Syntheses, rearrangements, and structural analyses of unsaturated nitrogen donor ligands derived from diphenyldiazomethane and the chiral rhenium Lewis acid [(η⁵-C₅H₅)Re(NO)(PPh₃)]⁺

Diphenyldiazomethane and a labile chlorobenzene complex of [(η⁵-C₅H₅)Re(NO)(PPh₃)]⁺ BF₄⁻ react to give the η¹ adduct [(η⁵-C₅H₅)Re(NO)(PPh₃)(NNCPh₂)]⁺ BF₄⁻ (73%). When this is conducted in the presence of copper powder, a 3-phenyl-1H-indazole complex derived from carbon-hydrogen bond activation, [(η⁵-C₅H₅)Re(NO)(PPh₃)( 000000000000000 111111111111100 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 000000000000000 N 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 C(Ph) 000000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 100000000000000 111111111111100 000000000000000 C CHCH CHCH C 000000000000000 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 001111111111111 000000000000000 N 000000000000000 001111111111111 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000001 000000000000000 H)]⁺ BF₄⁻, is obtained (65%). Subsequent reaction with NaOCH₃ gives indazolyl complex (η⁵-C₅H₅)Re(NO)(PPh₃)( N C CHCH CHCH C C(Ph) N ) (85%), derived from NH deprotonation and a 1,2-rhenium shift. Crystal structures of the three new complexes are determined. DFT calculations are used to probe the mechanism of the 1,2-shift and energetics of alternative Re-N rotamers and linkage isomers, and assign bond orders and dominant resonance formulations.