Abstract
Lanthanide(III) chelates of DOTA-tetraamide ligands have been an area of particular interest since the discovery that water exchange kinetics are dramatically affected by the switch from acetate to amide side-chain donors. More recently these chelates have attracted interest as potential PARACEST agents for use in MRI. In this paper we report the results of studies using chemical exchange saturation transfer (CEST) and some more recently reported chelates to re-examine the exchange processes in this class of chelate. We find that the conclusions of Parker and Aime are, for the most part, solid; water exchange is slow and a substantial amount of prototropic exchange occurs in aqueous solution. The extent of prototropic exchange increases as the pH increases above 8, leading to higher relaxivities at high pH. However, amide protons are found to contribute only a small amount to the relaxivity at high pH.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 6759-6764 |
| Number of pages | 6 |
| Journal | Dalton Transactions |
| Volume | 40 |
| Issue number | 25 |
| DOIs | |
| State | Published - Jul 7 2011 |
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ASJC Scopus subject areas
- Inorganic Chemistry
Cite this
Investigations into whole water, prototropic and amide proton exchange in lanthanide(III) DOTA-tetraamide chelates. / Woods, Mark; Pasha, Azhar; Zhao, Piyu; Tircso, Gyula; Chowdhury, Somdatta; Kiefer, Garry; Woessner, Donald E.; Sherry, A. Dean.
In: Dalton Transactions, Vol. 40, No. 25, 07.07.2011, p. 6759-6764.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Investigations into whole water, prototropic and amide proton exchange in lanthanide(III) DOTA-tetraamide chelates
AU - Woods, Mark
AU - Pasha, Azhar
AU - Zhao, Piyu
AU - Tircso, Gyula
AU - Chowdhury, Somdatta
AU - Kiefer, Garry
AU - Woessner, Donald E.
AU - Sherry, A. Dean
PY - 2011/7/7
Y1 - 2011/7/7
N2 - Lanthanide(III) chelates of DOTA-tetraamide ligands have been an area of particular interest since the discovery that water exchange kinetics are dramatically affected by the switch from acetate to amide side-chain donors. More recently these chelates have attracted interest as potential PARACEST agents for use in MRI. In this paper we report the results of studies using chemical exchange saturation transfer (CEST) and some more recently reported chelates to re-examine the exchange processes in this class of chelate. We find that the conclusions of Parker and Aime are, for the most part, solid; water exchange is slow and a substantial amount of prototropic exchange occurs in aqueous solution. The extent of prototropic exchange increases as the pH increases above 8, leading to higher relaxivities at high pH. However, amide protons are found to contribute only a small amount to the relaxivity at high pH.
AB - Lanthanide(III) chelates of DOTA-tetraamide ligands have been an area of particular interest since the discovery that water exchange kinetics are dramatically affected by the switch from acetate to amide side-chain donors. More recently these chelates have attracted interest as potential PARACEST agents for use in MRI. In this paper we report the results of studies using chemical exchange saturation transfer (CEST) and some more recently reported chelates to re-examine the exchange processes in this class of chelate. We find that the conclusions of Parker and Aime are, for the most part, solid; water exchange is slow and a substantial amount of prototropic exchange occurs in aqueous solution. The extent of prototropic exchange increases as the pH increases above 8, leading to higher relaxivities at high pH. However, amide protons are found to contribute only a small amount to the relaxivity at high pH.
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U2 - 10.1039/c1dt10616c
DO - 10.1039/c1dt10616c
M3 - Article
VL - 40
SP - 6759
EP - 6764
JO - Dalton Transactions
JF - Dalton Transactions
SN - 1477-9226
IS - 25
ER -