Diamine complexes of nickel(II) nitrate: X-ray single crystal structural analysis of trans-[NiL2(NO3)2] [L = 1-(2-aminoethyl)piperidine]

Trans-[NiL^sub 2^(H^sub 2^O)^sub 2^](NO^sub 3^)^sub 2^ (pale blue) (1), trans-[NiL^sub 2^(NO^sub 3^)^sub 2^] (dark blue) (2), [L = 1-(2-aminoethyl)piperidine] and trans-[NiL^sub 2^^sup '^(H^sub 2^O)^sub 2^](NO^sub 3^)^sub 2^ (blue) (3) [L = 1-(2-aminoethyl)pyrrolidine] have been prepared. Complexes (1) and (3) upon heating undergo deaquation-anation yielding trans-[NiL^sub 2^(NO^sub 3^)^sub 2^] (dark blue) (2) and cis-[NiL^sub 2^'(NO^sub 3^)](NO^sub 3^) (blue) (3a), respectively. The X-ray single crystal structure of complex (2) has been determined.[PUBLICATION ABSTRACT]