Acid‐Controlled Synthesis of Carboxylate‐Stabilized Ti₄₄‐Oxo Clusters: Scaling up Preparation, Exchangeable Protecting Ligands, and Photophysical Properties

Abstract

Ar ange of polyoxotitaniumc lusters (PTCs) was constructed by tuning the type of acid (inorganic and organic) in alcoholics olvents, from Ti 4 ,T i 6 ,T i 9 ,T i 11 ,t oT i 16 .A fter removingthe tBuOH solvent, giant carboxylate-stabilized Ti 44oxo clusters in which propionic acid serves as both ligand and solvent were ultimately obtained. The four labile sites in the Ti 44 clusterc ore can be occupied by two formate and two propionatea nions (PTC-165)o rapairo fg lutarate( PTC-166)o r3 -methylglutarate anions( PTC-167). According to the synthesis of PTC-155 to PTC-167,t he propionic acid solvent plays ac rucial role in the constructiono fg iant Ti oxo clusters. Their one-poty ields,w hichr eadily reached up to 8.75 gf or PTC-165 and 9.96 gf or PTC-166,p rovedt he feasibility of large-scale preparation.M ore interestingly,t he ob-tainedT i 44 -oxo clusters are almostc ompletelys urroundedb y carboxylate ligands, which allow them to retain crystalline stabilityi na ir for aboutt hree weeksa nd in either acidic or basic aqueous solutiono ver aw ide pH range for at least 6h. In addition, PTC-165 and PTC-166 exhibit excellent UV photocurrentr esponse and reversible photochromice ffect. This work providesasystematic approachf or constructing highnuclearity and stable PTCs on al arge scale, which is significant for futurea pplicationso fP TC-based photochemical devices.

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] …”

Metal–Organic Frameworks Based on Group 3 and 4 Metals

“…Note that only representative MOFs based on group 3 and 4 metals (excluding Sc and Hf) since 2018 and previous MOF milestones are listed; b) Linkers are abbreviated as: ABTC = 3,3′,5,5′-azobenzene-tetracarboxylate; AZDC = azobenzene-3,3′-dicarboxylate; ATDB = 4,4′-(4-amino-4H-1,2,4-triazole-3,5-diyl)-dibenzoate; ATPC = 4′,4′′,4′′′,4′′′′-(anthracene-9,10-diylidenebis(methan-1,1-diyl-1-ylidene))tetrabiphenyl-4-carboxylate; ATBC = 4,4′,4′′,4′′′-(anthracene-9,10-diylidenebis(methan-1,1-diyl-1-ylidene)) tetrabenzoate; BDC = terephthalate; BTTC = benzotristhiophene carboxylate; BHPB = hexakis(4-(4-carboxyphenyl)phenyl)benzoate; BDHA = benzene-1,4-dihydroxamic acid; BDB = 4,4′-(benzene-1,3-diyl)dibenzoate; BTDB = 4,4′-(benzo[c] [1,2,5]thiadiazole-4,7-diyl)dibenzoate; BTBA = 4,4′,4′′-(1H-benzo-[d]imidazole-2,4,7-triyl)tribenzoate; BPDC = biphenyl-4,4′-dicarboxylate; BPyDC = 2,2′-bipyridyl-5,5′-dicarboxylate; BTB = 1,3,5-benzenetrisbenzoate; CPTPY = 4′-(4-carboxyphenyl)-terpyridine; BTB = benzene tribenzoate; CBTB = 4,4′,4′′,4′′′-(9H-carbazole-1,3,6,8-tetrayl)tetrabenzoate; DCDPS = 4,4′-dicarboxydiphenyl sulfone; DTPP = 5,15-di(3,4,5-trihydroxyphenyl)porphyrin; DOTA = 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid; EDDB = 4,4′-(ethyne-1,2-diyl)dibenzoate; FUM = fumarate; 2,6-NDC = naphthalene-2,6-dicarboxylate; HBCPB = 1,2,3,4,5,6-hexakis[3,5-bis(4-carboxyphenyl)phenoxymethyl]benzene; HCHC = hexakis(4-carboxyphenyl)hexabenzocoronene; H 6 CPB/HCBB = 1′,2′,3′,4′,5′,6′-hexakis(4carboxyphenyl)benzene; H 6 TTHA = 1,3,5-triazine-2,4,6-triamine hexaacetic acid; H 2 DHBQ = 2,5-dihydroxybenzoquinone; INA = isonicotinate; L-AA = L-Aspartic acid; MDIP = 3,3′,5,5′-tetracarboxydiphenylmethane; PDC = 2,5-pyridinedicarboxylate; P-2COOH = N,N′-di-(4-benzoic acid)-1,2,6,7-tetrachloroperylene-3,4,9,10-tetracarboxylic acid diimide; TCPP = meso-tetrakis(4-carboxylatephenyl)porphyrin; TTFTB = tetrathiafulvalene-tetrabenzoate; TDHT = 2,4,6-tri(3,4-dihydroxyphenyl)-1,3,5triazine; TCPC = 5,10,15-tris(p-carboxylphenyl)corrole; TBAPY = 1,3,6,8-tetrakis(p-benzoic acid)pyrene; TTFTB = tetrathiafulvalene tetrabenzoate; TPHB = 4,4′,4′′,4′′′,4′′′′,4′′′′-(triphenylene-2,3,6,7,10,11-hexayl)hexabenzoate; THPP = 5,10,15,20-tetrakis(3,4,5-trihydroxyphenyl)porphyrin); THBPP = 5,10,15,20-tetrakis(3,4,5-trihydroxybiphenyl)porphyrin; TPDC = 2′,5′-dimethyl-terphenyl-4,4′′-dicarboxylate; TTDA = 5′-(1H-tetrazol-5-yl)-1,1′:3′,1′′-terphenyl-4,4′′-dicarboxylate; TBCPB = 1,2,4,5-tetrakis [ Ti-oxo clusters are widely considered as a TiO 2 nanomaterial at a molecular level, and receive considerable attention due to their structural diversity as well as potential applications in catalysis, biomedicine and environments. [48] The number of Ti atoms in Ti-oxo clusters ranges from 3 to 32, including Ti 3 , [49][50][51][52] Ti 4 , [50,[52][53][54][55][56][57] Ti 5 , [57] Ti 6 ,…”

Odd-membered cyclic hetero-polyoxotitanate nanoclusters with high stability and photocatalytic H2 evolution activity

“…The EPR spectrum of this black sample showed an obvious signal at g = 1.950, corresponding to the paramagnetic Ti 3+ ions (Fig. S12) [50,51]. However, no EPR resonance was observed in the dark.…”