Synthesis, X-ray Structure and Hirshfeld Surface Analysis of Zn(II) and Cd(II) Complexes with s-Triazine Hydrazone Ligand

The two group IIB complexes [Cd(DMPT)Cl₂] (6) and [Zn(DMPT)Cl₂] (7) of the tridentate ligand (DMPT), 2,4-bis(morpholin-4-yl)-6-[(E)-2-[1-(pyridin-2-yl) ethylidene]hydrazin-1-yl]-1,3,5-triazine were synthesized, and their structural aspects were elucidated with the aid of X-ray crystallography. Both complexes crystallized in the monoclinic crystal system, with P2₁/n as a space group. The unit cell parameters for 6 are a = 14.1563(9) Å, b = 9.4389(6) Å, c = 16.5381(11) Å and β = 91.589(5)° while the respective values for 7 are 11.3735(14), 13.8707(13), 14.9956(16), and 111.646(2)°. The unit cell volume is slightly less (2198.9(4) ų) in complex 7 compared to complex 6 (2209.0(2) ų). Both complexes have a penta-coordination environment around the metal ion, where the DMPT ligand acts as a neutral tridentate NNN-chelate via the pyridine, hydrazone, and one of the s-triazine N-atoms. The penta-coordination environment of the Cd(II) in complex 6 is close to a square pyramidal configuration with some distortion. On the other hand, the ZnN₃Cl₂ coordination environment is highly distorted and located intermediately between the trigonal bipyramidal and square pyramids. Supramolecular structure analysis of 6 with the aid of Hirshfeld calculations indicated the importance of the Cl…H, O…H, and C…H interactions. Their percentages were calculated to be 20.9, 9.1, and 8.7%, respectively. For 7, the Cl…H, O…H, C…H, and N…H contacts are the most important. Their percentages are 20.3, 9.0, 7.0, and 8.4%, respectively. In both complexes, the major intermolecular interaction is the hydrogen–hydrogen interactions which contributed 45.5 and 46.6%, respectively.