Synthesis, characterization, crystal structure and preliminary reactivity behaviour of new heteropolytopic ligands based on the 1,3,5-triazine spacer and pyrazolyl, tris-pyrazolylmethyl and tris-pyrazolylethoxy bonding fragments

Abstract

Four new potentially polytopic nitrogen donor ligands based on the 1,3,5-triazine fragment, L¹–L⁴ (L¹ = 2-chloro-4,6-di(1H-pyrazol-1-yl)-1,3,5-triazine, L² = N,N′-bis(4,6-di(1H-pyrazol-1-yl)-1,3,5-triazin-2-yl)ethane-1,2-diamine, L³ = 2,4,6-tris(tri(1H-pyrazol-1-yl)methyl)-1,3,5-triazine, and L⁴ = 2,4,6-tris(2,2,2-tri(1H-pyrazol-1-yl)ethoxy)-1,3,5-triazine) have been synthesized and characterized. The X-ray crystal structure of L³ confirms that its molecular nature consists of a 1,3,5-triazine ring bearing three tripodal tris(pyrazolyl) arms. L¹, L², and L⁴ react with Cu^I, Cu^II, Pd^II and Ag^I salts yielding mono-, di-, and oligonuclear derivatives: [Cu(L¹)(Cy₃P)]ClO₄, [{Ag₂(L²)}(CF₃SO₃)₂]·H₂O, [Cu₂(L²)(NO₃)₂](NO₃)₂·H₂O, [Cu₂(L²)(CH₃COO)₂](CH₃COO)₂·3H₂O, [Pd₂(L²)(Cl)₄]·2H₂O, [Ru(L²)(Cl)(OH)]·CH₃OH, [Ag₃(L⁴)₂](CF₃SO₃)₃ and [Ag₃(L⁴)₂](BF₄)₃. The interaction of L³ with Ag^I, Cu^II, Zn^II and Ru^II complexes unexpectedly produced the hydrolysis of the ligand with formation, in all cases, of tris(pyrazolyl)methane (TPM) derivatives. In detail, the already known [Ag(TPM)₂](CF₃SO₃) and [Cu(TPM)₂](NO₃)₂, as well as the new [Zn(TPM)₂](CF₃SO₃)₂ and [Ru(TMP)(p-cymene)]Cl(OH)·2H₂O complexes have been isolated. Single-crystal XRD determinations on the latter derivatives confirm their formulation, evidencing, for the Ru^II complex, an interesting supramolecular arrangement of the anions and crystallization water molecules.