Protonation of triruthenium carbonyl cluster complexes containing a bridging 1-azavinylidene ligand. Experimental results and EHMO calculations (original) (raw)
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Journal of Organometallic Chemistry, 2000
The 16-electron complex [(C 5 Me 5 )RuCl(PMe i Pr 2 )] (1) was obtained by reaction of [{(C 5 Me 5 )RuCl} 4 ] with PMe i Pr 2 in petroleum. This compound appears to be in equilibrium with the dimer [{(C 5 Me 5 )Ru(PMe i Pr 2 )} 2 (m-Cl) 2 ] as inferred from low-temperature NMR studies. The 18-electron complex [(C 5 Me 5 )RuCl(PMe i Pr 2 ) 2 ] was formed upon addition of PMe i Pr 2 to 1. The related species [(C 5 H 5 )RuCl(PMe i Pr 2 ) 2 ] (2) was obtained by reaction of [(C 5 H 5 )RuCl(PMe i Pr 2 )(PPh 3 )] with PMe i Pr 2 , followed by column chromatography. A range of Ru IV dihydrides [(C 5 R 5 )RuH 2 (PR 3 ) 2 ][BPh 4 ] (R=Me, H; PR 3 = PMe i Pr 2 , PEt 3 ) have been prepared and characterised. The corresponding monohydrido complexes [(C 5 R 5 )RuH(PR 3 ) 2 ] were obtained by deprotonation of the cationic dihydrides. Protonation at low temperature of either of these monohydrido complexes yielded back the corresponding dihydrido derivative, except in the case of [(C 5 Me 5 )RuH(PEt 3 ) 2 ], for which the metastable cationic dihydrogen complex [(C 5 Me 5 )Ru(H 2 )(PEt 3 ) 2 ] + was obtained and characterised by NMR spectroscopy. This compound rearranges to its dihydrido tautomer as the temperature is raised, and a kinetic study of such process was accomplished. Interestingly, the only isolable dinitrogen adduct of the type [(C 5 R 5 )Ru(N 2 )(PR 3 ) 2 ][BPh 4 ] among all possible combinations of phosphines and cyclopentadienyl ring substituents was [(C 5 Me 5 )Ru(N 2 )(PEt 3 ) 2 ][BPh 4 ].
Journal of Organometallic Chemistry, 2008
Reaction of [Ru 3 (CO) 12 ] with tri(2-furyl)phosphine, P(C 4 H 3 O) 3 , at 40°C in the presence of a catalytic amount of Na[Ph 2 CO] furnishes two triruthenium complexes [Ru 3 (CO) 10 {P(C 4 H 3 O) 3 } 2 ] (1) and [Ru 3 (CO) 9 {P(C 4 H 3 O) 3 } 3 ] (2) with the ligand coordinated through the phosphorus atom. Treatment of 1 and 2 with Me 3 NO at 40°C affords the dinuclear phosphido-bridged complexes [Ru 2 (CO) 6 (lg 1 ,g 2 -C 4 H 3 O){l-P(C 4 H 3 O) 2 }] (3) and [Ru 2 (CO) 5 (l-g 1 ,g 2 -C 4 H 3 O){l-P(C 4 H 3 O) 2 }{P(C 4 H 3 O) 3 }] (4), respectively, that are formed via phosphorus-carbon bond cleavage of a coordinated phosphine followed by coordination of the dissociated furyl moiety to the diruthenium center in a r,p-alkenyl mode. Reaction of [Ru 3 (CO) 12 ] with tri(2-furyl)phosphine in refluxing benzene gives, in addition to 3 and 4, low yields of the cyclometallated complex [Ru 3 (CO) 9 {l-g 1 ,g 1 -P(C 4 H 3 O) 2 (C 4 H 2 O)} 2 ] (5). Treatment of 3 with EPh 3 (E = P, As, Sb) at room temperature yields the monosubstituted derivatives [Ru 2 (CO) 5 (l-g 1 ,g 2 -C 4 H 3 O){l-P(C 4 H 3 O) 2 }(EPh 3 )] (E = P, 8; E = As, 9; E = Sb, 10). Similar reactions of 3 with P(C 4 H 3 O) 3 , P(OMe) 3 and Bu t NC yield 4, [Ru 2 (CO) 5 (l-g 1 ,g 2 -C 4 H 3 O){l-P(C 4 H 3 O) 2 }{P(OMe) 3 }] (11) and [Ru 2 (CO) 5 (l-g 1 ,g 2 -C 4 H 3 O){l-P(C 4 H 3 O) 2 }(NCBu t )] (12), respectively. The molecular structures of complexes 3, 4 and 8 have been elucidated by single crystal X-ray diffraction studies. Each complex contains a bridging r,p-alkenyl group and while in 4 the phosphine is bound to the r-coordinated metal atom, in 8 it is at the p-bound atom. Protonation of 3 and 4 gives the hydride complexes [(l-H)Ru 2 (CO) 6 (l-g 1 ,g 2 -C 4 H 3 O){l-P(C 4 H 3 O) 2 }] + (6) and [(l-H)Ru 2 (CO) 5 (l-g 1 ,g 2 -C 4 H 3 O){l-P(C 4 H 3 O) 2 }{P(C 4 H 3 O) 3 }] + (7), respectively, while heating 3 with dimethylacetylenedicarboxylate (DMAD) in refluxing toluene gives the cyclotrimerization product, C 6 (CO 2 Me) 6 .
Organometallics, 2002
The reactions of the allenylidene complexes [Cp*Ru{dCdCdC(R)Ph}(dippe)][BPh 4 ] (R) H (1), Ph (2)) with different substrates have been studied, providing a new form of allenylidene-ruthenium reactivity. The observed reactivity pattern depends strongly on the substituents on the γ-carbon. The secondary allenylidene 1 undergoes addition of weakly nucleophilic reagents such as pyrazole, 3,5-dimethylpyrazole, or thiophenol to the CC γ double bond, yielding substituted vinylidene compounds [Cp*Ru{dCdCHCH(L)Ph}(dippe)]-[BPh 4 ] (L) pyrazolyl (3), 3,5-dimethylpyrazolyl (4), phenylsulfanyl (5)). The reaction of 1 with pyrrole or 2-methylfuran to afford analogous complexes [Cp*Ru{dCdCH-CH(L)Ph}-(dippe)][BF 4 ] (L) 2-pyrrolyl (6), 5-methyl-2-furanyl (7)) takes place only in the presence of acid. This suggests that an initial protonation at the-carbon of the allenylidene occurs, enhancing the electrophilic character of the γ-carbon atom. This mechanism involves the formation of dicationic carbyne ruthenium complexes [Cp*Ru{tC-CHdC(R)Ph}(dippe)] 2+ (R) H (8), Ph (9)), which have been isolated and characterized as [B(Ar F) 4 ] (Ar F) 3,5-(CF 3) 2 C 6 H 3) salts, by protonation of the cationic allenylidenes with [H(Et 2 O) 2 ][B(Ar F) 4 ]. The X-ray crystal structure of the carbyne compound 9 is reported. A series of neutral functionalized alkynyl compounds [Cp*Ru{CtCCR(L)Ph}(dippe)] (L) CH 3 COCH 2 , R) H (10), R) Ph (11); L) pyrazolyl, R) H (12); R) Ph (13)) have also been synthesized by regioselective addition of anionic nucleophiles such as potassium acetonate or potassium pyrazolate. The structures of 11 and 13 in the solid state have been determined by X-ray diffraction analysis. Protonation of 10 and 11 with HBF 4 ‚Et 2 O yields the vinylidene compounds [Cp*Ru{dCdCH-CR(CH 2 COCH 3)Ph}(dippe)][BF 4 ] (R) H (14), Ph (15)).
Journal of the American Chemical Society, 2005
All manipulations were carried out under an atmosphere of dry oxygen-free nitrogen using standard Schlenk techniques. Solvents were distilled from the appropriate drying agents and degassed before use. Elemental microanalyses were performed with a Perkin-Elmer 2400 CHN microanalyzer. IR spectra were recorded as Nujol mulls on a Perkin-Elmer PE 883 IR spectrometer. 1 H, 13 C{ 1 H} and 31 P{ 1 H} NMR spectra were recorded on a Varian Unity 300 or on a Varian Unity Innova 500 spectrometer. Chemical shifts (ppm) are relative to TMS (1 H, 13 C NMR) or 85% H 3 PO 4 (31 P NMR) (s = singlet, bs = broad singlet, d = doublet, t = triplet, m = multiplet). Unless specified otherwise, the 13 C resonances are singlets. COSY spectra: standard pulse sequence, acquisition time 0.214 s, pulse width 10 µs, relaxation delay 1 s, 16 scans, 512 increments. The nOe difference spectra were recorded with 5000 Hz, acquisition time 3.27 s, pulse width 90°, relaxation delay 4 s, and irradiation power 5-10 dB. For the variable temperature spectra the temperature of the probe (±1 K) was controlled by a standard unit calibrated with a methanol reference. T 1 values were obtained on the basis of the inversion recovery method. [Cp*RuCl 2 ] n 1 and the ligand PPh 2 py 2 were prepared according to literature methods. HBF 4 .Et 2 O was used as supplied from Aldrich. Synthesis of compounds Synthesis of [Cp*Ru(κ κ κ κ 2-P,N-PPh 2 py)(PPh 2 py)]Cl (1) Over a suspension of [Cp*RuCl 2 ] n (0.125 g, 0.41 mmol) in 20 mL of CH 2 Cl 2 PPh 2 py was added (0.216 g, 0.82 mmol) and an excess of Zn powder (0.134 g, 2,05 mmol). This mixture was stirred at room temperature for 6 hours. The resulting brown dark solution was filtered
Journal of Organometallic Chemistry, 2014
The reactivity of thiophene (T), 2-methylthiophene (2-MeT), and benzothiophene (BT) with [Ir(cod)-(IPr)(L)]BF 4 complexes (L = acetone (1), pyridine (2) or dimethylphenylphosphine (3); IPr = 1,3-bis(2,6diisopropylphenyl)imidazol-2-ylidene) in the presence of molecular hydrogen has been investigated. Under these conditions the 1,5-cyclooctadiene ligand is hydrogenated to cyclooctane, which renders an unsaturated species (Ir-IPr-L) able to coordinate the thiophene moiety. The coordination mode of T, 2-MeT, and BT depends on the nature of the substrate and the ligand trans to the IPr (L). The reaction of 1 with T and 2-MeT leads to dissociation of the acetone ligand to afford the complexes [Ir(H) 2 (IPr)(η 5-T)]BF 4 (4) and [Ir(H) 2 (IPr)(η 2-2-MeT)(κS-2-MeT)]BF 4 (5), respectively, but no stable complex is observed on reaction with BT. Analogously to 1, complex 2 does not give a stable complex on reaction with BT, while reaction with 2-MeT yields complex 5 again. Conversely, reaction with T affords a mixture of complexes, [Ir(H) 2 (IPr)(η 2-T)(Py)]BF 4 (6) and [Ir(H) 2 (IPr)(κS-T) 2 (Py)]BF 4 (6′), both featuring a coordinated pyridine ligand. The reaction of 3 with T, 2-MeT, and BT yields in all cases κS complexes, namely [Ir(H) 2 (IPr)(κS-T) 2 (PPhMe 2)]BF 4 (7), [Ir(H) 2 (IPr)(κS-2-MeT) 2 (PPhMe 2)]BF 4 (8) in equilibrium with [Ir(H) 2 (IPr)(κS-2-MeT)(PPhMe 2)]-BF 4 (8′), and [Ir(H) 2 (IPr)(κS-BT) 2 (PPhMe 2)]BF 4 (9). Finally, DFT calculations were employed to rationalize the coordination modes of T, 2-MeT, and BT, as well as the tendency of these complexes to undergo hydrogenation instead of hydrogenolysis of the thiophene moiety under catalytic conditions.
…, 2002
The novel P-coordinated diphenyl(phenylethynyl)phosphine complexes [Cp*MCl 2 (PPh 2 Ct CPh)] [M) Rh 1, Ir 2] have been prepared by the bridge splitting of [Cp*MCl 2 ] 2 with PPh 2 Ct CPh. Treatment of 1 and 2 with AgTfO and PPh 2 CtCPh affords the corresponding cationic compounds [Cp*MCl(PPh 2 CtCPh) 2 ](OTf) [M) Rh 3, Ir 4, OTf) triflate], respectively. The analogous neutral Ru(II) derivative [Cp*RuCl(PPh 2 CtCPh) 2 ] 5 has been obtained by reaction of PPh 2 CtCPh and the binuclear complex [Cp*RuCl 2 ] 2 in the presence of Zn as the reductor. The molecular structures of 1 and 3-5 have been determined by single-crystal X-ray diffraction. The alkynyl fragments in cations 3 and 4 and in the neutral ruthenium derivative 5 are eclipsed, but the C R ‚‚‚C R interligand distances are longer than the minimal separation necessary (3.2-3.4 Å) to promote alkynyl coupling. The reactivity of these mono (1, 2) and bis[diphenyl(phenylethynyl)phosphine] (3-5) complexes toward [cis-Pt(C 6 F 5) 2 (THF) 2 ] has been explored. Treatment of 1 with 1 equiv of [cis-Pt(C 6 F 5) 2 (THF) 2 ] in CH 2 Cl 2 affords the doubly chloride bridged [(PPh 2 CtCPh)Cp*Rh(µ-Cl) 2 Pt(C 6 F 5) 2 ] 6. In contrast, the analogous iridium derivative [Cp*IrCl 2 (PPh 2 CtCPh)] 2 reacts with [cis-Pt(C 6 F 5) 2 (THF) 2 ], leading to a mixture of isomers [(PPh 2 CtCPh)Cp*Ir(µ-Cl) 2 Pt(C 6 F 5) 2 ] 7a and [Cp*ClIr(µ-Cl)(µ-κP:η 2-PPh 2 CtCPh)Pt(C 6 F 5) 2 ] 7b (7a/7b ≈ 2.5:1). Similar cationic [(PPh 2 CtCPh)Cp*M(µ-Cl)(µ-κP:η 2-PPh 2 CtCPh)Pt(C 6 F 5) 2 ](OTf) [M) Rh 8, Ir 9] and neutral [(PPh 2 CtCPh)Cp*Ru(µ-Cl)(µ-κP:η 2-PPh 2 CtCPh)Pt(C 6 F 5) 2 ] 10 hetero-bridged complexes are formed by treatment of the bis[diphenyl(phenylethynyl)]phosphine (3-5) complexes with [cis-Pt(C 6 F 5) 2 (THF) 2 ] in CH 2 Cl 2. The structure of 10 has been confirmed by a single-crystal X-ray diffraction analysis.