Study by infrared spectroscopy, Raman and SERS of imidazole …phdthesis.uaic.ro/PhDThesis/Aștefanei, Dan, Study by infrared... · 5 III. Personal researches Objectives PhD thesis

UNIVERSITY ”ALEXANDRU IOAN CUZA” OF IA ȘI

FACULTY OF CHEMISTRY

DOCTORAL SCHOOL OF CHEMISTRY AND LIFE SCIENCES

Study by infrared spectroscopy, Raman and

SERS of imidazole derivatives

PhD THESIS SUMMARY

Scientific supervisor:

Prof. univ. dr. Mangalagiu Ionel

PhD student:

Aștefanei Dan

2013

2

Contents Keywords ................................................................................................................................................ 3

General .................................................................................................................................................... 4

II. Computational details ......................................................................................................................... 4

III. Personal researches ........................................................................................................................... 5

Objectives .............................................................................................................................. 5

III.1 Experimental (Selective) ................................................................................................ 5

III.1.1 Synthesis .............................................................................................................................. 6

III.1.2 Study by infrared spectroscopy, Raman and SERS of imidazole derivatives.Vibrational analysis. Adsorption on the silver surface....................................................................................... 7

Final conclusions .................................................................................................................................. 25

References (selective) ........................................................................................................................... 26

3

Keywords

• IR, Raman, SERS

• vibrational analysis

• adsorption on the silver surface

• imidazole derivatives

• benzimidazole derivatives

4

General

Infrared spectroscopy (FT-IR), Raman and SERS are techniques commonly used to identify

drugs and their precursors. Infrared spectroscopy and Raman spectroscopy provides detailed

information on molecular vibrations. Raman spectroscopy is an analytical method used frequently in

the analysis of pigments [1-3]. SERS (Surface-Enhanced Raman Spectroscopy) has become an

extremely useful method used in determining the structure of bioorganic compounds [4].

In order to understand correctly the infrared spectra, Raman and SERS of molecules, it is

required to identify the vibrational modes. Quantum mechanics methods ab-initio and DFT (Density

Functional Theory) are used. These methods calculate the theoretical vibration modes and

subsequently assigned to the results obtained experimentally.

The thesis is divided into three chapters. The first part briefly describes the techniques of

infrared spectroscopy, Raman and SERS investigation of imidazole derivatives used in the

experimental investigation of this thesis.

Section Two describes briefly the method of computational simulation used to determine the

theoretical vibratory modes of the imidazole derivatives investigated in the experimental part of this

thesis.

Personal researches are summarized in the third chapter of this thesis and present the FT-IR

spectra, Raman and SERS.

II. Computational details

Theoretical calculations were investigated with Firefly [5, 6]. DFT calculations are made

according to the method of Becke exchange functional [7] and Perdew-Wang 91 method (B3PW91)

[8]. Also, B3LYP method was used. This method contains hybrid parameters using Lee-Yang-Parr

correlation [9, 10].

DFT/B3LYP, DFT/B3PW91 methods were used, and ab initio HF with 6-31G basis set *.

5

III. Personal researches

Objectives

PhD thesis entitled “Study by infrared spectroscopy, Raman and SERS of imidazole

derivatives“ aims vibrational spectroscopic investigation of a series of organic compounds,

investigation in conjunction with computational methods of theoretical simulations.

The research presented in this paper had the following objectives:

1. Synthesis of imidazole derivatives by previously established methods.

2. The main objective was to investigate the synthesized imidazole derivatives by infrared

spectroscopy, Raman and SERS. Raman spectroscopy provides complementary information, but due

to fluorescence which may present some organic compounds, information may be limited. SERS

technique can be used instead.

3. Calculation of vibrational modes of the compounds studied by computational methods.

Interpretation of vibrational spectra (FT -IR , Raman and SERS ) is a difficult task. Identification of

vibrational modes is difficult in the case of complex spectra. The interpretation and identification of

vibrational modes in the spectra may be facilitated by comparison of experimentally obtained data

with computational simulation data.

4. Identification of functional groups involved in adsorption of molecules on the surface of

the particle of colloidal silver.

5. Development of SERS technique for the class of compounds studied. This technique is

highly sensitive. Spectra can be recorded with very small amounts of substance. The method can be

used for the detection and identification of compounds present in traces. The identification can be

used to create a database.

III.1 Experimental (Selective)

Infrared spectra were recorded with the Bruker VERTX 70, spectral resolution 2 cm-1 /pixel

within 3500 – 300 cm-1.

Raman and SERS spectra were recorded with Raman-Horiba Jobin Yvon RPA-HE 532

spectrometer.

The final concentration of analyte in the sol was approximately 1·10-3 M. NaOH and H2SO4

were used to adjust the pH value.

6

III.1.1 Synthesis

The synthesis of imidazole derivatives (Fig. III.1 and Fig. III.2) [11, 12].

1a

N

NH

N

NH1b

CN

N

N

N

N2b

CN

CN

3.a. R= X= I; Y= NH2 b. R= X= Br; Y= OCH3 c. R= X= Br; Y= OC2H5N

N

N

N

CN

CN

X

O

Y

X= I; Y= NH2 X= Br; Y= OCH3, OC2H5

YO

Y

O

X

X

3.d. X= I; Y= NH2 e. X= Br; Y= OCH3 f. X= Br; Y= OC2H5

2a

Fig.III.1 Synthesis of imidazole derivatives

1a

N

NH

N

NH1b

COOR

N

N

N

N2b

COOR

COOR

N

N

N

N

COOR

COOR

X

O

Y

X= I; Y= NH2 X= Br; Y= OCH3, OC2H5

YO

Y

O

X

X

2a

R= C2H5

3. d. R= C2H5; X= I; Y= NH2 e. R= C2H5; X= Br; Y= OCH3 f. R= C2H5; X= Br; Y= OC2H5

4. d. R= C2H5; X= I; Y= NH2 e. R= C2H5; X= Br; Y= OCH3 f. R= C2H5; X= Br; Y= OC2H5

Fig.III.2 Synthesis of imidazole derivatives

In basic medium, the salts of imidazole derivatives formed the corresponding ylides.

The characterization of ylide by SERS technique is scarce [13, 14].

III.1.2 Study by infrared spectroscopy, Raman and SERS of imidazole

derivatives.Vibrational analysis

III.2 Study by infrared spectroscopy, Raman and SERS of

imidazole. Adsorption on the

Fig.III.2.1 FT-IR (b) and Raman

N-(2-cyanoethil)-imidazole

Fig. III.2.3 Molecule adsorption in neutral and basic medium

Conclusions In neutral and basic medium the molecule is adsorbed via In acidic medium the molecule is adsorbed via the electronic cloud of imidazole.

7

Study by infrared spectroscopy, Raman and SERS of imidazole

derivatives.Vibrational analysis. Adsorption on the silver surface.

Study by infrared spectroscopy, Raman and SERS of

the silver surface.

Raman (a) spectra of imidazole

Fig. III.2.2 SERS spectra of

cyanoethil)-imidazole in different media(a) acidic, (b) neutral

Molecule adsorption in neutral and

basic medium Fig. III.2.4 Molecule adsorption in acidic

medium

In neutral and basic medium the molecule is adsorbed via nitrogen atom In acidic medium the molecule is adsorbed via the electronic cloud of imidazole.

Study by infrared spectroscopy, Raman and SERS of imidazole

Study by infrared spectroscopy, Raman and SERS of N-(2-cyanoethil)-

SERS spectra of N-(2-in different media:

ral and (c) basic

Molecule adsorption in acidic

medium

nitrogen atom N3. In acidic medium the molecule is adsorbed via the electronic cloud of imidazole.

8

III.3 Study by infrared spectroscopy, Raman and SERS of N-(2-cyanoethil)-

benzimidazole. Adsorption on the silver surface.

Fig. III.3.1 Raman (a) and FT-IR (b)

spectra of N-(2-cyanoethil)-benzimidazole

Fig. III.3.2 SERS spectra of N-(2-cyanoethil)-

benzimidazole at different pH values

Fig. III.3.3 Molecule adsorption in neutral

medium

Fig. III.3.4 Molecule adsorption in acidic and

basic medium Conclusions The molecule is adsorbed via nitrogen atom N3 in neutral medium. The molecule is adsorbed via nitrogen atom N13 in acidic and basic medium

3500 3000 2500 2000 1500 1000 500

2972 88

7 477

1265

1178

1202

631

1737

1032

1361

772

2246

442

994

1494

1594

2247

b

a

Wavenumber / cm-1

Ram

an in

tens

ity

A

bsor

ptio

n

3092

2923

3500 3000 2500 2000 1500 1000 500

541

776

776

772

1009

2988

299

429

88pH=3

pH=7

pH=12

2250

Ram

an in

tens

ity

Wavenumber / cm-1

9

III.4 Study by infrared spectroscopy, Raman and SERS of 3-(2-amino-2-

oxoethyl)-1-(2-cyanoethyl)-1H-imidazol-3-ium iodide. Adsorption on the silver surface.

Fig. III.4.1 Raman (a) and FT-IR (b) spectra of 3-(2-amino-2-oxoethyl)-1-(2-cyanoethyl)-1H-

imidazol-3-ium iodide

Fig. III.4.2 SERS spectra of 3-(2-amino-

2-oxoethyl)-1-(2-cyanoethyl)-1H-imidazol-3-ium iodide at different pH

values

Fig. III.4.3 Molecule adsorption on silver surface

Conclusions The molecule is adsorbed on the silver surface via nitrile and amide groups.

3500 3000 2500 2000 1500 1000 500

1684

614

1093

1422

2923

2252

760

116614

01

1560

1609

3241

2956

3075

1693

b22

54

a

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

3500 3000 2500 2000 1500 1000 500

1577

2917

2256

2255 61

1 558

1300

1626

1511

1511

1452

2844

722

559

87711

4212

08

1452

1577

1629 12

97

1208

558

1300

1452

1511

1577

1629

pH=3

pH=7

2850

pH=12

Ram

an in

tens

ity

Wavenumbers (cm-1)

10


oxoethyl)-1-(2-cyanoethyl)-1H-benzo[d]imidazol-3-ium iodide. Adsorption on the silver

surface.

Fig. III.5.1 Raman (a) and FT-IR (b) spectra of 3-(2-amino-2-oxoethyl)-1-(2-cyanoethyl)-

1H-benzo[d]imidazol-3-ium iodide

Fig. III.5.2 SERS spectra of 3-(2-amino-2-

oxoethyl)-1-(2-cyanoethyl)-1H-benzo[d]imidazol-3-ium iodide at different

pH values


Conclusions The molecule is adsorbed on the silver surface via nitrile and amide groups.

3500 3000 2500 2000 1500 1000 500

1426

772

77210

12

1348

1424

296230

62

1609

2911

2243

427

497

597

1009 90

9

760

1134

118813

02

156016

1416

85

3345

3255

3181 30

65

2912

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

2245

3500 3000 2500 2000 1500 1000 500

614

130

0

120

8

772

2922

284

7

1208

1142

877

558

1297

142116

29

100

2

151

115

11

120

8

1303

284

2

558

136115

11

157

715

7715

77

1452

145

2

pH=12

pH=7

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

1452

11

III.6 Study by infrared spectroscopy, Raman and SERS of 1-(2-cyanoethyl)-3-(2-

methoxy-2-oxoethyl)-1H-imidazol-3-ium bromide. Adsorption on the silver surface.

Fig. III.6.1 Raman (a) and FT-IR (b) spectra

of 1-(2-cyanoethyl)-3-(2-methoxy-2-oxoethyl)-1H-imidazol-3-ium bromide

Fig. III.6.2 SERS spectra of 1-(2-

cyanoethyl)-3-(2-methoxy-2-oxoethyl)-1H-imidazol-3-ium bromide at different pH

values


Conclusions

The molecule is adsorbed on the silver surface via nitrile and ester groups.

3500 3000 2500 2000 1500 1000 500

1647

419

628

82196

8

1420

1230

1167

1569

1753

2854

3086

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

2247

3500 3000 2500 2000 1500 1000 500

558

164

8

611

718

772

92710

481180

130

7

358

225

5

292

0

136

1

151

1

305

4

1573

316

0

772

145

2

225

52844 11

43

877

614

559

1422

1297

1511

162

9

292

029

49

877

614

558

129

713

61

1452

1511

157

71

629

pH=12

pH=7

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

2922

12

III.7 Study by infrared spectroscopy, Raman and SERS of 1-(2-cyanoethyl)-3-(2-

methoxy-2-oxoethyl)-1H-benzo[d]imidazol-3-ium bromide. Adsorption on the silver

surface.

Fig. III.7.1 FT-IR (b) and Raman (a) spectra

of 1-(2-cyanoethyl)-3-(2-methoxy-2-oxoethyl)-1H-benzo[d]imidazol-3-ium

bromide


cyanoethyl)-3-(2-methoxy-2-oxoethyl)-1H-benzo[d]imidazol-3-ium bromide at different

pH values


Conclusions The molecule is adsorbed on the silver surface via nitrile and ester groups.

3500 3000 2500 2000 1500 1000 500

1016

772

1348

1612

1613

2252

1431

1362

1229

967

757

428

2960

628

3072

3019

1738

1554

3108

Abs

orpt

ion

Ram

an In

tens

ity

Wavenumbers (cm-1)

a

b

2252

3500 3000 2500 2000 1500 1000 500

136

1

614

772

931

131

0

118

0

150

815

70

1648

3158

559

296

2

1296

1142

772

120

8

101

3

2252

1511

1613

1428

135

8306

2

614

559614

145

2

1142

1296

136

1

150

815

77

292

2

3062

1648

292

02

2951

pH=12

pH=7

Abs

orpt

ion

Ram

an

inte

nsity

Wavenumbers (cm-1)

pH=3

225

2

13

III.8 Study by infrared spectroscopy, Raman and SERS of ethyl 3-(1H-imidazol-

1-yl)propanoate. Adsorption on the silver surface.


of ethyl 3-(1H-imidazol-1-yl)propanoate

Fig. III.8.2 SERS spectra of ethyl 3-(1H-imidazol-1-yl)propanoate at different pH

values


Conclusions The molecule is adsorbed on the silver surface via ester group.

3500 3000 2500 2000 1500 1000 500

1506

814940

663

73315

793441

3053 2875

2981

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

1731

3500 3000 2500 2000 1500 1000 500

931 81

6

611

1030

1347

1570

2922

926

614

772

1452

1421

614

1344

558

103

4

164

8

292

2

772

151

115

73

2967

136116

48

1511

1577

pH=12

pH=7

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

2920

14

III.9 Study by infrared spectroscopy, Raman and SERS of methyl 3-(1H-

imidazol-1-yl)propanoate. Adsorption on the silver surface.

Fig. III.9.1 Raman (a) and FT-IR (b) spectra of methyl 3-(1H-imidazol-1-yl)propanoate

Fig. III.9.2 SERS spectra of methyl 3-(1H-imidazol-1-yl)propanoate at different pH

values


Conclusions The molecule is adsorbed on the silver surface via and ester group.

3500 3000 2500 2000 1500 1000 500

1729

2954

2848

1080

664

823

1507

746

1348

1079

1030

841

1439

3111

1507 90

7

624

2957

3114

2850

903

1286

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b17

38

3500 3000 2500 2000 1500 1000 500

841

1573 15

08

1310

611

772

1180

1361

1030

1508

1341

1461

1314

2952

559

1239

1086

1645

838

1273

1385

1121 10

73

pH=12

pH=7

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

1648

15

III.10 Study by infrared spectroscopy, Raman and SERS of 3-(1H-imidazol-1-

yl)propanamide. Adsorption on the silver surface.


of 3-(1H-imidazol-1-yl)propanamide

Fig. III.10.2 SERS spectra of 3-(1H-

imidazol-1-yl)propanamide at different pH values

Fig. III.10.3 Molecule adsorption on silver

surface in basic medium

Fig. III.10.4 Molecule adsorption on silver

surface in acidic medium

Conclusions The molecule is adsorbed via amide group. The molecule is vertical on surface in

basic medium. In acidic medium the molecule adopts a tilted position relative to the surface.

3500 3000 2500 2000 1500 1000 500

Abs

orpt

ion

1084

1516

1228 83

6

1083

629

1671

75911

11

1038

1276

1672 14

14

479

1296

3147 29

65

3387

915

3145

3109

475

1344

666

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

3386

3500 3000 2500 2000 1500 1000 500

611

924

403

772

1125

1180

1361

1310

1508

1573

1058

924

1344

1208

1648

1511

1577

2928

558

1300

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

pH=7

pH=12

1452

16

III.11 Study by infrared spectroscopy, Raman and SERS of 3-(1H-

benzo[d]imidazol-1-yl)propanamide. Adsorption on the silver surface.


of 3-(1H-benzo[d]imidazol-1-yl)propanamide

Fig. III.11.2 SERS spectra of 3-(1H-

benzo[d]imidazol-1-yl)propanamide at different pH values


Conclusions The molecule is adsorbed on the silver surface via amide group.

3500 3000 2500 2000 1500 1000 500

1771

465

419

901

1246

1365

1493

1410

1611

1672

580

745

1003

1167

3350

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

3350

3500 3000 2500 2000 1500 1000 500

1009

3070

2844

1009

1645

1364

1577

1648

1452

559

411

1518

1418

1334

1307

772

611

884

1511

776

881

1080

1511

629

1191

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

pH=7

pH=12

1645

17


oxoethyl)-1-methyl-1H-imidazol-3-ium iodide. Adsorption on the silver surface.


spectra of 3-(2-amino-2-oxoethyl)-1-methyl-1H-imidazol-3-ium iodide

Fig. III.12.2 SERS spectra of 3-(2-amino-2-

oxoethyl)-1-methyl-1H-imidazol-3-ium iodide at different pH values


Conclusions The molecule is adsorbed on the silver surface via amide group. The molecule adopts

a tilted position relative to the surface.

3500 3000 2500 2000 1500 1000 500

1687

972

2986

3247

3314

1688

622

1107

1034

1173

838

756

1020

856

1204

970

1104

411

625

673

1344

1299

1415

540

592

3161

1393

2954

1423

1612

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

3147

3500 3000 2500 2000 1500 1000 500

2845 11

80

1361

1310

559

2922

611

772

1570

1508

2946

1648

1421

1125

1101

1452

1648

1511

1097

555

311

pH=12

pH=7

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

2845

18

III.13 Study by infrared spectroscopy, Raman and SERS of 3-(2-ethoxy-2-

oxoethyl)-1-methyl-1H-imidazol-3-ium iodide. Adsorption on the silver surface.

Fig. III.13.1 Raman (a) and FT-IR (b) spectra of 3-(2-ethoxy-2-oxoethyl)-1-

methyl-1H-imidazol-3-ium iodide

Fig. III.13.2 SERS spectra of 3-(2-ethoxy-2-oxoethyl)-1-methyl-1H-imidazol-3-ium iodide at

different pH values

III.13.3 Molecule adsorption on silver surface

Conclusions The molecule is adsorbed on the silver surface via ester group. The molecule adopts a

tilted position relative to the surface.

3500 3000 2500 2000 1500 1000 500

410

373

411

1020

1201

644

772

906

1567

1369

633

708

1031

989

1179

881

2933

1344

2850

1415

2830

3015

310631

53

904

768

128

573

1754

1567

374

Ram

an in

tens

ity

Abs

orpt

ion

Wavenumbers (cm-1)

a

b

1752

3500 3000 2500 2000 1500 1000 500

1629

2946

2912

1300 10

97

772

1577

2844

614

2845

129715

77

562

1452

558

1649 10

94

552

1511

1511

pH=12

pH=7

Ram

an in

tens

ityWavenumbers (cm-1)

pH=3

1452

19

III.14 Study by infrared spectroscopy, Raman and SERS of 1-(2-cyanoethyl)-3-

(2-ethoxy-2-oxoethyl)-1H-imidazol-3-ium bromide. Adsorption on the silver surface.

Fig. III.14.1 Raman (a) and FT-IR (b) spectra of 1-(2-cyanoethyl)-3-(2-ethoxy-2-oxoethyl)-

1H-imidazol-3-ium bromide

Fig. III.14.2 SERS spectra of 1-(2-cyanoethyl)-3-(2-ethoxy-2-oxoethyl)-1H-imidazol-3-ium bromide at different pH

values


Conclusions The molecule is adsorbed on the silver surface via ester and nitrile groups.

3500 3000 2500 2000 1500 1000 500

623

116922

55 1398

759

1018

1568

1232

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

1746

a

b

3500 3000 2500 2000 1500 1000 500

2276

1104

284

551

2922

1104

967

729

450

835

1505

1418

729

2922

2920

2962

2960 14

18

1108

1348

1418

3163

2262

1571

2259

1587

2960

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

pH=7

pH=12

3163

20

III.15 Study by infrared spectroscopy, Raman and SERS of 1-(2-cyanoethyl)-3-

(2-ethoxy-2-oxoethyl)-1H-benzo[d]imidazol-3-ium bromide. Adsorption on the silver

surface.

Fig. III.15.1 Raman (a) and FT-IR (b) spectra of 1-(2-cyanoethyl)-3-(2-ethoxy-2-oxoethyl)-

1H-benzo[d]imidazol-3-ium bromide


cyanoethyl)-3-(2-ethoxy-2-oxoethyl)-1H-benzo[d]imidazol-3-ium bromide at different

pH values

N

N

N

O O

Ag surface

Ag surface

Br


Conclusions The molecule is adsorbed on the silver surface via ester and nitrile groups.

3500 3000 2500 2000 1500 1000 500

1182

91710

161211

1431

1613

3075 29

60

967

1229

772

756

1554

42862

8

1362

2252

2957

1738

3019

3108

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

2252

3500 3000 2500 2000 1500 1000 500

225 9

1013

6 11

770

12081 3

5814

2514

2514

8 2

1358

1 425

1013

773

773

2920

2 259 16

13

292 2

101 3

1208

2 256

3065

3 065

2922

2949

306 5

1139

pH=12

pH=7

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

1 613

21


oxoethyl)-1-(3-ethoxy-3-oxopropyl)-1H-imidazol-3-ium bromide. Adsorption on the

silver surface.

Fig. III.16.1 Raman (a) and FT-IR (b) spectra of 3-(2-ethoxy-2-oxoethyl)-1-(3-ethoxy-3-oxopropyl)-1H-imidazol-3-ium bromide

Fig. III.16.2 SERS spectra of 3-(2-ethoxy-2-oxoethyl)-1-(3-ethoxy-3-oxopropyl)-1H-imidazol-3-ium bromide at different pH

values


Conclusions The molecule is adsorbed on the silver surface via ester groups.

3500 3000 2500 2000 1500 1000 500

1377

1030

2935

1020

1424

1567

762

939

576

2970

2981

1096

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

624

3500 3000 2500 2000 1500 1000 500

407

3 166

1 574

773

1090

56313

6113

11

1181

61416

49

1508

1191

5 5961

41283

7 69

1361

2 960

1 570 15081648

131 0

136 1

164 8

1408

1573

1508

772

141 8

2920

823

2922

614

102 3

1180

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=12

pH=7

pH=3

2922

22


oxopropyl)-3-(2-methoxy-2-oxoethyl)-1H-imidazol-3-ium bromide. Adsorption on the

silver surface.


spectra of 1-(3-ethoxy-3-oxopropyl)-3-(2-methoxy-2-oxoethyl)-1H-imidazol-3-ium

bromide

Fig. III.17.2 SERS spectra of 1-(3-ethoxy-3-oxopropyl)-3-(2-methoxy-2-oxoethyl)-1H-

imidazol-3-ium bromide at different pH values

N

N

O O

Ag surface

Ag surface

O O

Br



3500 3000 2500 2000 1500 1000 500

622

1096

767163

5

939

855

1024

575

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

156

7

3500 3000 2500 2000 1500 1000 500

2957

611

559

1649

1297

1361

1508

773

615

1421

1361

1307

1508

1573

1511

1648

2922

77215

7316

48

1180

2946

1421

614

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=3

pH=7

pH=12

2922

23


oxoethyl)-1-(3-methoxy-3-oxopropyl)-1H-imidazol-3-ium bromide. Adsorption on the

silver surface.

Fig. III.18.1 Raman (a) and FT-IR (b) spectra of 3-(2-ethoxy-2-oxoethyl)-1-(3-methoxy-3-

oxopropyl)-1H-imidazol-3-ium bromide

Fig. III.18.2 SERS spectra of 3-(2-ethoxy-2-oxoethyl)-1-(3-methoxy-3-oxopropyl)-1H-


N

N

O O

Ag surface

Ag surface

O O

Br



3500 3000 2500 2000 1500 1000 500

6 251 7

36

1 424

1023

1566

578

1021

144

0

843

1735

1348

29 3

629

57

841

7 02

626

7 61

1376

1636

1 108

406

936Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b8 7

0

3500 3000 2500 2000 1500 1000 500

163

5

558

292 2

156

7

1 418

3163

614

102

3

1097

1 508 13

61

772

141

8

316

5

1310

2922

1 570

1648

6 14

1 180

Ram

an in

tens

ity

Wavenumbers (cm-1)

pH=12

pH=7

pH=3

24

III.19 Study by infrared spectroscopy, Raman and SERS of 3-(2-methoxy-2-

oxoethyl)-1-(3-methoxy-3-oxopropyl)-1H-imidazol-3-ium bromide. Adsorption on the

silver surface.

Fig. III.19.1 Raman (a) and FT-IR (b) spectra of 3-(2-methoxy-2-oxoethyl)-1-(3-methoxy-3-oxopropyl)-1H-imidazol-3-ium

bromide

Fig. III.19.2 SERS spectra of 3-(2-methoxy-2-oxoethyl)-1-(3-methoxy-3-oxopropyl)-1H-



Conclusions

The molecule is adsorbed on the silver surface via ester groups.

3500 3000 2500 2000 1500 1000 500

902

770 62

4

845

1347

626

902

842

1034

142428

52

Abs

orpt

ion

Ram

an in

tens

ity

Wavenumbers (cm-1)

a

b

2957

3500 3000 2500 2000 1500 1000 500

927

614

7 72

1 180

1104

136 1

434

559

555

1570

2946

2 920

1 635

2 847

3163

2847

2845

2946

2922

1 30715

08 1 418

1023

3161

1422

1 125

1 648

Ram

an in

tens

ityWavenumbers (cm-1)

pH=12

pH=7

pH=3

156 7

25

Final conclusions

• In this thesis nineteen imidazole derivatives were synthesized and studied by infrared spectroscopy,

Raman and SERS.

• Twelve imidazole derivatives were evaluated and optimized by computational methods type a- initio

(HF) and DFT methods B3PW91/6-31G* and B3LYP/6-31G*.

• The theoretical vibrational modes were corrected according to the literature; for ab-inito method has

been applied a correction factor of 0.8953; for DFT methods (B3LYP and B3PW91) has been applied

a correction factor of 0.9614

• The theoretical data are consistent with the experimental values.

• The FT- IR spectra of the imidazole derivatives studied (with some exceptions) are clear and sharp.

• Raman spectra show a strong fluorescence. In some cases no useful information occurs. In other

cases, on the contrary, complete the FT -IR spectra.

• The adsorption mechanisms on classes of compounds in SERS spectra were elucidated. Imidazole

derivatives with amide or ester groups are strongly adsorbed on the particle surface of the colloidal

silver. The band corresponding to the vibration of C ═ O in amide and ester groups is shifted towards

lower wave numbers.

• The nitrile group of imidazole derivatives studied is involved in the adsorption process. Imidazole

derivatives containing only nitrile functional group can be adsorbed on the silver surface through the

electronic cloud of the imidazole nucleus.

• These results can provide a basis for building a database to allow rapid identification of imidazole

derivatives from various materials.

• The results of this study were published in two papers in ISI journals.

26

References (selective)

1. Buzgar, N., Buzatu, A., Apopei, A. I., Aștefanei, D., Topoleanu, F., Raman study of the brownish-yellow pigment from a Roman Basilica (Dobrogea, Romania - 4th -6th century A.D.) Analele Știintifice ale Universității "Al. I. Cuza" din Iași, Geologie, 2011. 57(2): p. 15-18.

2. Buzgar, N., Bodi, G., Buzatu, A., Apopei, I. A., Aștefanei, D., Raman and XRD studies of black pigment from Cucuteni ceramics. Analele Știintifice ale Universității "Al. I. Cuza" din Iași, Geologie, 2010. LVI (2).

3. Buzgar, N., Bodi, G., Aștefanei, D., Buzatu, A., Apopei, I. A., The Raman study of white, red and black pigments used in Cucuteni Neolithic painted ceramics. Analele Știintifice ale Universității "Al. I. Cuza" din Iași, Geologie, 2010. LVI (1).

4. Ells, R., et al., Arachidonic acid increases antifungal susceptibility of Candida albicans and Candida dubliniensis. Journal of Antimicrobial Chemotherapy, 2009. 63(1): p. 124-128.

5. Granovsky, A.A., Firefly version 7.1.G, www http://classic.chem.msu.su/gran/firefly/index.html.

6. Schmidt, M.W., et al., General Atomic and Molecular Electronic-Structure System. Journal of Computational Chemistry, 1993. 14(11): p. 1347-1363.

7. Becke, A.D., Density-Functional Exchange-Energy Approximation with Correct Asymptotic-Behavior. Physical Review A, 1988. 38(6): p. 3098-3100.

8. Perdew, J.P. and Y. Wang, Accurate and Simple Analytic Representation of the Electron-Gas Correlation-Energy. Physical Review B, 1992. 45(23): p. 13244-13249.

9. Becke, A.D., A New Mixing of Hartree-Fock and Local Density-Functional Theories. Journal of Chemical Physics, 1993. 98(2): p. 1372-1377.

10. Baia, M., Astilean, S., Iliescu, T., Raman and SERS Investigations of Pharmaceuticals. 2008: Springer.

11. Risca, M., Moldoveanu, C., Astefanei, D., Mangalagiu, I. I., Microwave Assisted Reactions of Imidazole Derivatives of Potential Practical Applications. Revista De Chimie, 2010. 61(3): p. 303-305.

12. Zbancioc, G., Bejan, V., Risca, M., Moldoveanu, C., Mangalagiu, I. I., Microwave Assisted Reactions of Some Azaheterocylic Compounds. Molecules, 2009. 14(1): p. 403-411.

13. Cao, P.G., R.A. Gu, and Z.Q. Tian, Surface-enhanced Raman spectroscopy studies on the interaction of imidazole with a silver electrode in acetonitrile solution. Journal of Physical Chemistry B, 2003. 107(3): p. 769-777.

14. Bukowska, J., A. Kudelski, and K. Jackowska, The Use of Surface Enhanced Raman-Scattering (Sers) to Probe the Interaction of Imidazole with the Silver Electrode Surface. Journal of Electroanalytical Chemistry, 1991. 309(1-2): p. 251-261.

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Study by infrared spectroscopy, Raman and SERS of imidazole …phdthesis.uaic.ro/PhDThesis/Aștefanei, Dan, Study by infrared... · 5 III. Personal researches Objectives PhD thesis