Ligand-Induced Structural, Photophysical, and Electrochemical Variations in Tricarbonyl Rhenium(I) Tetrazolato Complexes

Abstract

Treatment of [Re(CO) 5 X] (X = Cl, Br) with 2-(2-tert-butyltetrazol-5-yl)pyridine yielded neutral mononuclear complexes by exchange of two CO ligands for the chelating tetrazolato ligand. Treatment of [Re(CO) 5 Br] with phenyltetrazolate resulted in the assembly of an anionic dinuclear rhenium tricarbonyl species bridged by three tetrazole rings. The reaction of [Re(CO) 5 Br] with (2-tert-butyltetrazol-5yl)benzene formed an analogous neutral dinuclear complex bridged by a tetrazole ring as well as two bromide ligands; however this complex was found to be rather unstable in solution and was only structurally characterized via X-ray diffraction. The first three complexes were investigated for their photophysical properties, highlighting phosphorescent emission from their triplet metal-to-ligand charge transfer excited states, although in the case of the dinuclear species the quantum yield was found to be extremely low. The complexes are also characterized for their electrochemical behavior, and while the neutral mononuclear species show irreversible oxidations, the dinuclear complex displays one reversible and simultaneous two-electron oxidation.

Fluorescence probes for prokaryotic and eukaryotic cells using Re(CO)3+complexes with an electron withdrawing ancillary ligand

“…These results present similar values than those published by different authors using analogous complexes [72][73][74][75][76][77][78][79][80][81]. Interphase: Pt|1.C1, rhenium oxidations appear at E p 1.51 V, which seems to be electrochemically irreversible, and a second of reversible character at E ½ 1.90 V. On the other hand C2 presents same peaks at E p 1.46 V and E ½ 1.86 V, respectively.…”

The effect of group-substitution on structures and photophysical properties of rhenium(I) tricarbonyl complexes with pyridyltetrazole ligand: A DFT/TDDFT study

“…All the calculations were carried out with Gaussian 09 software package [46]. Table 1 shows that the bond lengths and angles in complexes 1-5 display typical features of Re(I) tricarbonyl diimine complexes [23][24][25][26][27].The optimized bond lengths and angles of 1 are in satisfactory agreement with the experimental values based upon crystallographic data from the literature [30]. The slight deviations between calculated and experimental values are probably from the fact that theoretical calculations refer to gas phase but experiment results are from the close-packed crystal lattice.…”

“…Recently, the photophysical properties of mononuclear and dinuclear tricarbonyl rhenium(I) tetrazolato complexes and the indirect influence of the tetrazolato ancillary ligand in governing the relative energy of the 3 MLCT [5d(Re)→π*(diimine)] excited states via stabilization or destabilization of 5d orbitals of Re have been researched by Wright et al [28][29]. As a continuation of the work, fac-[Re (CO) 3 (L)(N^N)] (L = Cl or Br; N^N = tert-butylated pyridyltetrazole) were successfully synthesized [30]. The photophysical and electrochemical properties of these species were also investigated and corroborated by computational calculations.…”

Versatility of Terpyridine‐Functionalised Aryl Tetrazoles: Photophysical Properties, Ratiometric Sensing of Zinc Cations and Sensitisation of Lanthanide Luminescence

“…Alkylation of the tetrazole ring in H TzPhTpy was first attempted by reaction with trifluoroacetic acid and sulfuric acid in tert ‐butanol. This procedure was chosen because its regioselectivity for the N2 position of the tetrazole ring was previously demonstrated , . However, this reaction failed to yield the target alkylated species.…”