Two new POM-based compounds modified by lanthanide–Schiff base complexes with interesting NLO properties

Abstract

Two POM‐based lanthanide derivatives, namely {triaqua[2,6‐diacetylpyridine bis(semicarbazone)‐κ5O,N,N′,N′′,O′]terbium(III)}‐μ‐oxido‐[tricosa‐μ2‐oxido‐dodecaoxido‐μ12‐phosphato‐dodecamolybdenum(VI)] pentahydrate (1), [Tb(C11H15N7O2)(H2O)3][PMo12O40]·5H2O, and the dysprosium(III) analogue (2), have been isolated successfully by the reaction of Keggin–POM [PMo12O40]3− (abbreviated as PMo12), the Ln3+ ion and the Schiff base 2,6‐diacetylpyridine bis(semicarbazone) (DAPSC) ligand under hydrothermal conditions. [Ln(DAPSC)(H2O)3][PMo12O40]·5H2O is a PMo12‐supported cluster featuring a lanthanide–Schiff base complex [denoted Ln–L(Schiff base)]. Single‐crystal X‐ray diffraction analysis reveals that the LnIII ion is in a distorted tricapped trigonal prismatic arrangement, coordinated by six O atoms and three N atoms. Two O atoms and three N atoms are provided by one DAPSC ligand, while the additional O atoms originate from a PMo12 cluster and three water molecules. Hydrogen‐bonding interactions between adjacent clusters form an interesting three‐dimensional supramolecular structure. The identities of 1 and 2 were characterized by IR spectroscopy, thermogravimetric analysis and powder X‐ray diffraction. Interestingly, both compounds possess excellent two‐photon absorption (TPA) responses to the third‐order nonlinear optics (NLO) (2264 GM for 1 and 941 GM for 2), suggesting that they have potential applications in the field of nonlinear optics (NLO). To our knowledge, 1 and 2 are the first POM‐based Ln–L(Schiff base) complexes showing excellent two‐photon responses. Meanwhile, the electrochemical properties of both compounds were studied in detail.

Polyoxometalate-Based Well-Defined Rodlike Structural Multifunctional Materials: Synthesis, Structure, and Properties

“…This phenomenon is the result of the fact that those clusters bear a combination of intriguing physical properties and fascinating geometrical features (oxygen-rich surfaces, strong coordinating ability, adjustable size, innovative aesthetic structure, etc. ), providing unmatched potential applications in traditional fields and emerging areas, including catalysis, magnetism, electrochemistry, energy, medicine, and nonlinear optics. , Xu and co-workers synthesized as an example Keggin-POM-supported transition-metal complexes, [Ni­(2,2′-bipy) 3 ] 1.5 [PW 12 O 40 Ni­(2,2′-bipy) 2 (H 2 O)]·0.5H 2 O and [Co­(1,10′-phen) 3 ] 1.5 [PMo 12 O 40 Co­(1,10′-phen) 2 (H 2 O)]·0.5H 2 O under hydrothermal conditions . Since then, chemical modification for POMs, such as the construction of inorganic–organic functional materials, has rapidly advanced. − …”

An isolated doughnut-like molybdenum(v) cobalto-phosphate cluster exhibiting excellent photocatalytic performance for carbon dioxide conversion

“…Polyoxometalates (POMs), as a kind of inorganic metal oxygen cluster with redox properties and excellent multi-electron transfer ability, have been subject to extensive studies in numerous domains, such as medicine, 22–24 optics, 25–27 catalysis, 28–35 electrochemistry, 36–40 etc . Among plenty of POM-based clusters, molybdenum( v ) cobalto-phosphate clusters have been considered as prospective promising photocatalysts for CO 2 reduction owing to the presence of reduced Mo V and Co II centers.…”

“…Hence, it is vital to develop reductive CO 2 photocatalysts with high efficiency, high selectivity and low cost for facilitating this reaction process. [12][13][14][15][16][17][18][19][20][21] Polyoxometalates (POMs), as a kind of inorganic metal oxygen cluster with redox properties and excellent multi-elec-tron transfer ability, have been subject to extensive studies in numerous domains, such as medicine, [22][23][24] optics, [25][26][27] catalysis, [28][29][30][31][32][33][34][35] electrochemistry, [36][37][38][39][40] etc. Among plenty of POMbased clusters, molybdenum(V) cobalto-phosphate clusters have been considered as prospective promising photocatalysts for CO 2 reduction owing to the presence of reduced Mo V and Co II 42 Although some achievements have been made, there are no reports on isolated inorganic wheellike cobalto-phosphate clusters as CO 2 reduction reaction (CO 2 RR) catalysts until now.…”