.3337 / 0.055295 / 1.00428 / 1.54 / 1.3339
0.070497 / 1.00517 / 1.56 / 1.3338 / 0.070432 / 1.00610 / 1.57 / 1.3341
0.085695 / 1.00674 / 1.59 / 1.3339 / 0.085595 / 1.00789 / 1.60 / 1.3343
w1 = 0.005b / w2 = 0.005b
0.010021 / 0.99962 / 1.41 / 1.3339 / 0.010018 / 0.99999 / 1.42 / 1.3336
0.025083 / 1.00105 / 1.48 / 1.3340 / 0.025066 / 1.00173 / 1.49 / 1.3337
0.040181 / 1.00249 / 1.53 / 1.3341 / 0.040138 / 1.00355 / 1.54 / 1.3338
0.055311 / 1.00398 / 1.57 / 1.3342 / 0.055227 / 1.00549 / 1.57 / 1.3340
0.070475 / 1.00548 / 1.60 / 1.3343 / 0.070333 / 1.00749 / 1.61 / 1.3342
0.085671 / 1.00702 / 1.64 / 1.3344 / 0.085459 / 1.00948 / 1.65 / 1.3343

aStandard uncertainties u are: u(ρ) = 5×10-5 kg∙m-3, u(η) =0.003 mP∙s, u(nD) =0.0002, u(pH) =0.01 and u(T) =0.01K.
bw1 and w2 are mass fractions of α and β-cyclodextrin in aqueous mixture respectively.

Table S4. Data for surface tension and conductivity study of aqueous but4NI-α-CD system at 298.15Ka

Volm of
α-CD
(mL) / Total volm
(mL) / Conc of
(but4NI) (mM) / Conc of α-CD
(mM) / Surface tension
(mN m-1) / Conductuvity
(mS m-1)
0 / 10 / 10.000 / 0.000 / 60.3 / 1.20
1 / 11 / 9.091 / 0.909 / 62.1 / 1.11
2 / 12 / 8.333 / 1.667 / 63.9 / 1.02
3 / 13 / 7.692 / 2.308 / 65.5 / 0.93
4 / 14 / 7.143 / 2.857 / 67.1 / 0.86
5 / 15 / 6.667 / 3.333 / 68.6 / 0.80
6 / 16 / 6.250 / 3.750 / 69.8 / 0.74
7 / 17 / 5.882 / 4.118 / 70.7 / 0.69
8 / 18 / 5.556 / 4.444 / 71.7 / 0.64
9 / 19 / 5.263 / 4.737 / 72.5 / 0.59
10 / 20 / 5.000 / 5.000 / 72.8 / 0.55
11 / 21 / 4.762 / 5.238 / 73.0 / 0.51
12 / 22 / 4.545 / 5.455 / 73.2 / 0.47
13 / 23 / 4.348 / 5.652 / 73.4 / 0.46
14 / 24 / 4.167 / 5.833 / 73.6 / 0.45
15 / 25 / 4.000 / 6.000 / 73.7 / 0.44
16 / 26 / 3.846 / 6.154 / 73.8 / 0.43
17 / 27 / 3.704 / 6.296 / 74.0 / 0.42
18 / 28 / 3.571 / 6.429 / 74.1 / 0.41
19 / 29 / 3.448 / 6.552 / 74.3 / 0.40
20 / 30 / 3.333 / 6.667 / 74.5 / 0.39

a Standard uncertainties in temperature u are: u(T) = ±0.01 K.

Table S5. Data for surface tension and conductivity of aqueousbut4NI-β-CD system at 298.15Ka

Volm of
β-CD
(mL) / Total volm
(mL) / Conc of
(but4NI) (mM) / Conc of β-CD
(mM) / Surface tension
(mN m-1) / Conductuvity
(mS m-1)
0 / 10 / 10.000 / 0.000 / 60.3 / 1.20
1 / 11 / 9.091 / 0.909 / 62.2 / 1.10
2 / 12 / 8.333 / 1.667 / 64.1 / 1.01
3 / 13 / 7.692 / 2.308 / 65.8 / 0.91
4 / 14 / 7.143 / 2.857 / 67.3 / 0.84
5 / 15 / 6.667 / 3.333 / 68.8 / 0.78
6 / 16 / 6.250 / 3.750 / 70.0 / 0.71
7 / 17 / 5.882 / 4.118 / 71.1 / 0.67
8 / 18 / 5.556 / 4.444 / 72.0 / 0.61
9 / 19 / 5.263 / 4.737 / 72.7 / 0.56
10 / 20 / 5.000 / 5.000 / 72.9 / 0.52
11 / 21 / 4.762 / 5.238 / 73.2 / 0.49
12 / 22 / 4.545 / 5.455 / 73.4 / 0.46
13 / 23 / 4.348 / 5.652 / 73.6 / 0.45
14 / 24 / 4.167 / 5.833 / 73.8 / 0.44
15 / 25 / 4.000 / 6.000 / 74.0 / 0.43
16 / 26 / 3.846 / 6.154 / 74.2 / 0.42
17 / 27 / 3.704 / 6.296 / 74.4 / 0.41
18 / 28 / 3.571 / 6.429 / 74.6 / 0.40
19 / 29 / 3.448 / 6.552 / 74.7 / 0.39
20 / 30 / 3.333 / 6.667 / 74.9 / 0.38

a Standard uncertainties in temperature u are: u(T) = ±0.01 K.

Table S6. Apparent molar volume (ϕV), (ηr-1)/√m and molar refraction (RM) of selectedionicsolidin different mass fractions of aqueous α and β-cyclodextrin mixtures at298.15 Ka

molality
/mol∙kg-1 / ϕV ×106
/ m3 mol-1 / (ηr-1)/√m
/kg1/2mol-1/2 / RM×106
/m3 mol-1 / molality
/mol∙kg-1 / ϕV ×106
/ m3 mol-1 / (ηr-1)/√m
/kg1/2mol-1/2 / RM×106
/m3 mol-1
but4NI
w1 = 0.001b / w2 = 0.001b
0.010047 / 199.65 / 0.072 / 76.2016 / 0.010045 / 199.61 / 0.067 / 76.2459
0.025191 / 197.84 / 0.117 / 76.1786 / 0.025184 / 195.40 / 0.110 / 76.2310
0.040424 / 196.64 / 0.151 / 76.1591 / 0.040410 / 192.59 / 0.143 / 76.2209
0.055746 / 195.55 / 0.180 / 76.1428 / 0.055719 / 190.40 / 0.171 / 76.2128
0.071155 / 194.64 / 0.206 / 76.1314 / 0.071111 / 188.58 / 0.195 / 76.2074
0.086653 / 193.81 / 0.228 / 76.1186 / 0.086586 / 187.17 / 0.216 / 76.2006
w1 = 0.003b / w2 = 0.003b
0.010040 / 202.52 / 0.072 / 76.3145 / 0.010039 / 205.49 / 0.068 / 76.3092
0.025175 / 199.31 / 0.118 / 76.2907 / 0.025172 / 200.88 / 0.111 / 76.2551
0.040397 / 196.76 / 0.153 / 76.2730 / 0.040391 / 197.23 / 0.145 / 76.2188
0.055706 / 194.87 / 0.182 / 76.2562 / 0.055695 / 194.29 / 0.172 / 76.1906
0.071101 / 193.22 / 0.207 / 76.2435 / 0.071081 / 191.75 / 0.196 / 76.1624
0.086581 / 191.91 / 0.230 / 76.2321 / 0.086544 / 188.93 / 0.218 / 76.1342
w1 = 0.005b / w2 = 0.005b
0.010034 / 207.39 / 0.077 / 76.3308 / 0.010032 / 70.74 / 0.069 / 76.3102
0.025161 / 202.79 / 0.126 / 76.2866 / 0.025156 / 63.54 / 0.112 / 76.2329
0.040375 / 199.63 / 0.163 / 76.2540 / 0.040369 / 59.73 / 0.146 / 76.1695
0.055676 / 197.11 / 0.194 / 76.2272 / 0.055670 / 55.82 / 0.174 / 76.1087
0.071062 / 194.95 / 0.222 / 76.2028 / 0.071051 / 52.73 / 0.198 / 76.0464
0.086528 / 192.49 / 0.246 / 76.1735 / 0.086518 / 50.84 / 0.220 / 76.0003

aStandard uncertainties u are: u(T) =0.01K.
bw1 and w2 are mass fractions of α and β-cyclodextrin in aqueous mixture respectively.

Table S7. Limiting apparent molar volume (ϕVo), experimental slope (SV*), viscosity A and B-coefficient and limiting molar refraction (RMo) of but4NIindifferent mass fractions of aqueous α and β-cyclodextrin mixtures at 298.15 Ka

Aq. solvent mixture / ϕ0V×106
/ m3 mol-1 / S*V×106
/m3mol- 3/2kg1/2 / B
/kgmol-1 / A
/kg1/2 mol-1/2 / RMO×106
/m3 mol-1
but4NI
w1 = 0.001b / 202.6 / -64.33 / 1.48 / -0.097 / 76.25
w1 = 0.003b / 208.0 / -85.85 / 1.52 / -0.098 / 76.36
w1 = 0.005b / 214.9 / -88.95 / 1.56 / -0.099 / 76.41
but4NI
w1 = 0.001b / 205.7 / -30.02 / 1.64 / -0.103 / 76.27
w1 = 0.003b / 214.3 / -55.25 / 1.68 / -0.104 / 76.39
w1 = 0.005b / 220.3 / -75.68 / 1.76 / -0.111 / 76.48

aStandard uncertainties u are: u(T) =0.01K.
bw1 and w2 are mass fractions of α and β-cyclodextrin in aqueous mixture respectively.

Table S8. Frequencies at FTIR spectra ofα-CD, β-CD,but4NIand solid inclusion complexes

α-Cyclodextrin / β-Cyclodextrin
wave number
/ cm-1 / group / wave number
/ cm-1 / group
3412.10 / stretching of O-H / 3349.84 / stretching of O-H
2930.79 / stretching of –C-H from –CH2 / 2921.52 / stretching of –C-H from –CH2
1406.76 / bending of –C-H from –CH2 and bending of O-H / 1412.36 / bending of –C-H from –CH2 and bending of O-H
1154.39 / bending of C-O-C / 1157.57 / bending of C-O-C
1030.39 / stretching of C-C-O / 1033.51 / stretching of C-C-O
952.36 / skeletal
vibration involving
α-1,4linkage / 938.53 / skeletal vibration involving α-1,4linkage
but4NI / but4NI -α-CD inclusion complex
wave number
/ cm-1 / group / wave number
/ cm-1 / group
3443.34 / stretching of N-C-H bond / 3393.00 / stretching of O-H of α-CD
2958.31 / stretching of –C-H from –CH2 of salt / 2931.03 / stretching of –C-H from –CH2 of α-CD
2256.11 / stretching of –C=N / 1646.08 / bending of –C-H from –CH2 and bending of O-H of α-CD
1640.24 / bending of –C-H from –CH2 of salt / 1380.64 / bending of C-O-C of α-CD
1464.54 / bending of –C-H from –CH3 of salt / 1149.61 / skeletal vibration involving α-1,4linkage
but4NI -β-CD inclusion complex
wave number
/ cm-1 / group
3423.64 / stretching of O-H
of β-CD
2930.46 / stretching of –C-H from –CH2 of β-CD
1634.99 / bending of –C-H from –CH2 and bending of O-H of β-CD
1457.20 / bending of C-O-C of β-CD
1213.51 / stretching of C-C-O of β-CD
1030.39 / skeletal vibration involving α-1,4linkage of β-CD

Schemes

Scheme S1. Feasible and restricted inclusionsof the guest into the host molecule.

Scheme S2. Different stoichiometries of host-guest inclusion complexes.

References

1. Masson D O 1929 Solute Molecular Volumes in Relation to The Solvation and Ionization Phil. Mag.8 218
2. Jones G and Dole D 1929 The viscosity of aqueous solutions of strong electrolytes with special reference to barium chlorideJ. Am. Chem. Soc.512950
3. Exner O 1975 Dipole Moments in Organic Chemistry (Georg Thieme Verlag, Stuttgart) p.3
4. Roy M N, Ekka D, Saha S and Roy M C 2014 Host–guest inclusion complexes of α and β-cyclodextrins with α -amino acids RSC Adv.4 42383

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