(plaintiff, a partnership, granted façade easement on certified historic structure to National Architecture Trust; easement required grantor to obtain prior written consent from NAT before making any changed to façade; plaintiff claimed $10.7 million deduction for donation on partnership tax return and IRS fully disallowed deduction because at time of grant, plaintiff owned first 14 floors of building and third party owned top 6 floors and plaintiff did not own entire exterior of structure; plaintiff claimed that easement terms imposed enforceable restrictions on entire exterior and that under state (IL) law ownership of entire exterior not required to grant easement imposing enforceable restrictions on entire exterior; court agreed with IRS on basis that while state law determines nature of property rights, federal law determines appropriate tax treatment of those rights; based on state law, court noted that plaintiff only had rights to two sides of structure and did not have assignable right in entire exterior via maintenance agreement or need to get prior approval to make alterations).