Ethyl(nitrosyl)ruthenium [TpRuCl(Et)(NO)] (2) was isolated from the reaction of [TpRuCl2(NO)] (1) with LiBHEt3. NO insertion of 2 was observed from heating a solution of 2. In the presence of PPh3, nitrosoethane complex [TpRuCl{N(=O)Et}(PPh3)] (3) was isolated, but the absence of PPh3 led to nitrosoethane-bridged dimer [(TpRuCl)2{μ-N(=O)Et}2] (6). Also, in complex 3, conversion of the nitrosoethane moiety to acetaldoxime and acetonitrile was observed.

Nitrosylruthenium arylbutadiynyl complexes having a Tp ligand (Tp = BH(pyrazol-1-yl)3) were prepared, and their reactivities toward PPh3 incorporation in the presence of HBF4·Et2O were described. The PPh3 incorporation of mono(arylbutadiynyl) complex TpRuCl(CC−CC−C6H4Me)(NO) (1) resulted in the β-phosphonioalkenyl complex (E)-[TpRuCl(CHC(PPh3)−CC−C6H4Me)(NO)]BF4 (2·BF4), whereas when bis(arylbutadiynyl) TpRu(CC−CC−C6H4Me)2(NO) (3) was treated, mono- and bis(β-phosphonioalkenyl) complexes (E)-[TpRu(CC−CC−C6H4Me)(CHC(PPh3)−CC−C6H4Me)(NO)]BF4 (4·BF4) and (E, E)-[TpRu(CHC(PPh3)−CC−C6H4Me)2(NO)](BF4)2 {5·(BF4)2} were obtained depending on the reaction conditions. On the other hand, an unsymmetrically mixed (arylbutadiynyl)(3-hydroxyalkynyl) complex, TpRu(CC−CC−C6H4Me){CCCPh2(OH)}(NO) (6), was allowed to react with PPh3 in the presence of the protic acid to give the α-phosphonioallenyl [TpRu(CC−CC−C6H4Me){C(PPh3)CCPh2}(NO)]BF4 (7·BF4). Interestingly, thermal isomerization of 7·BF4 to a ruthena-2-PPh3-cyclobuta[b]naphthalene [TpRu{CH(PPh3)[3-Ph-8-(MeC6H4−CC)−C10H4]}(NO)]BF4 (8·BF4) was observed.