w​‌‍‍‍‌‍‍‍‌‍‍‍‌‌‌‌‌‌‍‍​rite an introduction about synthesis of metal organic framework MOF from long flexible organic linker and possible of preparing it in powder form not crystals​‌‍‍‍‌‍‍‍‌‍‍‍‌‌‌‌‌‌‍‍​ and why not form in single Crystal and what is the effect of long flexible linker on MOF formation. I need the references in ACS American Chemical Society​‌‍‍‍‌‍‍‍‌‍‍‍‌‌‌‌‌‌‍‍​.