Oxygen Tripod Ligand Research Articles

Syntheses, structures, and magnetic properties of acetate-bridged lanthanide complexes based on a tripodal oxygen ligand.

Four homodinuclear lanthanide complexes, Dy2 (LOEt)2(OAc)4 (1), Tb2 (LOEt)2(OAc)4 (2), Ho2(LOEt)2(OAc)4 (3), and Gd2 (LOEt)2(OAc)4 (4), have been synthesized and characterized based on a tripodal oxygen ligand Na [(η5-C5H5)Co(P(O)(OC2H5)2)3] (NaLOEt). Structural analyses show that the acetate anions bridge two symmetry-related Ln3+ ions in the μ2:η1:η1 and μ2:η1:η2 coordination patterns, and each lanthanide (III) ion owns a twisted square antiprism (SAPR) conformation. Static magnetic measurements reveal the weak intramolecular ferromagnetic interaction between dysprosium (III) ions in 1 and antiferromagnetic Ln3+···Ln3+ couplings in the other three complexes. Through the analysis of the ligand-field effect and magnetic anisotropy axis orientation, the reasons for the lack of dynamic magnetic behavior in 1 were identified.

A Nitrido-bridged Heterometallic Ruthenium(IV)/Iron(IV) Phthalocyanine Complex Supported by A Tripodal Oxygen Ligand, [Co(η5-C5H5){P(O)(OEt)2}3]−: Synthesis, Structure, and Its Oxidation to Give Phthalocyanine Cation Radical and Hydroxyphthalocyanine Complexes

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) Å, 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 couple at +0.18 V versus Fc+/0 (Fc = ferrocene). The oxidation of 2 with [N(4-BrC6H4)3]SbCl6 led to isolation of the cationic complex [Cl2(LOEt)RuIV(μ-N)FeIV(Pc·+)(H2O)][SbCl6]0.85[SbCl5(OH)]0.15 (2[SbCl6]0.85[SbCl5(OH)]0.15), whereas that with PhICl2 yielded the chloride complex [Cl2(LOEt)RuIV(μ-N)FeIV(Pc·+)Cl] (3). Complexes 2[SbCl6]0.85[SbCl5(OH)]0.15 and 3 have been characterized by X-ray crystallography. The UV/visible spectra of 2+ (λmax = 515 and 747 nm) and 3 (λmax = 506 and 748 nm) displayed absorption bands that are characteristic of Pc cation radical. The EPR spectrum of 3 showed a signal with the g value of 2.0012 (width = 5 G) that is consistent with an organic radical. The spectroscopic data support the formulation of 2+ and 3 as RuIV-FeIV Pc cation radical complexes. The reaction of 2 with PhI(CF3CO2)2 in dried CH2Cl2 afforded a mixture of [Cl2(LOEt)RuIV(μ-N)FeIV(Pc·+)(CF3CO2)] (4) and a hydroxyphthalocyanine complex, [Cl2(LOEt)RuIV(μ-N)FeIV(Pc-OH)(H2O)](CF3CO2) (5), whereas that in wet CH2Cl2 (containing ca. 0.5% water) led to isolation of 5 as the sole product. Complex 4 was independently prepared by salt metathesis of 3 with AgCF3CO2.

Synthesis, Structure, and Reductive Elimination of Cationic Monoarylpalladium(IV) Complexes Supported by a Tripodal Oxygen Ligand

Cationic monoaryl–PdIV complexes supported by the Kläui tripodal ligand [Co(η5‐C5H5){P(O)(OEt)2}3]– (LOEt–) were synthesized, and their reductive elimination was studied. Treatment of trans‐[Pd(PPh3)2(Ar)(I)] and [{Pd(η2‐ppytBu)Cl}2] [ppytBuH = 2‐(4‐tert‐butylphenyl)pyridine] with [AgLOEt] afforded [Pd(Ar)(PPh3)(η2‐LOEt)] [Ar = Ph (1), p‐tolyl (2)] and [Pd(η2‐ppytBu)(η2‐LOEt)] (3), respectively. Chlorination of 1, 2, and 3 with PhICl2 in the presence of NH4PF6 afforded the cationic aryl–PdIV chloride complexes [Pd(Ph)(PPh3)(Cl)(LOEt)](PF6) (4), [Pd(p‐tolyl)(PPh3)(Cl)(LOEt)](PF6) (5), and [Pd(η2‐ppytBu)(Cl)(LOEt)](PF6) (6), respectively. Complexes 4 and 5 underwent C(sp2)–Cl elimination at 40 °C in acetonitrile to give a PdII–LOEt species and the corresponding chloroarene. On the other hand, the C(sp2)–Cl elimination of 6 occurred at room temperature and afforded a PdII species, presumably [Pd(ClppytBuH)(LOEt)](PF6), which further reacted with PhICl2 to yield [Pd(η2‐ClppytBu)Cl(LOEt)](PF6) (7) [ClppytBuH = 2‐(4‐tert‐butyl‐2‐chlorophenyl)pyridine]. The structures of complexes 1, 4, 6, and 7 were established by X‐ray crystallography.

Heterobimetallic cerium(iv) oxo clusters supported by a tripodal oxygen ligand.

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.

Dinuclear Ruthenium Nitrido Complexes Supported by an Oxygen Tripodal Ligand

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.

A Stable Iridium(IV) Complex Containing the Kläui Tripodal Ligand [Co(η5‐C5H5){P(O)(OEt)2}3]–

AbstractIridium and rhodium complexes containing the Kläui oxygen tripodal ligand [Co(η5‐C5H5){P(O)(OEt)2}3]– (LOEt–) have been synthesized and their redox chemistry investigated. Treatment of [Ir(COE)2Cl]2 (COE = cyclooctene) with [AgLOEt] afforded [Ir(LOEt)Cl2(COE)] (1), which reacted with AgNO3, 4,4′‐di‐tert‐butyl‐2,2′‐bipyridyl (dtbpy), and NH4PF6 to give [Ir(LOEt)(dtbpy)(COE)][PF6] (2). Ozonolysis of complex 1 in CH2Cl2 afforded the IrIV complex [Ir(LOEt)Cl3] (3), which exhibited an EPR signal (CH2Cl2, 4 K) with g = 1.65 and 1.06. The IrIV/IrIII reduction potential for complex 3 in acetonitrile was determined to be ca. 0 V vs. ferrocenium/ferrocene. Treatment of [Rh(bpy)Cl3(DMF)] (bpy = 2,2′‐bipyridyl; DMF = N,N‐dimethylformamide) with [AgLOEt] and Ag(OTf) (OTf– = triflate) afforded [Rh(LOEt)(bpy)Cl][OTf] (4), which reacted with AgOTf in refluxing acetone to yield [Rh(LOEt)(bpy)(acetone)][OTf]2 (5). Reaction of [RhLOEtCl2]2 with 1 equiv. or an excess of tert‐butylamine in refluxing tetrahydrofuran afforded [Rh(LOEt)Cl2(NH2tBu)] (6) or [Rh(LOEt)Cl2(NH2tBu)2] (7). Complex 7 contains one chlorido ligand and one noncoordinated chloride ion that is hydrogen‐bonded to the two tert‐butylamine ligands. The crystal structures of complexes 1, 3, and 7 were determined.

Synthesis and Structure of a Bismuth(III)/Chromium(VI) Oxo Cluster Containing a Bi4Cr4O12Core

Bismuth(III) compounds containing the Kläui's oxygen tripodal ligand [CpCo{P(O)(OEt)(2)}(3)](-) (L(OEt)(-)) have been synthesized, and their interactions with dichromate in aqueous media were studied. The treatment of Bi(5)O(OH)(9)(NO(3))(4) with NaL(OEt) in water afforded [L(OEt)Bi(NO(3))(2)](2) (1), whereas that of BiCl(3) with NaL(OEt) in CH(2)Cl(2) yielded L(OEt)BiCl(2) (2). Chloride abstraction of 2 with AgX afforded [L(OEt)BiX(2)](2) [X(-) = triflate (OTf(-)) (3), tosylate (OTs(-)) (4)]. In aqueous solutions at pH > 4, 4 underwent ligand redistribution to give the bis(tripod) complex [(L(OEt))(2)Bi(H(2)O)][OTs] (5). The treatment of 4 with Na(2)Cr(2)O(7) in acetone/water afforded the Bi(III)/Cr(VI) oxo cluster [(L(OEt))(4)Bi(4)(μ(3)-CrO(4))(2)(μ(3)-Cr(2)O(7))(2)] (6) containing a unique Bi(4)Cr(4)O(12) oxometallic core. Compound 6 oxidized benzyl alcohol to give ca. 6 equiv of benzaldehyde. The reaction between 2 and CrO(3) yielded [L(OEt)Bi(OCrO(2)Cl)](2)(μ-Cl)(2) (7). The crystal structures of complexes 4-7 have been determined.

Synthesis, structures and reactivity of ruthenium nitrosyl complexes containing Kläui's oxygen tripodal ligand

Ruthenium nitrosyl complexes containing the Kläui's oxgyen tripodal ligand L(OEt)(-) ([CpCo{P(O)(OEt)(2)}(3)](-) where Cp = η(5)-C(5)H(5)) were synthesized and their photolysis studied. The treatment of [Ru(N^N)(NO)Cl(3)] with [AgL(OEt)] and Ag(OTf) afforded [L(OEt)Ru(N^N)(NO)][OTf](2) where N^N = 4,4'-di-tert-butyl-2,2'-bipyridyl (dtbpy) (2·[OTf](2)), 2,2'-bipyridyl (bpy) (3·[OTf](2)), N,N,N'N'-tetramethylethylenediamine (4·[OTf](2)). Anion metathesis of 3·[OTf](2) with HPF(6) and HBF(4) gave 3·[PF(6)](2) and 3·[BF(4)](2), respectively. Similarly, the PF(6)(-) salt 4·[PF(6)](2) was prepared by the reaction of 4·[OTf](2) with HPF(6). The irradiation of [L(OEt)Ru(NO)Cl(2)] (1) with UV light in CH(2)Cl(2)-MeCN and tetrahydrofuran (thf)-H(2)O afforded [L(OEt)RuCl(2)(MeCN)] (5) and the chloro-bridged dimer [L(OEt)RuCl](2)(μ-Cl)(2) (6), respectively. The photolysis of complex [2][OTf](2) in MeCN gave [L(OEt)Ru(dtbpy)(MeCN)][OTf](2) (7). Refluxing complex 5 with RNH(2) in thf gave [L(OEt)RuCl(2)(NH(2)R)] (R = tBu (8), p-tol (9), Ph (10)). The oxidation of complex 6 with PhICl(2) gave [L(OEt)RuCl(3)] (11), whereas the reduction of complex 6 with Zn and NH(4)PF(6) in MeCN yielded [L(OEt)Ru(MeCN)(3)][PF(6)] (12). The reaction of 3·[BF(4)](2) with benzylamine afforded the μ-dinitrogen complex [{L(OEt)Ru(bpy)}(2)(μ-N(2))][BF(4)](2) (13) that was oxidized by [Cp(2)Fe]PF(6) to a mixed valence Ru(II,III) species. The formal potentials of the RuL(OEt) complexes have been determined by cyclic voltammetry. The structures of complexes 5,6,10,11 and 13 have been established by X-ray crystallography.

Hydrolysis of Bis(p-nitrophenyl)phosphate by Tetravalent Metal Complexes with Kläui’s Oxygen Tripodal Ligand

The treatment of HfCl(4) with NaL(OEt) (L(OEt)(-) = [(eta(5)-C(5)H(5))Co{P(O)(OEt)(2)}(3)](-)) in nitric acid afforded L(OEt)Hf(NO(3))(3) (1). Hydrolysis of 1 in acetone/water (4:1, v/v) yielded the hydroxy-bridged dimer [(L(OEt))(2)Hf(2)(H(2)O)(4)(mu-OH)(2)][NO(3)](4) (2). The treatment of (NH(4))(2)[Ce(NO(3))(6)] with 2 equiv of NaL(OEt) in water afforded (L(OEt))(2)Ce(NO(3))(2) (3), whereas that with 1 equiv of NaL(OEt) in CH(2)Cl(2) gave L(OEt)Ce(NO(3))(3) (4). While 4 is stable in organic solvents such as acetone, it was converted completely to 3 in acetone/water. The treatment of 3 with bis(p-nitrophenyl)phosphate (BNPP) afforded (L(OEt))(2)Ce[eta(1)-OPO(OR)(2)](2) (5; R = p-NO(2)C(6)H(4)), whereas the reaction of 4 with NaPO(2)(OR)(2) yielded dinuclear [L(OEt)Ce(NO(3))(2){mu-O(2)P(OR)(2)}](2) [R = p-NO(2)C(6)H(4) (6), Ph (7)]. The addition of 3 in acetone to an aqueous solution of NaH(2)PO(4) yielded the cerium(IV) dihydrogen phosphate complex (L(OEt))(2)Ce(PO(4)H(2))(2) (8). Complexes 1-5 and 7 have been characterized by X-ray crystallography. The hydrolysis of BNPP with L(OEt)M(NO(3))(3) (M = Zr, Hf, Ce) in acetone/water has been studied by (1)H NMR spectroscopy. At 25 degrees C, with [Ce] = 20[BNPP], in an acetone-d(6)/N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid (4:1, v/v) buffer solution (50 mM) (4:1, v/v), the hydrolysis of BNPP with 4 was found to exhibit first-order kinetics with a rate constant of (1.1 +/- 0.1) x 10(-3) s(-1).

Synthesis and structures of zirconium(IV) hydrogensulfato and carboxylato complexes with Kläui’s oxygen tripodal ligand

Interaction of [L OEtZrF 3] ( L OEt - = [Co(η 5-C 5H 5){P(O)(OEt) 2} 3] −) ( 1) with 3 equivalents of bis(trimethylsilyl) sulfate afforded the Zr IV hydrogensulfato complex [(L OEt) 2Zr 2(SO 4) 2(HSO 4) 2] ( 2) that reacted with Et 3N to give [Et 3NH][L OEtZr(H 2O)(SO 4) 2] ( 3). Treatment of complex 1 with 3 equivalents of trimethylsilyl acetate afforded [L OEtZr(OCOCH 3) 3] ( 4), whereas that with 1 and 2 equivalents of trimethylsilyl trimethylsiloxyacetate yielded [L OEtZrF(OCOCH 2O)] 2 ( 5) and [L OEtZr(OCOCH 2OH)(OCOCH 2O)] 2 ( 6), respectively. The crystal structures of complexes 2 and 6 have been determined.

Actinide complexes with the Kläui tripodal oxygen ligand – crystal structure of [{η 4-C 5H 5(CH 2C(CH 3) 3)}Co{P(O)(OC 2H 5) 2} 3] 2U

Reaction between [(C 5H 5)Co{P(O)(OEt) 2} 3] 2UCl 2 and neopentyl lithium affords the novel complex, [{η 4-C 5H 5(CH 2C(CH 3) 3)}Co{P(O)(OEt) 2} 3] 2U, in which the uranium metal center has been dehalogenated and the neopentyl nucleophiles have attacked the cyclopentadienyl groups on the Kläui ([(C 5H 5)Co{P(O)(OEt) 2} 3] −) ligands. The uranium atom in the title compound possesses octahedral geometry defined by the oxygen atoms from two sets of tripodal oxygen ligands, while the cyclopentadienyl ligands are bound η 4 to the cobalt atoms. The formation of this complex suggests that the Kläui ligand may not be a suitable ligand framework for supporting organometallic complexes of oxophilic early actinides.

Polymerization of vinyl chloride catalyzed by a titanium complex with an anionic oxygen tripod ligand

Poly(vinyl chloride) (PVC) was prepared using a titanium complex with an anionic oxygen tripod ligand [CpCo{P(O)(OEt) 2} 3] − ( L OEt - ) as catalyst and methyl aluminoxane (MAO) as cocatalyst. The polymerization behavior was compared with that of pentamethyl cyclopentadienyl titanium trichloride (Me 5CpTiCl 3). It is observed that L OEtTiCl 3 can polymerize vinyl chloride with activity comparable to that of Me 5CpTiCl 3. The PVC samples prepared with L OEtTiCl 3/MAO exhibit bimodal molecular weight distribution and the fraction of high molecular weight peak decreases with polymerization temperature. The microstructure and thermal decomposition of the PVC obtained were studied. Five types of structural defect were detected by 1H-NMR. Only saturated structural defects are found at low polymerization temperature, but at high polymerization temperature unsaturated structural defects, possibly resulting from dehydrochlorination of the saturated structural defects, appear as well. No head-to-head structural defect is observed. 13C-NMR shows that the PVC prepared by L OEtTiCl 3 has an atactic stereostructure. Compared with the PVC from radical polymerization and anionic polymerization, the PVC samples prepared with L OEtTiCl 3 show improved thermal stability.

Synthesis and Crystal Structure of a ChiralC3-Symmetric Oxygen Tripodal Ligand and Its Applications to Asymmetric Catalysis

Treatment of Na[P(O)(S-BINOL)] (S-BINOL = (S)-(−)-bi-2-naphthol) with [CpCo(CO)I2] afforded the chiral C3-symmetric oxygen tripodal ligand Na[Co{P(O)(S-BINOL)}3] (Na(1)). Recrystallization of Na(1) from acetone/toluene yielded Na(1)(C6H12O2)2 (C6H12O2 = diacetone alcohol), which has been characterized by X-ray diffraction. The solid-state structure of Na(1)(C6H12O2)2 features a six-coordinated Na with one η2 and one η1 diacetone alcohol ligand. Treatment of Na(1) with [(η6-p-cymene)RuCl2]2, [Ru(CO)Cl(CHCHPh)(PPh3)3], and [Pr(OTf)3] (OTf = triflate) afforded [(η6-p-cymene)Ru(1)][PF6] (3), [Ru(1)(CO)(CHCHPh)(PPh3)] (4), and [Pr(1)2(OTf)] (5), respectively. Treatment of Na(1) with [Cu(MeCN)4][BF4] in the presence of PhC⋮CH and Me3SiC⋮CSiMe3 afforded [Cu(1)(η2-PhC⋮CH)] (6) and [Cu(1)(η2-Me3SiC⋮CSiMe3)] (7), respectively, which have been characterized by X-ray diffraction. In both 6 and 7, the Cu atom exhibits a distorted 2 + 1 tripod ligand coordination with one Cu−O bond significantly longer than the other two. Na(1) has been employed for the Cu-catalyzed enantioselective aziridination of styrene, the Ti-catalyzed azidolysis of cyclohexene oxide, and the allylation of benzaldehyde with allyltrichlorosilane.

Tripodal oxygen and tripodal nitrogen ligands in hydroformylation reactions: formation of novel rhodium(III) carbonyl bis(acyl) complexes

The rhodium(I) complexes TpmsRh(CO) 2 ( 1) and TpmsRh(cod) ( 2) of the tripodal nitrogen ligand tris(pyrazolyl)methanesulfonate, Tpms −=[(pz) 3CSO 3] −, catalyze the hydroformylation of 1-hexene. Addition of phosphine has a negative effect on the activity. The hydroformylation activity reaches a maximum at about 60 °C. At temperatures above 80 °C hydrogenation becomes an important secondary reaction. When the catalysis is performed at 60 °C in acetone with 1 or 2 as catalyst precursor all of the rhodium is recovered in the form of the rhodium(III) bis(acyl) complex TpmsRh(CO)(COC 6H 13) 2 ( 9). A similar behaviour is observed with rhodium(I) complexes bearing the tripodal oxygen ligand L OMe −=[(cyclopentadienyl)tris(dimethylphosphito- P) cobalt O, O ′, O″] −. In this case all of the rhodium is transformed into L OMeRh(CO)(COC 6H 13) 2 ( 10). These hitherto unknown bis(acyl) rhodium(III) complexes show the same catalytic activity as the rhodium(I) starting compounds.

(C5H5)Co(P(O)(OH)2)3H]: a novel organometallic tris-phosphonic acid that dissolves glass to form a six-coordinate silicon complex.

The sodium salt of the tripodal oxygen ligand Na[(C5H5)Co(P(O)(OMe)2)3] (1) reacts with gaseous hydrogen chloride in dichloromethane to give sodium chloride and [(C5H5)Co(P(O)(OMe)2)3H2]Cl (2). Addition of an equimolar amount of 1 leads to precipitation of sodium chloride again to yield the acid form of the ligand [(C5H5)Co(P(O)(OMe)2)3H] (3). Its solid-state structure contains a very short intramolecular OH.O hydrogen bond. The compound hydrolyses in boiling water to give methanol and the title complex [(C5H5)Co(P(O)(OH)2)3H] (4). This complex is a rather strong tris-phosphonic acid (pK(a1) 2.0, pK(a2) 4.0, pK(a3) 6.3, and pK(a4) 9.6). Attempts to grow single crystals of this highly water-soluble yellow crystalline compound lead to the silicon complex [((C5H5)Co[P(O)(OH)2]2[P(O)2(OH)])(2)Si].8 H2O (5). The crystal structure determination shows that it is a molecular complex of two tris-phosphonic acids that each act as a tris-chelating ligand. Additional water molecules form a complex net of hydrogen bonds between the complexes of 5. The SiO6 octahedron is only insignificantly distorted with Si-O bond lengths of 1.78 A. Complex 4 reacts with stoichiometric amounts of potassium carbonate to yield the potassium salt K[(C5H5)Co(P(O)(OH)2)3] (6). The crystal structure of 6 has also been determined. In the solid state it is a two-dimensional coordination polymer with each potassium ion being coordinated by twelve oxygen atoms of six tris-phosphonic acids.

Nitrogen Tripod Ligand/Oxygen Tripod Ligand Indium(III) Complexes: The First Structurally Characterized Trofimenko−Kläui Complex [η5-(C5H5)Co{P(OCH3)2(O)}3InHB(pz)3][InCl4] (pz = pyrazol-1-yl)

Indium(III) complexes [LRInTp*]X {LR = (cyclopentadienyl)tris[diorganylphosphi(ni)to-P]cobaltate(1−) [η5-(C5H5)Co{PR2(O)}3]−, R = OCH3, CH2CH3; Tp* = hydrotris(3,5dimethylpyrazol-1-yl)borate} have been prepared from [Tp*InCl2(NCCH3)] and AgLOMe or TlLEt. Alternatively, equilibration of a 1:1 mixture of the homoleptic complexes [In(LOMe)2][PF6] and [In(Tp)2][PF6] in aqueous methanol slowly yielded the heteroleptic indium(III) complex [LOMeInTp][PF6]. An X-ray crystal structure determination revealed a fac-N3O3 coordination sphere for the [LOMeInTp][InCl4] complex. These indium compounds represent the first structurally characterized complexes where the tripodal oxygen ligand LR and the tripodal nitrogen ligand Tp are coordinated to the same metal center. Indium(III) is classified as a class a, i.e. a hard metal ion, but it evidently prefers an antisymbiotic arrangement of ligands.

Reactivity of [η 5-CpCo{P(O)(OMe) 2} 3]MoOCl 2 toward H 2O 2 and NaOMe: syntheses and X-ray structures of [η 5-CpCo{P(O)(OMe) 2} 3]MoO 2X (X=Cl, OH)

The reaction of L OMeMoOCl 2 (L OMe=η 5-CpCo{P(O)(OMe) 2} 3) with NaOMe in dry THF gives (L OMe)MoO 2Cl ( 1), while (L OMe)MoO 2(OH) ( 2) was readily obtained from the oxidation of (L OMe)MoOCl 2 with H 2O 2 in organic solvents. The molecular structures of compounds 1 and 2 were analyzed by X-ray diffraction studies. The dioxomolybdenum(VI) compounds 1 and 2 have a six-coordinate Mo(VI) with the anionic cobalt(III)-based oxygen tripod ligand occupying three facial positions. The coordination geometries of 1 and 2 are determined as distorted octahedral structures due to the trans influence of bound chloro or hydroxo ligand.

Ruthenium thiocarbonyl and phosphoniodithiocarboxylate complexes with an oxygen tripod ligand

Treatment of [Ru(CO) 2Cl 2] x with NaL OEt (L OEt −=[Co(η 5-C 5H 5){P(O)(OEt) 2} 3] −) afforded [L OEtRu(CO) 2Cl] ( 1), which reacted with AgBF 4 in acetone–H 2O to give [L OEtRu(CO) 2(H 2O)][BF 4] ( 2). Reaction of [L OEtRu(CHCHPh)(CO)(PPh 3)] with HCl gave [L OEtRuCl(CO)(PPh 3)] ( 3), which has been characterized by X-ray crystallography. The RuC, RuP, RuCl and average RuO distances in 3 are 1.993(7), 2.2811(13), 2.376(2) and 2.137 Å, respectively. Interaction of [L OEtRu(PPh 3) 2Cl] with CS 2 and PR 3 in the presence of [NH 4][PF 6] afforded the ruthenium(II) phosphoniodithiocarboxylate species [L OEtRu(PPh 3)(η 2-S 2CPR 3)][PF 6] (R=Ph ( 4) or cyclohexyl ( 5)). Oxidation of 4 with AgBF 4 yielded the ruthenium(III) complex [L OEtRu(PPh 3)(η 2-S 2CPPh 3)][BF 4][PF 6] ( 6), which has been characterized by X-ray crystallography. The RuP, average RuO and average RuS distances in 6 are 2.3978(10), 2.078 and 2.2910 Å, respectively. The ruthenium(II) thiocarbonyl complex [L OEtRu(CS)Cl(PPh 3)] ( 7) was prepared from NaL OEt and [Ru(CS)Cl 2(PPh 3) 2] 2. The RuCl, RuP, RuC and average RuO distances in 7 are 2.3681(10), 2.3043(9), 1.823(4), and 2.140 Å, respectively. Treatment of 7 with AgBF 4 in acetone–H 2O afforded [L OEtRu(CS)(PPh 3)(H 2O)][BF 4] ( 8). On the basis of the Ru(III/II) formal potential, CS was found to be a stronger π acid ligand than CO.

Tripodal Oxygen Ligand Supported Palladium(II) Complexes: Alkylation, Carboxymethylation, and CO Insertion Reactions – X-ray Crystal Structure Determination of [PdL2], L = [(C5H5)Co{P(O)(OMe)2}3], a Novel Homoleptic Oxygen Ligand Palladium Complex

Tripodal Oxygen Ligand Supported Palladium(II) Complexes: Alkylation, Carboxymethylation, and CO Insertion Reactions – X-ray Crystal Structure Determination of [PdL2], L = [(C5H5)Co{P(O)(OMe)2}3], a Novel Homoleptic Oxygen Ligand Palladium Complex

Synthesis and reactivity of nitrido-rhenium and -osmium complexes with an oxygen tripod ligand

Interaction of [ReNCl3(PPh3)2] or [ReOCl2(PPh3)3] with NaLOEt (LOEt = [Co(η5-C5H5){PO(OEt)2}3]) afforded [ReLOEtN(PPh3)Cl] 1 and [ReLOEtOCl2] 2, respectively. Reaction of 1 with AgBF4 gave the nitridorhenium(VI) complex [ReLOEtN(PPh3)Cl]BF41·BF4, which has a μeff of 1.8 μB. Treatment of 1 with MeOSO2CF3, PhCH2Br or [Ph3C]BF4 afforded the respective organoimido species [ReLOEt(NMe)(PPh3)Cl][CF3SO3] 3, [ReLOEt(NCH2Ph)(PPh3)Cl]Br 4, and [ReLOEt(NCPh3)(PPh3)Cl] 5. Reaction of 1 with [Au(PPh3)(CF3SO3)], [Ru(Et2dtc)(PPh3)2(CO)(CF3SO3)], or [ReMeO3] yielded the bimetallic nitrido complexes [Au(PPh3){NReLOEt(PPh3)Cl}][CF3SO3] 6, [Ru(Et2dtc)(PPh3)(H2O)(CO){NReLOEt(PPh3)Cl}][CF3SO3] 7 or [ReMeO3{NReLOEt(PPh3)Cl}] 8, respectively. Treatment of [NBu4n][OsNCl4] with NaLOEt gave [OsLOEtNCl2] 9. The average Os–O, Os–Cl and Os–N distances in 9 are 2.066, 2.289 and 2.58(1) A, respectively. Reaction of 9 with PPh3 afforded the osmium(IV) phosphoran iminate species [OsLOEt(NPPh3)Cl2] 10, which has a μeff of 2.0 μB. The average Os–O, Os–Cl and Os–N distances in 10 are 2.099, 2.342, 1.893(5) A, respectively, the Os–N–P angle being 137.5(3)°. The formal potentials of the LOEt–Re and –Os complexes have been determined by cyclic voltammetry. On the basis of the ReVI–ReV formal potential, the π-donor strength was found to decrease in the order N3− > [NAu(PPh3)]2− > NMe2−.