Acetic Acid Mediated Synthesis of Phosphonate‐Substituted Titanium Oxo Clusters

Abstract

New phosphonate/acetate-substituted titanium oxo/alkoxo clusters were prepared from Ti(OiPr)4 and bis(trimethylsilyl) phosphonates in the presence of acetic acid, which served to generate water in situ through ester formation. The process led to clusters with a higher degree of condensation than in previously known phosphonate-substituted titanium oxo clusters. The clusters [Ti6O4(OiPr)10(OAc)2(O3PR)2] (OAc = acetate) were obtained for a large variety of functional and non-functional groups R under a range of reaction conditions. This cluster type, which is also retained in solution, therefore appears to be very robust. Two other clusters, [Ti5O(OiPr)11(OAc)(O3PCH2CH2CH2Br)3] and [Ti5O3(OiPr)6(OAc)4(O3P-xylyl)2], were only isolated in special cases.

Bandgap Engineering of Titanium–Oxo Clusters: Labile Surface Sites Used for Ligand Substitution and Metal Incorporation

“…So phosphonate‐stabilized titanium clusters (PTC) can have the potential to do ligand substitution and then serve as proper candidates for bandgap adjustment investigation. Schubert has recently reported a stable {Ti 6 } cluster core, [Ti 6 O 4 (O i Pr) 10 (O 3 PR) 2 (OAc) 2 ] (OAc=acetate), that can be formed with different bridging phosphonate ligands . By carefully analyzing the structure of this {Ti 6 } cluster core, we find that it does present 3×2=6 labile coordination sites from its two {Ti 3 (μ 3 ‐O)} outer faces (Figure ).…”

A 3.6 nm Ti52–Oxo Nanocluster with Precise Atomic Structure

“…Moreover, these TOCs show cluster-size dependent photocatalytic hydrogen evolution activities with Ti 52 giving a H 2 production rate up to 398 µmol/h/g, which is also the highest record in the family of TOCs. [11][12] Since the first crystal structure of the initial crystalline hydrolysis product of titanium tetraethoxide was determined by X-ray diffraction in 1967, 13 tremendous progress has been made on the research on crystalline titanium−oxo clusters (TOCs). Solar energy driven water splitting has become a promising way for the clean and sustainable production of hydrogen, and will provide a practicable solution to the global energy and environment crisis.…”

“…[1][2][3] Titanium dioxide (TiO 2 ) and related Ti−O nanomaterials are the most widely applied catalytic materials for water splitting due to their low cost, high activity and environment friendly characteristics. 12,14,[19][20][21][22][23][24][25][26][27] Moreover, although most of the driving forces of the research on TOCs come from simulating the photocatalytic titanium oxide materials, the studies on their photocatalytic H 2 evolution applications still remain very rare. [9][10] To build structure-property relationship and achieve chemical fine tuning, understanding the binding modes and electronic structures of Ti−O materials at the molecular level is crucial.…”

Isomerism in Titanium‐Oxo Clusters: Molecular Anatase Model with Atomic Structure and Improved Photocatalytic Activity

“…[1][2][3][4][5][6][7] More recently,t ou nderstand the binding modes of Ti-O materials at the molecular level and to build structureproperty relationships,m uch attention has been devoted to atomically precise polyoxo-titanium clusters (PTCs), which can be seen as molecular models of TiO 2 . [12] However,a lthough numerous PTCs have been synthesized during the past decades, [13][14][15][16][17][18][19][20][21][22] none of them contains the Ti-O units of anatase TiO 2 . [12] However,a lthough numerous PTCs have been synthesized during the past decades, [13][14][15][16][17][18][19][20][21][22] none of them contains the Ti-O units of anatase TiO 2 .…”

“…[8][9][10][11] It is well known that TiO 2 has interesting mineral phase isomerism with the anatase form exhibiting better photocatalytic activity than rutile and brookite. [12] However,a lthough numerous PTCs have been synthesized during the past decades, [13][14][15][16][17][18][19][20][21][22] none of them contains the Ti-O units of anatase TiO 2 .…”