The X-ray crystal structure of bis(glycinohydroxamato)nickel(II). A novel co-ordination of nickel by a hydroxamic acid via the nitrogen atom of the NHOH group

Nickel Ion Complexes of Amino Acids and Peptides

“…Due to the presence of the amino-N in chelatable position to the hydroxamate moiety, the aminohydroxamic acids are able to form not only the well-known hydroxamate-type fi ve-membered (O,O)-chelate (Scheme 1, structure I), but also the (N,N) one (structure II) and, if the stability of the two chelates is comparable, the mixed type binding mode (structure III) is also possible. With Ni(II), the trans (N,N) coordination of two glycinehydroxamates in a square planar complex, trans-[NiL 2 ], was proven by X-ray in the early 1980s by Brown et al [62]. It was also established that one of the coordinated ligands releases its -NOH proton at high pH, which results in the formation of the even more stable planar cis-[NiL 2 H Ϫ1 ] Ϫ [63].…”

Bis(ethylenediaminium) bis[oxalohydroxamato(3–)]nickelate(II) dihydrate

“…The latter ring is puckered, with a deviation of the Ni atom from the plane de®ned by the other four atoms of 0.0376 (1) A Ê . The CÐO, NÐO and CÐN bond lengths in the coordinated hydroxamate group suggest its existence in the hydroxamic form rather than in the oximic form (Brown et al, 1982).…”

Structural characteristics of the hydroxamic acid group. Crystal structure of formohydroxamic acid

“…'s less than 0.01 ,/k or R < 0.076. Two complexes with N,N' ligands rather than O,O' [bis(glycinhydroxamato)nickel(II), Brown, Roche, Pakkanen, Pakkanen & Smolander (1982), and sodium bis(aminoacetohydroxamato-N,N')nickel(II) trihydrate, Julien-Pouzol, Jaulmes, Laruelle, Carvalho & Paniago (1985)] were not included in the sample.…”