Nitrogen containing 2,4,6-tris(2-pyridyl)-s-triazine (tpt) ligand and its metal complexes exhibit various pharmacological activities such as antiviral, antitumor, analgesic, antioxidant, antidepressant, antibacterial, and antimicrobial. In additional, they possess catalytic activities in some polymerization and oxidation processes and are used as analytical reagents in spectrophotometric determination of some species in pharmaceutical formulations.

Two new mononuclear manganese(II) complexes, cationic [Mn(tpt)(NO3)(H2O)2](NO3) (1) and neutral [Mn(is)(tpt)(MeOH)(Cl)] • (H2O) (2), (tpt = 2,4,6-tris(2-pyridyl)-s-triazine, His = isobutyric acid), have been synthesized under ultrasonic irradiation by interaction of manganese(II) pivalate or manganese(II) isobutyrate with tpt in the presence of Dy(NO3)3 • 6H2O for 1 or 2-[bis(2-hydroxyethyl)amino]acetonitrile hydrochloride for 2 in ethanol and methanol solvent, respectively. Compound 1 crystallizes in the monoclinic C2/c space group, a = 20.436(1), b = 13.361(1), c = 16.727(1) Å, β = 107.782(4)°, compound 2 - in the triclinic P-1 space group, a = 8.813(1), b = 10.955(1), c = 15.129(1) Å, α = 71.115(4), β = 81.894(4), γ = 68.777(5)°.

In both complexes tpt molecule serves as a tridentate NNN ligand which forms two five-membered metallocycles with Mn-N distances 2.231 - 2.379 Å in cationic 1 and 2.295 - 2.412 Å in neutral 2. Additionally, manganese atom coordinates NO3- anion and two water molecules in 1 or isobutyrate and chlorine anion and water molecules in 2, resulting in pentagonal bipyramidal surrounding of the metal atom (Figures). The NO3- and isobutyrate anions coordinate in bidentate mode with Mn-O distances 2.269 and 2.412 Å (1) and 2.226 and 2.308 Å (2). The Mn-O distances with the water molecules in apical position in 1 equal 2.139 and 2.193 Å, and in 2 Mn-Cl = 2.486 Å and Mn-O(MeOH) = 2.294 Å.