| Abstract
| - Heating ofsolid[LRuII(bqdi)(N3)](PF6)(4) to 160 °C generates N2 and theparamagnetic nitrido-bridged complex[{LRu(o-C6H4(NH)2)2}2(μ-N)](PF6)2(5), the crystal structure of which shows that thecoordinatedo-C6H4(NH)22-dianion has considerable o-phenylenediamide(2−)character. In 4 and similar complexes, the same ligandis coordinated as neutral o-benzoquinone diimine. It isnot possible to assign conventional oxidation states to the metal ions(or ligands) in 5; theC6H4(NH)2n-moiety is noninnocent.
- Reaction of LRuIIICl3 (L= 1,4,7-trimethyl-1,4,7-triazacyclononane) with 1,2-phenylenediamine(opdaH2) in H2Oin the presence of air affords[LRuII(bqdi)(OH2)](PF6)(1), where (bqdi) represents the neutral ligando-benzoquinonediimine. From an alkaline methanol/water mixture of 1was obtained the dinuclear species[{LRuII(bqdi)}2(μ-H3O2)](PF6)3(1a). The coordinated water molecule in 1 islabile and can be readily substituted under appropriatereaction conditions by acetonitrile, yielding[LRuII(bqdi)(CH3CN)](PF6)2(2), and by iodide and azide anions,affording[LRuII(bqdi)I](PF6)·0.5H2O(3) and[LRu(bqdi)(N3)](PF6)·H2O(4), respectively. Heating of solid 4invacuum at 160 °C generates N2 and the dinuclear,nitrido-bridged complex[{LRu(o-C6H4(NH)2)}2(μ-N)](PF6)2(5). Complex 5 is a mixed-valent,paramagnetic species containing one unpaired electron per dinuclearunitwhereas complexes 1−4 are diamagnetic. Thecrystal structures of 1,1a·3CH3CN, 3,4·H2O, and5·3CH3CN·0.5(toluene) have been determined by X-ray crystallography: 1crystallizes in the monoclinic space groupP21/m, Z= 2, with a = 8.412(2) Å, b =15.562(3) Å, c = 10.025 Å, and β =109.89(2)°; 1a·3CH3CN, in themonoclinicspace group C2/c, Z = 4, with a =19.858(3) Å, b = 15.483(2) Å, c =18.192(3) Å, and β = 95.95(2)°; 3, intheorthorhombic space group Pnma, Z = 4, witha = 18.399(4) Å, b = 9.287(2) Å,and c = 12.052(2) Å,4·H2O,in the monoclinic space group P21/c,Z = 4, with a = 8.586(1) Å,b = 15.617(3) Å, c = 16.388(5) Å,and β =90.84(2)°; and5·3CH3CN·0.5(toluene), in themonoclinic space group P21/c,Z = 4, with a = 15.003(3) Å,b =16.253(3) Å, c = 21.196(4) Å, and β =96.78(3)°. The structural data indicate that in complexes1−4 the neutralo-benzoquinone diimine ligand prevails. In contrast, in5 this ligand has predominantlyo-phenylenediamidecharacter, which would render 5 formally a mixed-valentRuIVRuV species. On the other hand,the Ru−N bondlengths of the Ru−N−Ru moiety at 1.805(5) and 1.767(5) Åare significantly longer than those in othercrystallographically characterizedRuIVNRuIV units (1.72−1.74 Å). Itappears that the C6H4(NH)2ligand in5 is noninnocent and that formal oxidation state assignmentsto the ligands or metal centers are not possible.
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