ISSN:
1434-1948
Keywords:
Platinum
;
Palladium
;
Platinum blues
;
Naphthyridine complexes
;
Trinuclear complexes
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
All three dinuclear complexes [Pd2(donp)2(bpy)2] (1) (H2donp = 1,8-naphthyridin-2,7-dione), [Pd2(H2nonp)2(bpy)2](ClO4)2 (2), and [Pt2(H2nonp)2(bpy)2](PF6)2 (3) (H3nonp = 7-amino-1,8-naphthyridin-2-one) exhibit the μ-1ĸN1:2ĸN8 bridging mode for their head/tail orientated naphthyridine ligands. Whereas 1 and 3 may be prepared by direct reaction of the dinucleating ligand with [MCl2(bpy)], formation of competing tripalladium(II) complexes must be avoided for 2 by employment of the precursor H2acnonp (7-acetamido-1,8-naphthyridin-2-one), which affords [H2nonp]- on cleavage of its original acetyl group. A mixture of the head/tail (4a) and head/head (4b) isomers of [Pd3(Hnonp)2(bpy)3](ClO4)2 is obtained when H3nonp is treated with [PdCl2(bpy)] and LiOH at room temperature for 2 d, followed by precipitation with LiClO4. Contrastingly exclusive formation of 4a is observed upon refluxing this reaction mixture for 3 d in aqueous solution. The [Hnonp]2- ligands exhibit a μ3-1ĸN1:2ĸN8:3ĸN7 bridging mode that leads to short Pd···Pd interactions of 2.781(2) and 2.775(2) Å. Similar metal-metal distances of 2.771(3) and 2.816(3) Å are observed in head/head-[Pt3(acnonp)(Hnonp)(bpy)3]Cl2 (5). An in situ 2e--oxidation (Ag+/Ag) of the [Pt3]6+ core in triplatinum(II) species such as 5 formed by the reaction of [PtCl2(bpy)] with H2acnonp allows the isolation of diamagnetic dark-brown head/head-[Pt3(Hnonp)2(NO3)(bpy)3](ClO4)2(NO3) (6) with an average oxidation state of Pt (2.67+). The Pt-Pt distances of 2.723(2) and 2.670(2) Å are markedly shorter than in 5.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
