Synthesis and structure determination of [Cu (α-L)(N 3)] NO 3 and [Cu (α-L)(NCS) 2] complexes with α-L= trans-5 (R), 7 (R), 12 (S), 14 (S)-tetramethyl-6, 13-dinitro-1, 4, 8, 11-tetraazacyclotetradecane