Need to update Material/Renderer before they can be applied?

Hi All.

I'm having a problem and not managed to find a solution scouring the net. I have one material, I create another which is the same but with some emission. When I switch the material on the renderer from the non-emissive to the emissive one, there is no change, however while it's playing in the editor and I click on the material, it then updates in game window. Is there an update function I need to run? I can't find reference to any.

Example code below:

public class UGroundMaterials : MonoBehaviour {

 public Material baseMat;
 private Material emissive;
 public Color emission;
 private MeshRenderer mr;


 // Use this for initialization
 void Start () {
     mr = GetComponent<MeshRenderer>();
     mr.material = baseMat;
     emissive = new Material(Shader.Find("Standard"));
     emissive.CopyPropertiesFromMaterial(baseMat);
     emissive.SetColor("_EmissionColor",emission * 0.5f);
 }

 void Update()
 {
     if (Input.GetMouseButtonDown (0))
     {
         mr.material = emissive;

     }
 }
 

}

Thanks guys.