Extending the structural landscape of Mo(vi) hydrazonato inorganic–organic POM-hybrids: an experimental and computational study

Abstract

Five hexamolybdate and five octamolybdate-based organic-inorganic hybrid assemblies, with dioxomolybdenum(VI) hydrazonato complex cations, were synthesized from the [MoO2(acac)2] and isonicotinoyl hydrazone ligands bearing OH (H2L1,2) and OMe (H2L3,4) electron-donating groups....

Impact of POM's coordination mode and Mo-hybrid constituents on the binding, stability, and catalytic properties of hybrid (pre)catalysts

“…The reactions of [MoO 2 (acac) 2 ] with H 2 L 1 and H 2 L 3 in a molar ratio of 10 : 1 in acetonitrile proceeded similarly. Despite the presence of a higher amount of [MoO 2 (acac) 2 ], which is more favourable for the formation of octamolybdates, 45 the reactions with H 2 L 1 and H 2 L 3 always resulted in the formation of hexamolybdate hybrids [MoO 2 (HL 1 )(H 2 O)] 2 [Mo 6 O 19 ] ( 1H w ) and [{MoO 2 (HL 3 )} 2 Mo 6 O 19 ]·2CH 3 CN ( 3H ·2CH 3 CN). This could be due to the better stability of the hexamolybdate anion in acetonitrile in the presence of Mo-complexes with these two ligands.…”

“…So far, only Class I octamolybdate hybrids with coordinated solvent molecules on the {MoO 2 } 2+ core have been studied, offering valuable insight into their structural properties. 45,46…”

“…In all structures of ionic type of hybrids, polyoxometalate anions are classical Lindqvist ones, Mo 6 It should be highlighted that in all structurally characterized compounds, except the 2O$2CH 3 CN$H 2 O one, the hydrazone ligand coordinates in the monoanionic form via O1, N1 and O2 atoms, which is evident from the relevant bond distances (Scheme 1, Tables S1 and S2 in the ESI †), and also consistent with previously reported examples. 45 It is also interesting to note that coordinated ligands assume in most cases an essentially In contrast to 1H a $2CH 3 COCH 3 , the presence of additional hydrogen bond donors, i.e. coordinated water molecules in [MoO 2 (HL)(H 2 O)] + , affords a complex hydrogen bonded networks in both cases.…”

“…So far, only Class I octamolybdate hybrids with coordinated solvent molecules on the {MoO 2 } 2+ core have been studied, offering valuable insight into their structural properties. 45,46 When comparing the structures of 1H and 3H$2CH 3 CN, one observes the difference in the engagement of the protonated pyridine moiety in the hydrogen bonding due to the presence of solvent molecules in 3H$2CH 3 CN (Fig. 3).…”

“…POM anions tend to associate with cationic Mo-complexes via multiple non-covalent interactions and give ionic hybrids (Class I). [44][45][46] However, investigation of their potential was limited by their low stability. Coordination of POM to metal centres offers a way to overcome this issue and allows the discovery of new POM coordination modes.…”