"Tree"-like Multidentate Ligand-Assisted Synthesis of Polymolybdate-Based Architectures with Multinuclear Metal Clusters: Supercapacitor and Electrochemical Sensing Performances.

In this work, aiming for constructing multinuclear metal cluster-modified polymolybdate-based architectures with novel conformation, the "tree"-like multidentate ligand 5-(3-pyridyl)-1 H -tetrazole) (3-ptzH) is introduced into the polymolybdate reaction system. Three new polymolybdate-based architectures with various multinuclear metal clusters, H 4 [Cu 6 (μ 3 -OH) 2 (3-ptz) 6 (γ-Mo 8 O 28 ) (H 2 O) 2 ]·2H 2 O ( BOHU-1 ), H 2 [Ag 4 (3-ptz) 2 (Mo 8 O 26 )] ( BOHU-2 ), and H 4 [Cu 5 (3-ptzH) 2 (3-ptz) 2 (MnMo 9 O 32 ) 2 (H 2 O) 4 ] ( BOHU-3 ) (BOHU = Bohai University), have been prepared via the hydrothermal method and structurally characterized. In BOHU-1 , a kind of pentanuclear copper cluster unit: [Cu 5 (μ 3 -OH) 2 (3-ptz) 6 ] 2+ is formed, which connects to construct a one-dimensional (1D) cluster-based chain. The 1D chains are extended to a two-dimensional (2D) layer via the Cu ions, which are further linked by the 4-connected [γ-Mo 8 O 28 ] 8- anions to build a three-dimensional (3D) framework. In BOHU-2 , when a Ag I ion was used as the central metal, the 3-ptz adopts different coordination modes to link the Ag ions, forming hexanuclear [Ag 6 (3-ptz) 4 ] 2+ cluster and finally 1D chains. These 1D cluster-based chains are connected by the 6-connected [γ-Mo 8 O 26 ] 4- anions to establish a 2D layer, which is further extended by [Mo 8 O 26 ] n 4 n - 1D chains to a 3D framework. For BOHU-3 , the chiral [MnMo 9 O 32 ] 6- anions are introduced and coordinated with the Cu ions to build left- and right-handed 1D chains, which are connected via the [Cu 3 (3-ptz) 4 ] 2+ cluster to form a 1D ladder-like chain. The effects of 3-ptz on the formation of multinuclear clusters, as well as the metals and polymolybdates on the multinuclear clusters and final structures of BOHU-1 ∼ 3 , are discussed. The electrochemical performances of BOHU-1 ∼ 3 as electrode materials for supercapacitors and electrochemical sensors are investigated.