
TY  - JOUR
A1  - Engelhardt, LM 
A1  - Keegan, EA 
A1  - Lawrance, GA 
A1  - White, AH 
T1  - Synthesis, Characterization and Enhanced Cleavage of Diphosphate and Triphosphate Bound to Tetraaminecobalt(III) Centers. Crystal Structure of [N,N-Bis(2-aminoethyl)ethane-1,2-diamine](diphosphato)cobalt(III) Perchlorate Monohydrate
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1989
VL  - 42
IS  - 7
SP  - 1045
EP  - 1055
KW  - 
UR  - https://doi.org/10.1071/CH9891045 
N2  - The complexes [Co( tren )(P2O7H2)] (ClO4).H2O, [Co( tren )(P3010H3)] (ClO4) (tren = N,N-bis(2- aminoethyl )ethane-1,2-diamine) and [Co( cyclen )(P2O7H2)](ClO4)(cyclen = 1,4,7,10-tetraazacy-clododecane ) have been prepared and characterized. The complex [Co( tren )(P207H2)](C104).H20 crystallized in the monoclinic space group P21/n,a 10.655(3), b 14.675(5), c 11.260(4) Å , &#946; 98.49(3) for a single-crystal structure determination R was 0.041 for 4043 'observed' reflections. Despite the presence of a primary and a tertiary nitrogen donor in the plane of the cobalt and the phosphate oxygen donors, bond distances to Co-N(primary) and Co-N(tertiary) at 1.926(3) and 1.924(3) Å respectively are equivalent, as are the Co-O distances of 1.940(2) and 1 .943(3) to the N(primary) and N(tertiary) respectively. Axial Co-N(primary) bonds (av. 1.952 A) are elongated compared with the in-plane N(primary), and the axial N-Co-N angle is distorted (171.6º). The hydrolysis of the diphosphate and triphosphate complexes at pH 7.3 in the presence of an assisting complex, [Co( tn )2(OH2)(OH)]2+ ( tn = propane-1,3-diamine) or [Co( tren )(OH2)(0H)]2+, was followed by 31P n.m.r. spectroscopy, and rate enhancements of up to about 104 compared with free polyphosphate were observed, with the diphosphato complexes being least sensitive to cleavage by added complex. Intermediates in which the polyphosphate bridges two metal centres are apparently involved; the inability of [Pd(en)(0H2)2]2+(en= 1,2-ethanediamine) to enhance cleavage is consistent with this, since this ion does not form complexes with polyphosphates. [Co( tren )(ATP)](ATP=adenosine triphosphate ) was also prepared but not isolated; assisted hydrolysis with [Co( tren )(OH2)(OH)]2+ is about 104 faster than unassisted hydrolysis of free ATP under similar conditions. 
ER  -

