Object rotation on mouse Click

hello, I am trying to rotate my game object on mouse click, for 90 degrees but it doesn’t work !!!

using UnityEngine;
using System.Collections;

public class TurnCam : MonoBehaviour {

public GameObject gOb;
//private float smoth = 1f;
//private Vector3 targetAngle;
//private bool isTurned;
private int turnedDeg;
// Use this for initialization
void Start () {
	//turnedDeg = 0;
}

void OnMouseDown()
{
	for (int i = 0; i <=90;) 
	{
			gOb.transform.Rotate (Vector3.up, 1);
			i = i + 1;
	}
}

// Update is called once per frame
void Update () {

}

}

Hi,

to rotate the object instantly use:

void OnMouseDown()
 {
      gOb.transform.Rotate (Vector3.up, 90.0f);
 }

If you want a smooth rotation over time do it like here: