Flexible Pores of a Metal Oxide-Based Capsule Permit Entry of Comparatively Larger Organic Guests

摘要

In zeolites and rigid functional materials, substrates whose sizes exceed those of the pore dimensions are rigorously excluded. Meanwhile, cavities within flexible metal-organic frameworks (MOFs) can accommodate substrates by reversible, stepwise structural expansion ("breathing"). Now, using a "capsule-like" molybdenum oxide-based framework as a soluble analogue of porous solid-state (rigid) oxides, we find that branched-alkane "guests" can negotiate passage through flexible subnanometer Mo_9O_9 apertures whose geometrical dimensions are smaller than the entering species.