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首页> 外文期刊>Crystal growth & design >Three transition-metal substituted polyoxotungstates containing Keggin fragments: From trimer to one-dimensional chain to two-dimensional sheet
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Three transition-metal substituted polyoxotungstates containing Keggin fragments: From trimer to one-dimensional chain to two-dimensional sheet

机译：包含Keggin片段的三种过渡金属取代的聚氧钨酸盐：从三聚体到一维链再到二维片材

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摘要

Three novel transition-metal substituted polyoxotungstates based on Keggin fragments, Cs_3K_3[Co(H_2O)_6] _2[Co(H_2O)_3(α-GeW_(11)CoO _(38))_3]·30H_2O (1), K _(18){[Mn(H_2O)_3]_2[Mn(H _2O)_2][(B-β-SiW_9O_(33)(OH))Mn _3(H_2O)(B-β-SiW_8O_(30-) (OH))] _2}·16H_2O (2), and K_8[Cd(H _2O)_3]_2[Cd_4(H_2O) _2(B-α-SiW_9O_(34))_2] ·20H_2O (3), have been synthesized by reaction of dilacunary Keggin precursors K_8[γ-GeW_(10)O_(36)] ·6H_2O/K_8[γ-SiW_(10)O_(36)] · 12H_2O with transition-metal salts at ambient temperature and characterized by inductively coupled plasma (ICP) analyses, IR spectra, UV spectra, and single-crystal X-ray diffraction. The polyoxoanion of 1 is a novel trimer constructed from three mono-Co~(II) substituted Keggin fragments [α-GeW_(11)CoO_(38)]~(4-) linked by six W-O-Co/W bridges and a capping [Co(H_2O)_3]~(2+) bridge. 2 displays the one-dimensional chain built by tetrameric {[Mn(H_2O) _3]2_[Mn(H_2O)_2][(B-β-SiW _9O_(33)(OH))Mn_3(H_2O)(B-β-SiW _8O_(30)(OH))]_2}~(18-) units, which is the first one-dimensional silicotungstate containing asymmetric sandwich-type moieties constructed from [B-β-SiW_9O_(34)] and [B-β-SiW_8O_(31)]~(10-) fragments. 3 utilizes the two-dimensional sheet established by tetra-Cd~(II) substituted sandwich-type [Cd_4(H_2O)_2(B-α-SiW _9O_(34))_2]~(12-) units and [Cd(H _2O)_3]~(2+) linkers, representing the first two-dimensional (3,6-topological network with a Schl?fli symbol of 3 ~6 4~65~3 built by sandwich-type Keggin units in polyoxometalate chemistry. Magnetic susceptibility measurements indicate antiferromagnetic exchange interactions within Co~(II) ions in 1 and within Mn~(II) ions in 2. The best least-squares fitting values for 2 are J =-1.16 cm~(-1) and g = 2.13 based on the isostropic spin model. Furthermore, the room-temperature solid-state photoluminescence of 3 displays two emission bands, which are derived from O → Cd ligand-to-metal charge transfer transitions and O → W ligand-to-metal charge transfer transitions, respectively.
机译：基于Keggin片段的三个新颖的过渡金属取代的聚氧钨酸盐Cs_3K_3 [Co（H_2O）_6] _2 [Co（H_2O）_3（α-GeW_（11）CoO _（38））_ 3]·30H_2O（1），K _ （18）{[Mn（H_2O）_3] _2 [Mn（H _2O）_2] [（B-β-SiW_9O_（33）（OH））Mn _3（H_2O）（B-β-SiW_8O_（30-）（ OH））] _2}·16H_2O（2）和K_8 [Cd（H _2O）_3] _2 [Cd_4（H_2O）_2（B-α-SiW_9O_（34））_ 2]·20H_2O（3）已合成通过在环境温度下使过渡金属的Keggin前体K_8 [γ-GeW_（10）O_（36）]·6H_2O / K_8 [γ-SiW_（10）O_（36）]·12H_2O与过渡金属盐反应而表征等离子体（ICP）分析，红外光谱，紫外光谱和单晶X射线衍射。 1的多氧阴离子是由三个单Co-（II）取代的Keggin片段[α-GeW_（11）CoO_（38）]〜（4-）组成的新型三聚体，该片段由六个WO-Co / W桥和一个封盖连接[Co（H_2O）_3]〜（2+）桥。图2显示了由四聚体[[Mn（H_2O）_3] 2_ [Mn（H_2O）_2] [（B-β-SiW_9O_（33）（OH））Mn_3（H_2O）（B-β- SiW _8O_（30）（OH））_ 2}〜（18-）单元，这是由[B-β-SiW_9O_（34）]和[B-β构成的第一个一维含硅钨酸盐的不对称夹心型结构部分-SiW_8O_（31）]〜（10-）片段。图3利用由四-Cd〜（II）取代的夹心型[Cd_4（H_2O）_2（B-α-SiW_9O_（34））_ 2]〜（12-）单元和[Cd（H _2O）_3]〜（2+）接头，表示通过多金属氧酸盐化学中的三明治型Keggin单元建立的第一个二维（3,6-拓扑网络，其Schlfli符号为3〜6 4〜65〜3）。磁化率测量表明1中的Co〜（II）离子和2中的Mn〜（II）离子之间的反铁磁交换相互作用。2的最佳最小二乘拟合值为J = -1.16 cm〜（-1）和g =基于等熵自旋模型的2.13。此外，3的室温固态光致发光显示两个发射带，这是从O→Cd配体到金属的电荷转移跃迁和O→W配体到金属的电荷转移获得的转移过渡。

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