Synthesis and properties of new thiourea-functionalized poly(propylene imine) dendrimers and their role as hosts for urea functionalized guests

U. Boas, A.J. Karlsson, B.F.M. Waal, de, E.W. Meijer

Research output: Contribution to journalArticleAcademicpeer-review

82 Citations (Scopus)

Abstract

Five generations of poly(propylene inline) dendrimers have been modified by palmityl and adamantyl endgroups via a thiourea linkage. The synthesis of the thiourea dendrimers DAB-dendr-(NHCSNHAd)(n) and DAB-dendr-(NHCSNHC16H33)(n) (n = 4, 8, 16,32, 64) proceeds smoothly via the amino-terminated DAB dendrimer :ind the adamantyl and palmityl isothiocyanates, respectively. The properties of the thiourea dendrimers have been studied by IR and H-1 NMR, including relaxation (T1, T2) measurements. The thiourea dendrimers are used as multivalent hosts for a number of guest molecules containing a terminal urea-glycine unit in organic solvents. The host-guest interactions have been investigated using 1D- and NOESY-NMR. These investigations show that the guest molecules bind to the dendritic host via thiourea (host)-urea (guest) hydrogen bonding, and ionic bonding between the terminal guest carboxylate moiety and the outer shell tertiary amines of the dendrimer. The ability to bind guest molecules of the adamantyl- and palmitylthiourea dendrimers has been compared with their respective urea containing dendrimer analogues, by NMR-titration, and competition experiments. Upon complexation, the thiourea dendrimer hosts show a larger downfield NH. shift than the corresponding urea dendrimer hosts, indicative of stronger hydrogen bonding in the complexed state. Furthermore, microcalorimetry has been used to determine binding constants for formation of the host-guest complexes; the binding constants are typically in the order of 10(4) M-1. Both NMR and microcalorimetric studies show that the thiourea dendrimers bind the urea containing guests with somewhat higher affinity than the corresponding urea dendrimers
Original languageEnglish
Pages (from-to)2136-2145
Number of pages10
JournalJournal of Organic Chemistry
Volume66
Issue number6
DOIs
Publication statusPublished - 2001

Fingerprint

Dendrimers
Thiourea
Urea
Nuclear magnetic resonance
Molecules
poly(propyleneimine)
Hydrogen bonds
Isothiocyanates
Complexation
Titration
Glycine
Organic solvents
Amines
Polypropylenes

Cite this

@article{10ef158df203416c8c6892d657a2375a,
title = "Synthesis and properties of new thiourea-functionalized poly(propylene imine) dendrimers and their role as hosts for urea functionalized guests",
abstract = "Five generations of poly(propylene inline) dendrimers have been modified by palmityl and adamantyl endgroups via a thiourea linkage. The synthesis of the thiourea dendrimers DAB-dendr-(NHCSNHAd)(n) and DAB-dendr-(NHCSNHC16H33)(n) (n = 4, 8, 16,32, 64) proceeds smoothly via the amino-terminated DAB dendrimer :ind the adamantyl and palmityl isothiocyanates, respectively. The properties of the thiourea dendrimers have been studied by IR and H-1 NMR, including relaxation (T1, T2) measurements. The thiourea dendrimers are used as multivalent hosts for a number of guest molecules containing a terminal urea-glycine unit in organic solvents. The host-guest interactions have been investigated using 1D- and NOESY-NMR. These investigations show that the guest molecules bind to the dendritic host via thiourea (host)-urea (guest) hydrogen bonding, and ionic bonding between the terminal guest carboxylate moiety and the outer shell tertiary amines of the dendrimer. The ability to bind guest molecules of the adamantyl- and palmitylthiourea dendrimers has been compared with their respective urea containing dendrimer analogues, by NMR-titration, and competition experiments. Upon complexation, the thiourea dendrimer hosts show a larger downfield NH. shift than the corresponding urea dendrimer hosts, indicative of stronger hydrogen bonding in the complexed state. Furthermore, microcalorimetry has been used to determine binding constants for formation of the host-guest complexes; the binding constants are typically in the order of 10(4) M-1. Both NMR and microcalorimetric studies show that the thiourea dendrimers bind the urea containing guests with somewhat higher affinity than the corresponding urea dendrimers",
author = "U. Boas and A.J. Karlsson and {Waal, de}, B.F.M. and E.W. Meijer",
year = "2001",
doi = "10.1021/jo001573x",
language = "English",
volume = "66",
pages = "2136--2145",
journal = "Journal of Organic Chemistry",
issn = "0022-3263",
publisher = "American Chemical Society",
number = "6",

}

Synthesis and properties of new thiourea-functionalized poly(propylene imine) dendrimers and their role as hosts for urea functionalized guests. / Boas, U.; Karlsson, A.J.; Waal, de, B.F.M.; Meijer, E.W.

In: Journal of Organic Chemistry, Vol. 66, No. 6, 2001, p. 2136-2145.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Synthesis and properties of new thiourea-functionalized poly(propylene imine) dendrimers and their role as hosts for urea functionalized guests

AU - Boas, U.

AU - Karlsson, A.J.

AU - Waal, de, B.F.M.

AU - Meijer, E.W.

PY - 2001

Y1 - 2001

N2 - Five generations of poly(propylene inline) dendrimers have been modified by palmityl and adamantyl endgroups via a thiourea linkage. The synthesis of the thiourea dendrimers DAB-dendr-(NHCSNHAd)(n) and DAB-dendr-(NHCSNHC16H33)(n) (n = 4, 8, 16,32, 64) proceeds smoothly via the amino-terminated DAB dendrimer :ind the adamantyl and palmityl isothiocyanates, respectively. The properties of the thiourea dendrimers have been studied by IR and H-1 NMR, including relaxation (T1, T2) measurements. The thiourea dendrimers are used as multivalent hosts for a number of guest molecules containing a terminal urea-glycine unit in organic solvents. The host-guest interactions have been investigated using 1D- and NOESY-NMR. These investigations show that the guest molecules bind to the dendritic host via thiourea (host)-urea (guest) hydrogen bonding, and ionic bonding between the terminal guest carboxylate moiety and the outer shell tertiary amines of the dendrimer. The ability to bind guest molecules of the adamantyl- and palmitylthiourea dendrimers has been compared with their respective urea containing dendrimer analogues, by NMR-titration, and competition experiments. Upon complexation, the thiourea dendrimer hosts show a larger downfield NH. shift than the corresponding urea dendrimer hosts, indicative of stronger hydrogen bonding in the complexed state. Furthermore, microcalorimetry has been used to determine binding constants for formation of the host-guest complexes; the binding constants are typically in the order of 10(4) M-1. Both NMR and microcalorimetric studies show that the thiourea dendrimers bind the urea containing guests with somewhat higher affinity than the corresponding urea dendrimers

AB - Five generations of poly(propylene inline) dendrimers have been modified by palmityl and adamantyl endgroups via a thiourea linkage. The synthesis of the thiourea dendrimers DAB-dendr-(NHCSNHAd)(n) and DAB-dendr-(NHCSNHC16H33)(n) (n = 4, 8, 16,32, 64) proceeds smoothly via the amino-terminated DAB dendrimer :ind the adamantyl and palmityl isothiocyanates, respectively. The properties of the thiourea dendrimers have been studied by IR and H-1 NMR, including relaxation (T1, T2) measurements. The thiourea dendrimers are used as multivalent hosts for a number of guest molecules containing a terminal urea-glycine unit in organic solvents. The host-guest interactions have been investigated using 1D- and NOESY-NMR. These investigations show that the guest molecules bind to the dendritic host via thiourea (host)-urea (guest) hydrogen bonding, and ionic bonding between the terminal guest carboxylate moiety and the outer shell tertiary amines of the dendrimer. The ability to bind guest molecules of the adamantyl- and palmitylthiourea dendrimers has been compared with their respective urea containing dendrimer analogues, by NMR-titration, and competition experiments. Upon complexation, the thiourea dendrimer hosts show a larger downfield NH. shift than the corresponding urea dendrimer hosts, indicative of stronger hydrogen bonding in the complexed state. Furthermore, microcalorimetry has been used to determine binding constants for formation of the host-guest complexes; the binding constants are typically in the order of 10(4) M-1. Both NMR and microcalorimetric studies show that the thiourea dendrimers bind the urea containing guests with somewhat higher affinity than the corresponding urea dendrimers

U2 - 10.1021/jo001573x

DO - 10.1021/jo001573x

M3 - Article

VL - 66

SP - 2136

EP - 2145

JO - Journal of Organic Chemistry

JF - Journal of Organic Chemistry

SN - 0022-3263

IS - 6

ER -