Synthesis, crystal structure and magnetic properties of new molecular, macrocyclic building blocks of Ni(II) and Cu(II)

► NiII and CuII macrocyclic complexes as new molecular building blocks. ► Weakly interacting paramagnetic centers indicate by magnetic measurements. ► DFT calculation evidence the pathway of the magnetic exchange interactions. ► Good precursors in design and synthesis high spin magnetic materials. New macrocyclic building blocks [NiL1Cl2] (1) (L1=N-dl-2,9-dimethyl-1,5,8,12-tetraazacyclotetradecan) and [CuL2(ClO4)2] (2) (L2=N-d-2,3,9,10 tetramethyl-1,5,8,12-tetraazacyclotetradeka-1,8 diene) were synthesized and the crystal structure of both compounds were determined. Complexes 1 and 2 crystallizes in monoclinic, space group P 21/c. Their magnetic properties were studied over the temperature range 1.8–300K using a Quantum Design SQUID magnetometer (MPMSXL-5-type). The results indicate that both compounds behave as weakly interacting paramagnetic centers in the crystal lattice. The effects of hydrogen bond mediating the magnetic exchange interactions on the spin density have been evidenced by DFT calculations.