Object color change

Hello

I am trying to change my game object color through script, I have defined my game object and my buttons as game objects, but when I click on them, color of game object does not change.

public class ChangeColor : MonoBehaviour {

 // Define C911B game object
 private GameObject C911B = new GameObject();

 // Define buttons
 private GameObject turnred = new GameObject();
 private GameObject turnblack = new GameObject ();
 private GameObject turnwhite = new GameObject ();
 private GameObject turnyellow = new GameObject ();

 // Use this for initialization
 void Start () {
     GameObject.Find ("911B").renderer.enabled = true;
     GameObject.Find ("turn-red").renderer.enabled = true;
     GameObject.Find ("turn-black").renderer.enabled = true;
     GameObject.Find ("turn-white").renderer.enabled = true;
     GameObject.Find ("turn-yellow").renderer.enabled = true;

     C911B = GameObject.Find ("911B");
     turnred = GameObject.Find ("turn-red");
     turnblack = GameObject.Find ("turn-black");
     turnwhite = GameObject.Find ("turn-whit");
     turnyellow = GameObject.Find ("turn-yellow");
 
 }
 
 // Update is called once per frame
 //void Update () {
 //
 //}

 void OnMouseClick ()
 {
     if (turnred) {
                     C911B.renderer.material.color = new Color (232, 0, 0, 255);
             } else if (turnblack) {
                     C911B.renderer.material.color = new Color (0, 0, 0, 255);
             } else if (turnwhite) {
                     C911B.renderer.material.color = new Color (184, 184, 184, 255);
             } else if (turnyellow) {
                     C911B.renderer.material.color = new Color (201, 187, 0, 255);
             }
 }

}