Transition metal complexes with thiosemicarbazide-based ligands. XV. A square-pyramidal Ni^IIcomplex with an asymmetric coordination of 2,6-diacetylpyridine bis(S-methylisothiosemicarbazone)

Abstract

The title compound, [diacetylpyridine bis(S-methylisothiosemicarbazonato)]iodonickel(II), [Ni(C(13)H(18)N(7)S(2))I], is the first example of a complex involving the (2)N coordination of the isothiosemicarbazide moiety. 2,6-Diacetylpyridine bis(S-methylisothiosemicarbazone), as a potentially pentadentate ligand (N(5)), is coordinated as a tetradentate species, whereby one (deprotonated) isothiosemicarbazide moiety is coordinated in the usual way ((1)N(4)N), but the other (neutral) is bonded via the (2)N atom only, the fourth ligator being the pyridine nitrogen. The difference in coordination mode of the isothiosemicarbazide moiety is reflected in the (1)N-(2)N bond lengths of 1.359 (4) and 1.379 (3) A in the deprotonated and undeprotonated moieties, respectively. The structure contains three fused chelate rings in a 5:5:6 arrangement. The six-membered ring has a non-planar conformation.

A square-planar NiIIcomplex with an asymmetric coordination of a novel polynucleative 2,6-diacetylpyridine bis{[2-(hydroxyimino)propanoyl]hydrazone} ligand

“…The Ni-N coordination bond lengths (Table 1) fall in the range 1.828 (3)-1.888 (3) Å and are typical for square-planar Ni II complexes with deprotonated amide ligands (Leininger et al, 2000;Leovac et al, 2000;Hlavica & Lewis, 2001;Moroz et al, 2006). The azomethine double-bond distances N2 C6 and N5 C11 [1.295 (5) and 1.301 (4) Å , respectively] are about the same.…”

Some Aromatic Schiff Bases and Their Metal Complexes

“…These anions are counter ions in the outer coordination sphere. In the paper [94], a Ni(II) compound with the previous ligand is described. In the presented complex the DAP-ITSC ligand coordinates asymmetrically through the pyridine N; amino N and azomethine N from one ITSC arm, and hydrazine N atom from the other ITSC arm (Figure 12c).…”

“…Together with the pyridine N, the ligand is coordinated by the 4 N donor set. By comparing the planarity of the same ligand in two complexes with Ni(II) [94] and Fe(III) [96] it is clear that the same DAP-ITSC ligand with different metal ions and in the presence of different anions is arranged differently in the coordination polyhedron.…”

Synthesis and crystal structure of copper(II) complexes with pyridoxal S-methylisothiosemicarbazone bearing a new coordination mode

“…[1][2][3]9 However, some very rare coordination modes of isothiosemicarbazones are also known, e.g., coordination through the sulfur atom of the S-alkyl moiety, 10 or lack of coordination of the isothioureido fragment. 11 Coordination of the mentioned NH 2 -group in tridentate isothiosemicarbazones results in its frequent condensation with, for example, salicyl-and pyridine-2-aldehyde 12 or 2-(diphenylphosphino)benzaldehyde, 13 thus forming complexes with tetradentate N 2 O 2 , N 3 O and N 2 OP donors, respectively. It was also found that bis(isothiosemicarbazones) of pentan-2,4-dione are able to stabilize some less usual oxidation states: Fe(IV), 14,15 Ni(III) 16 and Cu(III).…”