A ferrocenecarboxylate-functionalized titanium-oxo-cluster: the ferrocene wheel as a sensitizer for photocurrent response

Abstract

Sensitized titanium-oxo clusters (TOCs) have attracted growing interest. However, reports on TOCs incorporated with a metal complex as photosensitizers are still very rare. In the present work, the organometallic complex ferrocene was used as a sensitizer for a titanium-oxo cluster. A ferrocenecarboxylate-substituted titanium-oxo cluster [Ti(μ-O)(OiPr)(OCFc)] (Fc = ferrocenyl) was synthesized and structurally characterized, in which the ferrocene wheel performs as a sensitizer for photocurrent response. For comparison, naphthalene-sensitized titanium-oxo clusters [Ti(μ-O)(OiPr)(NA)] (NA = 1-naphthoate) and [Ti(μ-O)(OiPr)(NAA)] (NAA = 1-naphthylacetate) with the same {Ti} core structure were also synthesized. The structures, optical behaviors, electronic states and photoelectrochemical properties of these sensitized {Ti} clusters were investigated. It is demonstrated that the introduction of ferrocene groups into the titanium-oxo cluster significantly reduces the band gap and enhances the photocurrent response in comparison with the naphthalene-sensitized clusters. The substantially reduced band gap of the ferrocene-sensitized cluster was attributed to the introduction of Fe(ii) d-d transitions and the possible contribution from the Fc → {Ti} charge transfer. For the naphthalene-sensitized clusters, the better electronic coupling between the dye and the {Ti} core in the 1-naphthoate (NA) substituted cluster results in higher photoelectrochemical activity.

Titanium‐Oxo Clusters with Bi‐ and Tridentate Organic Ligands: Gradual Evolution of the Structures from Small to Big

“… R=Et: R’=C 6 H 4 OPh [84] R= i Pr: R’=H, [29] Me, [85,86] Et, [87] Bu, [31] i Bu, [88] t Bu, [89] CHCl 2 , [24] cyclohex‐3‐enyl, [64] CH 2 Ph, [90] CH 2 ‐naphthyl, naphthyl, [91] C 6 H 4 Ph, C 6 H 4 t Bu, [92] anthracenyl, [62] adamantyl, [54] C 6 H 4 COO i Pr, [14b] C 6 H 4 NH 2 , [93] C 6 H 3 (X)NHMe (X=H, F, Cl), [93b] C 6 H 4 NMe 2 , [54] C 5 H 4 N, [25] C 5 H 3 N−CO 2 i Pr, [94] ferrocenyl [88,91] R=Bu: R’= t Bu [95] R= i Bu: R’= t Bu, [95] CMe 2 Et [83] R= t Bu: R’=Et, [31] CMe 2 Et, CH 2 t Bu [44] R=CH 2 t Bu: R’= i Pr, [14a] Ph [73] R=SiMe 3 : R’= t Bu, [95] CH 2 t Bu, CMe 2 Et [95a] …”

“…R= i Pr: R’=H, [29] Me, [85,86] Et, [87] Bu, [31] i Bu, [88] t Bu, [89] CHCl 2 , [24] cyclohex‐3‐enyl, [64] CH 2 Ph, [90] CH 2 ‐naphthyl, naphthyl, [91] C 6 H 4 Ph, C 6 H 4 t Bu, [92] anthracenyl, [62] adamantyl, [54] C 6 H 4 COO i Pr, [14b] C 6 H 4 NH 2 , [93] C 6 H 3 (X)NHMe (X=H, F, Cl), [93b] C 6 H 4 NMe 2 , [54] C 5 H 4 N, [25] C 5 H 3 N−CO 2 i Pr, [94] ferrocenyl [88,91] …”

Synthesis, structural and physicochemical characterization of a new type Ti6-oxo cluster protected by a cyclic imide dioxime ligand

“…3a), 36,37 and the second one consisting of two planar {Ti3O3} units parallel to each other (Fig. 3b); 12,[27][28][29][30][31][32][33][34][35][36][37][38][39]42 (ii) six configurations with the six Ti IV lying almost on a planar arrangement {Ti6 55 and {Ti6(μ2-O)9} ( Fig. 3f), 56 exhibiting two {Ti3(μ2-O)3} units parallel to each other; and (iv) {Ti6(μ3-O)2(μ2-O)2} ( Fig.…”

Two new hexanuclear titanium oxo cluster types and their structural connection to known clusters

“…The cluster cores of the known Ti 6 clusters are schematically shown in Scheme 1. The Ti 6 cluster type with the highest d c (and a wide variety of R/R 0 combinations) is Ti 6 O 6 (OR) 6 (OOCR 0 ) 6 , [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] where all oxygen atoms are m 3 -O. This leaves 12 positive charges unbalanced and 18 coordination sites unoccupied which are compensated by 6 terminal OR (one per Ti) and 6 bridging carboxylate ligands.…”