Insights into the acid-base properties of Pt IV-diazidodiam(m) inedihyroxido complexes from multinuclear NMR spectroscopy

Luca Ronconi; Ana M. Pizarro; Ruth J. McQuitty; Peter J. Sadler

doi:10.1002/chem.201002792

Insights into the acid-base properties of Pt ^IV-diazidodiam(m) inedihyroxido complexes from multinuclear NMR spectroscopy

Luca Ronconi
, Ana M. Pizarro
, Ruth J. McQuitty
, Peter J. Sadler

University of Edinburgh
University of Padova
University of Warwick

Research output: Contribution to a Journal (Peer & Non Peer) › Article › peer-review

12 Citations (Scopus)

Abstract

Platinum(IV) am(m)ine complexes are of interest as potential anticancer pro-drugs, but there are few reports of their acid-base properties. We have studied the acid-base properties of three photoactivatable anticancer platinum(IV)-diazidodiam(m)ine complexes (cis,trans,cis-[Pt ^IV(N ₃) ₂(OH) ₂(NH ₃) ₂], trans,trans,trans-[Pt ^IV(N ₃) ₂(OH) ₂(NH ₃) ₂], and cis,trans-[Pt ^IV(N ₃) ₂(OH) ₂(en)]) using multinuclear NMR methods and potentiometry. In particular, the combination of both direct and indirect techniques for the detection of ¹⁵N signals has allowed changes of the chemical shifts to be followed over the pH range 1-11; complementary ¹⁴N NMR studies have been also carried out. A distinct pK _a value of approximately 3.4 was determined for all the investigated complexes, involving protonation/deprotonation reactions of one of the axial hydroxido groups, whereas a second pH-dependent change for the three complexes at approximately pH 7.5 appears not to be associated with a loss of an am(m)ine or hydroxido proton from the complex. Our findings are discussed in comparison with the limited data available in the literature on related complexes.

Original language	English
Pages (from-to)	12051-12058
Number of pages	8
Journal	Chemistry - A European Journal
Volume	17
Issue number	43
DOIs	https://doi.org/10.1002/chem.201002792
Publication status	Published - 17 Oct 2011
Externally published	Yes

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This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Keywords

NMR spectroscopy
acid-base properties
anticancer complexes
bioinorganic chemistry
pK values
platinum

Access to Document

10.1002/chem.201002792

Cite this

@article{b0479de7ae7d4713971acce221e2c329,

title = "Insights into the acid-base properties of Pt IV-diazidodiam(m) inedihyroxido complexes from multinuclear NMR spectroscopy",

abstract = "Platinum(IV) am(m)ine complexes are of interest as potential anticancer pro-drugs, but there are few reports of their acid-base properties. We have studied the acid-base properties of three photoactivatable anticancer platinum(IV)-diazidodiam(m)ine complexes (cis,trans,cis-[Pt IV(N 3) 2(OH) 2(NH 3) 2], trans,trans,trans-[Pt IV(N 3) 2(OH) 2(NH 3) 2], and cis,trans-[Pt IV(N 3) 2(OH) 2(en)]) using multinuclear NMR methods and potentiometry. In particular, the combination of both direct and indirect techniques for the detection of 15N signals has allowed changes of the chemical shifts to be followed over the pH range 1-11; complementary 14N NMR studies have been also carried out. A distinct pK a value of approximately 3.4 was determined for all the investigated complexes, involving protonation/deprotonation reactions of one of the axial hydroxido groups, whereas a second pH-dependent change for the three complexes at approximately pH 7.5 appears not to be associated with a loss of an am(m)ine or hydroxido proton from the complex. Our findings are discussed in comparison with the limited data available in the literature on related complexes.",

keywords = "NMR spectroscopy, acid-base properties, anticancer complexes, bioinorganic chemistry, pK values, platinum",

author = "Luca Ronconi and Pizarro, \{Ana M.\} and McQuitty, \{Ruth J.\} and Sadler, \{Peter J.\}",

year = "2011",

month = oct,

day = "17",

doi = "10.1002/chem.201002792",

language = "English",

volume = "17",

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journal = "Chemistry - A European Journal",

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TY - JOUR

T1 - Insights into the acid-base properties of Pt IV-diazidodiam(m) inedihyroxido complexes from multinuclear NMR spectroscopy

AU - Ronconi, Luca

AU - Pizarro, Ana M.

AU - McQuitty, Ruth J.

AU - Sadler, Peter J.

PY - 2011/10/17

Y1 - 2011/10/17

N2 - Platinum(IV) am(m)ine complexes are of interest as potential anticancer pro-drugs, but there are few reports of their acid-base properties. We have studied the acid-base properties of three photoactivatable anticancer platinum(IV)-diazidodiam(m)ine complexes (cis,trans,cis-[Pt IV(N 3) 2(OH) 2(NH 3) 2], trans,trans,trans-[Pt IV(N 3) 2(OH) 2(NH 3) 2], and cis,trans-[Pt IV(N 3) 2(OH) 2(en)]) using multinuclear NMR methods and potentiometry. In particular, the combination of both direct and indirect techniques for the detection of 15N signals has allowed changes of the chemical shifts to be followed over the pH range 1-11; complementary 14N NMR studies have been also carried out. A distinct pK a value of approximately 3.4 was determined for all the investigated complexes, involving protonation/deprotonation reactions of one of the axial hydroxido groups, whereas a second pH-dependent change for the three complexes at approximately pH 7.5 appears not to be associated with a loss of an am(m)ine or hydroxido proton from the complex. Our findings are discussed in comparison with the limited data available in the literature on related complexes.

AB - Platinum(IV) am(m)ine complexes are of interest as potential anticancer pro-drugs, but there are few reports of their acid-base properties. We have studied the acid-base properties of three photoactivatable anticancer platinum(IV)-diazidodiam(m)ine complexes (cis,trans,cis-[Pt IV(N 3) 2(OH) 2(NH 3) 2], trans,trans,trans-[Pt IV(N 3) 2(OH) 2(NH 3) 2], and cis,trans-[Pt IV(N 3) 2(OH) 2(en)]) using multinuclear NMR methods and potentiometry. In particular, the combination of both direct and indirect techniques for the detection of 15N signals has allowed changes of the chemical shifts to be followed over the pH range 1-11; complementary 14N NMR studies have been also carried out. A distinct pK a value of approximately 3.4 was determined for all the investigated complexes, involving protonation/deprotonation reactions of one of the axial hydroxido groups, whereas a second pH-dependent change for the three complexes at approximately pH 7.5 appears not to be associated with a loss of an am(m)ine or hydroxido proton from the complex. Our findings are discussed in comparison with the limited data available in the literature on related complexes.

KW - NMR spectroscopy

KW - acid-base properties

KW - anticancer complexes

KW - bioinorganic chemistry

KW - pK values

KW - platinum

UR - https://www.scopus.com/pages/publications/80054016126

U2 - 10.1002/chem.201002792

DO - 10.1002/chem.201002792

M3 - Article

SN - 0947-6539

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JO - Chemistry - A European Journal

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