Tellurotungstate-Based Organotin–Rare-Earth Heterometallic Hybrids with Four Organic Components

Abstract

A family of unprecedented tellurotungstate-based organotin-rare-earth (RE) heterometallic hybrids [HN(CH)]HNa {[Sn(CH)WO(IN)][(B-α-TeWO)RE(HO) (Ac)]}·25HO [RE = Ce (1), Pr (2), Nd (3), Sm (4), Eu (5), Gd (6), Tb (7); HIN = isonicotinic acid, HAc = acetic acid] were synthesized and characterized by elemental analyses, IR spectra, UV spectra, thermogravimetric analyses, powder X-ray diffraction, and single-crystal X-ray diffraction. The polyoxoanionic skeletons {[Sn(CH)WO(IN)][(B-α-TeWO)RE(HO) (Ac)]} of 1-7 are constructed from two symmetrical units {[Sn(CH)WO(IN)][(B-α-TeWO)RE(HO) (Ac)]} linked by two acetate connectors, which not only represent the first inorganic-organic hybrid RE-substituted tellurotungstates involving three different organic ligands, but also stand for the first samples of organotin-RE heterometallic polyoxometalate derivatives. The solid-state luminescent emission properties of 2-5 mainly display the characteristic emission bands of RE cations, whereas during the emission procedure of 7, [B-α-TeWO] segments make a nonignorable contribution to the PL behavior of 7 accompanying by the occurrence of the intramolecular energy transfer from O→W LMCT energy to Tb centers. Furthermore, 4@CTAB composites with peanutlike and honeycombed morphologies were prepared by a surfactant cetyltrimethylammonium bromide (CTAB). The time-resolved emission spectra of the 4@CTAB composite with CTAB/4 = 0.033/0.05 consolidate the energy transfer from CTAB to RE centers. Variable-temperature magnetic susceptibility measurements for 2, 3, and 4 were performed.

Unprecedented Selenium and Lanthanide Simultaneously Bridging Selenotungstate Aggregates Stabilized by Four Tetra‐vacant Dawson‐like {Se2W14} Units

“…The lifetime decay curve of 1 under monitoring the most intense emission at 544 nm (Figure S10 b in the Supporting Information) is well fitted with a second‐order exponential function, affording the lifetimes τ 1 and τ 2 being 1.20 μs (9.95 %) and 12.80 μs (90.05 %) and the average decay time being 11.64 μs. Clearly, the average decay time ( τ *) of 1 is longer than that (5.29 μs) of the tetrameric tetra‐Tb‐incorporated tellurotungstate [H 2 N(CH 3 ) 2 ] 6 H 12 Na 2 {[Sn(CH 3 )W 2 O 4 (IN)][(B‐α‐TeW 8 O 31 )Tb(H 2 O)(Ac)] 2 } 2 ⋅ 25 H 2 O, the main reason of which may be that the high frequency O−H oscillators of aqua ligands and the high frequency C−H oscillators of acetates around the Tb 3+ ions in [H 2 N(CH 3 ) 2 ] 6 H 12 Na 2 {[Sn(CH 3 )W 2 O 4 (IN)][(B‐α‐TeW 8 O 31 )Tb(H 2 O)(Ac)] 2 } 2 ⋅ 25 H 2 O in some degree quench the luminescence emission and further lead to its shorter decay time . In addition, the lifetime decay curves of 2 – 4 in the visible region also obey the second‐order exponential function (Figure S10 d, f, h, j in the Supporting Information) and their τ * are 5.61 μs for 2 , 5.72 μs for 3 , and 4.69 μs for 4 , which are very near to those (6.56 μs for Ln=Dy III , 6.07 μs for Ln=Ho III , 5.85 μs for Ln=Er III ) of our previously reported tetrameric tetra‐Ln‐incorporated arsenotungstates [H 2 N(CH 3 ) 2 ] 6 Na 6 H 4 [Ln 4 W 8 O 19 (H 2 O) 10 (OH) 2 (Ser) 2 (B‐α‐AsW 9 O 33 ) 4 ] ⋅ 38 H 2 O (Ln=Dy III , Ho III , Er III ) …”

Three Types of Mixed Alkali‐Metal‐, Transition‐Metal‐, or Rare‐Earth‐Substituted Sandwich‐Type Arsenotungstates with Supporting Rare‐Earth Pendants

“…Therefore, the average decay time ( τ *) can be determined with the formula τ * = ( A 1 τ 1 2 + A 2 τ 2 2 )/( A 1 τ 1 + A 2 τ 2 ), and the average lifetime was calculated to be 5.64 µs. In comparison with that of the tellurotungstate‐based organotin–rare‐earth heterometallic hybrid [H 2 N(CH 3 ) 2 ] 6 H 12 Na 2 {[Sn(CH 3 )W 2 O 4 (IN)][(B‐α‐TeW 8 O 31 )Sm(H 2 O)(OAc)] 2 } 2 · 25H 2 O ( τ * = 10.68 µs; HIN = isonicotinic acid), the decay time for 4 is much shorter. This behavior can be attributed to the fact that nine‐coordinate [Sm(H 2 O) 8 ] 3+ cations in 4 have eight coordinated water molecules and one oxygen atom from the [B‐α‐AsW 9 O 33 ] 9 – fragment, whereas the nine‐coordinate [Sm(H 2 O)(OAc)] 2+ cations in [H 2 N(CH 3 ) 2 ] 6 H 12 Na 2 {[Sn(CH 3 )W 2 O 4 (IN)][(B‐α‐TeW 8 O 31 )Sm(H 2 O)(OAc)] 2 } 2 · 25H 2 O have one coordinated water molecule, four oxygen atoms from the [B‐α‐TeW 8 O 31 ] 10– fragment, one oxygen atom from the [W 2 O 4 (IN)] 3+ segment, and three carboxyl oxygen atoms from the organic ligands.…”

Multicomponent Self‐Assembly of a Giant Heterometallic Polyoxotungstate Supercluster with Antitumor Activity

“…25 kDa. To the best of our knowledge, 1 a is the largest organotin‐ and Ln‐functionalized POM reported to date, and one of only three examples of this new compound class [31, 32] …”

“…The {W 41 } units are assembled around a central C 4 v ‐symmetric {TeW 4 } fragment, [TeW 4 O 20 ] 12− , where a central (rarely observed) square‐pyramidal [Te IV O 4 ] links four [WO 6 ] units in corner‐sharing mode (Figure 1 a; Figure S4). Around the {TeW 4 } fragment, four tetra‐vacant lacunary Keggin anions {TeW 8 } (=[B‐α‐TeW 8 O 31 ] 10− ) [31] are assembled. The aggregate is linked by four Ce 3+ cations and four Sn(CH 3 ) 2 + groups, each forming three Sn‐O‐ M bonds (M=Ce, W), resulting in a {CeSn} linkage (Figure 1 a; Figures S5–S9).…”

“…To the best of our knowledge, 1 a is the largest organotin-and Ln-functionalized POM reported to date, and one of only three examples of this new compound class. [31,32] The structure of the large polyanion can be rationalized as follows: 1 a, {W 82 } is a dimeric species composed of two principal, symmetry-equivalent {W 41 [31] are assembled. The aggregate is linked by four Ce 3+ cations and four Sn(CH 3 ) 2 + groups, each forming three Sn-O-M bonds (M = Ce, W), resulting in a {CeSn} linkage (Figure 1 a; Figures S5-S9).…”