Synthesis and characterization of new mononitrosyl complexes of osmium-containing quinoline-8-olates

Abstract

A high yield synthetic route to osmium mononitrosyls of type [OsX(NO)Q2] (2) IX = C1 or Br, Q = anions of quinolin-8-ol (HQ 1) and its substituted species (HQ2)] from [OsX2Qz] (I) is described. The orange-red complexes are diamagnetic and exhibit v(NO) at ca. 1910 cm-1 in their i.r. spectra, indicating a high degree of nitrosonium ion (NO +) character. A single sharp Qz methyl signal is in line with the geometry of (2). The complexes display both spin-allowed and spin-forbidden charge transfer transitions in the 800 200 nm range. Chemical reactions toward nucleophiles, namely acetylacetone and propiophenone, clearly establish the electrophilic nature of the bound NO.

Synthesis, characterization and photophysical properties of quinolin-8-olato chelated osmium(II) organometallics bearing a pendant imine-phenol motif and electrogeneration of trivalent analogue

“…We assign structure 3 to it in analogy with the stereochemistry of other Os II (quinolin-8-olato) complexes [38,39] and also by comparing with acetate, thioxanthate, pyridine-2-thiolato chelated ruthenium/osmium organometallics [27,31,32].…”

“…Changes in the coordination mode and tautomeric state of the Schiff base ligand accompany the synthetic reaction. It may be noted that the chemistry of osmium quinolin-8-olate appears to have relatively less attention [36][37][38][39] but to the best of my knowledge organoosmium compounds incorporating 8-hydroxyquninoline are unprecedented. Another point of special interest is that such species are potentially luminescent in the visible region and are electrochemically oxidizable to the trivalent analogue.…”