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Tetravalent cerium alkoxide complexes supported by the Klaui tripodal ligand [Co(η5-C5H5){P(O)(OEt)2}3]- (LOEt-) have been synthesized, and their nucleophilic and redox reactivity have been studied. Treatment of the Ce(IV) oxo complex [CeIV(LOEt)2(O)(H2O)]·MeCONH2 (1) with iPrOH or reaction of [CeIV(LOEt)2Cl2] (2) with Ag2O in iPrOH afforded the Ce(IV) dialkoxide complex [CeIV(LOEt)2(OiPr)2] (3-iPr). The methoxide and ethoxide analogues [CeIV(LOEt)2(OR)2] (R = Me (3-Me), Et (3-Et)) have been prepared similarly from 2 and Ag2O in ROH. Reaction of 3-iPr with an equimolar amount of 2 yielded a new Ce(IV) complex that was formulated as the chloro-alkoxide complex [CeIV(LOEt)2(OiPr)Cl] (4). Treatment of 3-iPr with HX and methyl triflate (MeOTf) afforded [Ce(LOEt)2X2] (X- = Cl-, NO3-, PhO-) and [CeIV(LOEt)2(OTf)2], respectively, whereas treatment with excess CO2 in hexane led to isolation of the Ce(IV) carbonate [CeIV(LOEt)2(CO3)]. 3-iPr reacted with water in hexane to give a Ce(III) complex and a Ce(IV) species, presumably the reported tetranuclear oxo cluster [CeIV4(LOEt)4(O)5(OH)2]. The Ce(IV) alkoxide complexes are capable of oxidizing substituted phenols, possibly via a proton-coupled electron transfer pathway. Treatment of 3-iPr with ArOH afforded the Ce(III) aryloxide complexes [CeIII(LOEt)2(OAr)] (Ar = 2,4,6-tri-tert-butylphenyl (5), 2,6-diphenylphenyl (6)). On the other hand, a Ce(III) complex containing a monodeprotonated 2,2'-biphenol ligand, [CeIII(LOEt)2(tBu4C12H4O2H)] (7) (tBu4C12H4O2H2 = 4,4',6,6'-tetra-tert-butyl-2,2'-biphenol), was isolated from the reaction of 3-iPr with 2,4-di-tert-butylphenol. The crystal structures of complexes 3-iPr, 3-Me, 3-Et, and 5-7 have been determined.

Treatment of [Ru 3 (CO) 12 ] with 2,5-di(2-pyridyl)pyrrole (HL1) and 2,5-di(2-(5-bromopyridyl)pyrrole (HL2) in refluxing toluene afforded the dinuclear Ru(I) carbonyl complexes [Ru 2 (CO) 4 (L)] (L = L1 ( 1 ), L2 ( 3 ), respectively). Alternatively, 1 along with a minor mononuclear product [Ru(CO) 2 (L1) 2 ] ( 2 ) was synthesized from reaction of [Ru(CO) 2 Cl 2 ] n with HL1 in methanol in the presence of triethylamine. Complexes 1 – 3 have been fully characterized by NMR, IR, UV–vis, ESI-MS, and elementary analysis. Single-crystal X-ray diffraction indicates that both 1 and 3 feature a Ru–Ru single bond and the di(pyridyl)pyrrolide ligands bind to the two Ru(I) centers in a μ-κ 2 N,N’ :κ 1 N” chelating-bridging mode. Complex 2 is mononuclear Ru(II) complex with two κ 2 N , N ’ di(pyridyl)pyrrolide ligand. The spectroscopic and electrochemical properties of 1 and 3 were also explored.

In an effort to synthesize cyclometalated iridium complexes containing a tridentate C^N^C ligand, transmetallation of [Hg(HC^N^C)Cl] (1) (H2C^N^C = 2,6-bis(4-tert-butylphenyl)pyridine) with various organoiridium starting materials has been studied. The treatment of 1 with [Ir(cod)Cl]2 (cod = 1,5-cyclooctadiene) in acetonitrile at room temperature afforded a hexanuclear Ir4Hg2 complex, [Cl(κ2C,N-HC^N^C)(cod)IrHgIr(cod)Cl2]2 (2), which features Ir–Hg–Ir and Ir–Cl–Ir bridges. Refluxing 2 with sodium acetate in tetrahydrofuran (thf) resulted in cyclometalation of the bidentate HC^N^C ligand and formation of trinuclear [(C^N^C)(cod)IrHgIr(cod)Cl2] (3). On the other hand, refluxing [Ir(cod)Cl]2 with 1 and sodium acetate in thf yielded [Ir(C^N^C)(cod)(HgCl)] (4). Chlorination of 4 with PhICl2 gave [Ir(C^N^C)(cod)Cl]·HgCl2 (5·HgCl2) that reacted with tricyclohexylphosphine to yield Hg-free [Ir(C^N^C)(cod)Cl] (5). Chloride abstraction of 5 with silver(I) triflate (AgOTf) gave [Ir(C^N^C)(cod)(H2O)](OTf) (6) that can catalyze the cyclopropanation of styrene with ethyl diazoacetate. Reaction of 1 and [Ir(CO)2Cl(py)] (py = pyridine) with sodium acetate in refluxing thf afforded [Ir(C^N^C)(HgCl)(py)(CO)] (7), in which the carbonyl ligand is coplanar with the C^N^C ligand. On the other hand, refluxing 1 with (PPh4)[Ir(CO)2Cl2] and sodium acetate in acetonitrile gave [Ir(C^N^C)(κ2C,N-HC^N^C)(CO)] (8), the carbonyl ligand of which is trans to the pyridyl ring of the bidentate HC^N^C ligand. Upon irradiation with UV light 8 in thf was isomerized to 8′, in which the carbonyl is trans to a phenyl group of the bidentate HC^N^C ligand. The isomer pair 8 and 8′ exhibited emission at 548 and 514 nm in EtOH/MeOH at 77 K with lifetime of 84.0 and 64.6 μs, respectively. Protonation of 8 with p-toluenesulfonic acid (TsOH) afforded the bis(bidentate) tosylate complex [Ir(κ2C,N-HC^N^C)2(CO)(OTs)] (9) that could be reconverted to 8 upon treatment with sodium acetate. The electrochemistry of the Ir(C^N^C) complexes has been studied using cyclic voltammetry. Reaction of [Ir(PPh3)3Cl] with 1 and sodium acetate in refluxing thf led to isolation of the previously reported compound [Ir(κ2P,C-C6H4PPh2)2(PPh3)Cl] (10). The crystal structures of 2–5, 8, 8′, 9 and 10 have been determined.

In an attempt to synthesize heterometallic cerium nitrido complexes, we studied the reactions of cerium complexes supported by the Klaui tripodal ligand [Co(η5-C5H5){PO(OEt)2}3]- (LOEt-) with transition-metal nitrides. Whereas no reactions were found between Ce-LOEt complexes and [RuVI(LOEt)(N)Cl2] (2), treatment of the Ce(iv) oxo complex [CeIV(LOEt)2(O)(H2O)]·MeCONH2 (1) with 2 resulted in reduction of both the Ce(iv) and Ru(vi) complexes, and formation of a heterometallic Ce(iii)/Ru(iii) complex with a bridging deprotonated acetamide ligand, [(LOEt)2(H2O)CeIII{μ-O,N-MeC(O)NH}RuIII(LOEt)Cl2] (4), along with a minor product, [CeIII(LOEt)2(NO3)]. Ce(iv)-LOEt complexes such as [CeIV(LOEt)2Cl2] (3) can oxidize [ReV(LOEt)(N)(PPh3)Cl] to give the Re(vi) nitride [ReVI(LOEt)(N)(PPh3)Cl]+. Chloride abstraction of 3 by TlPF6 followed by reaction with [PPh4]2[MnV(N)(CN)4] afforded a diamagnetic red solid that is tentatively formulated as a heterometallic Ce(iv)/Mn(v) complex, [Ce(LOEt)2(H2O){Mn(N)(CN)4}] (5). Reactions of 3 with [nBu4N][MVI(N)(cat)2] (cat2- = catecholate(2-)) afforded the Ce(iii)/M(vi) complexes [(LOEt)2CeIII{(μ-cat)2MVI(N)}] [M = Ru (6), Os (7)], in which the Ce(iii) and M(vi) centers are bridged by two oxygen atoms of the two catecholate ligands. Similarly, the catecholate-bridged Ce(iii)/Re(v) complex [(LOEt)2CeIII{(μ-cat)2ReV(O)}] (8) was prepared from 3 and [Me4N][ReV(O)(cat)2]. In CH2Cl2, 8 was air-oxidized to the Ce(iii)/Re(vii) complex [CeIII(LOEt)2(H2O)2][cis-{ReVII(O)2(cat)2}] (9) with a cis-dioxo-Re(vii) counter-anion. The crystal structures of 4, 6, and 9 have been determined.

Iridium porphyrin complexes containing μ-nitrido, hydroxo, hydrosulfido, and alkynyl ligands have been synthesized and structurally characterized, and their oxidation has been studied. The alkyl-IrIII porphyrin complex [Ir(tpp)R] (tpp2- = 5,10,15,20-tetraphenylporphyrin dianion; R = C8H13; 1) was synthesized by reaction of [Ir(cod)Cl]2 (cod = 1,5-cyclooctadiene) with H2tpp in refluxing monoethylene glycol. Treatment of 1 with PPh3 and [(LOEt)Ru(N)Cl2] (LOEt- = [(η5-C5H5)Co{P(O)(OEt)2}3]-) gave [Ir(tpp)(R)(PPh3)] (2) and the μ-nitrido complex [R(tpp)Ir(μ-N)RuCl2(LOEt)] (3), respectively. The cyclic voltammogram of 3 exhibited a reversible oxidation couple at 0.44 V versus Fc+/0 (Fc = ferrocene). The oxidation of 3 with [(4-BrC6H4)3N](SbCl6) resulted in Ir-C bond homolysis and formation of the chloride complex [Cl(tpp)Ir(μ-N)RuCl2(LOEt)] (4). The short Ir-N(nitrido) bond distances in 3 [1.944(3) A] and 4 [1.831(4) A] are indicative of multiple bond character and thus these two μ-nitrido complexes can be described by the two resonance forms: IrIII-N[triple bond, length as m-dash]RuVI and IrV[double bond, length as m-dash]N[double bond, length as m-dash]RuIV. Similarly, the oxidation of 2 with [(4-BrC6H4)3N](SbCl6) yielded [Ir(tpp)Cl(PPh3)] (5). Chloride abstraction of 5 with TlPF6 in tetrahydrofuran (thf) afforded [Ir(tpp)(PPh3)(thf)](PF6) (6) that reacted with CsOH·H2O and Li2S to give the hydroxo [Ir(tpp)(OH)(PPh3)] (7) and hydrosulfido [Ir(tpp)(PPh3)(SH)] (8) complexes, respectively. Treatment of 6 with phenylacetylene in the presence of CuI and Et3N yielded the bimetallic complex [Ir(tpp)(PPh3)(μ-η1:η2-C[triple bond, length as m-dash]CPh)(CuI)] (9), whereas the transmetallation of 6 with LiC[triple bond, length as m-dash]CPh afforded the mononuclear alkynyl complex [Ir(tpp)(PPh3)(C[triple bond, length as m-dash]CPh)] (10). The electrochemistry of the Ir porphyrin complexes has been studied using cyclic voltammetry. On the basis of the measured redox potentials of [Ir(tpp)(PPh3)X], the ability of X- to stabilize the IrIV state is ranked in the order: R- > PhC[triple bond, length as m-dash]C- > Cl- ∼ OH-. Oxidation of 8 and 9 with [(4-BrC6H4)3N](SbCl6) led to isolation of 5 and [Ir(tpp)(PPh3)(H2O)]+, respectively. The crystal structures of complexes 3, 4, and 7-10 have been determined.

The 4-coordinated RuII chalcogenolate complexes [Ru(STipp)2(PPh3)2] (Tipp = 2,4,6-triisopropylphenyl, 1) and [Ru(SeMes)2(PPh3)2] (Mes = 2,4,6-trimethylphenyl, 2) have been synthesized, and their reactions with PhICl2 and organic azides have been studied. Complex 2 synthesized from [RuII(PPh3)3Cl2] and NaSeMes displays a seesaw structure with P–Ru–P and Se–Ru–Se bond angles of 103.43(13) and 145.26(6)°, respectively. Natural bond order analyses revealed that in each of 1 and 2, there are two n → σ* (donor–acceptor) π interactions between the chalcogen lone pairs and the Ru–P antibonding molecular orbitals. The calculated second-order perturbation interaction energies of the two interactions for 1 (20.5 and 18.3 kcal mol−1) are stronger than those of 2 (13.6 and 11.0 kcal mol−1), suggesting the thiolate ligand (TippS−) is a stronger π-donor than the selenolate ligand (MesSe−) with respect to RuII. Chlorination of 1 with PhICl2 afforded the dichloride complex [Ru(STipp)2Cl2(PPh3)] (3), which was hydrolyzed to the hydroxo complex [Ru(STipp)2(OH)Cl(PPh3)] (4) after column chromatography on silica in air. Treatment of 4 with HCl and methyl triflate gave 3 and [Ru(STipp)2(OH)(OTf)(PPh3)] (OTf = triflate, 5), respectively. Reactions of 1 and 2 with p-tolyl azide (p-tolN3) afforded the tetrazene complexes [Ru{N4(p-tol)2}(ER)2(PPh3)] (ER = STipp (6), SeMes (7)), whereas that with tosyl azide (TsN3) gave the imido complexes [Ru(κ2-NTs)(STipp)2(PPh3)] (ER = STipp (8), SeMes (10)). The short Ru–Nimido distances in 8 [1.883(3) A] and 10 [1.892(2) A] are indicative of multiple bond character. Treatment of 8 with TsN3 afforded the tetrazene complex [Ru(N4Ts2)(STipp)2(PPh3)] (9), but no cycloaddition was found between 10 and TsN3. Nucleophilic attack of the imido ligand in 10 with methyl triflate yielded the amido complex [Ru(κ2-NMeTs)(SeMes)2(PPh3)](OTf) (11). The crystal structures of 2, 4, 6, and 8–11 have been determined.

Tetravalent cerium alkoxide complexes supported by the Kläui tripodal ligand [Co(η

Dinuclear iron nitrido phthalocyanine complexes are of interest owing to their applications in catalytic oxidation of hydrocarbons. While nitrido-bridged diiron phthalocyanine complexes are well documented, the oxidation chemistry of heterodinuclear iron(IV) phthalocyanine nitrides has not been well explored. In this paper we report on the synthesis of a heterometallic FeIV/RuIV phthalocyanine nitride and its oxidation to yield phthalocyanine cation radical and hydroxyphthalocyanine complexes. Treatment of [FeII(Pc)] (Pc2– = phthalocyanine dianion) with [RuVI(LOEt)(N)Cl2] (LOEt– = [Co(η5-C5H5){P(O)(OEt)2}3]−) (1) afforded the heterometallic μ-nitrido complex [Cl2(LOEt)RuIV(μ-N)FeIV(Pc)(H2O)] (2) that contains an RuIV=N = FeIV linkage with the Ru–N and Fe–N distances of 1.689(6) and 1.677(6) A, respectively, and Ru–N–Fe angle of 176.0(4)°. Substitution of 2 with 4-tert-butylpyridine (Bupy) gave [Cl2(LOEt)RuIV(μ-N)FeIV(Pc)(Bupy)]. The cyclic voltammogram of 2 displayed a reversible Pc-centered oxidation cou...

Treatment of Mn(OAc)2·4H2O with 3 equiv. HN(iPr2PO)2 in the presence of nBu4NCl in acetonitrile resulted in isolation of a tetranuclear {Mn3IIIMnIV} complex [Mn4(μ3-O)3(μ3-Cl)(μ-OAc)3{N(iPr2PO)2}3]·0.5C6H14 (1·0.5C6H14), and a dinuclear {MnIIMnIII} complex [Mn2{N(iPr2PO)2}{μ2,η3-(iPrPO2)NH(iPr2PO)}2{η2-(iPrPO2)NH(iPr2PO)}2]·0.25AcOH (2·0.25AcOH) with bis(diisopropylphosphinyl)imide ligands. The solid-state structures of two complexes have been established by single-crystal X-ray crystallography. The tetranuclear complex 1 belongs to a family of {Mn3IIIMnIVO3X} single-molecule magnets (SMMs) with effective energy barrier of 14.3 K by some further magnetic characterizations. A [Mn3IIIMnIVO3Cl]-core-based [Mn4(μ3-O)3(μ3-Cl)(OAc)3{N(iPr2PO)2}3] complex with single-molecule magnet (SMM) behaviour was prepared and structurally characterized, exhibiting slow magnetization relaxation under zero applied dc field with τ0 = 9.0 × 10−7 s and relaxation barrier Ueff = 14.3 K.

Tetranuclear Ru μ-nitrido complexes have been synthesized by reactions of Ru(II) cyclopentadienyl and pentamethylcyclopentadienyl complexes with Ru(VI) terminal nitrides. Treatment of [RuCp2] (Cp = η5-C5H5) with [LOEtRuVI(N)Cl2] (LOEt– = [CpCo{P(O)(OEt)2}3]−) (1) afforded a tetranuclear RuIV2-RuIII2 μ-nitrido complex, [CpRu{(μ-N)RuCl2LOEt}{(μ-Cl)RuClLOEt}{(μ-NC5H4NH)RuCl2LOEt}] (2), that contains a bridging monodeprotonated cyclopent-4-ene-1,3-diimine ligand. The formation of 2 possibly involves the migratory insertion of the Ru nitride with a Ru-η1-C5H5 intermediate derived from the η5–η1 ring slippage of [RuCp2] and subsequent C–H activation of the cyclopentadienylimido ligand by another molecule of 1. Treatment of [Cp*Ru(MeCN)3](PF6) (Cp* = η5-C5Me5) with [LOEtM(N)Cl2] afforded [{Cp*Ru(μ-N)M(LOEt)}2(μ-Cl)4](PF6)2 (M = Ru (3), Os (4)). Treatment of [Cp*Ru(MeCN)3](PF6) with mer-[Ru(N)Cl3(AsPh3)2] yielded [{Cp*Ru(μ-N)RuCl(AsPh3)}2(μ-Cl)4(μ-O2PF2)](PF6) (5), which contains a bridging difluorophosphate liga...

Despite widespread applications of tetravalent cerium compounds in organic synthesis and catalysis, the coordination and organometallic chemistry of cerium(IV) complexes has not been well explored, due, in part, to the high oxidizing power of Ce(IV). Using chelating O-donor supporting ligands, stable tetravalent cerium complexes bearing various ligand functionalities have been isolated, thus making it possible to investigate the reaction chemistry of cerium(IV) complexes systematically. This review summarizes the recent developments of the coordination chemistry of cerium(IV) complexes bearing O-, N-, and C-donor ligands. Special attention will be directed to cerium(IV) complexes supported by a tripodal oxygen ligand.

Heterobimetallic nitrido porphyrin complexes with the [(L)(por)M–N–M′(LOEt)Cl2] formula {por2– = 5,10,15,20-tetraphenylporphyrin (TPP2–) or 5,10,15,20-tetra(p-tolyl)porphyrin (TTP2–) dianion; LOEt– = [Co(η5-C5H5){P(O)(OEt)2}3]−; M = Fe, Ru, or Os; M′ = Ru or Os; L = H2O or pyridine} have been synthesized, and their electrochemistry has been studied. Treatment of trans-[Fe(TPP)(py)2] (py = pyridine) with Ru(VI) nitride [Ru(LOEt)(N)Cl2] (1) afforded Fe/Ru μ-nitrido complex [(py)(TPP)Fe(μ-N)Ru(LOEt)Cl2] (2). Similarly, Fe/Os analogue [(py)(TPP)Fe(μ-N)Os(LOEt)Cl2] (3) was obtained from trans-[Fe(TPP)(py)2] and [Os(LOEt)(N)Cl2]. However, no reaction was found between trans-[Fe(TPP)(py)2] and [Re(LOEt)(N)Cl(PPh3)]. Treatment of trans-[M(TPP)(CO)(EtOH)] with 1 afforded μ-nitrido complexes [(H2O)(TPP)M(μ-N)Ru(LOEt)Cl2] [M = Ru (4a) or Os (5)]. TTP analogue [(H2O)(TTP)Ru(μ-N)Ru(LOEt)Cl2] (4b) was prepared similarly from trans-[Ru(TTP)(CO)(EtOH)] and 1. Reaction of [(H2O)(por)M(μ-N)M(LOEt)Cl2] with pyridine gave ad...

The 4-coordinated Ru

International audience; A combined experimental and theoretical investigation on the cerium(IV) oxo complex [(L-OEt)(2)Ce(=O)(H2O)].MeC(O)NH2 (1; L-OEt(-)=[Co(eta(5)-C5H5){P(O)(OEt)(2)}(3)](-)) demonstrates that the intermediate spin-state nature of the ground state of the cerium complex is responsible for the versatility of its reactivity towards small molecules such as CO, CO2, SO2, and NO. CASSCF calculations together with magnetic susceptibility measurements indicate that the ground state of the cerium complex is of multiconfigurational character and comprised of 74 % of Ce-IV and 26 % of Ce-III. The latter is found to be responsible for its reductive addition behavior towards CO, SO2, and NO. This is the first report to date on the influence of the multiconfigurational ground state on the reactivity of a metal-oxo complex.

Treatment of Ru(NO)Cl3 with NaSC6F4H (C6F4HSH = 2,3,5,6-tetrafluorothiophenol) afforded the hydroxo-bridged dimer Na(H2O)2[Ru(NO)(SC6HF4)2]2(μ-SC6HF4)2(μ-OH) (Na(H2O)21), in which the {Na(H2O)2}+ moiety binds to the diruthenium core via the μ-hydroxo ligand and three ortho fluorine atoms of the thiolate ligands. Metathesis of Na(H2O)21 with Bun4NBr and Ph4PCl afforded Na-free (Bun4N)[1] and (Ph4P)[1], respectively. Treatment of Ru(NO)Cl3 with NaSBut afforded the trinuclear oxo-sulfido cluster Na(H2O)2[Ru(NO)(SBut)(μ-SBut)]3(μ3-S)(μ3-O) (Na(H2O)22) that contains a trinuclear {Ru3(SBut)3} core capped by a μ3-oxo and a μ3-sulfido ligand. The {Na(H2O)2}+ moiety binds to the triruthenium core via the μ3-oxo and two terminal thiolate ligands. Metathesis of Na(H2O)22 with Bun4NBr gave (Bun4N)[2]. Treatment of Ru(NO)Cl3 with NaStipp (tipp = 2,4,6-triisopropylphenyl) gave mononuclear Ru(NO)(Stipp)3(tippSH) (3). The crystal structures of Na(H2O)21, (Ph4P)[1], and Na(H2O)22 have been determined.

Cerium(IV) pseudohalide complexes supported by the Klaui tripodal ligand [Co(η5-C5H5){P(O)(OEt)2}3]− (LOEt−) have been synthesized and structurally characterized. The treatment of [CeIV(LOEt)2Cl2] (1) with 2 equivalents of [AgX] in acetonitrile afforded [CeIV(LOEt)2X2] [X− = NCS− (2), N3− (3), F− (4)]. The reaction of 1 with [AgCN] in dichloromethane at −40 °C led to formation of a bimetallic CeIV/AgI cyanide complex that decomposed in solution at room temperature. In the presence of BPh3, 1 reacted with [AgCN] to yield the cyanoborate complex [CeIV(LOEt)2(NCBPh3)2] (6) that is stable in solution. The chlorination of [CeIII(LOEt)2(NO3)] with PhICl2 afforded [CeIV(LOEt)2(NO3)Cl] (7) that reacted with [AgCN] to yield the heterometallic CeIV/AgI cyanide complex [{Ce(LOEt)2(NO3)}2{μ-Ag(CN)2}][AgCl2] (8). The reaction of [CeIV(LOEt)Cl3] with [AgN3] afforded the tetranuclear CeIV oxo azido cluster [Ce4(LOEt)4(μ4-O)(μ2-O)2(μ2-N3)6] (9). The structures of complexes 2, 3, 6 and 9 have been established by X-ray crystallography.

Reactions of [Ce(IV)(LOEt)2Cl2] (LOEt(-) = [Co(η(5)-C5H5){P(O)(OEt)2}3](-)) and [Ce(μ-O){N(Pr(i)2PO)2}4Cl2] with PhIO afford the λ3-iodane complexes [Ce(IV)(LOEt)2{OI(Cl)Ph}2] and [Ce{N(Pr(i)2PO)2}3{OI(Cl)Ph}], respectively, whereas that between [Ce(IV)(LOEt)2Cl2] and PhIO2 or excess PhIO yields the λ5-iodane adduct [Ce(IV)(LOEt)2{OI(O)ClPh}2]. The crystal structures of the Ce(IV)λ3- and λ5-iodane complexes have been determined and their oxo transfer reactivities have been investigated.

Heterometallic Ce(IV)/M (M = Mo(VI), Re(VII), V(V)) oxo clusters supported by the Kläui tripodal oxygen ligand [(η(5)-C5H5)Co{P(O)(OEt)2}3](-) (LOEt(-)) have been synthesized and structurally characterized, and the catalytic activity of the Ce(IV)/V(V) oxo cluster in the oxidation of thioanisoles has been studied. Treatment of [Ce(LOEt)Cl3] (1) with [Ag2MoO4] afforded the reported Ce(IV)/Mo(VI) cluster [H4(CeLOEt)6Mo9O38] (2), whereas that with [AgReO4] yielded the Ce(IV)/Re(VII) cluster [{LOEtCe(ReO4)2(H2O)(μ-ReO4)}2] (3) that contains an 8-membered Ce2Re2O4 ring. Treatment of 1 with [Ag3VO4] afforded the Ce(IV)/V(V) cluster [H2(CeLOEt)4(V[double bond, length as m-dash]O)4(μ4-O)(μ3-O)12] (4) containing a {Ce4V4O13} oxo-metallic core. The solid-state structure of 4 consists of four {VO4}(3-) units bridged by four {LOEtCe(3+)} moieties and a μ4-oxo ligand. Each Ce atom in 4 is 9-coordinated, whereas the geometry around each V atom is pseudo square pyramidal with a terminal oxo at the apical position. Cluster 4 is an active catalyst for the oxidation of substituted thioanisoles with tert-butyl hydroperoxide. For example, the oxidation of thioanisole with tert-butyl hydroperoxide in the presence of 0.01 mol% of 4 gave a ca. 30 : 1 mixture of the sulfoxide and sulfone products in 96% yield.

A tetranuclear Ce(IV) oxo cluster compound containing the Klaui tripodal ligand [Co(η(5) -C5 H5 ){P(O)(OEt)2 }3 ](-) (LOEt (-) ) has been synthesized and its reactions with H2 O2 , CO2 , NO, and Bronsted acids have been studied. The treatment of [Ce(LOEt )(NO3 )3 ] with Et4 NOH in acetonitrile afforded the tetranuclear Ce(IV) oxo cluster [Ce4 (LOEt )4 O7 H2 ] (1) containing an adamantane-like {Ce4 (μ2 -O)6 } core with a μ4 -oxo ligand at the center. The reaction of 1 with H2 O2 resulted in the formation of the peroxo cluster [Ce4 (LOEt )4 (μ4 -O)(μ2 -O2 )4 (μ2 -OH)2 ] (2). The treatment of 1 with CO2 and NO led to isolation of [Ce(LOEt )2 (CO3 )] and [Ce(LOEt )(NO3 )3 ], respectively. The protonation of 1 with HCl, ROH (R=2,4,6-trichlorophenyl), and Ph3 SiOH yielded [Ce(LOEt )Cl3 ] (3), [Ce(LOEt )(OR)3 ] (4), and [Ce(LOEt )(OSiPh3 )3 ] (5), respectively. The chloride ligands in 3 are labile and can be abstracted by silver(I) salts. The treatment of 3 with AgOTs (OTs(-) =tosylate) and Ag2 O afforded [Ce(LOEt )(OTs)3 ] (6) and 1, respectively. The electrochemistry of the Ce-LOEt complexes has been studied by using cyclic voltammetry. The crystal structures of complexes 1-5 have been determined.

Treatment of [(LOEt)2CeCl2] (LOEt− = [(η5-C5H5)Co{P(O)(OEt)2}3]-) (1) with NaIO4 in water afforded a Ce(IV) periodate complex, 2. Recrystallization of 2 from Et2O afforded orange single crystals that were found to consist of two independent molecules: [(LOEt)2Ce(IO4)2] (2a) and [(LOEt)2Ce(IO4)(H2O)][IO4] (2b). Similarly, treatment of 1 with K2S2O8 in water afforded the Ce(IV) persulfate complex [(LOEt)2Ce(η2-S2O8)] (3). Reaction of [(LOEt)2CeCl2] with I2O5 in MeCN in the presence of a small amount of water led to isolation of the iodate complex [(LOEt)2Ce(IO3)2]⋅H+ICl2− (4). The Ce(IV) periodate and persulfate complexes have been characterized by single-crystal X-ray diffraction. The reduction potentials of the Ce(IV) complexes have been determined by cyclic voltammetry. The Ce(IV) periodate and iodate complexes can oxidize methyl p-tolyl sulfide to sulfoxide.

Rhenium nitrido complexes containing the Kläui tripodal ligand [Co(η(5)-C5H5){P(O)(OEt)2}3](-) (LOEt(-)) have been synthesised and their reactions with [Ir(I)(cod)Cl]2 (cod = 1,5-cyclooctadiene) and [Rh(II)2(OAc)4] (OAc(-) = acetate) have been studied. The treatment of [Bu(n)4N][Re(VI)(N)Cl4] with NaLOEt in methanol afforded the Re(VI) nitride [Re(VI)(LOEt)(N)Cl(OMe)] (1). Reactions of 1 with [Ir(I)(cod)Cl]2 and [Rh(II)2(OAc)4] gave the μ-nitrido complexes [(LOEt)(OMe)ClRe(VI)(μ-N)Ir(I)(cod)Cl] (2) and [Rh(II)2(OAc)4{(μ-N)Re(VI)(LOEt)(OMe)Cl}2] (4), respectively. [(LOEt)Cl(PPh3)Re(V)(μ-N)Ir(I)(cod)Cl] (3) and [(LOEt)Cl(PPh3)Re(VI)(μ-N)Ir(I)(cod)Cl][PF6] (3·PF6) have been synthesised from the reactions of [Ir(I)(cod)Cl]2 with [Re(V)LOEt(N)Cl(PPh3)] and [Re(VI)LOEt(N)Cl(PPh3)](PF6), respectively. Similarly, the redox pair [Rh(II)2(OAc)4{(μ-N)Re(V)(LOEt)(PPh3)Cl}2] (5) and [Rh(II)2(OAc)4{(μ-N)Re(VI)(LOEt)(PPh3)Cl}2](PF6)2 (·(PF6)2) have been synthesised from the reactions of [Rh2(OAc)4] with [Re(V)LOEt(N)Cl(PPh3)] and [Re(VI)LOEt(N)Cl(PPh3)](PF6), respectively. While [(LOEt)Cl2Ru(VI)(μ-N)Ir(I)(cod)] (6) was obtained from [Ru(VI)(LOEt)(N)Cl2] and [Ir(I)(cod)Cl]2, the interaction between [Ru(VI)(LOEt)(N)Cl2] and [Rh(II)2(OAc)4] in CH2Cl2 is reversible. The crystal structures of complexes 2, 3, 3·PF6, 5, 5·(PF6)2 and 6 have been determined. X-ray crystallography indicates that the nitrido bridges in 2, 3, 3·PF6 and 6 can be described as MN-Ir (M = Re, Ru) showing Ir-N multiple bond character, whereas the interaction between Re≡N and Rh in 5 and 5·(PF6)2 is mostly of the donor-acceptor type. The electrochemistry of the Re nitrido complexes has been investigated by cyclic voltammetry.

The treatment of [Ce(LOEt)2(NO3)2] (LOEt– = [Co(η5-C5H5){P(O)(OEt)2}3]–) with KMnO4 in water afforded a diamagnetic purple solid 1, which is tentatively formulated as a CeIV permanganate complex, “[Ce(LOEt)2(MnO4)2]”. The ZrIV analogue, [Zr(LOEt)2(MnO4)2] (2), has been prepared similarly from [Zr(LOEt)2(NO3)2] and KMnO4. The recrystallization of 1 from CH2Cl2/hexanes at –18 °C led to the isolation of dinuclear [(CeLOEt)2(μ-LOEt′)2][MnO4]2 (3), which contains the dianionic tripodal ligand [LOEt′]2– ([(η5-C5H5)Co{P(O)(OEt)2}2{P(O)2(OEt)}]2–). The reactions of 1 with K[ReO4] and [NH4][OsO3N] afforded the heterodimetallic complexes [Ce(LOEt)2(ReO4)2] (4) and [Ce(LOEt)2(NOsO3)2] (5), respectively. The crystal structures of 3 and 5 have been determined. Freshly prepared 1 can oxidize alkylbenzenes such as toluene, ethylbenzene, and cumene at room temperature to give the corresponding ketone and/or alcohol products. Ce–LOEt complexes are efficient promoters of the aerobic oxidation of alkylbenzenes by a radical mechanism. For example, cumene in the presence of [Ce(LOEt)2(H2O)2]Cl (1 mM) in air at 100 °C for 10 h afforded a ca. 6:1 mixture of 2-phenyl-2-propanol and acetophenone with a total turnover number of 6810.

The protonation of trans-[Os(OMe)2{N(Pri2PS)2}2] (1) with HBF4, followed by treatment with NH3(g) afforded the oxo-bridged dimer [Os2(μ-O){N(Pri2PS)2}4F2] (2). Reaction of 2 with Ag(OTf) (OTf− = triflate) gave the heterometallic Os(IV)/Ag(I) complex [Os2(μ-O){N(Pri2PS)2}4F2(AgOTf)2] (3), in which each Ag(OTf) moiety binds to three sulfur atoms of two [N(Pri2PS)2]− ligands. The solid-state structures of complexes 2 and 3 have been established by X-ray crystallography.

Tetraarylruthenium(IV) complexes have been synthesized and their migratory insertion, reductive coupling, and bromination reactions investigated. Treatment of [Ru(acac)3] (acac– = acetylacetonate) ...

Treatment of dirhodium(II) tetra-acetate Rh2(OAc)4 with HN(Ph2PS)2 in refluxing tetrahydrofuran (THF) yielded a typical mononuclear Rh(III) complex Rh[N(Ph2PS)2]3 (1). Reaction of Rh2(OAc)4 with HN(iPr2PS)2 in a similar condition resulted in the mixed Rh(III) complexes Rh[N(iPr2PS)2)]3 (2) in a major product and Rh[N(iPr2PS)2][κ2S,κC-N(iPr2PS)(iPr(C3H6)PS)] (3) in a minor product, while the similar reaction by use of HN(tBu2PS)2 led to isolation of complex Rh[N(tBu2PS)2][κ2S,κC-N(tBu2PS)(tBu(C4H8)PS)] (4) as a sole product. Novel C–H bond activation of one methyl group in the ligands [N(R2PS)2]− (R = iPr, tBu) was observed in complexes 3 and 4, which was further confirmed by the analysis of X-ray crystallography along with other spectroscopic properties.

Rhodium complexes containing the dithioimidodiphosphinate ligand [N(iPr2PS)2]– have been synthesized and their oxidative addition of methyl iodide investigated. Treatment of [Rh(PPh3)3Cl] with K[N(iPr2PS)2] afforded [Rh{N(iPr2PS)2}(PPh3)2] (1). Recrystallization of 1 from hexane in the presence of adventitious oxygen yielded the peroxo complex [Rh{N(iPr2PS)2}(PPh3)2(η2-O2)] (2). Oxidative addition of methyl iodide to 1 gave [Rh(Me)(I){N(iPr2PS)2}(PPh3)2] (3), which reacted with K[N(iPr2PS)2] to afford [Rh(Me){N(iPr2PS)2}2] (4). Treatment of K[N(iPr2PS)2] with [Rh(coe)2Cl]2 (coe = cyclooctene) yielded the tetranuclear sulfido cluster [Rh4(μ3-S)2{iPr2PNP(S)iPr2}2{N(iPr2PS)2}2] (5) containing two four-coordinate RhI and two five-coordinate RhIII centers. Oxidative addition of methyl iodide to 5 gave the monomethyl compound [Rh4(μ3-S)2(Me)(μ-I){iPr2PNP(S)iPr2}2{N(iPr2PS)2}2] (6). In benzene solution, 6 underwent spontaneous reductive elimination of methyl iodide to give 5. The crystal structures of complexes 2–6 have been determined.

Whereas terminal oxo complexes of transition and actinide elements are well documented, analogous lanthanide complexes have not been reported to date. Herein, we report the synthesis and structure of a cerium(IV) oxo complex, [CeO(LOEt )2 (H2 O)]⋅MeC(O)NH2 (1; LOEt (-) =[Co(η(5) -C5 H5 ){P(O)(OEt)2 }3 ](-) ), featuring a short CeO bond (1.857(3) Å). DFT calculations indicate that the hydrogen bond to cocrystallized acetamide plays a key role in stabilizing the CeO moiety of 1 in the solid state. Complex 1 exhibits oxidizing and nucleophilic reactivity.

Treatment of [Et4N][RuCl4(MeCN)2] with 2,4,6-trimethylthiophenol (HSMes) in the presence of NaOMe afforded the trigonal–bipyramidal ruthenium(IV) complex [Ru(SMes)4(MeCN)] (1), which reacted with propargylic alcohols HC CCR2OH (R = Me, Et) at ambient temperature to give the novel vinyl complexes of diruthenium(IV) thiolates [(μ-SMes)Ru{η1-O,η1-C-OCR2CH C(SMes)}(SMes)]2 (R = Me 2, Et 3). The crystal structures of 2 and 3 have been determined. The Ru−Cα bond distances are 2.011(3) and 2.023(5) A for 2 and 3, respectively.

The alkylation of [Ru(NPPh3)(PPh3)2Cl3] with Me3SiCH2MgCl afforded the RuIV trialkyl complex [Ru(CH2SiMe3)3(PPh3)Cl] (1), which exhibits a trigonal bipyramidal geometry with the three alkyl groups occupying the equatorial plane. DFT calculations reveal that 1 possesses a (dxz,dyz)4 singlet ground state, consistent with the observed diamagnetism of the complex. The electronic spectrum of 1 displayed two absorptions at 455 and 505 nm, which, on the basis of TDDFT calculations, are attributed to metal-centered d–d transitions with a significant contribution from the alkyl ligands. Chloride abstraction of 1 with Ag(OTf) (OTf– = triflate) provided the triflate complex [Ru(CH2SiMe3)3(PPh3)(OTf)] (2) that proved to be a useful starting material for RuIV trialkyl complexes. Substitution of 2 with NaX afforded [Ru(CH2SiMe3)3(PPh3)(X)] (X = N3– (3) or SCN– (4)). Treatment of 2 with excess sodium 2,3,5,6-tetrafluorophenoxide (NaORf) in tetrahydrofuran resulted in desilylation of two alkyl groups, and formation of th...

Reaction of RuCl(CH CHPh)(CO)(PPh3)2 with K[N(Ph2PS)2] afforded a σ-aryl complex, Ru(CO)[η1(C),η2(S,S′)-N{(C6H4)PhPS}(Ph2PS)](PPh3)2 (1), with an ortho-metalated bis(diphenyl-thiophosphoryl)imide ligand in a quantitative yield. Treatment of 1 with an excess hydrogen chloride in diethyl ether solution led to isolation of a binuclear complex {RuCl(CO)(PPh3)}2(μ-Cl)(μ-η2(S),η2(S′)-N(Ph2PS)2) (2) which was also obtained from the direct reaction of RuCl(CH CHPh)(CO)(PPh3)2 with HN(Ph2PS)2 in dichloromethane. The structures of complexes 1 and 2 have been established by X-ray crystallography.

Treatment of [Ru(PPh 3 ) 3 Cl 2 ] or [RuHCl(CO)(PPh 3 ) 3 ] with 1-(4-chlorophenyl)imidazole-2-thione (Htim Ar ) in tetrahydrofuran (THF) at reflux afforded the mononuclear complex [Ru( κ 1 - S -Htim Ar ) 2 (PPh 3 ) 2 Cl 2 ] ( 1 ) and [RuH(CO)( κ 1 - S -Htim Ar )(PPh 3 ) 2 Cl] ( 4 ), respectively, whereas interaction of [Ru(PPh 3 ) 3 Cl 2 ] or [RuHCl(CO)(PPh 3 ) 3 ] with Htim Ar in the presence of NaOMe in THF gave the mononuclear complex cis -[Ru( κ 2 - S , N -tim Ar ) 2 (PPh 3 ) 2 ] ( 2 ) and [RuH(CO)( κ 2 - S , N -tim Ar )(PPh 3 ) 2 ] ( 5 ), respectively. Reaction of [RuCl 2 (PPh 3 ) 3 ] with 1 equiv. of Htim Ar in the presence of Et 3 N and H 2 O 2 gave a Ru(III) complex, [Ru( κ 2 - S , N -tim Ar )(PPh 3 ) 2 Cl 2 ] ( 3 ). Reaction of [( η 6 - p -cymene)RuCl( μ -Cl)] 2 with Htim Ar in THF at reflux in the presence of NaOMe and K[PF 6 ] gave the μ - S , N -tim Ar -bridged dinuclear complex [{( η 6 - p -cymene)Ru} 2 { μ - η 1 ( S ), η 1 ( N )-tim Ar }{ μ - η 2 ( S ), η 1 ( N )-tim Ar }{ κ 1 - S -Htim Ar }][PF 6 ] 2 ( 6 ). Reaction of [RuHCl(CO)(PPh 3 ) 3 ] or [Ru(PPh 3 ) 3 Cl 2 ] with the bulky ligand [HB(tim Ar ) 3 ] − at reflux resulted a ruthenaboratrane complex, [Ru(CO){ κ 4 - B , S , S , S -B(tim Ar ) 3 }(PPh 3 )] ( 7 ) and a typical Ru⋯H–B complex, [Ru{ κ 3 - H , S , S -HB(tim Ar ) 3 }( κ 2 - S , N -tim Ar )(PPh 3 )] ( 8 ), respectively. All complexes have been spectroscopically and electrochemically characterized. The structures of 1 ·CH 2 Cl 2 , 2 , 3 ·CH 2 Cl 2 , 4 ·C 6 H 14 , 6 , 7 ·CH 3 OH·0.5H 2 O, and 8 ·0.5C 6 H 14 ·0.5CH 2 Cl 2 ·2H 2 O have also been determined by single-crystal X-ray diffraction.

The treatment of [Ru(CO)2Cl2]x with 4,4′,4″-tri-tert-butyl-2,2′:6′,6″-terpyridyl (tbtpy) in tetrahydrofuran at reflux afforded trans-[Ru(tbtpy)Cl2(CO)] (1). The alkylation of complex 1 with excess Me3SiCH2MgCl afforded a mixture of trans-[Ru(tbtpy)(CH2SiMe3)2(CO)] (2) and trans-[Ru(tbtpy)(CH2SiMe3)Cl(CO)] (3), whereas complex 3 could be obtained in good yield by the alkylation of complex 1 with 1 equiv. of Me3SiCH2MgCl. On the other hand, the alkylation of 1 with MeLi and PhCH2MgBr afforded the monoalkyl complexes [Ru(tbtpy)(Me)Cl(CO)] (4) and [Ru(tbtpy)(CH2Ph)Cl0.5Br0.5(CO)] (5), respectively. The crystal structure of complex 5 was determined. Complex 2 and the previously prepared mer-[Ru(dtbpy)(CH2SiMe3)3(NO)] (dtbpy = 4,4′-di-tert-butyl-2,2′-bipyridyl) were immobilized on SBA-15 by treating the Ru complexes with SBA-15 in benzene at room temperature. 1H NMR spectroscopy indicated that the reaction of complex 2 and [Ru(dtbpy)(CH2SiMe3)3(NO)] with SBA-15 in C6D6 resulted in the formation of approximately 1 equiv. of SiMe4, which suggests the grafted species are possibly (≡SiO)Ru(tbtpy)(CH2SiMe3)(CO) and (≡SiO)Ru(dtbpy)(CH2SiMe3)2(NO), respectively. The Ru-grafted SBA-15 materials were characterized by IR, reflectance UV/Vis, and X-ray photoelectron spectroscopy as well as transmission electronic microscopy, and their catalytic performance in the oxidation of benzyl alcohol with tert-butyl hydroperoxide was examined.

The reaction of the RuVI nitride LOEtRuVI(N)Cl2 (1; LOEt– = [Co(η5-C5H5){P(O)(OEt)2}3]−) with RhIII(mes)3 (mes = mesityl) results in insertion of the Ru≡N group into the Rh–C bonds and formation of...

Ruthenium(VI) complexes with a sterically bulky bidentate Schiff base ligand, 2-[(2,6-diisopropylphenyl)imino]methyl-4,6-dibromophenolate (L−), have been synthesized and their reactivity studied. Treatment of [Bun4N][Ru(N)Cl4] in tetrahydrofuran with 2 equivalents of NaL afforded cis-[Ru(N)Cl(L)2] (1) that reacted with Ag(OTf) (OTf− = triflate) in acetone to give trans-[Ru(N)(H2O)L2][OTf] (2). Reactions of complex 1 with Me3NO and elemental sulfur afforded cis-[Ru(NO)(Cl)L2] (3) and cis-[Ru(NS)(Cl)L2] (4), respectively. Reaction of complex 1 with Me3SiN3 in MeCN afforded [Ru(MeCN)(Cl)L2], which could alternatively be prepared by photolysis of complex 3 in CH2Cl2–MeCN with UV light. The crystal structures of complexes 1 and 2 have been determined.

A cationic bis-cyclometalated iridium(III) complex, [Ir(hfppq)2(bipy)][PF6]·0.5H2O (hfppq = 1,1,1,3,3,3-hexafluoro-2(2-phenylquinolin-4-yl)propan-2-ol, bipy = 2,2′-bipyridine, 1), was obtained from the reaction of the μ-chloro-bridged dimeric complex [Ir(hfppq)2(μ-Cl)]2 and bipy in the presence of KPF6. Complex 1 shows a strong emission both in the solid state (ca. 595 nm) and in CH2Cl2 solution (ca. 585 nm) at room temperature with the phosphorescence quantum yield of ca. 0.698 and emission lifetime of 0.96 μs. Density functional theory (DFT) calculation was performed on the ground and excited states of complex 1 to provide insight into the structural, electronic, and optical properties of the cationic cyclometalated iridium(III) complex.

Reactions of [RuHCl(CO)(PPh3)3] with NaBmR (BmR = bis(2-mercapto-1-arylimidazolyl)borates, R = 4-chloro-phenyl; 4-methyl-phenyl; 4-nitro-phenyl) in refluxing THF afforded hydrido ruthenium complexes [RuH(CO)(PPh3)(κ3-H,S,S′-BmR)] (1–3). Treatment of 1 in refluxing chloroform gave ruthenium chloride complex [RuCl(CO)(κ3-H,S,S′-BmR)(PPh3)] (4). Interactions of 1 with Br2 or I2 in THF at room temperature led to isolation of ruthenium bromide complex [RuBr(CO)(κ3-H,S,S′-BmR)(PPh3)] (5) and ruthenium iodide complex [RuI(CO)(κ3-H,S,S′-BmR)(PPh3)] (6), respectively. Complexes 1–6 were characterized by microanalyses, IR, and (1H, 11B, 13C, 31P) NMR spectroscopies. The molecular structures of 1, 2, 5, and 6 have been determined by single-crystal X-ray diffraction.

Dinuclear ruthenium nitrido complexes supported by the Kläui's tripodal ligand [CpCo{P(O)(OEt)(2)}(3)](-) (L(OEt)(-)) have been synthesized starting from the ruthenium(VI) nitrido precursor [L(OEt)Ru(VI)(N)Cl(2)] (1). Heating a solution of 1 in CCl(4) at reflux, followed by recrystallization from hexane under nitrogen, afforded the mixed-valence ruthenium(V)-ruthenium(IV) μ-nitrido complex [L(OEt)Cl(2)Ru(V)(μ-N)Ru(IV)Cl(2)L(OEt)] (2). The cyclic voltammogram of 2 exhibited reversible couples at 0.19 and 1.13 V versus Cp(2)Fe(+/0), which are assigned as the Ru(V)-Ru(IV)/Ru(IV)-Ru(IV) and Ru(V)-Ru(V)/Ru(V)-Ru(IV) couples, respectively. Recrystallization of 2 from Et(2)O/heptane in air yielded the diamagnetic Ru(IV)-Ru(IV) complex [H(13)O(6)][{L(OEt)Ru(IV)Cl(2)}(2)(μ-N)] ([H(13)O(6)][2]), which underwent cation exchange with n-Bu(4)NOH to give [n-Bu(4)N][2]. X-ray diffraction revealed that the complex anions in [H(13)O(6)][2] and [n-Bu(4)N][2] contain linear, symmetric Ru-N-Ru bridges. Treatment of 1 with [(η(6)-p-cymene)Ru(II)Cl(2)](2) in benzene afforded the tetranuclear ruthenium(IV) complex [L(OEt)Cl(2)Ru(IV)(μ-N)Ru(IV)(H(2)O)Cl(2)](2) (3) containing symmetric Ru(IV)-N-Ru(IV) bridges. The reaction of 1 with [Ru(II)(H)(Cl)(CO)(PCy(3))(2)] (Cy = cyclohexyl) gave the ruthenium(VI)-ruthenium(II) nitrido complex [L(OEt)Cl(2)Ru(VI)(μ-N)Ru(II)(H)Cl(CO)(PCy(3))(2)] (4). The observed short Ru(II)-N bond distance [1.915(5) Å] and high C-O stretching frequency (1985 cm(-1)) in 4 are suggestive of π interaction between Ru(II) and the nitride.

Reaction of [LOEtRuCl2]2 (LOEt– = [CpCo{P(O)(OEt)2}3]−) (1) with the organic azides RN3 in CH2Cl2 at room temperature, followed by recrystallization from Et2O, afforded [LOEtRuCl2(NH2R)] (R = Ph (2), 4-NO2C6H4 (3), 1-adamantyl (Ad) (4)). Complex 1 can catalyze the reduction of 4-nitrophenyl azide to 4-nitroaniline by cyclohexene. Heating 1 with AdN3 in toluene at reflux led to formation of the cyclometalated Ru(III) complex [LOEtRu(κ2C,N-AdN═CHC6H4)Cl] (5), possibly via double C–H activation of toluene by an imido intermediate. The crystal structures of 3 and 5 have been determined.