The reaction between neutral bis(picolinate)copper(II) complexes and copper(II)-monosubstituted Keggin-type phosphotungstate anions formed in situ leads to the formation of the hybrid [C(NH₂)₃]₁₀[{PW₁₁O₃₉Cu(H₂O)}₂{Cu(pic)₂}]·10H₂O compound (1, pic = picolinate) in the presence of structure-directing guanidinium cations. Single-crystal X-ray diffraction studies demonstrate that 1 contains dimeric {PW₁₁O₃₉Cu(H₂O)}₂{Cu(pic)₂} molecular species constituted by two Keggin-type anions linked by one {Cu(pic)₂} octahedral complex through axial coordination to their terminal oxygen atoms. The extensive hydrogen-bonding network established by guanidium cations and Keggin clusters plays a key role in retaining the crystallinity of the system throughout dehydration to allow a single-crystal-to-single-crystal (SCSC) transformation into the anhydrous [C(NH₂)₃]₁₀[{PW₁₁O₃₉Cu}₂{Cu(pic)₂}] (2a) at 170 °C. Structural modifications involve the re-orientation, shifting in ca. 1.5 Å and condensation of all the {PW₁₁O₃₉Cu} units to result in {PW₁₁O₃₉Cu}_n chains in an unprecedented solid-state polymerisation. This phase transition also implies the cleavage of Cu–O bonds induced by the rotation and translation of Keggin-type anions, in such a way that hybrid dimeric units in 1 are dismantled and {Cu(pic)₂} complexes become square planar. The irreversibility of the phase transition has been confirmed by combined thermal and diffractometric analyses, which evidence that the anhydrous phase adsorbs only one water molecule per cluster to become the [C(NH₂)₃]₁₀[{PW₁₁O₃₉Cu}₂{Cu(pic)₂}]·2H₂O (2h) hydrated derivative without any significant alteration in its cell parameters, nor in its crystalline structure. Phase transformations have been monitored by electron paramagnetic resonance spectroscopy.

中文翻译：

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单取代 [PW11O39Cu(H2O)]5− Keggin 型阴离子的晶体到晶体聚合

中性双(吡啶甲酸)铜( II )配合物与原位形成的铜( II )-单取代Keggin型磷钨酸盐阴离子之间的反应导致形成杂化物[C(NH ₂ ) ₃ ] ₁₀ [{PW ₁₁ O ₃₉ Cu(H ₂ O)} ₂ {Cu(pic) ₂ }]·10H ₂ O 化合物（1， pic = 吡啶甲酸）在结构导向胍盐阳离子存在下。单晶X射线衍射研究表明1含有二聚{PW ₁₁ O ₃₉ Cu(H ₂ O)} ₂ {Cu(pic) ₂ }分子种类，由两个Keggin型阴离子通过一个{Cu(pic)连接而成₂ } 八面体复合物通过与其末端氧原子进行轴向配位。由胍阳离子和 Keggin 簇建立的广泛氢键网络在整个脱水过程中保持系统的结晶度方面发挥着关键作用，从而允许单晶到单晶 (SCSC) 转变为无水 [C(NH ₂₎ ) ₃ ] ₁₀ [{PW ₁₁ O ₃₉ Cu} ₂ {Cu(pic) ₂ }] ( 2a ) 在 170 °C。结构修改涉及重新定位、大约变化。 1.5 Å，所有{PW ₁₁ O ₃₉ Cu}单元缩合，以前所未有的固态聚合形成{PW ₁₁ O ₃₉ Cu} _n链。这种相变还意味着由 Keggin 型阴离子的旋转和平移引起的 Cu-O 键断裂，从而使1中的混合二聚体单元被分解，{Cu(pic) ₂ } 复合物变成方形平面。结合热分析和衍射分析证实了相变的不可逆性，这证明无水相每个簇仅吸附一个水分子，成为 [C(NH ₂ ) ₃ ] ₁₀ [{PW ₁₁ O ₃₉ Cu} ₂ {Cu(pic) ₂ }]·2H ₂ O ( 2h ) 水合衍生物，其晶胞参数及其晶体结构没有任何显着改变。相变已通过电子顺磁共振波谱监测。