Achieving Operational Universality through a Turing Complete Chemputer.

The most fundamental abstraction underlying all modern computers is the Turing Machine, that is, if any modern computer can simulate a Turing Machine, an equivalence which is called "Turing completeness", it is theoretically possible to achieve any task that can be algorithmically described by executing a series of discrete unit operations. In chemistry, the ability to program chemical processes and ensure unit operations are understood at a high level of abstraction and then reduced to practice is extremely challenging. Herein, we exploit the concept of Turing completeness applied to robotic chemical platforms that execute unit operations to synthesize complex molecules using a chemically aware programming language, XDL. We leverage the concept of computability by computers to synthesizability of chemical compounds by automated synthesis machines. The results of an interactive demonstration of Turing completeness using the color gamut and conditional logic are presented to serve as a proxy for conceptual, chemical space exploration. This formal description establishes a formal framework in future chemical programming languages to ensure complex logic operations are expressed and executed correctly, with the possibility of error correction, in the autonomous pursuit of increasingly complex molecules.