It doesnt even matter if its a rocky/molten/plasma/etc core, the conditions before the core are so extreme that any complex molecule cannot be formed...Why? Metallic Hydrogen is the answer. Its state will "dissolve" anything that comes close enough. Just to simplify things: Gas giants are "almost the same" compared to stars. Jupiter produces more heat than it receives from the sun and if it were 70-80 times more mass, it could use hydrogen to produce energy just like our sun. Brown dwarfves are failed stars. Just because a planet has liquid, it doesnt mean its like our ocean and it doesnt mean its composed by water. It has a "ocean of metallic hydrogen...thats pretty much bad for life, considering that some conditions must exist to allow important chemical reactions to happen. (temperature = 10.000K, pressure = 1974000 atm)
