They are not leaves, they are cotyledons and basically play no part in the growth of the plant.
Their main "job" is to protect the growing tip as it pushes through the soil.
The first true leaves will emerge from the center area once the cotyledons fold back and open.
That they are of a purplish color is of no consequence and is quite common.
They will dry up, die and fall off (usually) within the first 2-3 weeks................all this is normal.