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

A family of unprecedented tellurotungstate-based organotin-rare-earth (RE) heterometallic hybrids [H₂N(CH₃)₂]₆H₁₂Na₂ {[Sn(CH₃)W₂O₄(IN)][(B-α-TeW₈O₃₁)RE(H₂O) (Ac)]₂}₂·25H₂O [RE = Ce^III (1), Pr^III (2), Nd^III (3), Sm^III (4), Eu^III (5), Gd^III (6), Tb^III (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(CH₃)W₂O₄(IN)][(B-α-TeW₈O₃₁)RE(H₂O) (Ac)]₂}₂^20- of 1-7 are constructed from two symmetrical units {[Sn(CH₃)W₂O₄(IN)][(B-α-TeW₈O₃₁)RE(H₂O) (Ac)]₂}^10- 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^III cations, whereas during the emission procedure of 7, [B-α-TeW₈O₃₁]^10- 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 Tb³⁺ 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^III centers. Variable-temperature magnetic susceptibility measurements for 2, 3, and 4 were performed.