Site isolated vanadium ions supported on zeolites are central in many catalytic processes. However, an atomistic description of the species formed is often hampered by the heterogeneous nature of zeolites and the random distribution of active species. In this contribution we applied pulsed electron paramagnetic resonance spectroscopy on ¹⁷O exchanged ZSM-5 zeolite loaded with V⁴⁺ ions, via gas phase reaction with VCl₄ vapors. From the magnetic parameters relative to ¹H, ¹⁷O, ²⁷Al and ⁵¹V isotopes we prove that a single, structurally well-defined VO(OH)⁺ species is formed at zeolite Al framework sites and derive a detailed atomistic model inclusive of bond lengths and angles. Comparison is set to vanadyl aquo complexes, highlighting analogies between surface and solution coordination chemistry. The results showcase the power of EPR spectroscopy and ¹⁷O isotopic labelling in the geometrical and electronic characterisation of inorganic complexes formed at the surface of oxide materials. Pulsed EPR on disorder systems can therefore compete in structural insight with more well-established X-ray techniques.

在许多催化过程中，负载在沸石上的位点分离钒离子是关键。然而，沸石的异质性和活性物质的随机分布常常阻碍了对所形成物质的原子描述。在这一贡献中，我们通过与VCl ₄蒸气的气相反应，对负载了V ⁴⁺离子的¹⁷ O交换ZSM-5沸石进行了脉冲电子顺磁共振光谱分析。从相对于¹ H，¹⁷ O，²⁷ Al和⁵¹ V同位素的磁参数，我们证明了一个结构上明确定义的VO（OH）⁺在沸石Al骨架位点上形成该物种，并推导出包括键长和角度在内的详细的原子模型。将对钒基水合物进行比较，突出显示表面和溶液配位化学之间的类比。结果显示了EPR光谱学和¹⁷ O同位素标记在形成氧化物材料表面形成的无机配合物的几何和电子特征方面的强大能力。因此，对疾病系统的脉冲EPR可以与更完善的X射线技术竞争结构洞察力。