Half Sandwich Electron Deficient N , N′ , N′′ ‐Triarylguanidinatoruthenium(II) Complexes: Syntheses, Reactivity Studies, and Structural Aspects

Three symmetrical N , N′ , N′′ ‐triarylguanidinatoruthenium(II) complexes, [(η 6 ‐ p ‐cymene)RuCl{κ 2 ( N , N′ )((ArN) 2 C‐N(H)Ar)}] (Ar = 2‐(CF 3 )C 6 H 4 ( 1 ), 4‐(CF 3 )C 6 H 4 ( 2 ) and 3,5‐(CF 3 ) 2 C 6 H 3 ( 3 )) were isolated in good yields. The reaction of 3 with NaOAc, NaN 3 and KSCN afforded [(η 6 ‐ p ‐cymene)RuX{κ 2 ( N , N′ )((ArN) 2 C‐N(H)Ar)}] (X = OAc ( 4 ), N 3 ( 5 ) and an admixture of SCN ( 6 ) and NCS ( 7 )) respectively in very good yields. On the other hand, metathesis reaction of 3 with AgSbF 6 in the presence of MeCN afforded [(η 6 ‐ p ‐cymene)Ru(MeCN){κ 2 ( N , N′ )((ArN) 2 C‐N(H)Ar)}][SbF 6 ] ( 8 ) in good yield. Complex 5 upon treatment with diethylacetylenedicarboxylate and bis(diphenylphosphanyl)acetylene separately afforded guanidinate(1–) complex, [(η 6 ‐ p ‐cymene)Ru(N 3 C 2 (C(O)OEt) 2 ){κ 2 ( N , N′ )((ArN) 2 C‐N(H)Ar)}] ( 9 ) and guanidinate(2–) complex, [(η 6 ‐ p ‐cymene)Ru{κ 2 ( N , N′ )((ArN) 2 C=NAr)}(κ 1 P ‐Ph 2 PC≡CPPh 2 )] ( 10 ) in good yields. The formation 9 vs. 10 is ascribed to the subtle difference in the electron richness of alkynes. The new complexes were characterized by analytical, IR and NMR spectroscopy and single‐crystal X‐ray diffraction. Complex 3 catalyses [3+2] cycloaddition reaction involving phenylacetylene and 4‐tolyl azide to afford an admixture of 1,4‐ and 1,5‐disubstituted 1,2,3‐triazoles, 23 and 24 in 99 % conversion.