German inventor who produced the worlds first motorcycle in 1885 and later manufactured cars that he named for a friends daughter Mercedes?

The person you are referring to is Karl Benz, a German mechanical engineer and inventor who is widely regarded as the inventor of the first internal combustion engine-powered automobile. It was his wife's name, Bertha Benz, that he initially used as the brand name for his early automobiles, not a friends daughter.

While Karl Benz did not invent the first motorcycle, he did engineer the first internal combustion engine-powered two-wheeled vehicle, known as the Motorwagen, in 1885. However, it was Gottlieb Daimler and Wilhelm Maybach, also German engineers and inventors, who are generally credited with inventing the first motorcycle in 1885. Their invention, known as the Reitwagen, is widely considered the world's first internal combustion engine-powered two-wheeled vehicle.