A 3D Calcium Spirobifluorene Metal-Organic Framework_ Single-Crystal-to-Single-Crystal Transformation and Toluene Detection by a Quartz Crystal Microbalance Sensor.
A new 3D metal−organic framework Ca-SBF based on a zigzag-shaped tetranuclear calciumoxocluster and 9,9′-spirobi[9H-fluorene]-2,2′,7,7′-tetracar-boxylic acid was obtained and exhibited flu topology. Ca-SBF underwent a single-crystal-to-single-crystal trans-formation to form Ca-SBF-1 with a slight structure shrinkage. Activated Ca-SBF showed permanent porosity and CO 2 adsorption properties. A Ca-SBF-modified quartzcrystal microbalance sensor demonstrated selectiveresponse to toluene vapor.