Xie Zhen-Lang, An Dong-Li, Weng Wei-Zheng, Zhou Zhao-Hui
State Key Laboratory of Physical Chemistry of Solid Surfaces and College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.
Dalton Trans. 2022 Aug 2;51(30):11286-11294. doi: 10.1039/d2dt01360f.
Pyrazole-assisted tetranuclear microporous polyoxovanadates(III) (POVs) (NH)K[V(μ-OH)(ox)(pz)]·9HO (1, ox = oxalate and pz = pyrazole) and (NH)Na[V(μ-OH)(ox)(4-mpz)]·7HO (2, 4-mpz = 4-methylpyrazole) have been constructed in reduced media, along with their triazole neutral hexa- and octanuclear products K[V(μ-OH)(ox)(Hdatrz)]Cl·29.5HO (3) and [V(μ-OH)(SO)(Hdatrz)]·38HO (4, Hdatrz = 1-1,2,4-triazole-3,5-diamine) successively. Both polyanionic structures of 1 and 2 share similar inorganic building blocks that consist of regular {V(μ-OH)} skeletons with an inner diameter of 2.8 Å, while a paddle wheel-shaped cluster 3 contains a {V(μ-OH)} 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 {V(μ-OH)(SO)} 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 CO and O more favorably than N, CH and H 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 CO adsorption.
吡唑辅助的四核微孔多钒酸盐（III）（POVs）（NH）K[V(μ-OH)(ox)(pz)]·9HO（1，ox = 草酸盐，pz = 吡唑）和（NH）Na[V(μ-OH)(ox)(4-mpz)]·7HO（2，4-mpz = 4-甲基吡唑）已在还原介质中合成，同时还相继得到了它们的三唑中性六核和八核产物K[V(μ-OH)(ox)(Hdatrz)]Cl·29.5HO（3）和[V(μ-OH)(SO)(Hdatrz)]·38HO（4，Hdatrz = 1-1,2,4-三唑-3,5-二胺）。1和2的两个聚阴离子结构都具有相似的无机结构单元，由内径为2.8 Å的规则{V(μ-OH)}骨架组成，而桨轮状簇3包含一个{V(μ-OH)}骨架，在环中心周围包裹着两个氯化物，占据一个3.7 Å的孔。一种有趣的孤立的基于多金属氧酸盐的固有金属有机框架（POMOF）4以内径为5.2 Å的八核花瓣状骨架{V(μ-OH)(SO)}形式存在。键价和计算表明，1-4中所有V离子的 +3氧化态都严重降低，这得到了电荷平衡、结构和磁性数据的支持。此外，气体吸附表明，1、2和4对CO和O的吸附比对N、CH和H气体更有利。与1和2相比，由于POMOF 4内部微通道被路易斯碱氨基和羟基以及未配位的唑基N供体官能化，它对CO吸附应该具有显著的亲和力。
