Reaction of small molecules O 2 , NO, CO, and the Naldini salt (PPh 3 ) 2 MnBr 2 : Characterized by infrared spectroscopy, elemental analysis, and single‐crystal X‐ray diffraction

Addition of 2 equiv. of PPh 3 to MnBr 2 in tetrahydrofuran (THF) solution under N 2 atmosphere results in the formation of Naldini salt (PPh 3 ) 2 MnBr 2 ( 1 ). Reaction of Complex 1 and O 2 , NO, and CO (with reducing agent) leads to Complex (OPPh 3 ) 2 MnBr 2 ( 2 ), (PPh 3 ) 2 Mn(NO)Br 2 ( 3 ), and (PPh 3 ) 2 Mn(CO) 3 Br ( 4 ), respectively. Both Complexes 2 and 4 crystallize in the triclinic space group P‐1 with a = 9.94 Å, b = 10.11 Å, c = 10.53 Å; α = 65.42°, β = 63.16°, and γ = 89.22° of 2 and a = 10.23 Å, b = 12.26 Å, c = 14.44 Å and α = 97.03°, β = 104.34°, and γ = 106.33° of 4 . The isoelectronic replacement of 3CO with 2NO yields the {Mn(NO) 2 } 8 species (PPh 3 ) 2 Mn(NO) 2 Br ( 5 ). The single crystal of 5 is in the monoclinic space group C2/c with a = 23.17 Å, b = 9.62 Å, c = 15.92 Å, and β = 114.91°. In the THF solution, Complex 5 serves as an NO source in the presence of NO trapping, Co(TPP), Co(TPP) = 5,10,15,20‐tetraphenyl‐21 H ,23 H ‐porphine cobalt(II).