I must admit I'm not a chemist but a biologist, so please forgive me if I'm getting some of my terminology wrong. I want to ask a question about the biggest possible complex molecule that can exist in Nature.
I know that certain crystals like quartz and gems like ruby and diamond can grow very large and they could be called molecules. Also, polymers can grow very long with a complex 3D structure.
However my question is about a chemical compound which isn't a polymer but has a complex non-repetitive 3D structure of many covalently bound atoms. If we rely only on synthesis and try to construct the biggest molecule possible how big can we get?
Does the answer vary if we are talking about molecular size, molecular mass, number of atoms, 3D structure (I imagine there can be some very big molecules containing cavities which are lighter and have fewer atoms than other who have more atoms and are heavier but are dense) and so on ?
Or is there a single class or maybe even a single molecular species which combines all these characteristics and can produce the largest molecules no matter what characteristic we use to measure this quantity?
If there is such a class of compounds what it is and how do we synthesize it?