Synthesis, structure, spectroscopy and reactivity of new heterotrinuclear water oxidation catalysts

Abstract

Four heterotrinuclear complexes containing the ligands 3,5-bis(2-pyridyl)pyrazolate (bpp–) and 2,2′:6′,2′′-terpyridine (trpy) of the general formula {[RuII(trpy)]2(μ-[M(X)2(bpp)2])}(PF6)2 have been prepared for the first time.

Quantum Chemical Study of the Mechanism of Water Oxidation Catalyzed by a Heterotrinuclear Ru2Mn Complex

“…[41]), which is about 20 kcal mol À1 .T hism ay be attributed to the density functional used. The calculated value is somewhat underestimated compared with the experimental kinetic data (a TON of 12.2 in 10 min;c alculated from Figure 7i nR ef.…”

“…[41]), which is about 20 kcal mol À1 .T hism ay be attributed to the density functional used. Indeed, the electrochemical oxidation has a onset potentialo f1 .50 V, [41] which is higher than the potential of [Ru(bpy) 3 ] 3 + /[Ru(bpy) 3 ] 2 + (1.26 V). The calculated resultsa re displayed in Ta ble1.I mportantly,a ll functionals favor the direct coupling pathway for the OÀOb ond formation.T he total barrier increases to 11.0 kcal mol À1 when B3LYP-D3 was used and further to 15.4 kcal mol À1 when M06-D3 was used.…”

“…In photosystem II, aM n 4 Ca clusteri nt he oxygen evolution center (OEC) is known to catalyzet he oxidationo f water into molecular dioxygen. [41] (Figure 1), which is capable of mediating water oxidation both electrochemically andp hotochemically. [6][7][8][9][10] Other transition metals were also used for the synthesis of water oxidation catalysts, including Ru, [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Ir, [25,26] Fe, [27][28][29][30][31] Co, [32][33][34] Ni, [35][36][37] and Cu.…”

“…[1][2][3][4][5] During the past few decades, extraordinary efforts have been dedicated to the synthesis of manganese-based molecular complexes to mimic the structure and function of the OEC. [41] The photochemical reactionw as performed by using [Ru(bpy) 3 ] 2 + (bpy = 2,2'-bipyridine) as the photosensitizer and Na 2 S 2 O 8 as the sacrificial electron acceptori nn eutral phosphate buffer.At urnover number (TON) of 8w as obtained in about 10 min. [38][39][40] Recently,the Llobet group disclosed the synthesisofaheterotrinuclear Ru 2 Mn complex A 0 {[Ru II (tpy)] 2 (m-[Mn II (bpp) 2 ]) (OAc) 2 } 2 + [tpy = 2,2':6',2''-terpyridine, bpp = 3,5-bis(2-pyridyl)pyrazolate].…”

“…[6][7][8][9][10] Other transition metals were also used for the synthesis of water oxidation catalysts, including Ru, [11][12][13][14][15][16][17][18][19][20][21][22][23][24] Ir, [25,26] Fe, [27][28][29][30][31] Co, [32][33][34] Ni, [35][36][37] and Cu. For the electrochemical reaction, the differential pulse voltammetry (DPV) study of A displayed ac atalytic onset potentialo f1 .5 V. [41] Ar elated CoRu 2 complex was also reported, and the TON was estimated to be 50 when using the same 2 ])} 4 + [tpy = 2,2':6',2''-terpyridine, bpp = 3,5bis(2-pyridyl)pyrazolate] was foundt oc atalyze water oxidation both electrochemically and photochemicallyw ith [Ru(bpy) 3 ] 3 + (bpy = 2,2'-bipyridine) as the photosensitizer and Na 2 S 2 O 8 as the electron acceptori nn eutral phosphate buffer.T he mechanism of water oxidation catalyzed by this unprecedented trinuclear complex was studied by density functional calculations. [41] (Figure 1), which is capable of mediating water oxidation both electrochemically andp hotochemically.…”