I think you can use it, I am not talking about distance here, But i guess the Copper AOC breakout cables can be used for connection between, 2348 to 5600 nexus switch.
Please also check the NX-OS release version you are using, Also check the guide i have attached so it can give you more information on the compatibility and OS release.
http://www.cisco.com/c/en/us/td/docs/interfaces_modules/transceiver_modules/compatibility/matrix/40GE_Tx_Matrix.pdf