Montagner, Diego and Venzo, Alfonso and Zangrando, Ennio and Longato, Bruno
(2010)
Irreversible Insertion of Benzonitrile into Platinum
(
II
)
-
Nitrogen Bonds of
Nucleobase Complexes. Synthesis and Structural Characterization of Stable
Azametallacycle Compounds.
Inorganic Chemistry, 49.
pp. 2103-2110.
ISSN 0020-1669
Abstract
Deprotonation of 1-methylcytosine (1-MeCy) and 9-methyladenine (9-MeAd) promoted by cis-[L2Pt(μ-OH)]2(NO3)2 (L = PPh3, PMePh2, 1/2dppe) in PhCN causes the irreversible insertion of a nitrile molecule into the Pt−N4 and Pt−N6 bonds of the cytosinate and adeninate ligands, respectively, to form the stable azametallacycle complexes cis-[L2PtNH═C(Ph){1-MeCy(−2H)}]NO3 (L = PPh3, 1; PMePh2, 2; 1/2dppe, 3) and cis-[L2PtNH═C(Ph){9-MeAd(−2H)}]NO3 (L = PPh3, 4; PMePh2, 5) containing the deprotonated form of the molecules (Z)-9-N-(1-methyl-2-oxo-2,3-dihydropyrimidin-4(1H)-ylidene)benzimidamide and (Z)-N-(9-methyl-1H-purin-6(9H)-ylidene)benzimidamide. Single-crystal X-ray analyses of 2 and 4 show the metal coordinated to the N3 cytosine site [Pt−N3 = 2.112(7) Å̊] and to the N1 site of adenine [Pt−N1 = 2.116(6) Å̊] and to the nitrogen atom of the inserted benzonitrile [Pt−N2 = 2.043(6) and 2.010(6) Å̊ in 2 and 4, respectively], with the exocyclic nucleobase amino nitrogen bound to the carbon atom of the CN group. Complex 2, in solution, undergoes a dynamic process related to a partially restricted rotation around Pt−P bonds, arising from a steric interaction of the oxygen atom of the cytosine with one ring of the phosphine ligands. The reaction of 4 with acetylacetone (Hacac) causes the quantitative protonation of the anionic ligand, affording the acetylacetonate complex cis-[(PPh3)2Pt(acac)]NO3 and the free benzimidamide NH═C(Ph){9-MeAd(−H)}. In the same experimental conditions, complex 3 reacts with Hacac only partially.
Item Type: |
Article
|
Keywords: |
Irreversible Insertion; Benzonitrile; Platinum(II)−Nitrogen Bonds; Nucleobase Complexes; Synthesis; Structural Characterization; Stable Azametallacycle Compounds; |
Academic Unit: |
Faculty of Science and Engineering > Chemistry |
Item ID: |
7061 |
Identification Number: |
https://doi.org/10.1021/ic901508w |
Depositing User: |
Diego Montagner
|
Date Deposited: |
31 Mar 2016 15:14 |
Journal or Publication Title: |
Inorganic Chemistry |
Publisher: |
American Chemical Society |
Refereed: |
Yes |
URI: |
|
Use Licence: |
This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available
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