Successive constructions of regular tetra-, hexa- and octanuclear microporous polyoxovanadates(iii) for gas adsorption. Issue 30 (12th July 2022)

• Record Type: Journal Article
• Authors: Xie, Zhen-Lang; An, Dong-Li; Weng, Wei-Zheng; Zhou, Zhao-Hui
• Is Part Of: Dalton transactions. Volume 51:Issue 30(2022)
• Page Start: 11286
• Page End: 11294
• Publication Date: 2022-07-12
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/d2dt01360f
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Regular tetra-, hexa- and octanuclear microporous polyoxovanadates(iii ) 1–4 are constructed successively. An interesting isolated intrinsic POMOF 4 with the functionalization of microchannels exhibits a notable affinity toward CO2 adsorption. Abstract : Pyrazole-assisted tetranuclear microporous polyoxovanadates(iii ) (POVs) (NH4 )2 K2 [V4 (μ2 -OH)4 (ox)4 (pz)4 ]·9H2 O (1, ox = oxalate and pz = pyrazole) and (NH4 )2 Na2 [V4 (μ2 -OH)4 (ox)4 (4-mpz)4 ]·7H2 O (2, 4-mpz = 4-methylpyrazole) have been constructed in reduced media, along with their triazole neutral hexa- and octanuclear products K2 [V6 (μ2 -OH)6 (ox)6 (Hdatrz)6 ]Cl2 ·29.5H2 O (3 ) and [V8 (μ2 -OH)8 (SO3 )8 (Hdatrz)8 ]·38H2 O (4, Hdatrz = 1 H -1, 2, 4-triazole-3, 5-diamine) successively. Both polyanionic structures of 1 and 2 share similar inorganic building blocks that consist of regular {V4 (μ2 -OH)4 } skeletons with an inner diameter of 2.8 Å, while a paddle wheel-shaped cluster 3 contains a {V6 (μ2 -OH)6 } skeleton with two chlorides encapsulated around the center of the ring, occupying a hole of 3.7 Å. An interesting isolated intrinsic polyoxometalate-based metal–organic framework (POMOF) 4 exists as an octanuclear petaloid-like skeleton {V8 (μ2 -OH)8 (SO3 )8 } with an inner diameter of 5.2 Å. Bond valence sum calculations manifest that all V ions have severely reduced +3 oxidation states in 1–4, which are supported by charge balance, structural and magnetic data. Moreover, gas adsorptions indicate that 1, 2 and 4 can adsorb CO2 and O2 more favorably than N2, CH4 and H2 gases. Compared with 1 and 2, due to the functionalization of microchannels with Lewis base amino and hydroxy groups and uncoordinated azolate N-donors inside POMOF 4, it should have notable affinities toward CO2 adsorption.