Synthesis and reactivity of palladium and platinum diimine complexes containing boronate esters

Abstract

Condensation of a-diketones (2,3-butanedione, benzil, and acenaphthenequinone) with 3-H 2 NC 6 H 4 Bpin (pin = 1,2-O 2 C 2 Me 4 ) gave the corresponding boron-containing a-diimines. The addition of these ligands to [MCl 2 (coe)] 2 (coe = cis-cyclooctene, M = Pd or Pt) gave complexes of the type cis-MCl 2 (a-diimine) in moderate to high yields. The platinum complexes have been examined for their ability to bind to DNA using enzyme digest studies. These complexes were found to bind to single-stranded DNA as well as, or better than, the non-boron containing controls, and showed binding similar to that of cisplatin (cis-PtCl 2 (NH 3 ) 2 ).Résumé : La condensation d'a-dicétones (butane-2,3-dione, benzile, et acénaphtènequinone) avec le 3-H 2 NC 6 H 4 Bpin (pin = 1,2-O 2 C 2 Me 4 ) conduit à la formation d'a-diimines contenant du bore. L'addition de ces ligands au [MCl 2 (coe)] 2 (coe = cis-cyclooctène; M = Pd, Pt) fournit des complexes du type cis-MCl 2 (a-diimine) avec des rendements allant de modérés à élevés. Faisant appel à des études de digestion d'enzymes, on a évalué la capacité de ces complexes du platine à se fixer sur l'ADN. Vis-à-vis de l'ADN à brin unique, ces complexes se fixent aussi bien, ou mieux, que les contrôles ne contenant pas de bore et leur taux de fixation est semblable à celui du cisplatine, cis-PtCl 2 (NH 3 ) 2 .

Synthesis and reactivity of new functionalized Pd(II) cyclometallated complexes with boronic esters

“…Complexes 3b and 3c were also characterized by 13 C-{ 1 H} spectroscopy and their spectra were similar to those of the tetranuclear 2b and 2c complexes with the shift to higher frequency of the C6, and C1 resonances (as compared to the uncoordinated ligand) [17,18,20] and the lowfield shift of the C@N carbon resonance; with the resonance assigned to the C-O carbon showing a greater high frequency shift (ca. 22 ppm).…”

“…Complex 2c was also characterized by 13 C-{ 1 H} NMR spectroscopy. The most noticeable feature was the shift to higher frequency of the C6, C@N, and C1 resonances, as compared to their value in the spectrum of the uncoordinated ligand, confirming that metallation had occurred [17,18,20]; the smallest shift was observed for the C@N carbon resonance of only 2.7 ppm.…”

“…The IR spectrum showed the m(C@N) stretch at 1614 cm À1 , shifted to lower wavenumbers (as compared to the free ligand) due to N-coordination of the imine [15,16]. The 13 C-{ 1 H} spectrum showed the characteristic lowfield shift of the signals corresponding to the C@N, C1and C6 carbons consequent upon metallation (vide supra and experimental). The IR spectrum also showed strong bands assigned to the symmetric and asymmetric m(COO) vibrations, in agreement with bridging acetate ligands [25,26].…”

“…Although the synthesis and reactivity of boronic acids and esters is well studied, few complexes in which this group is part of a coordinated ligand are known [12][13][14].…”

Palladium(II) Schiff Base Complexes Derived from Allylamine and Vinylaniline

“…As part of our ongoing research into making novel metal complexes containing aminoboron ligands, 18 we decided to prepare a number of metal complexes containing pendant unsaturated allyl and vinyl fragments. Our initial investigations have been directed at making diamagnetic palladium (II) complexes owing to their ease of synthesis 19 and known biological activities.…”