10.1021/acs.inorgchem.6b02986.s002
Andrey B. Lysenko
Andrey B.
Lysenko
Ganna A. Senchyk
Ganna A.
Senchyk
Konstantin V. Domasevitch
Konstantin V.
Domasevitch
Merten Kobalz
Merten
Kobalz
Harald Krautscheid
Harald
Krautscheid
Jakub Cichos
Jakub
Cichos
Miroslaw Karbowiak
Miroslaw
Karbowiak
Patrícia Neves
Patrícia
Neves
Anabela A. Valente
Anabela A.
Valente
Isabel S. Gonçalves
Isabel S.
Gonçalves
Triazolyl, Imidazolyl, and Carboxylic Acid Moieties
in the Design of Molybdenum Trioxide Hybrids: Photophysical and Catalytic
Behavior
American Chemical Society
2017
ligand
compound
Molybdenum Trioxide Hybrids
protonated imidazolium group
acidic hydrothermal conditions
trPhCO 2 H
zigzag subtopological motif
zwitterionic tetradentate forms
μ 2
MoO 5 N
imidazol -4-yl acid
biomass-derived methyl oleate
trans -β- methylstyrene
tetradentate zwitterrionic trhis species
Mo 8 O 25
trethbz
Mo 4 O 12
MoO 4 N 2
Mo 2 O 6
2017-04-03 12:18:32
Dataset
https://acs.figshare.com/articles/dataset/Triazolyl_Imidazolyl_and_Carboxylic_Acid_Moieties_in_the_Design_of_Molybdenum_Trioxide_Hybrids_Photophysical_and_Catalytic_Behavior/4810978
Three
organic ligands bearing 1,2,4-triazolyl donor moieties, (<i>S</i>)-4-(1-phenylpropyl)-1,2,4-triazole (<i>trethbz</i>), 4-(1,2,4-triazol-4-yl)benzoic
acid (<i>trPhCO</i><sub>2</sub><i>H</i>), and
3-(1<i>H</i>-imidazol-4-yl)-2-(1,2,4-triazol-4-yl)propionic
acid (<i>trhis</i>), were prepared to evaluate their coordination
behavior in the development of molybdenum(VI) oxide organic hybrids.
Four compounds, [Mo<sub>2</sub>O<sub>6</sub>(<i>trethbz</i>)<sub>2</sub>]·H<sub>2</sub>O (<b>1</b>), [Mo<sub>4</sub>O<sub>12</sub>(<i>trPhCO</i><sub>2</sub><i>H</i>)<sub>2</sub>]·0.5H<sub>2</sub>O (<b>2a</b>), [Mo<sub>4</sub>O<sub>12</sub>(<i>trPhCO</i><sub>2</sub><i>H</i>)<sub>2</sub>]·H<sub>2</sub>O (<b>2b</b>), and
[Mo<sub>8</sub>O<sub>25</sub>(<i>trhis</i>)<sub>2</sub>(<i>trhisH</i>)<sub>2</sub>]·2H<sub>2</sub>O (<b>3</b>), were synthesized and characterized. The monofunctional <i>tr</i>-ligand resulted in the formation of a zigzag chain [Mo<sub>2</sub>O<sub>6</sub>(<i>trethbz</i>)<sub>2</sub>] built
up from <i>cis-</i>{MoO<sub>4</sub>N<sub>2</sub>} octahedra
united through common μ<sub>2</sub>-O vertices. Employing the
heterodonor ligand with <i>tr/–CO</i><sub>2</sub><i>H</i> functions afforded either layer or ribbon structures
of corner- or edge-sharing {MoO<sub>5</sub>N} polyhedra (<b>2a</b> or <b>2b</b>) stapled by <i>tr</i>-links in axial
positions, whereas −CO<sub>2</sub>H groups remained uncoordinated.
The presence of the <i>im-</i>heterocycle as an extra function
in <i>trhis</i> facilitated formation of zwitterionic molecules
with a protonated imidazolium group (<i>imH</i><sup><i>+</i></sup>) and a negatively charged −CO<sub>2</sub><sup>–</sup> group, whereas the <i>tr-</i>fragment
was left neutral. Under the acidic hydrothermal conditions used, the
organic ligand binds to molybdenum atoms either through [N–N]-<i>tr</i> or through both [N–N]-<i>tr</i> and
μ<sub>2</sub>-CO<sub>2</sub><sup>–</sup> units, which
occur in protonated bidentate or zwitterionic tetradentate forms (<i>trhisH</i><sup><i>+</i></sup> and <i>trhis</i>, respectively). This leads to a new zigzag subtopological motif
(<b>3</b>) of negatively charged polyoxomolybdate {Mo<sub>8</sub>O<sub>25</sub>}<sub><i>n</i></sub><sup>2<i>n</i>–</sup> consisting of corner- and edge-sharing <i>cis-</i>{MoO<sub>4</sub>N<sub>2</sub>} and {MoO<sub>6</sub>} octahedra, while
the tetradentate zwitterrionic <i>trhis</i> species connect
these chains into a 2D net. Electronic spectra of the compounds showed
optical gaps consistent with semiconducting behavior. The compounds
were investigated as epoxidation catalysts via the model reactions
of achiral and prochiral olefins (<i>cis</i>-cyclooctene
and <i>trans</i>-β-methylstyrene) with <i>tert</i>-butylhydroperoxide. The best-performing catalyst (<b>1</b>) was explored for the epoxidation of other olefins, including biomass-derived
methyl oleate, methyl linoleate, and prochiral dl-limonene.