ChemInform Abstract: Synthesis and Reactivity of (LRe(NO)(CO)(NCO))+ (L: 1,4,7-Triazacyclononane). Kinetics and Mechanisms of Its Formation and Transformation to (LRe(NO)(CO)X)n+ (X: NH3, Cl, HCO- 2, CF3SO- 3) and Other Species. Crystal Structure of (LRe(NO)(CO)(NH3))Br2.

ChemInform Abstract

The title complex (III) is synthesized from the dicarbonyl analogue (I) with a variety of nucleophiles (N₂H₄, NH₂NHMe, NH₂NMe₂, NH₂OH, N3^-) such as shown in the scheme using hydrazine (II). The kinetics and mechanism of the formation of (III) is investigated. (III) undergoes a series of reactions at the coordinated isocyanate ligand: e.g. conc. HCl or HBr react with (III) to produce the ammine derivative (IVa). The structure of the dibromide (IVa) (X: Br; space group P2₁/c, Z=4) is determined by X-ray analysis. The kinetics and mechanisms of the reaction of (III) with H⁺ is investigated. The oxidized, paramagnetic form (IVb) of (IVa) (X: Br) can be obtained by treatment of (III) with Br2 or electrochemically. CF₃SO₃H or HCOOH/NaBF4 react with (III) to yield the substitution products (Va) and (Vb). In the presence of NaI, (III) undergoes addition reactions in MeOH or EtOH to form alkyl carbamato complexes e.g. (Vc). Last can be converted into the N-nitrosocarbamato complex (VI) as demonstrated. Spectroscopic properties (¹H, ¹³C NMR, UV/VIS, IR) are reported for all compounds.