Quantum mechanical effect such as quantum mechanical tunneling, quantum mechanical confinement, quantum entanglement, or any other quantum mechanical effect to which I may not be aware, what is the largest scale that we have seen/verified these effects to have taken place at? Is it at the sub-atomic scale, at the atomic scale? At the molecular scale? At the complex molecular scale? At what scale do these effects drop off?
Quantum effects such as a wave like behavior are relevant until a measurment of the vector state occurs. At a complex molecular scale the particles are constantly measured by each other and the wave function collapses. Therefore the quantum effects remain at atomic scales and below.