Spectroscopic and electrochemical examination of the dark and photo-catalysed redox reactions that occur at the interface between solid α-[Hex4N]4[S2Mo18O62], solid triphenylphosphine and water

Electrochemical, Spectroscopic, Structural, and Magnetic Characterization of the Reduced and Protonated α-Dawson Anions in [Fe(η5-C5Me5)2]5[HS2Mo18O62]·3HCONMe2·2Et2O and [NBu4]5[HS2Mo18O62]·2H2O1

“…No EPR signal was observed from the polyoxometalate anion. EPR signals have been detected previously for (1 e - )- and (3 e - )-reduced forms of [S 2 Mo 18 O 62 ] 4- but not for a (2 e - )-reduced form …”

“…EPR signals have been detected previously for (1 e -)-and (3 e -)-reduced forms of [S 2 Mo 18 O 62 ] 4but not for a (2 e -)reduced form. 13 The room-temperature Mo ¨ssbauer spectrum consists of a single line which could be fitted as either a singlet or a quadrupole doublet in which the quadrupole splitting, ∆E Q , is very small (Figure S2; see the Experimental Section). The isomer shift δ ) 0.43(1) mm s -1 is the same for both fits.…”

“…The versatile chemistry of polyoxometalate anions continues to attract interest. , One aspect concentrates on the versatile acidic and redox properties which can be tuned for catalysis and photochemistry. − For the particular case of the Dawson anion α-[S 2 Mo 18 O 62 ] 4- an extensive series of reduction processes has been detected voltammetrically and photochemically. − Electrochemical syntheses of the simple (1 e - )- and (2 e - )-reduced forms [S 2 Mo 18 O 62 ] 5- and [S 2 Mo 18 O 62 ] 6- have been reported as well as those of the protonated (2 e - , 1 H + ), (2 e - , 2 H + ), (4 e - , 2 H + ), and (4 e - , 4 H + ) forms. , The use of phosphine reagents as reductants 15 also allows access to some of the above species, as well as to a salt characterized by X-ray crystallography as containing a (4 e - , 3 H + )-reduced anion …”

Voltammetry of [R4N]4[M18O54(SO3)2] and [Ru(bpy)3]2[M18O54(SO3)2] (M = Mo, W) as microcrystals adhered to a glassy carbon electrode surface in contact with ionic liquid media

“…It is known that photoexcited states of many polyoxometalate anions can be used to photooxidise organic compounds such as benzyl alcohol and generate reduced forms of the polyoxomatalate anions. 6,25- 28 In an earlier study 3 it was shown that the [a-W 18 O 54 (SO 3 ) 2 ] 4is photoactive. In this paper the photochemical properties of the [Ru(bpy) 3 ] 2 [a-W 18 O 54 (SO 3 ) 2 ] complex have been investigated.…”

Synthesis and Redox Characterization of the Polyoxo Anion, γ*-[S2W18O62]4-: A Unique Fast Oxidation Pathway Determines the Characteristic Reversible Electrochemical Behavior of Polyoxometalate Anions in Acidic Media

“…Its synthesis arose from a desire to compare its redox and photochemical properties with those of the intensively studied R-[S 2 Mo 18 O 62 ] 4ion. 10, [13][14][15][16][17][18][19][20][21] For the latter, an extensive series of reduction processes (addition of up to 26 electrons in acid media) has been identified. 17 The reduced anions are basic, and simulation of experimental data has unravelled many aspects of the coupling of electron and proton transfer in these systems.…”