trans-dioxocyclam (1,4,8,11-tetraazacyclotetradecane-2,9-dione) dihydrate and its Ni-II complex
UNSPECIFIED. (2001) trans-dioxocyclam (1,4,8,11-tetraazacyclotetradecane-2,9-dione) dihydrate and its Ni-II complex. ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS, 57 (Part 4). pp. 359-362. ISSN 0108-2701Full text not available from this repository.
The crystal structures are reported of trans-dioxocyclam dihydrate, C10H20N4O2. 2H(2)O, a structural isomer of the well known cis-dioxocyclam, and of its novel Ni complex, (1,4,8,-11-tetraazacyclotetradecane-2,9-dionato-kappa N-4)nickel(II) dihydrate, [Ni(C10H18N4O2)]. 2H(2) O, the first example of a transition metal complex of this ligand. Both molecules lie on crystallographic centres of inversion. The free ligand has two of its N atoms turned outwards from the ring and hydrogen bonded to water molecules. A major conformational change takes place in the complex in which the ligand binds in a trans tetradentate fashion, as suggested by the electronic spectrum. The nickel(II) ion is low spin, although the electronic spectrum of the complex in water indicates an equilibrium mixture of low-spin and high-spin species. The irreversible electrochemical oxidation of [NiL1] (L-1 is deprotonated transdioxocyclam, C10H18N4O2) in water occurs at a potential of 0.964 V [versus SHE (standard hydrogen electrode)], which is very similar to that for the Ni-cis-dioxocyclam complex.
|Item Type:||Journal Article|
|Subjects:||Q Science > QD Chemistry|
|Journal or Publication Title:||ACTA CRYSTALLOGRAPHICA SECTION C-CRYSTAL STRUCTURE COMMUNICATIONS|
|Publisher:||MUNKSGAARD INT PUBL LTD|
|Date:||15 April 2001|
|Number of Pages:||4|
|Page Range:||pp. 359-362|
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