Reactions of dipropargyl manolate,terephthalate with Co2(CO)8, Mo2Cp2(CO)4 and RuCo2(CO)11 give the di or tetranuclear clusters. The crystal structure of [CH2(CO2CH2C2H-μ)2][Co2(CO)6]2 and [p-(HC2CH2OCO)C6H4(CO2CH2C2H-μ)][Co2(CO)6]

The reactions of dipropargyl manolate and terephthalate, respectively, with Co₂(CO)₈ in THF at room temperature gave four new compounds [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ (R=CH₂, 1a; R=C₆H₄, 1b) and [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Co₂(CO)₆] (R=CH₂, 2a; R=C₆H₄-1,4-, 2b), and compounds 2a and b reacted with RuCo₂(CO)₁₁ to form two new linked clusters [R(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][RuCo₂(CO)₉] (R=CH₂, 3a; R=C₆H₄-1,4-, 3b). The treatment of two dipropargyl esters, respectively, with RuCo₂(CO)₁₁ afforded another two new clusters [R(CO₂CH₂C₂H-μ)₂][RuCo₂(CO)₉]₂ (R=CH₂, 4a; R=C₆H₄-1,4-, 4b). The reactions of dipropargyl manolate, terephalate with Mo₂Cp₂(CO)₄ gave rise to the formation of dinuclear complexes [(HC₂CH₂OCO)R(CO₂CH₂C₂H-μ)][Mo₂Cp₂(CO)₄] (R=CH₂, 5a; R=C₆H₄-1,4-, 5b), compound 5a reacted with Co₂(CO)₈ to produce the cluster [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆][Mo₂Cp₂(CO)₄] 6a. All the new clusters have been characterized by C/H elemental analysis, IR and ¹H NMR spectroscopies. The structure of [CH₂(CO₂CH₂C₂H-μ)₂][Co₂(CO)₆]₂ 1a and [p-(HC₂CH₂OCO)C₆H₄(CO₂CH₂C₂H-μ)][Co₂(CO)₆] 2b have been determined by single crystal X-ray diffraction methods.     

PREPARATION AND CHARACTERIZATION OF CLUSTERS CONTAINING THE CoMRuS (M=Mo OR W) CORE

Abstract

The reaction of (μ₃-S)RuCo₂(CO)₉ with functionally substituted cyclopentadienyl tricarbonyl metal anions M(CO)₃(C₅H₄C(O)R) (M = Mo, W; R = OEt, CH₂CH₂COOMe) in THF under reflux gave new chiral skeleton clusters (μ₃-S)RuCoM(CO)₈(C₅H₄C(O)R) [M = Mo, R = OEt (1); M = W, R = OEt (2); M = Mo, R = CH₂CH₂COOMe (3); M = W, R = CH₂CH₂COOMe (4)]. These complexes were characterized by elemental analysis, IR and ¹H NMR spectra. The molecular structure of compound (1) was determined by single-crystal X-ray diffraction methods.     

Synthesis reactivity and electrochemical properties of substituted cyclopentadienyl cobalt (III) complexes

Cyclopentadienyl cobalt complexes (η⁵‐C₅H₄R) CoLI₂ [L = CO,R=‐COOCH₂CH=CH₂ (3); L=PPh₃, R=‐COOCH₂‐CH=CH₂ (6); L=P(p‐C₆H₄O₃)₃, R = ‐COOC(CH₃) = CH₂ (7), ‐COOCH₂C₆H₅ (8), ‐COOCH₂CH = CH₂ (9)] were prepared and characterized by elemental analyses, ¹H NMR, ER and UV‐vis spectra. The reaction of complexes (η⁵‐C₅H₄R)CoLI₂ [L= CO, R= ‐COOC(CH₃) = CH₂ (1), ‐COOCH₂C₆H₅(2); L=PPh₃, R=‐COOC (CH₃) = CH₂ (4), ‐COOCH₂C₆H₅ (5)] with Na‐Hg resulted in the formation of their corresponding substituted cobaltocene (η⁵‐C₅H₄R)₂ Co[R=‐COOC(CH₃) = CH₂ (10), ‐COOCH₂C₆H₅ (11)]. The electrochemical properties of these complexes 1–11 were studied by cyclic voltammetry. It was found that as the ligand (L) of the cobalt (III) complexes changing from CO to PPh₃ and P(p‐tolyl)₃, their oxidation potentials increased gradually. The cyclic voltammetry of α,α′‐substituted cobaltocene showed reversible oxidation of one electron process.     

Rhenium-Komplexe von Sauerstoffchelatliganden: Ein Weg zu neuen Radiopharmaka?

Rhenium Complexes Stabilized by Tris-chelating Oxygen Ligands: Potential New Radiopharmaca? Ris-chelating oxygen ligands of the general formula L^? = [(C₅H₄R)Co{P(O)R′R″}₃]^? (R = COOCH₃, COOH and R′ = OCH₃; R = H and R′ = O(CH₂)₅COOCH₃, O(CH₂)₅COOH; R″ = OCH₃) have been synthesized. These ligands L^? and others of the same type have been used to prepare the rhenium oxo complexes [LReO₃] and [LReOX₂] (X = Cl, Br, I). In order to judge their use in radioimmunotherapy the corresponding complexes containing radioactive rhenium isotopes have also been synthesized. The rhenium(VII) as well as the diamagnetic rhenium(V) complexes are stable in air in the solid state as well as in organic solvents. They hydrolyze slowly in water to yield perrhenic acid. The X-ray structures of the sodium salt Na[(C₅H₄COOCH₃)Co{P(O)(OCH₃)₂}₃] and of the rhenium complex [LReOBr₂] (R = H, R′ = R″ = OCH₃) have been determined. The sodium salt crystallizes in trimeric units with the composition [(NaL)₃ · 3 H₂O]. Each sodium has a distorted octahedral oxygen coordination. In [LReOBr₂] the ReO₄Br₂ octahedron is only slightly distorted.     

The 31P NMR spectra of ArCr(CO)2P(C6H5)3 compounds in neutral and acidic media

The ³¹P NMR spectra of C₆H₅XCr(CO)₂P(C₆H₅)₃ (X = H, CH₃, OCH₃, N(CH₃)₂, COOCH₃) (I), p-C₆H₄X₂Cr(CO)₂P(C₆H₅)₃ (X = COOCH₃)(II) and C₆H₃X₃Cr(CO)₂P(C₆H₅)₃ (X = CH₃) (III) complexes in neutral and acidic media were investigated. The protonation of complexes I and III in trifluoroacetic acid results in the greater upfield shielding of ³¹P{¹H} signal. In this case the complexes I (X = H, CH₃, OCH₃) are completely protonated at the metal, complex I (X = COOCH₃)is partially protonated, while no protonation occurs in the case of complex II.Temperature-dependence of the ³¹P{¹H} NMR spectra was investigated for complexes I (X = H, OCH₃) in a 1/10 mixture of trifluoroacetic acid and toluene and for complexes I (X = COOCH₃) and II in trifluoroacetic acid. The degree of protonation was found to increase with decreasing temperature.     

Syntheses and crystal structures of Dimolybdenum complexes containing P2 and functionalized Cyclopentadienyl ligands

The dimolybdenum complex [(η⁵-RC₅H₄)₂Mo₂(CO)₆] (1, R = CH₃CO; II, R = CH₃O₂C) reacts with an equimolar amount of white phosphorus P₄ to yield the corresponding dimolybdenum complex containing the P₂ ligand [(η⁵-RC₅H₄)₂Mo₂(CO)₄(μ,η²-P₂)] (1, R = CH₃CO; 2, R = CH₃O₂C) in moderate yield. The two new compounds have been characterized by elemental analyses, ¹H?NMR, ¹³C?NMR, ³¹ P?NMR and IR spectroscopies and their crystal structures have been determined by X-ray diffraction methods.     

Syntheses and Reactions of Dimolybdenum Alkyne Compounds Containing Functionally Substituted Ligands. The Crystal Structure of [Co2Mo2(μ4-CHCH)(μ-CO)4(CO)4-(η5-C5H4C(O)Me)2]

Abstract

Three dimolybdenum alkyne complexes containing functionally substituted ligands [Mo₂(μ-CHCH)(CO)₄(η⁵?C₅H₄C(O)R)₂] [R ? OEt, (1a); R ? Me, (1b); R ? Ph, (1c)] were synthesized by reactions of acetylene with in situ generated metal-metal triply bonded complexes [Mo(CO)₂(η⁵?C₅H₄C(O)R)]₂ (R ? OEt, Me, Ph). Further reaction of (1a), (1b) or (1c) with Co₂(CO)₈ in refluxing toluene gave another three new butterfly compounds [Co₂Mo₂-(μ₄-CHCH)(μ-CO)₄(CO)₄(η⁵-C₅H₄C(O)R)₂] [R ? OEt, (2a); R ? Me, (2b); R ? Ph, (2c)]. The resulting compounds were characterized by elemental analyses, IR, ¹H NMR and MS. The crystal structure of (2b) was determined by single-crystal X-ray analysis. The results indicate that the existence of functional groups on the cyclopentadienyl ring has an influence on the reactivity of this type of complex.     

Synthetic and Structural Studies on Some New Butterfly Fe/S Cluster Complexes Containing 2,6-(CH2)2C5H3N or (CH2)2 Groups

Four new butterfly Fe/S cluster complexes bearing 2,6-(CH₂)₂C₅H₃N or (CH₂)₂ groups, as the active site models of [FeFe]-hydrogenase, have been prepared by condensation reaction and structurally characterized. Treatments of the parent complex Fe₂(CO)₆[(μ-SCH₂)₂CHCO₂H] (A) with 2,6-(HOCH₂)₂C₅H₃N or HOCH₂CH₂OH in the presence of 4-dimethylaminopyridine and dicyclohexylcarbodiimide afforded the single-butterfly Fe/S complexes Fe₂(CO)₆[(μ-SCH₂)₂CHC(O)OCH₂(2,6-C₅H₃N)CH₂OH] (1) and Fe₂(CO)₆[(μ-SCH₂)₂CHC(O)OCH₂CH₂OH] (3) and the double-butterfly Fe/S complexes [Fe₂(CO)₆(μ-SCH₂)₂CHC(O)OCH₂]₂(2,6-C₅H₃N) (2) and [Fe₂(CO)₆(μ-SCH₂)₂CHC(O)OCH₂]₂ (4). The new complexes 1–4 were fully characterized by elemental analysis, ESI-MS, IR, and ¹H (¹³C) NMR spectroscopy.     

Structural studies of diiron complexes with monophosphine ligands tris(4-chlorophenyl)phosphine or diphenyl-2-pyridylphosphine

Four diiron dithiolate complexes with monophosphine ligands have been prepared and structurally characterized. Reactions of (μ-SCH₂CH₂S-μ)Fe₂(CO)₆ or [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₆ with tris(4-chlorophenyl)phosphine or diphenyl-2-pyridylphosphine in the presence of Me₃NO·2H₂O afforded diiron pentacarbonyl complexes with monophosphine ligands (μ-SCH₂CH₂S-μ)Fe₂(CO)₅[P(4-C₆H₄Cl)₃] (1), (μ-SCH₂CH₂S-μ)Fe₂(CO)₅[Ph₂P(2-C₅H₄N)] (2), [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₅[P(4-C₆H₄Cl)₃] (3), and [μ-SCH(CH₃)CH(CH₃)S-μ]Fe₂(CO)₅[Ph₂P(2-C₅H₄N)] (4) in good yields. Complexes 1–4 were characterized by elemental analysis, ¹H NMR, ³¹P{¹H} NMR and ¹³C{¹H} NMR spectroscopy. Furthermore, the molecular structures of 1–4 were confirmed by X-ray crystallography.     

Molybdenum alkyl- and aryl-thiolates

The reaction between [(η⁵-C₅H₅)MoH(CO)₃] and disulphides gives dimeric or trimeric complexes depending upon the conditions. The syntheses of the novel trinuclear molybdenum carbonyl complex [{Mo(η⁵-C₅H₅)(SR)(μ-CO)(CO)}₃] (R = Me), and dinuclear compounds [Mo₂(η⁵-C₅H₅)(μ-SR)₃(CO)₄] (R = Me) and [Mo₂(η⁵-C₅H₅)₂(SR)₂(CO)₂(μ-SR)(μ-Br)] (R = Me or Ph) are reported.     

Reaction of [Fe4(μ3-CCH3)(CO)12]− with alkynes: Ethylidyne-alkyne coupling on a tetranuclear iron cluster anion

The [Fe₄(μ₄-η³-C(CH₃)C(R)C(R′)(μ-CO)₂(CO)₉]⁻ cluster anions have been obtained by the reaction of the Fe₄(μ₃-CCH₃)(CO)₁₂⁻ anion with RCCR alkynes in boiling 3-pentanone. In the cases in which R = R′ = C₆H₅ or CH₃, and R = H, R′ = C₆H₅ or t-Bu, only one isomer has been detected. In the case in which R = CH₃, and R′ = C₆H₅, two isomers with the C(CH₃)C(C₆H₅)C(CH₃) and C(CH₃)C(CH₃)C(C₆H₅) fragments have been identified.     

Ligand shift in mixed-cluster complexes: synthesis of alkyne-bridged Co2Mo2 clusters with two triply-bridging sulphur atoms: crystal structure of [Co2Mo2(η5-Cp)2(μ3-S)2(μ4-CF3C2Me)(CO)4]

Reaction of the complexes [(CO)₃Co(μ-RC₂R′)Co(CO)₃] (R = R′ = CF₃; R = Ph, CF₃ and R′ = H) with the MoMo dinuclear derivative [Mo₂Cp₂(μ-SMe)₂(CO)₂] leads to cleavage of both CS and CH bonds with the formation of closo-octahedral Mo₂CO₂C₂ clusters stabilised by a μ₄-η²-bound alkyne. An X-ray diffraction study has shown that the two Mo₂Co faces of the octahedron are capped by triply-bridging sulphur atoms.     

Derivate des borabenzols: XVIII. Vanadium-komplexe Des 1-methyl- und 1-phenylborinat-ions

Six borabenzene derivatives of vanadium are described. Reaction of the alkali metal borinates M(C₅H₅BR) (M = Na, K; R = Me, Ph) with VCl₃ yields the paramagnetic, sandwich complexes V(C₅H₅BR)₂. Reaction with HgCl₂ and [Na{O(CH₂CH₂OCH₃)₂}₂][V(CO)₆] affords the tetracarbonyl compounds V(CO)₄(C₅H₅BR). Upon heating in cycloheptatriene, the latter compounds produce the paramagnetic cycloheptatrienyl complexes V(C₅H₅BR)(C₇H₇) with sandwich structures. An X-ray structural study of V(CO)₄(C₅H₅BMe) shows that the V(CO)₄ fragment in the crystal is rotated by 10.4° relative to an ideal, eclipsed conformation where two CO groups are present in the plane through the B, V and C(4) atoms.     

Syntheses and crystal structures of butterfly M2Te2 complexes of molybdenum and tungsten with functionalized cyclopentadienyl ligands

Reactions of singly-bonded dinuclear complexes [(η⁵-CH₃O₂CC₅H₄)₂M₂(CO)₆] (I, M?=?Mo; II, M?=?W) with the diarenylditelluride [4-CH₃C₆H₄Te]₂ in refluxing toluene for 4–6?h afforded dinuclear complexes 1 and 2 trans/ae-[(η⁵-RC₅H₄)₂M₂(CO)₄(μ-ArTe)₂] (Ar?=?4-CH₃C₆H₄Te). Complexes 1 and 2 were also synthesized by reactions of triply-bonded dinuclear complexes [(η⁵-CH₃O₂CC₅H₄)₂M₂(CO)₄] (III, M?=?Mo; IV, M?=?W) with [4-CH₃C₆H₄Te]₂ in refluxing toluene for 1?h. Both complexes have been characterized by elemental analysis, ¹H NMR, ¹³C NMR and IR spectroscopy and X-ray diffraction. Preliminary low-temperature NMR experiments on complexes 1 and 2 have revealed that in solution each complex goes through a rapid inversion of the butterfly four-membered ring M₂Te₂.     

Synthetic and structural studies of the diiron toluenedithiolate carbonyl complexes with monophosphine ligands

Four diiron toluenedithiolate complexes 2–5 with monophosphine ligands are reported. Treatment of [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₆ (1) with tris(3-chlorophenyl)phosphine, tris(4-chlorophenyl)phosphine, tris(4-methylphenyl)phosphine or 2-(diphenylphosphino)benzaldehyde, and Me₃NO?2H₂O in MeCN resulted in the formation of [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[P(3-C₆H₄Cl)₃] (2), [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[P(4-C₆H₄Cl)₃] (3), [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[P(4-C₆H₄CH₃)₃] (4), and [μ-SC₆H₃(CH₃)S-μ]Fe₂(CO)₅[Ph₂P(2-C₆H₄CHO)] (5) in 64–82% yields. Complexes 2–5 have been characterized by elemental analysis, IR, ¹H NMR, ³¹P{¹H} NMR, ¹³C{¹H} NMR and further confirmed by single crystal X-ray diffraction analysis. The molecular structures show that 2–5 contain a butterfly diiron toluenedithiolate cluster coordinated by five terminal carbonyls and an apical monophosphine.     

Reactions of GeMe2-bridged dicyclopentadienes with molybdenum carbonyl: formation of germylidyne trimolybdenum clusters

In thermal reactions of the doubly bridged dicyclopentadienes (C₅H₃R(SiMe₂))(C₅H₃R(GeMe₂)) (R=H (1), ^tBu (5)) with Mo(CO)₆, the bridging GeMe₂ is cleaved to give the corresponding degermylated products [(η⁵-C₅H₃R)₂(SiMe₂)]Mo₂(CO)₆ (3, rac-7), or both GeMe₂ and SiMe₂ are cleaved to afford the nonbridged products [(η⁵-C₅H₄R)Mo(CO)₃]₂ (2, 6). The reactions also produce germylidyne trimolybdenum clusters [(η⁵-C₅H₃R)₂(SiMe₂)](η⁵-C₅H₄R)[Mo(CO)₂]₃(μ₃-GeMe) (4, rac-/meso-7) containing the Mo₃(μ₃-GeMe) units. Similarly, reaction of the single GeMe₂-bridged dicyclopentadienes (C₅H₅)₂GeMe₂ (9) with Mo(CO)₆ also results in the degermylated 2, as well as the similar trimolybdenum cluster [(η⁵-C₅H₅)Mo(CO)₂]₃(μ₃-GeMe) (10). The molecular structures of 4 and trans-5 were determined by X-ray diffraction.     

Bis(alkoxycarbonyl) complexes of platinum: preparation,reactivity and their role in carbonylation reactions

bis(alkoxycarbonyl) complexes of platinum of the type [Pt(COOR)₂L] [L = 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp), l,4-bis(diphenylphosphino)butane (dppb), 1,1'-bis(diphenylphosphino)ferrocene (dppf) or 1,2-bis-(diphenylphosphino)benzene (dpb); R = CH₃, C₆H₅ or C₂H₅] were obtained by reaction of [PtCl₂L] with carbon monoxide and alkoxides. Palladium and nickel complexes gave only carbonyl complexes of the type [M(CO)L] or [M(CO)₂L]. The new complexes were characterized by chemical and spectroscopic means. The X-ray structure of [Pt(COOCH₃)₂(dppf] · CH₃OH is also reported. The reactivity of some alkoxycarbonyl complexes was also investigated.     

η4‐HBCC‐σ,π‐Borataallyl Complexes of Ruthenium Comprising an Agostic Interaction

Thermolysis of [Cp*Ru(PPh₂(CH₂)PPh₂)BH₂(L₂)] 1 (Cp*=η⁵‐C₅Me₅; L=C₇H₄NS₂), with terminal alkynes led to the formation of η⁴‐σ,π‐borataallyl complexes [Cp*Ru(μ‐H)B{R‐C=CH₂}(L)₂] ( 2 a – c ) and η²‐vinylborane complexes [Cp*Ru(R‐C=CH₂)BH(L)₂] ( 3 a – c ) ( 2 a , 3 a : R=Ph; 2 b , 3 b : R=COOCH₃; 2 c , 3 c : R=p‐CH₃‐C₆H₄; L=C₇H₄NS₂) through hydroboration reaction. Ruthenium and the HBCC unit of the vinylborane moiety in 2 a – c are linked by a unique η⁴‐interaction. Conversions of 1 into 3 a – c proceed through the formation of intermediates 2 a – c . Furthermore, in an attempt to expand the library of these novel complexes, chemistry of σ‐borane complex [Cp*RuCO(μ‐H)BH₂L] 4 (L=C₇H₄NS₂) was investigated with both internal and terminal alkynes. Interestingly, under photolytic conditions, 4 reacts with methyl propiolate to generate the η⁴‐σ,π‐borataallyl complexes [Cp*Ru(μ‐H)BH{R‐C=CH₂}(L)] 5 and [Cp*Ru(μ‐H)BH{HC=CH‐R}(L)] 6 (R=COOCH₃; L=C₇H₄NS₂) by Markovnikov and anti‐Markovnikov hydroboration. In an extension, photolysis of 4 in the presence of dimethyl acetylenedicarboxylate yielded η⁴‐σ,π‐borataallyl complex [Cp*Ru(μ‐H)BH{R‐C=CH‐R}(L)] 7 (R=COOCH₃; L=C₇H₄NS₂). An agostic interaction was also found to be present in 2 a – c and 5 – 7 , which is rare among the borataallyl complexes. All the new compounds have been characterized in solution by IR, ¹H, ¹¹B, ¹³C NMR spectroscopy, mass spectrometry and the structural types were unequivocally established by crystallographic analysis of 2 b , 3 a – c and 5 – 7 . DFT calculations were performed to evaluate possible bonding and electronic structures of the new compounds.     

Conjugate additions of functionalized carbanions to the vinylidene groups of [M(CO)4{(Ph2P)2CCH2}] (M = W,Mo or Cr)

Treatment of complexes of the type [M(CO)₄{(Ph₂P)₂CCH₂}] (M = W, Mo or Cr) with functionalized lithium reagents, LiR, followed by hydrolysis gives complexes of the type [M(CO)₄{PH₂P)₂CHCH₂R}] in high yields; R = C₆H₄Me-4, C₆H₄OMe-2, C₆H₃(OMe)₂-2,6, C₆H₄OH-2, C₆H₄(COOH)-2, CH₂COPh or CH₂COMe. IR, and ³¹P and ¹H NMR data are given.     

Synthesis and characterization of linked alkyne-bridging Co2C2 tetrahedral clusters and expansion reactions of (Co2(CO)6(μ-HCCCH2OOC))2R with Fe3(CO)12

Two new linked alkyne-bridging tetrahedral carbonyl clusters containing Co₂C₂ Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₃COOCH₂CCH-μ)Co₂(CO)₆, 1, and Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₈COOCH₂CCH-μ)Co₂(CO)₆, 2, have been prepared by reactions of two dipropargyl esters (HC≡CCH₂OOC)₂R (R = (CH₂)₃, (CH₂)₈) with Co₂(CO)₈. Expansion reactions of 1 and Co₂(CO)₆(μ-HCCCH₂OOCCOOCH₂CCH-μ)Co₂(CO)₆, 3, with Fe₃(CO)₁₂ give two new mixed-metal linked clusters Co₂(CO)₆(μ-HCCCH₂OOC(CH₂)₃COOCH₂CCH-μ,η⁴)Co₂Fe₂(CO)₁₂, 4, and Co₂(CO)₆(μ-HCCCH₂OOCCOOCH₂CCH-μ,η⁴)Co₂Fe₂(CO)₁₂, 5. The new clusters were characterized by elemental analysis, IR, ¹H-NMR and ESI-MS analysis.