5-(2-Pyridil)-1H-tetrazole complexes with Mo(iv) and W(iv) cyanides

Abstract

The reactions of tetrazole ligand derived from 2-cyanopyridine with KNa[Mo(CN)O]·6HO and KNa[W(CN)O]·6HO in water-ethanol solution result in isolation of two new complexes with the following formulae: (PPh)[Mo(CN)O(pdt)]·2HO (1) (Hpdt = 5-(2-pyridil)-1H-tetrazole) and (PPh)[W(CN)O(pdt)]·3HO (2). The complexes were characterized by elemental analysis, single crystal X-ray structure measurements, IR and UV-Vis spectroscopy, cyclic voltammetry measurement as well as thermogravimetric measurement. The X-ray crystal structure measurements indicated the presence of two coordination isomers in a single crystal. The pyridine nitrogen occupies both trans and/or cis position to the M[double bond, length as m-dash]O bond, which is explained by similar pK of pyridine and tetrazole nitrogen. The DTG measurements indicate the stabilization of tetrazole upon coordination.

A Molybdenum(VI) Complex of 5-(2-pyridyl-1-oxide)tetrazole: Synthesis, Structure, and Transformation into a MoO3-Based Hybrid Catalyst for the Epoxidation of Bio-Olefins

“…Among 5-R-tetrazole derivatives, 5-(pyridyl)tetrazoles have attracted attention as ligands owing to their multiple coordination modes, which expand the coordination chemistry of the tetrazole fragment. In the case of 5-(2-pyridyl)tetrazole (Hptz), the pK a of the pyridyl N atom (pK a = 5.25) is very similar to that of N1 of the tetrazolyl ring (pK a = 4.9), which increases the proclivity of the molecule to coordinate as a bidentate ligand to metal centers [14]. This coordination mode is the most common among nine different possibilities [15], enabled by the deprotonation of Hptz to the tetrazolate anion (ptz − ).…”

A 5-(2-Pyridyl)tetrazolate Complex of Molybdenum(VI), Its Structure, and Transformation to a Molybdenum Oxide-Based Hybrid Heterogeneous Catalyst for the Epoxidation of Olefins

“…The coordination chemistry of (H)pytz has been mostly studied with respect to d-block elements in groups 7-12 of the periodic table (Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd) [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. To the best of our knowledge, a cyanide complex of Mo IV , with the formula (PPh 4 ) 2 [Mo(CN) 3 O(pytz)] 2 •H 2 O, is the only compound reported to date that comprises pytz − coordinated to Mo centers in a bidentate fashion [34]. Similarly, the 3D Mo/O/Mn II /tetrazole compound [Mn(pytz) Mo 2 O 7 ] appears to be the only example where a tetrazole moiety bridges adjacent Mo centers (in this case, the tetrazolate anion adopts a bridging µ 1,2,3,4 coordination mode to simultaneously connect two Mo atoms and two Mn atoms, with the pyridyl nitrogen left uncoordinated) [20].…”

Phenyltetrazole as a New Ligand for Immobilization of Palladium Nanoparticles on SBA‐15: A New Robust Catalyst with High Loading of Pd for Rapid Oxidation and Reduction

“…These simple 4 nitrogen-containing heterocycles may act as polydentate ligands for immobilization of transition metal, because of their aromaticity, excellent coordination capability and the possibility of offering new functionalized materials. [15][16][17][18][19] Recently, there have been several reports on immobilization of Palladium nanoparticles on heterogeneous support applied in organic transformations. Pd Nanoparticles Immobilized on Supported Magnetic GO@PAMPS for Suzuki-Miyaura Coupling Reaction, [20] cellulose sponge for cross-coupling, [21] magnetic carbon dots@Fe 3 O 4 nanocubes for hydrogen generation, [22] nanoceria for dehydrogenation of formic acid, [23] core-shell nanogels for Mizoroki-Heck Reaction, [24] Magnetic nanocomposite for Suzuki reaction, [25] Fe3O4@g-AlOOH nanocomposite for reduction, [26] nitrogen-doped carbon microtubes for Suzuki reaction, [27] mesoporous silica-based nanotubes for oxidation [28] and mesoporous carbon nitride for oxidation [29] was reported.…”

“…Tetrazoles can be prepared through a cyclization process. These simple 4 nitrogen‐containing heterocycles may act as polydentate ligands for immobilization of transition metal, because of their aromaticity, excellent coordination capability and the possibility of offering new functionalized materials . Recently, there have been several reports on immobilization of Palladium nanoparticles on heterogeneous support applied in organic transformations.…”

“…entry 14), by contrast, alkene and alkyne nitroarenes(Table 4, entries[16][17][18] and acidic nitroarenes (Table 4, entries 11 and 13) reduced without affecting the alkene, alkyne…”