1

Chromium based metallosurfactants: Synthesis, physicochemical characterization and

probing their interactions with xanthene dyes

Preeti Garg, Gurpreet Kaur*and Ganga Ram Chaudhary*

Department of Chemistry and Centre of Advanced studies in Chemistry, Panjab University,

Chandigarh

Corresponding authorsGurpreet Kaur (gurpreet14@pu.ac.in) Tel: 911722534431Ganga Ram Chaudhary (grc22@pu.ac.in)Tel: 911722534406Fax: +91-172-2545074

Electronic Supplementary Material (ESI) for New Journal of Chemistry.This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2017

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1H-NMR

(a)

6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 ppm

0.75

600.

7734

0.78

95

1.18

681.

2537

1.65

23

3.03

543.

2196

3.23

233.

2412

3.24

933.

2623

4.70

05

3.32

26.7

6

2.00

9.46

2.18

Current Data ParametersNAME Dec10-2015EXPNO 530PROCNO 1

F2 - Acquisition ParametersDate_ 20151211Time 11.22INSTRUM spectPROBHD 5 mm PABBO BB-PULPROG zg30TD 65536SOLVENT D2ONS 8DS 2SWH 12019.230 HzFIDRES 0.183399 HzAQ 2.7263477 secRG 645DW 41.600 usecDE 6.00 usecTE 293.2 KD1 1.00000000 secTD0 1

======== CHANNEL f1 ========NUC1 1HP1 10.90 usecPL1 -3.00 dBSFO1 400.1324710 MHz

F2 - Processing parametersSI 32768SF 400.1300000 MHzWDW EMSSB 0LB 0.30 HzGB 0PC 1.00

ABRUKERAVANCE II 400 NMRSpectrometerSAIFPanjab UniversityChandigarh

manishkumarmanu1986@gmail.com

3

(b)

4

(c)

Figure ES1. 1H- NMR spectra of (a) CTAC (b) CrC Ι (c) CrC ΙΙ.

5

(a)

(b)

6

(c)

7

(d)

8

Figure ES2. 35Cl-NMR spectra of (a) CrCl2 (b) CTAC (c) CrC Ι (d) CrC ΙΙ.

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TGA

Decomposition pathway of chromium complexes

CrC I

C19H42NCrCl3 Step -1 [C19H42N]+ + [CrCl3]- (S1)

[CrCl3]- Step -2 Cr (s) (S2)

CrC II

C38H84N2CrCl4 Step -1 [C38H84N2]+ + [CrCl4]2- (S3)

[CrCl4]2- Step -2 Cr (s) (S4)

Scheme ES1: Plausible mechanism for thermal decomposition of Chromium surfactant complexes.

The five different methods i.e.Coats-Redfern (CR), Horowitz–Metzger (HM),Madhusudanan

Krishnan Ninan (MKN), Van Krevelen (VK) and Wanjun–Yuwen–Hen– Cunxin (WYHC)

were applied for evaluationthe kinetic and thermodynamic parameters of chrmomium

complexes for the decomposition of step-1.

(і) CR method

(S5)RT/E2

eERT21

EART)(g

Taking natural log

(S6)RTE

ERT21

EARln

T)(gln 2

The fraction mass loss (α) and corresponding (1–α)n are calculated from TG curves,where n

depends upon the reaction model.

for n ≠1 (S7)RT303.2

EERT21

EARlog

)n1(T)1(1log 2

n1

for n=1 (S8)RT303.2

EERT21

EARlog

T)1log(log 2

10

A straight plot between the left hand side of the above equations against 1/T gives the slope (-

2.303E/R) and the intercept (A).

(іі)MKN method

(S9)RTE12040.0Eln9206.17678.3

EARln

T)(gln 9206.1

(ііі) WYHC method

(S10)

RTE0014.1Eln8946.16350.3

EARln

T)(gln 8946.1

(іᴠ) VK method

(S11)Tln1RTE

)1RTE(

)T/368.0(Aln)(glnm

a

m

a

RTE

mm

a

(ᴠ) HM method

Parameter T = Tm + θ is used here. If the order of reaction is 1, Tm is defined as the

temperatureat which (1 – α)m = 1/e = 0.368 and therefore

(S12)2)ln(lnmRT

E

Here, symbols β, Tm, E, A, Rare heating rate, DTG peak temperature, activation energy (kJmol–

1), pre-exponential factor (min–1) and gas constant (8.314 Jmol–1K–1), respectively. The

excellent correlation coefficients which indicate a good fit of the linear function were obtained

for all the methods (Figure II and Figure III). E values obtained from Coats-Redfern method

were used to calculate ΔH, ΔS and ΔG using following equations and data are reported in Table

ES3.

(S13)RkTAhS ]/log[303.2

(S14)RTEH

(S15)SG

11

where, h is Planck constant, T is temperature in K, A is Arrheniusconstant or frequency factor

and k represents Boltzmann constant.

0.00368 0.00370 0.00372 0.00374-11.3

-11.2

-11.1

-11.0

-10.9

-10.8

1/T

ln g

()/T

2 )

Experimental Linear fit

0.00370 0.00372 0.00374-10.9

-10.8

-10.7

-10.6

-10.5

-10.4

-10.3

1/T

ln(g

()/T

1.92

06)

0.00370 0.00372 0.00374-10.7

-10.6

-10.5

-10.4

-10.3

-10.2

1/T

ln(g

()/T

1.8

946 )

5.588 5.592 5.596 5.600 5.604-0.1

0.0

0.1

0.2

0.3

0.4

lnT

ln g

()

-2 -1 0 1 2 3

-0.1

0.0

0.1

0.2

0.3

0.4

ln ln

()

Figure ES3. Linearization curves obtained by (a) Coats–Redfern (CR), (b) Madhusudanan–Krishnan–Ninan (MKN), (c) Wanjun–Yuwen–Hen–Cunxin (WYHC), (d) van Krevelen (vK) methods and (e) Horowitz–Metzger (HM) methods for CrC Ι.

0.00370 0.00372 0.00374 0.00376

-11.2

-11.0

-10.8

Experimental Linear fit

1/T

ln g

()/T

2)

0.00370 0.00372 0.00374 0.00376

-10.8

-10.7

-10.6

-10.5

-10.4

1/T1/T

ln(g

()/T

1.9

206)

0.00370 0.00372 0.00374 0.00376

-10.6

-10.5

-10.4

-10.3

1/T

ln(g

()/T

1.8

946)

(a) (b) (c)

(d) (e)

(a) (b) (c)

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5.584 5.588 5.592 5.596-0.1

0.0

0.1

0.2

0.3

0.4

lnT

ln g

()

-2 -1 0 1 2-0.1

0.0

0.1

0.2

0.3

0.4

ln ln(

)

Figure ES4. Linearization curves obtained by (a) Coats–Redfern (CR), (b) Madhusudanan–Krishnan–Ninan (MKN), (c) Wanjun–Yuwen–Hen–Cunxin (WYHC), (d) van Krevelen (vK) methods and (e) Horowitz–Metzger (HM) methods for CrC ΙΙ.

Figure ES5 (a) Conductivity and (b) surface tension plot of CTAC.

Thermodynamic parameters of micellization

Thermodynamic parameters, (Gibbs free energy), (enthalpy) and (entropy) omG o

mH omS

of micellization of both chromium metallosurfactant in aqueous solution were calculated by

using following equations

(S16)cmcom XRTG ln)2(

(S17)dTXdRTH cmcom /ln)2(2

(S18)T/)GH(S om

om

om

(d) (e)

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where, R, T, β and Xcmcrepresents gas constant, absolute temperature, degree of ionization and

cmc in terms of mole fraction, respectively.

Compensation equations

(S19) )/1( cS om

om

(S20) /om

opm C

300 305 310 315

20

40

60

80

Con

trib

utio

n to

G

o (%)

Temperature (K)

300 305 310 31530

40

50

60

70

Con

trib

utio

n to

G

o (%

)

Temperature (K)

Figure ES6. Enthalpic ( ) and Entropic ( ) contributions to ΔGO for (a) CrC Ι (b) CrC ΙΙ.

(a)

(a) (b)

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(b)

Figure ES 7. Emission spectra of FL and Eosin Y in the presence of (a) different

concentrations of CrCl2 (b) CTAC.

Aggregation Number of micelles

The aggregation number (Nagg) of micelles were determined on the basis of steady state

fluorescence quenching method using pyrene as fluorescent probe and CPC as quencher. For

this method, the final concentration of pyrene was kept 2μM which ensures quenching of the

fluorescence of pyrene molecules that are solubilized in the micelles.

The aggrgation numberof the micelles of CTAC and chromium metallosurfactants was

calculated using the following equation N = {[S]-CMC} x slope of eq. 21

(S21)𝐿𝑛

𝐼𝑜

𝐼=

𝑁𝑎𝑔𝑔[𝑄]

([𝑆] ‒ 𝐶𝑀𝐶)

where I0 and I are the fluorescence intensity of pyrene in the absence and presence of the

quencher respectively, while Q is concentration of quencher i.e. CPC with concentration range

of 0.1-0.4mM and [S] is the concentration of CTAC/metallosurfactants that was five times the

CMC of respective system. Figure ES 9 gives the linear slope of the plot of ln(I0/I) versus [Q]

and using these value, the calculated aggregation number of different systems were calculated

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and aggregation number of CTAC, CrC I and CrC II was calculated to be 24, 12 and 19

respectively.

Figure ES 8. Plot of ln(I0/I) of pyrene as a function of concentration of CPC in the

solution of chromium metallosurfactants.

Figure ES 9.The binding plot of FL and Eosin Y with chromium complexes through (a) UV

and (b) fluorescence studies.

Table ES1. Vibrational peaks of CrCl2, CTAC and Chromium complexes

Modes of Vibration Peak position

(cm-1)CrCl2 CTAC CrC I CrC II

CH2 asymmetric stretching ----- 2914 2915 2915

CH3 symmetric stretching ----- 2847 2847 2847

-C-N stretching ----- 1261 1256 1255

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Table ES2 1H-NMR and 35Cl-NMR chemical shifts (ppm)of CTAC and chromium complexesin D2O

Complex νTerminal CH3 νN(CH3)3 νCH2 να-CH2 νβ-CH235Cl (ppm)

CrCl2 - - - - - 170.83

CTAC 0.77 (3H) 3.03 (9H) 1.18 (26H) 1.65(2H) 3.24 (2H) 12.78

CrC Ι 0.43 (3H) 2.73 (9H) 0.93 (26H) 1.33(2H) 4.39 (2H) 58.63

CrC ΙΙ 0.63 (3H) 2.92 (9H) 1.13 (26H) 1.53(2H) 4.59 (2H) 30.48

Table ES3. Thermodynamic decomposition parameters for the Chromium complexes using TGA.

Complex A/min-1 ΔG /kJmol-1 ΔH/kJmol-1 ΔS/JK-1mol-1

CrC Ι 1.23×1010 64.343 62.171 -8.098

CrC ΙΙ 4.4×109 59.042 56.674 -9.098

Table ES4. Values of Tc, σ and ΔCpfor Chromium surfactant complexes using

conductivity measurement.

Table ES5. 1H NMR chemical shifts (ppm) of Fluorescein (FL) and Eosin Y in D2O solution without and with Chromium complexes. The numbers refer to dyes atom numbering as given in the structures below, symbols in parentheses indicate signal multiplicity.

Sample 1(d) 2(t) 3(t) 5/10(d) 4(d) 7/8(s) 6/9(d)FL 7.80 7.60 7.50 7.26 6.69 6.7 6.65

FL in CrC Ι 8.14 7.35 7.30 7.02 6.78 6.71 6.51FL in CrC ΙΙ 8.02 7.44 7.34 7.06 6.72 6.77 6.54

Sample 1(d) 2(t) 3(t) 4(d) 5(s) 6(s)Eosin Y 7.76 7.25 7.58 7.51 7.02 7.56

Eosin Y in CrC Ι 8.21 7.39 7.41 7.33 7.20 7.29Eosin Y in CrC ΙΙ 8.19 7.35 7.42 7.32 7.04 7.30

Tc (K) σ (-) ΔCpo(KJmol-1 K-1)

CrC Ι 299.40 0.0523 0.226

CrC ΙΙ 111.85 0.1557 0.197

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O OHO

COOH

1

23

4

5

6

7 8

9

10

O

Br

HO

Br

Br

Br

COOH

O

1

2

3

4

56

Fluorescein Eosin Yellow