994.8 mg of dansyl chloride (3.7 mmol, 1 eq) were dissolved in 275 mL acetone and 7.5 mL H2O. Cystamine dihydrochloride (418.4 mg, 1.8 mmol, 0.5 eq) was dissolved in 25 mL NaHCO3
and added drop wise whereas pH value was kept to 7.5- 8 by adding NaOH solution (controlled via pH indicator stripes). Reaction progress was monitored via TLC in CH2Cl2 : MeOH = 20:1 (Rf = 0,75) until no further dansyl chloride was detected. After 2.5 hours, 100 mL CHCl3 were added and the solution was extracted with saturated NaHCO3 solution 4 times, followed by distilled water. The organic phase was dried over Na2SO4 and the solvent evaporated under reduced pressure. The remaining product was dried, yielding 855.1 mg (74.8%) of a fluffy, crispy yellow solid.
Dansyl cystamine was diluted in 200 mL EtOH. The yellowish solution turned greenish- blue after the alternating addition of 6.1 g Zn and 12.5 mL acetic acid. Again the reaction process was monitored via TLC in acetone : cyclohexane = 3+1. As educt was still present after 4 hours, the reaction was stirred overnight. Afterwards solids were removed by filtration and the solvent evaporated. The residue was redissolved in 100 mL CHCl3 and extracted with H2O dist. three times, followed by saturated NaHCO3 solution and brine. Again, the organic layer was dried over Na2SO4 and solvent was distilled off under reduced pressure yielding a yellowish-greenish film.
Experimental yield: 745.4 mg (86 %)
1H-NMR (δ, 20°C, CDCl3, 300 MHz): 8.57 (d, 1H, arom), 8.26 (dt, 2H, arom), 7.55 (p, 2H, arom), 7.20 (d, 1H, arom), 5.13 (t, 1H, NH), 3.08 (q, 2H, CH2N), 2.89 (s, 6H, N(CH3)2), 2.53 (dq, 2H, CH2S ), 1.20 (t, 1H, SH).
4.3.16 DANSYL- FUNCTIONALIZED POLY(ISOPRENE)PI4
50 mg (1 eq, 0.74 mmol) of poly(isoprene) were reacted with 114.1 mg of dansyl-cysteamine (0.5 eq, 0.37 mmol) in 2 mL of CHCl3. The reaction was initiated upon addition of 0.6 mg (0.1 mol% in respect to thiol) AIBN and allowed to stir for 72 h. After that time, the solvent was evaporated and the polymer purified upon precipitation in MeOH, filtered and dried.
yield: n.d.
1H-NMR (δ, 20°C, CDCl3, 300 MHz): 8.54 (dd, 1H, arom), 8.26 (t, 1.84H, arom), 7.53 (q, 2.24H, arom), 7.17 (dd, 1.15H, arom), 5.88-5.51 (bs, 0.50H, -CH=CH2), 5.23 (bs, 0.65H, NH), 5.23-4.77 (m, 0.97H, -CH=C(Me)-, -CH=CH2), 4.75-4.39 (d, 5.25H, -C(Me)=CH2), 3.03 (bs, 1.73H, CH2 N-dansyl), 2.88 (s, 5.82H, N(CH3)2), 2.48 (bs, 1.81H, CH2S-dansyl, CH2-S-CH2 and CH2-S-CH), 2.36-1.72 (bs, 9.60H, CH and -CH2- 1,4 and 3,4 functionalized), 1.71-1.46 (bs, 22.11H, -CH=C(CH3) and –C(CH3)=CH2), 1.46-1.06 (bs, 16.94H, CH2-C(Me)-), 1.05-0.73 (bs, 22.53H, -CH2-C(CH3)-).
IR (cm-1): 3307, 3070, 2925, 2864, 2782, 1642, 1578, 1450, 1402, 1377, 1324, 1260, 1198, 1144, 1071, 1020, 943, 882, 791, 683, 625, 570, 536, 496, 470.
GPC: Mn (g mol-1)= 30900, PDI= 1.9
Appendix
MEDA N, N- Dimethylcysteamine hydrochloride MeOH/ MeOD Methanol/ deuterated Methanol
Appendix
Figure 1-1 Structure and content of a typical Gram-positive bacteria cell ... 27
Figure 1-2 Gram-positive and -negative cell wall structure ... 28
Figure 1-3 Mode of action of antibacterial polymers with the cytoplasm membrane leading to the lysis of cell constituents and the death of the cell ... 31
Figure 1-4 Contact-killing via the polymeric spacer effect ... 32
Figure 1-5 Contact killing via phospholipid sponge effect61 ... 33
Figure 1-6 Polymer surface modifier concept ... 38
Figure 2-1 IR- spectra of poly(isoprene) and the thiol-ene modification thereof ... 47
Figure 2-2 1H NMR spectra of polymers PI - PI 2 recorded in CDCl3 ... 50
Figure 2-3 TGA of polymers PI- PI 3 ... 52
Figure 2-4 Surface properties of polymers under investigation ... 53
Figure 2-5 Reduction of CFU after 24 h ... 56
Figure 2-6 Thermo-Haake mini-extruder ... 58
Figure 2-7 Reference plate PP (left), PP+2.5 wt% PI 2 (middle) and PP+5.0 wt% PI 2 (right) .. 59
Figure 2-8 ATR-IR spectra of poly(propylene) and compounds ... 60
Figure 2-9 – potential measurements of PI 2, PP and compounds ... 61
Figure 2-10 CFU reduction after 24 h on compound plates ... 63
Figure 2-11 1H NMR spectra of Me2CySS (1) in CDCl3, Me2CySS+ (3) and Me2CySH+ (6) in MeOD (solvent residual peak marked with *) ... 78
Figure 2-12 13C{1H} NMR spectra of cysSH+ and cysSS+ (spectra recorded in D2O) ... 79
Appendix Figure 2-13 13C{1H} NMR of Me2CySS+ (3) (up) and Me2CySH+ (6) (down) in MeOD; solvent
peaks are reduced for clarity and denoted with * ... 80
Figure 2-14 1Hand 13C APT-NMR spectra of crude product 7 (solvent residual peak marked with *) ... 81
Figure 2-15 1H and 13C{1H} NMR spectra of 8 ... 84
Figure 2-16 Degradation of Cit2CySH+ under ambient conditions after one week ... 94
Figure 2-17 Oxidation of natural rubber (left: without radical initiator, right: with radical initiator) ... 97
Figure 2-18 FT-IR spectra after periodic illumination circles of COAT 1 ... 99
Figure 2-19 Surface properties of films under investigation ... 101
Figure 2-20 Reduction of CFU after 24h, dotted lines indicate the border line for antimicrobial behavior ... 102
Figure 2-21 Apportionment of soluble parts after soaking for 20 h in CDCl3 (COAT 3) ... 105
Figure 2-22 Apportionment of soluble parts after soaking for 20 h in CDCl3 (COAT 4) ... 105
Figure 2-23 Recovery of insoluble fractions of COAT 3 and COAT 4 (colored lines serve as guide for the eye) ... 106
Figure 2-24 Illustration of COAT 5 ... 107
Figure 2-25 ATR-IR measurements of dense film COAT 5 ... 108
Figure 2-26 Apportionment of soluble parts after soaking for 20 h in CDCl3 (COAT 5) ... 109
Figure 2-27 Polymer PI 4 under irradiation with UV light at a wavelength of 385 nm ... 111
Figure 2-28 Photo physical properties of PI 4 ... 112
L
IST OFS
CHEMES5.3
Scheme 1-1 Mechanism of radical thiol-ene coupling ... 12Scheme 1-2 Possible termination reactions of thiol-ene reaction ... 13
Scheme 1-3 Thiol-ene reaction with cis olefins ... 15
Scheme 1-4 General structure of the three most often used thiols for thiol-ene photo polymerization (left: alkyl 3-mercaptopropionate, middle: alkyl thioglycolate, right: alkylthiol) ... 15
Scheme 1-5 Mode of action of a type I photo initiator (DMAP) ... 16
Scheme 1-6 Mode of action of a type II photo initiator (benzophenone BP)21 ... 17
Scheme 1-7 Structure of 2,2´- azoisobutyronitrile AIBN ... 17
Appendix Scheme 1-8 Oxygen scavenging mechanism for thiol-ene reaction in the presence of aliphatic
thiols2, ... 18
Scheme 1-9 Approaches for surface modification via photo chemically induced thiol-ene click reactions (reproduced from Bowman and Hoyle11) ... 20
Scheme 1-10 Mechanism of thiol-ene radical reaction on poly(butadiene)43 ... 23
Scheme 1-11 Possible reaction pathways in thiol-ene photo crosslinking of high vinyl polyolefins ... 25
Scheme 1-12 Poly(hexamethylene biguanide) chloride PHMB ... 30
Scheme 1-13 right: possible structures of poly QUATs in the main (c) or side chain (a, b); left: possible structures of polymeric phosphonium biocidal material with the functional group in the main (f) or side chain (d,e) ... 36
Scheme 2-1 Thiol-ene reaction on styrene-butadiene rubber ... 43
Scheme 2-2 Thiol-ene modification of poly(isoprene) ... 46
Scheme 2-3 Synthesis of quaternary amines... 48
Scheme 2-4 Thiols used for thiol-ene reaction ... 66
Scheme 2-5 Irgacure® 651 (left) and Lucirin® TPO-L (right) ... 68
Scheme 2-6 Structure of Lithene AL as proposed by the producer ... 71
Scheme 2-7 MEDA- functionalized Lithene (PB 1) ... 72
Scheme 2-8 Reaction mechanism of the Leuckart-Wallach Reaction ... 75
Scheme 2-9 Conversion of cystamine dihydrochloride, following an Eschweiler-Clarke reaction (Me2CySS (1)) ... 76
Scheme 2-10 Derivatives of N,N,N´,N´- Tetramethylcystamine with quaternized amine functionalities (right: Me2CySS+ (2); middle: Me2CySS+ (3); left: Me2CySS+ (4)) ... 76
Scheme 2-11 Reduced derivatives of N,N,N´,N´- Tetramethylcysteamine with quaternized amine functionalities (right: Me2CySH+ (5), middle: Me2CySH+ (6), left: Me2CySH+ (7)) ... 77
Scheme 2-12 Proposed structure of 7 ... 82
Scheme 2-13 Proposed product due to aldol condensation ... 83
Scheme 2-14 Structure of compound 8 Et2CySS ... 83
Scheme 2-15 Conversion of cystamine dihydrochloride with several aldehydes ... 85
Scheme 2-16 Quaternization of Et2CySS- Cit2CySS ... 87
Scheme 2-17 Reduction reaction of methylated derivatives ... 88
Scheme 2-18 Conversion of chlormequat chloride via an intermediate Bunte salt to the free thiol ... 90
Scheme 2-19 Reaction pathway using thiourea via an intermediate isothiouronium salt ... 91
Appendix
Scheme 2-20 Hydrolysis of isothiouronium salt using sodium pyrosulfite ... 92
Scheme 2-21 Synthesis of dansyl chloride featuring thiol (27)119 ... 110
Scheme 2-22 Reaction of PI with 20 (up), reaction of PI 1 with danysl chloride (down) ... 111
Scheme 4-1 Synthesis of N,N, N´, N´- tetramethyl cystamine ... 126
Scheme 4-2 Synthesis of higher N,N,N´,N´-dialkyl thioamines... 127
Scheme 4-3 Methylation of thioamines ... 131
Scheme 4-4 Alkylation of N,N,N´,N´-tetramethyl cystamine ... 135
Scheme 4-5 Reduction of quaternary aminothiols ... 137
Scheme 4-6 Synthesis of 3-mercapto-N,N-dimethylpropan-1-aminium chloride... 141
Scheme 4-7 Synthesis of dansyl-cysteamine ... 144
L
IST OFT
ABLES5.4
Table 2-1 Thermal thiol-ene reaction with model substances ... 41Table 2-2 Characterization data for polymer under investigation ... 50
Table 2-3 Criterion temperature for polymers under investigation... 51
Table 2-4 Contact angles and surface energy values of PI- PI 3 ... 54
Table 2-5 Elemental analysis of compound materials ... 59
Table 2-6 CFUs after 24 h reduction in logarithmic values ... 63
Table 2-7 Conversion of unsaturated polymers with thiols in the Brabender® ... 67
Table 2-8 Thiol-ene reaction of thiolswith model small molecules; percent conversion rates of double bonds are depicted ... 69
Table 2-9 Yields of the conversion of cystamine dihydrochloride with several aldehydes ... 86
Table 2-10 Overview of obtained derivatives after quaternization (14-19) and reduction (20-25) ... 88
Table 2-11 Thiol-ene reactions of synthesized thiolswith model small molecules ... 93
Table 2-12 Surface energies and contact angles of films under investigation ... 101
Table 4-1 Coating formulations of COAT 1- COAT 5 ... 143