R1
configure terminal
ipv6 unicast-routing
interface FastEthernet0/0
ipv6 address 2001:1::1/64
ipv6 address 2001:1::/64 eui-64

R2
conf t
ipv6 unicast-routing
interface Fa0/0
ipv6 address 2001:1::2/64
ipv6 address 2001:1::/64 eui-64

Additional commands on both routers for
checking purpose:
show ipv6 interface Fa0/0
ping ipv6 "IPv6_address"