syn1‐Periplanar Bisazo Skeletons — Syntheses and Reactions with Carbonylmetal Complexes

Abstract

Preparatively useful synthesis for the novel, relatively mobile polycyclic syn1‐periplanar bisazo polycycles 4 and 5 are based on hydrazine condensation with readily available dienedione 6 and acid‐catalyzed rearrangement of bisurazole 12, respectively. In the preferred “closed” and “open” conformations of 4 and 5 the NN bonds are 314 and 496 pm, respectively, apart (MMX). From the reactions of 4 and 5 with carbonyliron and ‐ruthenium compounds, complexes are derived which are typical of monoazo ligands [4 · Fe(CO)4  20, 4 · Fe2(CO)721, 4 · Fe3(CO)922, 4[Fe2(CO)6]223, 4 · Ru3(CO)9 · 24, 5 · [Fe2(CO)6]2  25, 5 · Fe2(CO)6 · Fe3(CO)9  26]. For 21, 23 and 26 crystal structure analyses were performed, confirming i.a. in 26 the unique presence of a Fe2(CO)6 and a Fe3(CO)9 fragment attached to two azo units of the same molecule.

Platinum(II) Hydrazido Complexes

“…The N−N bond distance of 1.429(11) indicates that the hydrazido(2−) formulation is the best description. Shorter N−N bond distances (1.361−1.413 Å) are found in Fe 2 carbonyl complexes with this coordination mode. − These complexes are usually prepared from diazo compounds and apparently retain some diazo character. A Zr, W, and Sm , complex with this hydrazido(2−) bonding mode have also been reported.…”

Proximate, “Parallel‐In‐Plane” Preoriented Bis(diazenes) − In‐Plane Delocalized Bis(homoconjugated) 4N/5(6)e Anions

“…Syntheses B-Type Bis(diazenes) 4b؊f (Scheme 1): [22] The synthesis of bis(diazene) 4a, the parent B structure, from bicyclic dienedione 1a and hydrazine hydrate has been described in detail in the context of our attempts to use NϭN/NϭN complexation as a way to enforce closer proximity. [23] To recap, after a smooth double Michael addition of hydrazine to 1a, cyclization [cf. bis(pyrazolidine) 6], and dehydration, vigorous ''one-pot'' conditions (80°C, sealed ampoule, 10 d [2i] ) were necessary to effect the isomerization of the, thermodynamically less stable bis(pyrazoline) [bis(hydrazone)] 3a to 4a.…”

Electron ionization‐induced fragmentation of R2N2Fe2(CO)6 complexes with distinct geometries of the tetrahedral core: investigation of µ‐1,2‐(1,2‐diaza‐3‐methylcyclopentane)diylbis(tricarbonyliron) and bis(µ2‐acetophenoniminato)bis(tricarbonyliron)

“…In particular, in µ‐1,2‐(1,2‐diaza‐3‐methylcyclopentane)‐ diylbis(tricarbonyliron) ( 1 ), the nitrogen atoms are bridged by an aliphatic chain, CH 2 CH 2 CH(CH 3 ). Although usually the complexes of type I were obtained from azo compounds,1–7 1 has been formed by cyclization of acetaldazine (CH 3 CHN) 2 in the presence of dodecacarbonyl triiron 8. In contrast, ketazines such as [ p ‐RPhC(CH 3 )N) 2 , where R stands for H (this compound was the substrate for synthesis of bis(µ 2 ‐acetophenoniminato)bis(tricarbonyliron) ( 2 )) or OCH 3 ,9, 10 and also propionaldehyde azine,8 in reaction with Fe 3 (CO) 12 produce complexes of the type II , in which the original NN bond is cleaved and two chemically identical moieties originating from the parent molecule serve as independent ligands.…”