Advances in synthetic chemistry mean that the molecules now synthesized include increasingly complex entities with mechanical bonds or extensive frameworks. For these complex molecular and supramolecular species, single-crystal X-ray crystallography has proved to be the optimal technique for determining full three-dimensional structures in the solid state. These structures are curated and placed in structural databases, the most comprehensive of which (for organic and metallo–organic structures) is the Cambridge Structural Database. A question of increasing importance is how users can search such databases effectively for these structures. Here some of the classes of complex molecules and supramolecules and the challenges associated with searching for them are highlighted. The idea of substructure searches that involve topological searches as well as searches for molecular fragments is developed, and significant enhancements are proposed to substructure search programs that are both achievable and highly beneficial for both the database user community and the broader chemistry community.

中文翻译：

---

对新一代子结构搜索软件的需求

合成化学的进步意味着现在合成的分子包括越来越复杂的具有机械键或广泛框架的实体。对于这些复杂的分子和超分子物种，单晶 X 射线晶体学已被证明是确定固态完整三维结构的最佳技术。这些结构被整理并放置在结构数据库中，其中最全面的（对于有机和金属-有机结构）是剑桥结构数据库。一个日益重要的问题是用户如何有效地搜索这些数据库以获取这些结构。这里重点介绍了一些复杂分子和超分子的类别以及与搜索它们相关的挑战。