81739-55-1Relevant articles and documents
Kinetics of aquation and base hydrolysis of some cis- and trans-dichloro(1,4,7,10-tetraazatetradecane)chromium(III) cations. The CrCl2(3,2,3-tet)+ system
Yang, David,House, Donald A.
, p. 2999 - 3007 (2008/10/08)
The synthesis of cis-β-(RR,SS)-[CT(ox)(3,2,3-tet)]ClO4, Δ(-)589-cis-β-(RR)-[Cr(ox)(3,2,3-tet)][hydrogen dibenzoyl-(+)-tartrate], cis-β-(RR,SS)-[CrCl2(3,2,3-tet)]ClO4, Δ(-)589-cis-β-(RR)-[CrCl2(3,2,3-tet)]ClO 4, trans-(RR,SS)-[CrCl2(3,2,3-tet)]NO3, (-)589-trans-(RR)-[CrCl2(3,2,3-tet)]ClO4, trans-(RR,SS)-[Cr(NCS)2(3,2,3-tet)]NCS, and (-)589-trans-(RR)-[Cr(NCS)2(3,2,3-tet)][hydrogen dibenzoyl-(+)-tartrate] (3,2,3-tet = 1,5,8,12-tetraazatetradecane) is described. Conformational assignments have been made on the basis of chiral interconversions, Δ(-)589-cis-β-(RR)-Cr-(ox)(3,2,3-tet)+ → Δ(-)589-cis-β-(RR)-CrCl2(3,2,3-tet)+ → (-)589-trans-(RR)-CrCl2(3,2,3-tet)+, in acidic solution. The rates of loss of the first chloro ligand from the racemic dichloro cations have been measured in both acidic and basic solutions. The kinetic parameters at 298.2 K are as follows: kH(trans-(RR,SS)) = 1.06 × 10-6 s-1 (0.1 M HNO3), Ea = 94.7 kJ mol-1, and ΔS? = -50 J K-1 mol-1; kH(cis-β-(RR,SS)) = 1.02 × 10-4 s-1 (0.1 M HNO3), Ea = 88.7 kJ mol-1, and ΔS? = -32 J K-1; kOH(trans) = 5.76 × 10-1 M-1 s-1 (μ = 0.1 M, NaCl), Ea = 87.7 kJ mol-1, and ΔS? = +36 J K-1 mol-1; kOH(cis-β) = 11.2 M-1 s-1 (μ = 0.1 M, NaCl). For the loss of the second chloro ligand, the kinetic parameters (298.2 K) are KOH(trans) = 8.81 × 10-3 M-1 s-1 (μ = 0.1 M, NaCl), Ea = 97.3 kJ mol-1, and ΔS? = +34 J K-1 mol-1 and kOH(cis-β) = 4.0 × 10-2 M-1 s-1 (μ = 0.1 M, NaCl). (-)589-trans-(RR)-CrCl2(3,2,3-tet)+ racemizes in basic solution about 10 times faster than loss of the first chloro ligand, and at 298.2 K, krac = 5.93 M-1 s-1, Ea = 88.7 kJ mol-1, and ΔS? = +59 J K-1 mol-1.
