Metal(II)-assisted hydrolysis of 2,4,6-tris(2-pyrimidyl)-1,3,5-triazine (tpymt): synthesis, crystal structure and magnetic properties of [Co(bpcam) 2 ]ClO 4 . dmso . H 2 O, [Co(bpcam) 2 ] 2 [Co(NCS) 4 ] . dmso . H 2 O and [Ni(bpcam) 2 ] . H 2 O [Hbpcam = bis(2-pyrimidylcarbonyl)amide]