New picolinate-functionalized titanium-oxide clusters: syntheses, structures and photocatalytic H₂ evolution

Abstract

Two nanosized titanium-oxide clusters (TOCs), H4Ti12(μ2-O)14(μ3-O)4PA16 (1; PA = 2-picolinate) and H6Ti12(μ2-O)18PA18 (2) were synthesized by using 2-picolinic acid and Ti(OiPr)4 in one-pot reactions. Their structures were determined using single-crystal...

A cryptand-like Ti-coordination compound with visible-light photocatalytic activity in CO2 storage

“…Numerous reported metal-coordination compounds show EPR signals in the ground state, particularly that containing salicylate, catecholate, and picolinate ligands, which are attributed to organic radical cations from LMCT. 41–44 For Ti 12 Cs , the signals are ascribed to holes, likely 3,5-dibromobenzoate radical cations, consistent with the similar peak shape of Ti 12 Cs in CO 2 , air, and N 2 atmospheres. After Ti 12 Cs was exposed to visible-light under N 2 atmosphere, the signals were enhanced (curve e), suggesting that the concentration of holes increased.…”

Ligation of Titanium-oxide and {Mo2} Units for Solar CO2 Storage

“…The EPR spectrum of Ti 4 Mo 4 is almost the same as that of Ti 6 Mo 4 (Figure S2), indicating both contain the same paramagnetic species that are nonrelevant to the O i Pr group. Notably, there are many TOC molecules with EPR signals in the ground state, especially salicylate-, catecholate-, and picolinate-modified, due to ligand-to-metal charge transfer (LMCT). Hence, the paramagnetism does not necessarily mean that there is a stoichiometric amount of Ti III or a reduced state of the heterometal ion.…”

Enhancing the photocatalytic performance of a rutile unit featuring a titanium-oxide cluster by Pb2+ doping

“…S4 †) has been reported in several other TOCs, such as Cs@Ti 12 AA 6 (AA = amino acid), 24 and {Ti 12 O 18 PA 18 }. 25 This indicates the Ti 12 O 18 framework is a typical structure of TOCs, capable of encapsulating various monovalent and divalent cations.…”

“…The reaction became extremely sluggish in the absence of TBAB, which is known as an essential cocatalyst. 25,31,[37][38][39][40] Alternative cocatalysts including tetrabutylammonium chloride (TBAC) and iodide (TBAI), performed worse than TBAB. The reference catalysts, such as PbAc 2 , PbBz 2 , and TiO 2 showed much lower yields than Ti 12 Pb 2 .…”