The unusual substitution behaviour of terpyridylplatnium(II) complexes

Mureinik, R.J.; Bidani, Menashe

doi:10.1016/s0020-1693(00)89625-5

Cited by 29 publications

(10 citation statements)

References 17 publications

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“…These results are consistent with a wealth of previous condensed phase work,16, 17 which shows that the binding of metal ions and their complexes to nucleic acids is quite complex and depends on a number of factors including: (i) the acid base properties of the nucleic acid;18 (ii) which of the tautomeric forms of the nucleobase binds to the metal; (iii) the number of vacant coordination sites available at the metal centre; (iv) the ability to form macrochelates via coordination of two or more sites of the nucleic acid onto the metal centre;19 and (v) the ability of intramolecular hydrogen bonding to stabilize the complex 20. Although a detailed discussion of the literature is beyond the scope of this work, we note the following: [Pt(dien)Cl] + undergoes slower ligand substitution than [Pt(tpy)Cl] + ,21 consistent with the need for longer incubation times; thymine and its derivatives prefer binding to metals in the deprotonated form 18c…”

Section: Resultsmentioning

confidence: 99%

Can radical cations of the constituents of nucleic acids be formed in the gas phase using ternary transition metal complexes?

Wee

O’Hair

McFadyen

2005

Rapid Comm Mass Spectrometry

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Electrospray ionization (ESI) tandem mass spectrometry (MS/MS) of ternary transition metal complexes of [M(L(3))(N)](2+) (where M = copper(II) or platinum(II); L(3) = diethylenetriamine (dien) or 2,2':6',2''-terpyridine (tpy); N = the nucleobases: adenine, guanine, thymine and cytosine; the nucleosides: 2'deoxyadenosine, 2'deoxyguanosine, 2'deoxythymine, 2'deoxycytidine; the nucleotides: 2'deoxyadenosine 5'-monophosphate, 2'deoxyguanosine 5'-monophosphate, 2'deoxythymine 5'-monophosphate, 2'deoxycytidine 5'-monophosphate) was examined as a means of forming radical cations of the constituents of nucleic acids in the gas phase. In general, sufficient quantities of the ternary complexes [M(L(3))(N)](2+) could be formed for MS/MS studies by subjecting methanolic solutions of mixtures of a metal salt [M(L(3))X(2)] (where M = Cu(II) or Pt(II); L(3) = dien or tpy; X = Cl or NO(3)) and N to ESI. The only exceptions were thymine and its derivatives, which failed to form sufficient abundances of [M(L(3))(N)](2+) ions when: (a) M = Pt(II) and L(3) = dien or tpy; (b) M = Cu(II) and L(3) = dien. In some instances higher oligomeric complexes were formed; e.g., [Pt(tpy)(dG)(n)](2+) (n = 1-13). Each of the ternary complexes [M(L(3))(N)](2+) was mass-selected and then subjected to collision-induced dissociation (CID) in a quadrupole ion trap. The types of fragmentation reactions observed for these complexes depend on the nature of all three components (metal, auxiliary ligand and nucleic acid constituent) and can be classified into: (i) a redox reaction which results in the formation of the radical cation of the nucleic acid constituent, N(+.); (ii) loss of the nucleic acid constituent in its protonated form; and (iii) fragmentation of the nucleic acid constituent. Only the copper complexes yielded radical cations of the nucleic acid constituent, with [Cu(tpy)(N)](2+) being the preferred complex due to suppression, in this case, of the loss of the nucleobase in its protonated form. The yields of the radical cations of the nucleobases from the copper complexes follow the order of their ionization potentials (IPs): G (lowest IP) > A > C > T (highest IP). Sufficient yields of the radical cations of each of the nucleobases allowed their CID reactions (in MS(3) experiments) to be compared to their even-electron counterparts.

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Section: Resultsmentioning

confidence: 99%

Can radical cations of the constituents of nucleic acids be formed in the gas phase using ternary transition metal complexes?

Wee

O’Hair

McFadyen

2005

Rapid Comm Mass Spectrometry

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“…The reaction was complete at ambient temperature in 15-30 minutes. It has been suggested that the rapid rate of reaction in the Pt complex 1 (R --C1) is due to the n-trans effect which labilises the Pt-C1 bond [10]. In order to isolate the Pt complex 2 it was necessary to replace the relatively nucleophilic chloride ion by a much less nucleophilic counter ion.…”

Section: Syn Thesis" Of 4-picoline-22": 6"2"-terpyridine-platinum (mentioning

confidence: 99%

4‐Picoline‐2,2′:6′,2″‐terpyridine‐platinum(II) — A potent intercalator of DNA

McCoubrey

Latham²,

Cook³

et al. 1996

FEBS Letters

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“…[9][10][11] This is due to the ability of the terpyridine ligand to accept electrons from the platinum metal thereby stabilizing the five-coordinate intermediate. 12,13 In a related study, 14 addition of electron-donating groups on the ancillary positions of the terpy ligand has been shown to retard the rate of substitution of chloride ligand, while electron-withdrawing groups increase the rate of substitution. [14][15][16] Limited information relating to the factors that influence the activity of these compounds such as the role of extended π-conjugation has been reported.…”

Section: Introductionmentioning

confidence: 97%

The π-acceptor effect in the substitution reactions of tridentate N-donor ligand complexes of platinum(ii): a detailed kinetic and mechanistic study

Ongoma

Jaganyi

2012

Dalton Trans.

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The nucleophilic substitution reactions of complexes [Pt{4'-(2'''-CH(3)-phenyl)-2,2':6',2''-terpyridine}Cl]CF(3)SO(3), [CH(3)PhPtCl], [Pt{4'-(2'''-CH(3)-phenyl)-6-(3''-isoquinoyl)-2,2'bipyridine}Cl]SbF(6), [CH(3)PhisoqPtCl], [Pt{2-(2'-pyridyl)-1,10-phenanthroline}Cl]Cl, [pyPhenPtCl], and [Pt(terpyridine)Cl](+), [PtCl] with a series of nucleophiles: thiourea (TU), N,N-dimethylthiourea (DMTU), N,N,N,N-tetramethylthiourea (TMTU), I(-), Br(-), and SCN(-) were studied in 0.1 M LiCF(3)SO(3) in methanol (in the presence of 10 mM LiCl). The reactivity of the investigated complexes follows the order pyPhenPtCl > PtCl > CH(3)PhPtCl > CH(3)PhisoqPtCl. The lability of the chloride ligand is dependent on the strength of π-backbonding properties of the spectator ligands around the platinum centre. The experimental data is strongly supported by DFT calculations. The dependence of the second-order rate constants on concentration of the nucleophiles as well as the large negative values reported for the activation entropy (ΔS(‡)) confirmed an associative mechanism of substitution.

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The unusual substitution behaviour of terpyridylplatnium(II) complexes

Cited by 29 publications

References 17 publications

Can radical cations of the constituents of nucleic acids be formed in the gas phase using ternary transition metal complexes?

Can radical cations of the constituents of nucleic acids be formed in the gas phase using ternary transition metal complexes?

4‐Picoline‐2,2′:6′,2″‐terpyridine‐platinum(II) — A potent intercalator of DNA

The π-acceptor effect in the substitution reactions of tridentate N-donor ligand complexes of platinum(ii): a detailed kinetic and mechanistic study

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