6533b873fe1ef96bd12d4ada

RESEARCH PRODUCT

Copper(II)-assisted hydrolysis of 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine (tpymt): syntheses, crystal structures and magnetic properties of [Cu(bpcam)(H2O)2]ClO4·3H2O, [Cu(bpcam)(H2O)2][Cu(bpcam)(H2O)(SO4)]·2H2O and [Cu2(bpcam)2(H2O)2(SO4)]·H2O [bpcam=bis(2-pyrimidylcarbonyl)amidate]

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Abstract The reaction of the 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine (tpymt) ligand with copper(II) perchlorate or sulfate in aqueous solution affords complexes [Cu(bpcam)(H2O)2]ClO4 · 3H2O (1), [Cu(bpcam)(H2O)2][Cu(bpcam)(H2O)(SO4)] · 2H2O (2) and [Cu2(bpcam)2(H2O)2(SO4)] · H2O (3) [bpcam = bis(2-pyrimidylcarbonyl)amidate], whose structures have been determined by single-crystal X-ray diffraction studies. Copper(II) promotes the hydrolysis of tpymt in mild conditions yielding the bpcam group which is present in the structures of 1–3 as a tridentate ligand. The structure of 1 consists of mononuclear [Cu(bpcam)(H2O)2]+ cations, uncoordinated perchlorate anions and water of crystallization. The structure of 2 is made up of [Cu(bpcam)(H2O)2]+ cations, [Cu(bpcam)(H2O)(SO4)]− anions and lattice water whereas that of 3 contains the neutral dinuclear complex [Cu2(bpcam)2(H2O)2(SO4)] and lattice water. While the sulfate group act as a terminal monodentate ligand in 2, it adopts a bis-monodentate bridging mode in 3. The copper atom coordination sphere in 1–3 is distorted square pyramidal, with three bpcam nitrogen atoms (1–3) and a water molecule (1 and 2) or a sulfate oxygen (2 and 3) building the basal plane and another water molecule (1–3) in the apical position. The values of the shortest intermolecular copper–copper separation in 1 and 2 are 5.705 and 6.604 A, respectively, whereas that through bridging sulfato in 3 is 5.494 A. Variable-temperature magnetic susceptibility measurements show a Curie law behaviour for 2 whereas a weak intramolecular antiferromagnetic interaction [J = −7.0 cm−1, the Hamiltonian being defined as H ^ = - J S ^ 1 · S ^ 2 ] occurs in 3. The potential use for metal assembling of the stable mononuclear [Cu(bpcam)]+ unit is discussed in the light of the results obtained with the related [Cu(bpca)]+ complex [bpca = bis(2-pyridylcarbonyl)amidate].