On the relationship between the structures of Cu(II) complexes and their chemical transformations

Abstract

The experimental activation energies (E •) of dehydration of Cu(NH3)4(H20)SO 4, Cu(en)2(H20)X 2 (X = CI-, Br-), Cu(en)(H20)2SO 4, Cu(pY)2(H20)2SO4, CuCI2 9 2 H20 and M~CuCI 4 9 2 H20 (M ]-= NH 4, K, Rb) were obtained from their non-isothermal thermogravimetric curves using the Coats-Redfern method. These E ~ values were compared with known data on the structures of the Cu(ll) coordination polyhedra in the above complexes. No dependence of the E ~ values was found on either the central atom -released ligand bond length, or the number and lengths of the hydrogen bonds formed by the released water molecules. However, it was found that it is justified to seek some relationship between the E ~ values and the anisotropic temperature factors of the donor atoms of the ligands split off. Cu(NHa)4(H20)SO 4, Cu(aAa)2(H=O)X 2 c X = CI-vl Br-, CU(aAa)2(H20)2SO4, Cu(nHp.) 2(H 20)2SO4,CuCt~ 9 2 H2OHM~CuCI 4 9 2 H=O, rAeM I = NH4,K, Rb--6bmHonpe-AeneHbl H3 HeH3oTepMHqeCKVIX TepMoFpaBHMeTpHqeCKHX KpHBblX, HcnoRb3yR MaTO~I. KoyTca--PaA~epHa. nonyqaHHble 3HaHeHHR E + 6blJ'lH conoCTaBneHbl C H3BeCTHblMH AaHHblMH O cTpyKType Cu(II) KOOpAHHal/HOHHOrO nonHaApa B BblLUeyrlOMRHyTblX KOMnneKCaX. He 6blTla Ha~AeHa 3aBHCHMOCTb Me>KAy E + H AnHHOI~I CBR3VI I/eHTpagbHbl~l aTOM --BblAeRRIOU/HHCR NHFaHA, HH Me>KAy qHCEIOM H ATIIAHO~I BOJ~OpO~HblX CBR3eH, oSpa3OBaHHblMH BblAeRRIOLU, HMHCR MOJleKyJlaMH BO/~bl. OAHaKO, 6blYlO Ha~IAeHO, NTO oRpaBAaHHblM RBJqReTCR rlOHCK HeKOTOpO~I B3aHMOCBR3HMe>KAy 3HaHeHHeM E + H aHH3OTpOnHblMH TeMnepaTypHblMH Ci0aKTOpaMH AOHOpHblX aTOMOB NHFaH~OB.