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A rare all-inorganic high-nuclearity mixed-valent {Mn 11 } cluster embedded polyoxoniobate, K 25 H 43 {(Te 4 Nb 9 O 33 ) 3 (Nb 6 O 19 ) 5 (Te VI Nb 5 O 14 )[(Te IV O 3 ) 2 (MnII7MnIII4O 19 )]}·97H 2 O (1), has been synthesized by a one-pot reaction. Compound 1 contains the largest manganese cluster {Mn 11 } core among polyoxoniobates reported to date. {Mn 11 } consists of three quasi-cubane {Mn 3 O 4 } units and is simultaneously encapsulated by lacunary α-Keggin {Te 4 Nb 9 O 36 } and Lindqvist {Nb 6 O 19 } units. Compound 1 exhibits significant magnetic anisotropy and excellent water solubility and stability. The findings suggest a new, all-inorganic polynulear Mn-based structural paradigm for aqueous solution chemistry and magnetic materials.

Atomically precise metal clusters serve as a unique model for unraveling the intricate mechanism of the catalytic reaction and exploring the complex relationship between structure and activity. Herein, three series of water-soluble heterometallic clusters LnCu 6 , abbreviated as LnCu 6 -AC (Ln = La, Nd, Gd, Er, Yb; HAC = acetic acid), LnCu 6 -IM (Ln = La and Nd; IM = Imidazole), and LnCu 6 -IDA (Ln = Nd; H 2 IDA = Iminodiacetic acid) are presented, each featuring a uniform metallic core stabilized by distinct protected ligands. Crystal structure analysis reveals a triangular prism topology formed by six Cu 2+ ions around one Ln 3+ ion in LnCu 6 , with variations in Cu···Cu distances attributed to different ligands. Electrocatalytic oxygen evolution reaction (OER) shows that these different LnCu 6 clusters exhibit different OER activities with remarkable turnover frequency of 135 s -1 for NdCu 6 -AC, 79 s -1 for NdCu 6 -IM and 32 s -1 for NdCu 6 -IDA. Structural analysis and Density Functional Theory (DFT) calculations underscore the correlation between shorter Cu···Cu distances and improves OER catalytic activity, emphasizing the pivotal role of active-site distance in regulating electrocatalytic OER activities. These results provide valuable insights into the OER mechanism and contribute to the design of efficient homogeneous OER electrocatalysts., (© 2024 Wiley‐VCH GmbH.)

A 3D tellurium-substituted heteropolyoxoniobate framework H 5 K 3 Na[Cu(en) 2 ] 2 [Cu(en) 0.75 (H 2 O) 2.5 ]{[(Te 2 Nb 19 O 58 )(μ 3 -OH) 2 ]}·24H 2 O (1, en = ethylenediamine) with a 6-connected pcu topology is built from heart-shaped {Te 2 Nb 19 O 60 } clusters and copper complexes. The {Te 2 Nb 19 O 60 } cluster represents the new tellurniobate structure type with a 19-nuclearity Nb cluster. It consists of two new monovacant Lindqvist {Nb 5 O 19 } clusters, one boat-shaped {Nb 9 O 32 } cluster and two TeO 3 2- anions. The {Te 2 Nb 19 O 60 } polyanions are interlinked by [Cu(en) 2 ] 2+ complexes into a 2D (4, 4) grid-like layer containing rhombic sheets. The Cu 2+ supports the adjacent layers through Te-O-Cu-O-Te- bonds to form a three-dimensional heteropolyoxoniobate framework with 1D channels. This compound exhibits good chemical and solvent stability and proton conductivity, with a conductivity of 7.9 × 10 -3 S cm -1 at 85 °C under 98% RH.