How can I change the synthetic conditions for powder product into single crystal growth?

I am working on growing metal-organic frameworks crystals based on hexatopic linker for different metals. Upon using some synthetic conditions it gave fast precipitation into powder material after heating for half hour. My question is how to modulate the synthesis to grow single crystals for Zr, Fe, Al in my case? I used metal salt:linker as 10:1 using modulator 100 equivalent to metal salt.


