If you bought the items for the employer, then you can't take them, even if you were not reimbursed for them--having bought them for the employer, they belong to the employer, and your recourse, if not reimbursed, is to sue the employer for reimbursement  to which you are entitled. Taking items belonging to the employer would be theft. If the items were bought for yourself and used at work, then you can take them.Examples: your employer sent you out to buy a whiteboard; because you were specifically sent to buy it for the employer, it belongs to the employer. You may not take it.You don't like using a computer mouse and bought your own trackball; even though you used it at work, you chose to buy it for your own use. I is yours and you may take it.