Ruthenium Cyclopentadienyl Aryldiazenido Complexes. Synthesis of [Cp‘Ru(PR₃)₂(N₂C₆H₄OMe)][BF₄]₂and [Cp‘RuCl(PPh₃)(N₂C₆H₄OMe)][BF₄] (Cp‘ = Cp, Cp*) and X-ray Crystal Structure of [CpRu(PPh₃)₂(N₂C₆H₄OMe)][BF₄]₂, an Aryldiazenido Complex with a Large N−N−C(aryl) Angle and Near-Linear Ru−N−N−C(aryl) Skele

Abstract

The neutral ruthenium complexes Cp′Ru(PR 3 ) 2 Cl [Cp′ ) Cp, PR 3 ) PPh 3 , PMe 3 , or 1/2 dppe; Cp′ ) Cp*, PR 3 ) PMe 3 ] react with [p-MeOC 6 H 4 N 2 ][BF 4 ] in acetone to give new cyclopentadienyl ruthenium aryldiazenido dicationic complexes [Cp′Ru(PR 3 ) 2 (N 2 C 6 H 4 OMe)]-[BF 4 ] 2 [Cp′ ) Cp, PR 3 ) PPh 3 (1), PMe 3 (2), or 1/2 dppe (3); Cp′ ) Cp*, PR 3 ) PMe 3 (4)] in good yields. The dicationic complexes 1-3 may also be conveniently isolated in better yield by treatment of the acetonitrile ruthenium complexes [CpRu(PR 3 ) 2 (NCMe)][BF 4 ] with the arenediazonium salt. When the reaction of Cp′Ru(PPh 3 ) 2 Cl (Cp′ 5) or Cp* ( 6)]. Further, if the reaction of Cp*Ru(PPh 3 ) 2 Cl with diazonium salt is carried out in acetone, the binuclear complex [Cp*RuCl(N 2 C 6 H 4 OMe)] 2 [Cl] 2 (7) can be isolated in low yield in addition to 6. All new complexes 1-7 were fully characterized by NMR, FT-IR, and mass spectroscopies. The structure of [CpRu(PPh 3 ) 2 (N 2 C 6 H 4 OMe)][BF 4 ] 2 ‚0.93CHCl 3 (1‚ 0.93CHCl 3 ) was determined by single-crystal X-ray diffraction. The structure exhibits a nearlinear Ru-N-N-C geometry for the coordinated aryldiazenido group, with the NNC angle having a value of 159°, compared to the "sp 2 " value of approximately 120°commonly exhibited by other "singly bent" aryldiazenido complexes. On the basis of NMR spectroscopic data, 1 reacts with NaBH 4 at low temperature to give an arylhydrazido(2-) complex [CpRu(PPh 3 ) 2 -{NN(H)C 6 H 4 OMe}][BF 4 ], which readily converts to the corresponding aryldiazene complex [CpRu(PPh 3 ) 2 (NHdNC 6 H 4 OMe)][BF 4 ] by a hydrogen shift; at room temperature, the only product is the hydrido complex CpRuH(PPh 3 ) 2 .

Aryldiazenido complexes of ruthenium(II) with tris(pyrazolyl)borate: A DFT study

“…5. This hypothesis fits low-temperature NMR observations for the reaction between [Ru(N"NC 6 H 4 OMe) (Cp)(PPh 3 ) 2 ](BF 4 ) 2 and NaBH 4 [4].…”

“…Also, the structure of the [Ru(N"NPh)(Tp)(PPh 3 ) {P(OEt) 3 }] 2+ cation obtained from geometrical optimization with the constraint b angle = 120°does not show any particular interaction of the N 2 Ph fragment with other parts of the molecule. As described by Sutton et al [4], one explanation for the data in Table 1 comes from the p-acidity of aryldiazenido ligands; p backdonation from the metal centre weakens the N 1 -N 2 bond and reduces the b angle but, because of the dicat- [5], p back-donation from ruthenium to the aryldiazenido ligand is quite low and the [Ru]-N"N-Ar fragment is near-linear (see Fig. 3).…”

Ruthenium‐Catalyzed β‐Alkylation of Secondary Alcohols with Primary Alcohols

“…We have been able to present a clearer picture of the mechanistic aspects of the reaction, and more interestingly, we have demonstrated that the carbonyl complexes resulting from aldehyde decarbonylation, which is usually regarded as the cause of catalyst deactivation, are also active for the alkylation reactions. [14] CpRu-A C H T U N G T R E N N U N G (PPh 3 ) 2 Cl (M2), [15] CpRuA C H T U N G T R E N N U N G (dppm)Cl (M3), [16] TpRuA C H T U N G T R E N N U N G (PPh 3 ) 2 Cl (M4), [17] [18] cis-[Ru(6,6'- [19] and TpRuA C H T U N G T R E N N U N G (PPh 3 )(CO)Ph (M8) [10] were prepared according to literature methods.…”

Preparation and reactivity of diazoalkane complexes of ruthenium stabilised by an indenyl ligand

“…18 Coordination of the diazoalkane ligand in 3c shows a severely "bent" configuration, with a N(2)-N(1)-Ru bond angle of 150.5(2)°. Note that this angle is more acute than that found in Cp diaryldiazoalkane Ru complex [Ru(Cp)P 1 P 2 {NNC(Ph)-Tol}] [156.0(1)°], 13a or even in the 9-diazofluorene one [RuCl 2 {NNC (C 12 21 It should be noted that the N(1)-N(2)-C(11) bond angle is 171.2(3)°, revealing a sp character on the N(2) atom, quite different from the usual sp 2 geometry [about 120°] around this atom found in aryldiazenido compounds, 22 The bond distances at the diazenido moiety, Ru-N(1) of 1.990(2), N(1)-N(2) of 1.154(3) and N(2)-C(11) of 1.299(3) Å, are virtually the same values as those found in the abovementioned 9-diazofluorene ruthenium complex [RuCl 2 {NNC- (C 12 H 8 )}(PNP)], or in [Ru(Cp)P 1 P 2 {NNC(Ph)Tol}] + , in such a way that a double bond between the nitrogen atoms and also between N(2) and C(11) may be proposed. Due the multiple character of the Ru-N bond, its length is shorter than that found in nitrile complexes, like [Ru(Cp)(NCPh)P 1 P 2 ], 23 2.029(2) Å, or in other ruthenium benzonitrile complexes, average 2.033 Å.…”