I will be purchasing on behalf of a corporation, what legal documentation will I need to present?

The corporation papers name me as an officer and grant me permission to act on behalf of the corporation. Do I present these documents to the auctioneer or obtain “power of attorney”?

It will be you, not the corp, that qualifies to bid. Have checks made payable to you and be prepared to show a government issud photo ID. If you want the corp to own the property, then the vesting you give the auctioneer will be in the name of the corp. Be sure that the vesting is exactly the same as the registered name of the corporation. When you sell, the title company will want you to provided documentation for the corporation including a resolution for the sale.