Copper(II)-assisted hydrolysis of 2,4,6-tris(2-pyridyl)-1,3,5-triazine. Part 2. Crystal structures of [bis(2-pyridylcarbonyl)amido](pyridine-2-carboxamide)copper(II) trifluoromethanesulphonate and [bis(2-pyridylcarbonyl)amido][2,4,6-tris(2-pyridyl)-1,3,5-triazine]copper(II) trifluoromethanesuiphonate

Abstract

Two compounds of formula [Cu{(NC₅H₄Co)₂N}(NC₅H₄CONH₂)][CF₃SO₃](1) and [Cu{(NC₅H₄CO)₂N}(tptz)][CF₃SO₃], (2), where (NC₅H₄CO)₂N^– and NC₅H₄CONH₂ are bis(2-pyridylcarbonyl)amide and pyridine-2-carboxamide and tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine respectively, have been obtained from aqueous solutions of tptz and copper(II) trifluoromethanesulphonate. Crystals of complex (1) are monoclinic with a= 9.927(4), b= 26.727(5), c= 8.594(4)Åβ= 98.72(2)°, space group P2₁/n, and Z= 4. Crystals of complex (2) are triclinic with a= 9.177(3), b= 10.735(3), c= 18.231(4)Å, α= 102.65(2), β= 106.60(2), γ= 93.89(3)°, space group P, and Z= 2. The structure of (1) consists of [Cu{NC₅H₄CO)₂N}(NC₅H₄CONH₂)]⁺ mononuclear cations plus semi-co-ordinated CF₃SO₃ ^– anions. The copper(II) ion is in a distorted octahedral environment: the three nitrogen atoms of the bis(2-pyridylcarbonyl)amido ligand and the pyridine one of the carboxamide form a distorted square plane around the copper whereas the axial positions are occupied by the oxygen atom of the carboxamide and by an oxygen atom of the CF₃SO₃ ^– group with Cu–O bonds different from each other and significantly longer than the equatorial ones. The structure of (2) is made up of [Cu{(NC₅H₄CO)₂N}(tptz)]⁺ mononuclear cations and non-co-ordinated CF₃SO₃ ^– groups. The copper(II) ion is six-co-ordinated: the three nitrogen atoms of the bis(2 pyridylcarbonyl)amido ligand and one nitrogen atom of the triazine ring of tptz form a distorted square plane around the copper, while two nitrogen atoms from two pyridyl rings of tptz occupy the axial sites. The two Cu–N axial bonds are very close but significantly longer than the equatorial ones. The structure of (1) contains as ligands the two main products of the copper(II)-assisted tptz hydrolysis, whereas in the structure of (2) the co-ordination polyhedron around copper(II) is achieved by one of these products and tptz. The possibility of synthesizing copper(II) complexes containing unhydrolysed tptz is discussed in the light of the structure of complex (2).