Organometallic Osmium(II) Arene Anticancer Complexes Containing Picolinate Derivatives

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Organometallic Osmium(II) Arene Anticancer Complexes Containing Picolinate Derivatives. / van Rijt, SH; Peacock, Anna; Johnstone, RDL; Parsons, S; Sadler, PJ.

In: Inorganic Chemistry, Vol. 48, No. 4, 16.02.2009, p. 1753-1762.

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van Rijt, SH ; Peacock, Anna ; Johnstone, RDL ; Parsons, S ; Sadler, PJ. / Organometallic Osmium(II) Arene Anticancer Complexes Containing Picolinate Derivatives. In: Inorganic Chemistry. 2009 ; Vol. 48, No. 4. pp. 1753-1762.

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@article{61b36075f5a44c2b9eab7adfca2b1d14,
title = "Organometallic Osmium(II) Arene Anticancer Complexes Containing Picolinate Derivatives",
abstract = "Chlorido osmium(II) arene [(eta(6)-biphenyl)Os-II(X-pico)Cl] complexes containing X = Br (1), OH (2), and Me (3) as ortho, or X = Cl (4), CO2H (5), and Me (6) as para substituents; on the picolinate (pico) ring have been synthesized and characterized. The X-ray crystal structures of 1 and 6 show typical {"}piano-stool{"} geometry with intermolecular; pi-pi stacking of the biphenyl outer rings of 6. At 288 K the hydrolysis rates follow the order 2 >> 6 > 4 > 3 > 5 >> 1 with half-lives ranging from minutes to 4.4 h illustrating the influence of both electronic and steric effects of the substituents. The pK(a) values of the aqua adducts 3A, 4A, 5A, and 6A were all in the range of 6.3-6.6. The para-substituted pico complexes 4-6 readily formed adducts with both 9-ethyl guanine (9EtG) and 9-ethyl adenine (9EtA), but these were less favored for the ortho-substituted complexes 1 and 3 showing little reaction with 9EtG and 9EtA, respectively. Density-functional theory calculations confirmed the observed preferences for nucleobase binding for complex 1. In cytotoxicity assays with A2780, cisplatin-resistant A2780cis human ovarian, A549 human lung, and HCT116 colon cancer cells, only complexes 4 (p-Cl) and 6 (p-Me) exhibited significant activity (IC50 values <25 mu M). Both of these complexes were as active as cisplatin in A2780 (ovarian) and HCT116 (colon) cell lines, and even overcome cisplatin resistance in the A2780cis (ovarian) cell line. The inactivity of 5 is attributed to the negative charge on its para carboxylate substituent. These data illustrate how the chemical reactivity and cancer cell cytotoxicity of osmium arene complexes can be controlled and {"}fine-tuned{"} by the use of steric and electronic effects of substituents on a chelating ligand to give osmium(II) arene complexes which are as active as cisplatin but have a different mechanism of action.",
author = "{van Rijt}, SH and Anna Peacock and RDL Johnstone and S Parsons and PJ Sadler",
year = "2009",
month = "2",
day = "16",
doi = "10.1021/ic8020222",
language = "English",
volume = "48",
pages = "1753--1762",
journal = "Inorganic Chemistry",
issn = "0020-1669",
publisher = "American Chemical Society",
number = "4",

}

RIS

TY - JOUR

T1 - Organometallic Osmium(II) Arene Anticancer Complexes Containing Picolinate Derivatives

AU - van Rijt, SH

AU - Peacock, Anna

AU - Johnstone, RDL

AU - Parsons, S

AU - Sadler, PJ

PY - 2009/2/16

Y1 - 2009/2/16

N2 - Chlorido osmium(II) arene [(eta(6)-biphenyl)Os-II(X-pico)Cl] complexes containing X = Br (1), OH (2), and Me (3) as ortho, or X = Cl (4), CO2H (5), and Me (6) as para substituents; on the picolinate (pico) ring have been synthesized and characterized. The X-ray crystal structures of 1 and 6 show typical "piano-stool" geometry with intermolecular; pi-pi stacking of the biphenyl outer rings of 6. At 288 K the hydrolysis rates follow the order 2 >> 6 > 4 > 3 > 5 >> 1 with half-lives ranging from minutes to 4.4 h illustrating the influence of both electronic and steric effects of the substituents. The pK(a) values of the aqua adducts 3A, 4A, 5A, and 6A were all in the range of 6.3-6.6. The para-substituted pico complexes 4-6 readily formed adducts with both 9-ethyl guanine (9EtG) and 9-ethyl adenine (9EtA), but these were less favored for the ortho-substituted complexes 1 and 3 showing little reaction with 9EtG and 9EtA, respectively. Density-functional theory calculations confirmed the observed preferences for nucleobase binding for complex 1. In cytotoxicity assays with A2780, cisplatin-resistant A2780cis human ovarian, A549 human lung, and HCT116 colon cancer cells, only complexes 4 (p-Cl) and 6 (p-Me) exhibited significant activity (IC50 values <25 mu M). Both of these complexes were as active as cisplatin in A2780 (ovarian) and HCT116 (colon) cell lines, and even overcome cisplatin resistance in the A2780cis (ovarian) cell line. The inactivity of 5 is attributed to the negative charge on its para carboxylate substituent. These data illustrate how the chemical reactivity and cancer cell cytotoxicity of osmium arene complexes can be controlled and "fine-tuned" by the use of steric and electronic effects of substituents on a chelating ligand to give osmium(II) arene complexes which are as active as cisplatin but have a different mechanism of action.

AB - Chlorido osmium(II) arene [(eta(6)-biphenyl)Os-II(X-pico)Cl] complexes containing X = Br (1), OH (2), and Me (3) as ortho, or X = Cl (4), CO2H (5), and Me (6) as para substituents; on the picolinate (pico) ring have been synthesized and characterized. The X-ray crystal structures of 1 and 6 show typical "piano-stool" geometry with intermolecular; pi-pi stacking of the biphenyl outer rings of 6. At 288 K the hydrolysis rates follow the order 2 >> 6 > 4 > 3 > 5 >> 1 with half-lives ranging from minutes to 4.4 h illustrating the influence of both electronic and steric effects of the substituents. The pK(a) values of the aqua adducts 3A, 4A, 5A, and 6A were all in the range of 6.3-6.6. The para-substituted pico complexes 4-6 readily formed adducts with both 9-ethyl guanine (9EtG) and 9-ethyl adenine (9EtA), but these were less favored for the ortho-substituted complexes 1 and 3 showing little reaction with 9EtG and 9EtA, respectively. Density-functional theory calculations confirmed the observed preferences for nucleobase binding for complex 1. In cytotoxicity assays with A2780, cisplatin-resistant A2780cis human ovarian, A549 human lung, and HCT116 colon cancer cells, only complexes 4 (p-Cl) and 6 (p-Me) exhibited significant activity (IC50 values <25 mu M). Both of these complexes were as active as cisplatin in A2780 (ovarian) and HCT116 (colon) cell lines, and even overcome cisplatin resistance in the A2780cis (ovarian) cell line. The inactivity of 5 is attributed to the negative charge on its para carboxylate substituent. These data illustrate how the chemical reactivity and cancer cell cytotoxicity of osmium arene complexes can be controlled and "fine-tuned" by the use of steric and electronic effects of substituents on a chelating ligand to give osmium(II) arene complexes which are as active as cisplatin but have a different mechanism of action.

U2 - 10.1021/ic8020222

DO - 10.1021/ic8020222

M3 - Article

VL - 48

SP - 1753

EP - 1762

JO - Inorganic Chemistry

JF - Inorganic Chemistry

SN - 0020-1669

IS - 4

ER -