In this paper we describe the synthesis of the new mixed-donor ligand 1,8-bis(3,5-dimethyl-1H-pyrazol-1-yl)-3,6-dioxaoctane (L). The complexes [MCl2(L)] (M=Zn-II (1), Cd-II (2), Hg-II (3), Pd-II (4), Pt-II (6), Ni-II (7)) and [PdCl2(L)](2) (5) were prepared and fully characterized. X-ray crystal structures of complexes 1, 2, 4, 6, and 7 have been determined. The L ligand behaves either as a NN-bidentate (chelate or bridge) and NOON-tetradentate (equatorial or planar) ligand. In these structures, C-H center dot center dot center dot X (X=O, N or Cl/Cl-) intermolecular interactions have been identified and studied. Moreover, the Cd-113{H-1}, Pt-195{H-1}, and Hg-199{H-1} NMR spectra were measured to investigate the coordination environment of the metal in solution. Diffusion NMR studies have also been performed to characterize monomeric and dimeric species of Pd-II. Finally, we have observed that the dimeric complex 5 is converted into the corresponding monomeric complex 4.