Synthesis of new isoxazolidine (η<Superscript>5</Superscript>-cyclopentadienyl)manganese tricarbonyl complexes by 1,3-dipolar cycloaddition reaction

1,3-Dipolar cycloaddition reactions of nitrones of general formula R²CH=N(O)R¹, where R¹ = Me, Bu^t, Ph, R² = Ph, Cp[Mn(CO)₃] with styrene and vinyl-η⁵-(cyclopentadienyl) manganese tricarbonyl were studied. The products of these reactions, i.e., isoxazolidines, were isolated, purified, and identified. A high selectivity of the cycloaddition reactions involving both dipoles and dipolarophiles containing cyclopentadienylmanganese tricarbonyl group was demonstrated.     

ETC and Thermal Ligand Substitution in PhCCo3(CO)9 with 2,3-Bis(diphenylphosphino)-N-phenylmaleimide(bppm). X-Ray Diffraction Structure of Co3(CO)6[μ2,η2, η1-C(Ph)(O)](μ2-PPh2)

The reactivity of the bidentate ligand 2,3-bis(diphenylphosphino)-N-phenylmaleimide (bppm) with the tetrahedrane cluster PhCCo₃(CO)₉ under thermolysis and ETC conditions has been studied and found to ultimately give Co₃(CO)₆[μ₂,η²,η¹-C(Ph) ${\text{C}}{\text{ = }}{\text{ = }}{\text{C(PPh}}_{\text{2}} {\text{)C(O)NPhC}}$ (O)](μ₂-PPh₂) as the final product. The intermediate cluster compound PhCCo₃(CO)₇(bppm), which was observed by IR and ³¹P NMR spectroscopies, readily and rapidly transforms into the product cluster under the reactions conditions. The solid-state structure of Co₃(CO)₆[μ₂,η²,η¹-C(Ph)fptt(O)](μ₂-PPh$_{2})$ was unequivocally determined by X-ray crystallography. Co₃(CO)₆[μ₂, η², η¹-C(Ph)Õ(O)](μ₂-PPh₂) crystallizes in the monoclinic space group P2(1)/n, a = 11.825(5) Å, b = 31.20(1) Å, c = 11.831(5) Å, β = 108.720(7)°, V = 4134(7) ų, Z = 4, d _calc = 1.567 Mg/m³; R = 0.0350, R _w = 0.0817 for 4747 observed reflections with I > 2σ(I). The X-ray structure confirms the coupling of the benzylidyne ligand with the bppm ligand in Co₃(CO)₆[μ₂,η²,η¹-C(Ph)Õ(O)](μ₂-PPh₂). The course of the thermolysis reaction is identical to those reactions carried out with the related diphosphine ligands bma and bpcd. The utility of electron-transfer catalysis (ETC) in the preparation of PhCCo₃(CO)₇(bppm) is discussed relative to the reduction potential of the bppm ligand and the tricobalt cluster PhCCo₃(CO)₉.     

Synthese,Struktur und Reaktivität von funktionalisierten Stibanidokomplexen des Eisens und Rutheniums [(η5-C5Me5)(CO)2MSbR1R2] (M = Fe,Ru; R1, R2 = SiMe3, C(O)tBu,C(O)Ph,C(O)-1 Ad)

Synthesis, Structure, and Reactivity of Functionalized Stibanido Complexes of Iron and Ruthenium [(η⁵-C₅Me₅)(CO)₂MSbR¹R²] (M = Fe, Ru; R¹, R² = SiMe₃, C(O) t Bu, C(O)Ph, C(O)-1 Ad) The reaction of equimolar amounts of [(η⁵-C₅Me₅)(CO)₂RuSb(SiMe₃)₂] ( 1 b ) and the carboxylic chlorides RC(O)Cl (R = tBu, Ph, 1-adamantyl) afforded the acyl(trimethylsilyl)stibanido complexes [(η⁵-C₅Me₅)(CO)₂RuSb · {C(O)R}(SiMe₃)] 2 b (R = tBu), 4 b (R = Ph), and 6 b (R = 1-Ad). The treatment of 1 b with two molar equivalents of pivaloyl chloride and benzoyl chloride led to the diacylstibanido complexes [(η⁵-C₅Me₅)(CO)₂RuSb{C(O)R}₂] ( 3 b , 5 b ). Analogously, the iron complex [(η⁵-C₅Me₅)(CO)₂FeSb · (SiMe₃)₂] ( 1 a ) is converted into the corresponding diacylstibanido complexes 3 a (R = tBu), 5 a (R = Ph) and 7 a (R = 1-Ad) by an excess of acid chloride. The treatment of 1 a with equimolar amounts of RC(O)Cl gave inseparable mixtures of starting material and the monoacyl- and diacyl stibanido complexes. Oxalyl chloride reacted quantitatively with two equivalents of 1 a to give complex [{(η⁵-C₅Me₅) · (CO)₂FeSb(SiMe₃)C(O)}₂] ( 8 ). The molecular structures of 1 a , 2 b and 5 b were elucidated by single crystal X-ray analyses.     

Chalcogen–acetylide interaction and unusual reactivity of coordinated acetylide with water: synthesis and characterisation of [(η5-C5R5)Fe3(CO)6(μ3-E)(μ3-ECCH2RI)] (R=H,Me; RI=Ph,Fc; E=S,Se) and [(η5-C5R5)MoFe2(CO)6(μ3-S)(μ-SCCH2Ph)] (R=H,Me)

Photolysis of a benzene solution containing [Fe₃(CO)₉(μ₃-E)₂] (E=S, Se), [(η⁵-C₅R₅)Fe(CO)₂(CCR^I)] (R=H, Me; R^I=Ph, Fc), H₂O and Et₃N results in formation of new metal clusters [(η⁵-C₅R₅)Fe₃(CO)₆(μ₃-E)(μ₃-ECCH₂R^I)] (R=H, R^I=Ph, E=S 1 or Se 2; R=Me, R^I=Ph, E=S 3 or Se 4; R=H, R^I=Fc, E=S 5; R=Me, R^I=Fc, E=S 6 or Se 7). Reaction of [Fe₃(CO)₉(μ₃-S)₂]with [(η⁵-C₅R₅)Mo(CO)₃(CCPh)] (R=H, Me), under same conditions, produces mixed-metal clusters [(η⁵-C₅R₅)MoFe₂(CO)₆(μ₃-S)(μ-SCCH₂Ph)] (R=H 8; R=Me 9). Compounds 1–9 have been characterised by IR and ¹H and ¹³C-NMR spectroscopy. Structures of 1, 5 and 9 have been established crystallographically. A common feature in all these products is the formation of new C-chalcogen bond to give rise to a (ECCH₂R^I) ligand.     

Reactions of a phosphido-bridged unsymmetrical diiron complex (η-C5Me5)Fe2(CO)4(μ-CO)(μ-PPh2) with various alkynes

A phosphido-bridged unsymmetrical diiron complex (η⁵-C₅Me₅)Fe₂(CO)₄(μ-CO)(μ-PPh₂) (1) was synthesized by a new convenient method; photo-dissociation of a CO ligand from (η⁵-C₅Me₅)Fe₂(CO)₆(μ-PPh₂) (2) that was prepared by the reaction of Li[Fe(CO)₄PPh₂] with (η⁵-C₅Me₅)Fe(CO)₂I. The reactivity of 1 toward various alkynes was studied. The reaction of 1 with ^tBuCCH gave a 1:1 mixture of two isomeric complexes (η⁵-C₅Me₅)Fe₂(CO)₃(μ-PPh₂)[μ-CHC(^tBu)C(O)] (3) containing a ketoalkenyl ligand. The reactions of 1 with other terminal alkynes RCCH (R=H, CO₂Me, Ph) afforded complexes incorporating one or two molecules of alkynes and a carbonyl group. The principal products were dinuclear complexes bridged by a new phosphinoketoalkenyl ligand, (η⁵-C₅Me₅)Fe₂(CO)₃(μ-CO)[μ-CR¹CR²C(O)PPh₂] (4a: R¹=H, R²=H; 4b: R¹=CO₂Me, R²=H; 4c: R¹=H, R²=Ph). In the cases of alkynes RCCH (R=H, CO₂Me), dinuclear complexes having a new ligand composed of two molecules of alkynes, a carbonyl group, and a phosphido group; i.e. (η⁵-C₅Me₅)Fe₂(CO)₃[μ-CRCHCHCRC(O)PPh₂] (5a: R=H; 5b: R=CO₂Me), were also obtained. In all cases, mononuclear complexes, (η⁵-C₅Me₅)Fe(CO)[CR¹CR²C(O)PPh₂] (6a: R¹=H, R²=H; 6b: R¹=H, R²=CO₂Me; 6c: R¹=H, R²=Ph) were isolated in low yields. The structures of 1, 4c, 5b, and 6a were confirmed by X-ray crystallography. The detailed structures of the products and plausible reaction mechanisms are discussed.     

Zur Reaktivität der Ferriophosphaalkene [(η5‐C5Me5)(CO)2FeP=C(NR)R2] (NR = NMe2, NC5H10, R2 = Ph,tBu) gegenüber Protonsäuren,Alkylierungsmitteln und [{(Z)‐Cycloocten}Cr(CO)5]

Transition Metal‐substituted Phosphaalkenes. 42 Reactivity of the Ferriophosphaalkenes [(η⁵‐C₅Me₅)(CO)₂FeP=C(NR )R²] (NR = NMe₂, NC₅H₁₀, R² = Ph, t Bu) towards Protic Acids, Alkylation Reagents, and [{( Z )‐Cyclooctene}Cr(CO)₅] The reaction of equimolar amounts of [(η⁵‐C₅Me₅)(CO)₂FeP=C(NR )R²] ( 2 a : NR = NMe₂, R² = Ph; 2 b : NMe₂. tBu; 2 c : NC₅H₁₀, Ph) and etherial HBF₄ gave rise to the formation of [(η⁵‐C₅Me₅)(CO)₂FeP(H)C(NR )R²] (BF₄) ( 3 a – c ) which were isolated as light red powders. Compounds 2 a – c were converted into [(η⁵‐C₅Me₅)(CO)₂FeP(Me)C(NR )R²] (SO₃CF₃) ( 4 a – c ) by treatment with methyl trifluoromethane sulfonate. In addition 2 a and Me₃SiCH₂OSO₂CF₃ afforded light red [(η⁵‐C₅Me₅)(CO)₂FeP(CH₂SiMe₃)C(NMe₂)Ph](SO₃CF₃) ( 5 ). The black complex [(η⁵‐C₅Me₅)(CO)₂FeP{Cr(CO)₅}C(NMe₂)Ph] ( 6 ) resulted from the combination of 2 a with [{(Z)‐cyclooctene}Cr(CO)₅]. The novel products were characterized by elemental analyses and spectra (IR, ¹H‐, ¹³C‐ und ³¹P‐NMR).     

The formation of dimetallocycles from reactions of alkynes with (η-C5Me5)2Rh2(CO)2; X-ray structure of [(η-C5Me5)2Rh2(η-CO) {μ-η2,η2-C(O)C2-(CF3)2}]

The complexes (η-C₅Me₅)₂Rh₂(μ-CO) {μ-η²,η²-C(O)CRCR} are obtained from reactions between (η-C₅Me₅)₂Rh₂(CO)₂ and the alkynes RCCR (R  CF₃, CO₂Me, or Ph) at 25°C. The molecular geometry of the complex with R  CF₃ has been established by X-ray diffraction; the bridging 'ene-one' unit adopts a μ-η²,η² conformation. Other complexes isolated from these reactions include (η-C₅Me₅)Rh(C₆R₆) (R  CF₃, CO₂Me), (η-C₅Me)₂Rh₂(C₄R₄) (R  CO₂Me) and (η-C₅Me₅)₂Rh₂(CO₂C₂R₂) (R  Ph). The reaction between (η-C₅Me₅)₂Rh₂(CO)₂ and C₆F₅CCC₆F₅ gives (η-C₅Me₅)₂Rh₂(CO)₂(C₆F₅C₂C₆F₅). Mononuclear complexes such as (η-C₅Me₅)Co(C₄R₄CO) are the major products isolated from reactions between (η-C₅Me₅)₂CO₂(CO)₂ and alkynes at 25°C.     

Über den Phosphandiyl‐Transfer von invers‐polarisierten Phosphaalkenen R1P=C(NMe2)2 (R1 = tBu,Cy, Ph,H) auf Phospheniumkomplexe [(η5‐C5H5)(CO)2M=P(R2)R3] (R2 = R3 = Ph; R2 = tBu,R3 = H; R2 = Ph,R3 = N(SiMe3)2)

Phosphanediyl Transfer from Inversely Polarized Phosphaalkenes R¹P=C(NMe₂)₂ (R¹ = tBu, Cy, Ph, H) onto Phosphenium Complexes [(η⁵‐C₅H₅)(CO)₂M=P(R²)R³] (R² = R³ = Ph; R² = tBu, R³ = H; R² = Ph, R³ = N(SiMe₃)₂) Reaction of the freshly prepared phosphenium tungsten complex [(η⁵‐C₅H₅)(CO)₂W=PPh₂] ( 3 ) with the inversely polarized phosphaalkenes RP=C(NMe₂)₂ ( 1 ) ( a : R = tBu; b : Cy; c : Ph) led to the η²‐diphosphanyl complexes ( 9a‐c ) which were isolated by column chromatography as yellow crystals in 24‐30 % yield. Similarly, phosphenium complexes [(η⁵‐C₅H₅)(CO)₂M=P(H)tBu] (M = W ( 6 ); Mo ( 8 )) were converted into (M = W ( 11 ); Mo ( 12 )) by the formal abstraction of the phosphanediyl [PtBu] from 1a . Treatment of [(η⁵‐C₅H₅)(CO)₂W=P(Ph)N(SiMe₃)₂] ( 4 ) with HP=C(NMe₂)₂ ( 1d ) gave rise to the formation of yellow crystalline ( 10 ). The products were characterized by elemental analyses and spectra (IR, ¹H, ¹³C‐, ³¹P‐NMR, MS). The molecular structure of compound 10 was elucidated by an X‐ray diffraction analysis.     

Synthese und spektroskopische Charakterisierung einiger Pentacarbonylwolfram(0)‐Komplexe mit monound bicyclischen Phosphiran‐Liganden: Kristallstruktur von [{(Me3Si)2HCPC(H)H–C(H)Ph}W(CO)5]

Synthesis and Spectroscopic Characterisation of some Pentacarbonyltungsten(0) Complexes with Mono‐ and Bicyclic Phosphirane Ligands: Crystal Structure of [{(Me₃Si)₂HCPC(H)H–C(H)Ph}W(CO)₅] The tungsten(0) complex [{(Me₃Si)₂HCPC(Ph)=N}W(CO)₅] ( 1 ) reacts upon heating with alkene derivatives 2 , 6 , 8 , and 10 in toluene to form benzonitrile and the complexes [{(Me₃Si)₂HCPC(R¹,R²)–C(R³,R⁴}W(CO)₅] ( 4 , 7 a , b , 9 a , b , 11 a , b ) ( 4 (trans): R¹,R³ = Ph, R²,R⁴ = H, 7 a , b (cis, meso and rac): R¹,R³ = Ph, R²,R⁴ = H, 9 a , b (RR und SS): R¹ = Ph, R²,R³,R⁴ = H, 11 a , b : R¹=R³ = (CH₂)₄, R²,R⁴ = H). Spectroscopic and mass spectrometric data are discussed. The structure of the complex 9 a was determined by X‐ray single crystal structure analysis showing characteristic data for the phosphirane ring such as a narrow angle at phosphorus (49,2(2)°), different P–C distances (P–C(6) 182,1(5) and P–C(7) 185,2(4) pm) and 152,9(6) pm for the basal C–C bond.     

Chemistry of Fischer-type rhenacyclobutadiene complexes. II. Reactions with alkynes and sulfonium ylides, and rearrangements induced by nitriles and pyridine

Further investigations into the chemistry of the rhenacyclobutadiene complexes (CO)₄Re(η²-C(R)C(CO₂Me)C(X)) (1: R=Me, X=OEt (1a), O(CH₂)₃CCH (1b), NEt₂ (1c); R=CHEt₂, X=OEt (1d); R=Ph, X=OEt (1e)) are reported. Reactions of 1 with alkynes at reflux temperature of toluene and at ambient temperature either under photochemical conditions or in the presence of PdO yield ring-substituted η⁵-cyclopentadienylrhenium tricarbonyl complexes, 2. The symmetrical alkynes R^′CCR^′ (R^′=Ph, Me, CO₂Me) afford the pentasubstituted complexes (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)(Ph))Re(CO)₃ (2d), (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Me))Re(CO)₃ (2e), (η⁵-C₅(Me)(CO₂Me)(OEt)(CO₂Me)(CO₂Me))Re(CO)₃ (2f), and (η⁵-C₅(Me)(CO₂Me)(NEt₂)(CO₂Me)(CO₂Me))Re(CO)₃ (2i) on reaction with the appropriate 1, whereas the unsymmetrical alkynes R^′CCR″ (R^′=Ph; R″=H, Me) give either only one, (η⁵-C₅(Me)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2a)), or both, (η⁵-C₅(Me)(CO₂Me) (OEt)(Ph)(Me))Re(CO)₃ (2b) and (η⁵-C₅(Me)(CO₂Me)(OEt)(Me)(Ph))Re(CO)₃ (2c), (η⁵-C₅(Ph)(CO₂Me)(OEt)(Ph)H)Re(CO)₃ (2g) and (η⁵-C₅(Ph)(CO₂Me)(OEt)(H)(Ph))Re(CO)₃ (2h), of the possible products of [3 + 2] cycloaddition of alkyne to η²-C(R)C(CO₂Me)C(X). Thermolysis of (CO)₄Re(η²-C(Me)C(CO₂Me)C(O(CH₂)₃CCH)) (1b) containing a pendant alkynyl group proceeds to (η⁵-C₅(Me)(CO₂Me)(O(CH₂)₃)H)Re(CO)₃ (2j), a η⁵-cyclopentadienyl-dihydropyran fused-ring product. Competition experiments showed that each of PhCCH and MeO₂CCCCO₂Me reacts faster than PhCCPh with 1a. The results with unsymmetrical alkynes are rationalized by steric properties of substituents at the CC and ReC bonds and by a preference of ReC(Me) over ReC(OEt) to undergo alkyne insertion. A mechanism is proposed that involves substitution of a trans CO by alkyne in 1, insertion of alkyne into ReC bond to give a rhenabenzene intermediate, and collapse of the latter to 2. Complexes 1a and 1d undergo rearrangement in MeCN at reflux temperature to give rhenafuran-like products, (CO)₄Re(κ²-OC(OMe)C(CHCR₂)C(OEt)) (R=H (3a) or Et (3b)). The reaction of 1d also proceeds in EtCN, PhCN, and t-BuCN at comparable temperature, but is slower (especially in t-BuCN) than in MeCN. In pyridine at reflux temperature, 1a undergoes a similar rearrangement, with CO substitution, to give (CO)₃(py)Re(κ²-OC(OMe)C(CHCEt₂)C(OEt)) (4). A mechanism is proposed for these reactions. The sulfonium ylides Me₂SCHC(O)Ph and Me₂SC(CN)₂ (Me₂SCRR^′) react with 1a in acetonitrile at reflux temperature by nucleophilic addition of the ylide to the ReC(Me) carbon, loss of Me₂S, and rearrangement to a rhenafuran-type structure to yield (CO)₄Re(κ²-OC(OMe)C(C(Me)CRR^′)C(OEt)) (R=H, R^′=C(O)Ph (5a); R=R^′CN (5b)). All new compounds were characterized by a combination of elemental analysis, mass spectrometry, and IR and NMR spectroscopy.     

Derivative des borols: VI. Dehydrierende komplexierung von borolenen mit carbonylmetallen: (borol)metall-komplexe von mangan,eisen und cobalt

The reaction of 2-borolenes and 3-borolenes C₄H₆BR (R = Ph, Me, C₆H₁₁, OMe) with Mn, Fe, and Co carbonyls leads to dehydrogenating complexation with formation of simple, i.e. C-unsubstituted (η⁵-borole)metal complexes. Thus, Mn₂(CO)₁₀ gives the triple-decked complexes (μ-η⁵-C₄H₄BR)[Mn(CO)₃]₂ (R = Ph, OMe). By irradiation of Fe(CO)₅ the half-sandwich complexes Fe(CO)₃ (η⁵-C₄H₄BR) (R = Ph, Me, C₆H₁₁, OMe) are formed, whereas Co₂(CO)₈ yields the dinuclear complexes (μ-CO)₂[Co(CO)(η⁵-C₄H₄BR)]₂ (Co-Co) (R = Ph, Me). A low-temperature X-ray structure determination of Fe(CO)₃(η⁵-C₄H₄BPh) is described in detail.     

Palladium(II) compounds with planar chirality. X-Ray crystal structures of (+)-(R)-[{(η5-C5H4)–CHN–CH(Me)–C10H7}Fe(η5-C5H5)] and (+)-(Rp,R)-[Pd{[(Et–CC–Et)2(η5-C5H3)–CHN–CH(Me)–C10H7]Fe(η5-C5H5)}Cl]

A wide variety of planar chiral cyclopalladated compounds of general formulae [Pd{[(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}Cl(L)] (with L=py-d₅ or PPh₃), [Pd{[(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}(acac)] or [Pd{[(R¹–CC–R²)₂(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}Cl] (with R¹=R²=Et; R¹=Me, R²=Ph; R¹=H, R²=Ph; R¹=R²=Ph; R¹=R²=CO₂Me or R¹=CO₂Et, R²=Ph) are reported. The diastereomers {(R_p,R) and (S_p,R)} of these compounds have been isolated by either column chromatography or fractional crystallization. The free ligand (R)-(+)-[{(η⁵-C₅H₄)–CHN–CH(Me)–C₁₀H₇}Fe(η⁵–C₅H₅)] (1) and compound (+)-(R_p,R)-[Pd{[(Et–CC–Et)₂(η⁵-C₅H₃)–CHN–CH(Me)–C₁₀H₇]Fe(η⁵-C₅H₅)}Cl] (7a) have also been characterized by X-ray diffraction. Electrochemical studies based on cyclic voltammetries of all the compounds are also reported.     

Synthesis,structural characterisation and reactivity of molybdenum half-sandwich complexes containing keto- and amido-phosphines

The keto-functionalised N-pyrrolyl phosphine ligand PPh₂NC₄H₃{C(O)CH₃-2} L¹ reacts with [MoCl(CO)₃(η⁵-C₅R₅)] (R=H, Me) to give [MoCl(CO)₂(L¹-κ¹P)(η⁵-C₅R₅)] (R=H 1a; Me 1b). The phosphine ligands PPh₂CH₂C(O)Ph (L²) and PPh₂CH₂C(O)NPh₂ (L³) react with [MoCl(CO)₃(η⁵-C₅R₅)] in an analogous manner to give the compounds [MoCl(CO)₂(L-κ¹P)(η⁵-C₅R₅)] (L=L², R=H 2a, Me 2b; L=L³, R=H 3a, Me 3b). Compounds 1–3 react with AgBF₄ to give [Mo(CO)₂(L-κ²P,O)(η⁵-C₅R₅)]BF₄ (L=L¹, R=H 4a, Me 4b; L=L², R=H 5a, Me 5b; L=L³, R=H 6a, Me 6b) following displacement of chloride. The X-ray crystal structure of 4a revealed a lengthening of both Mo–P and CO bonds on co-ordination of the keto group. The lability of the co-ordinated keto or amido group has been assessed by addition of a range of phosphines to compounds 4–6. Compound 4a reacts with PMe₃, PMe₂Ph and PMePh₂ to give [Mo(CO)₂(L¹-κ¹P)(L)(η⁵-C₅H₅)]BF₄ (L=PMe₃ 7a; PMe₂Ph 7b; PMePh₂ 7c) but does not react with PPh₃, 5a reacts with PMe₂Ph, PMePh₂ and PPh₃ to give [Mo(CO)₂(L²-κ¹P)(L)(η⁵-C₅H₅)]BF₄ (L=PMe₂Ph 8b; PMePh₂ 8c; PPh₃ 8d), and 6a reacts with PMe₃, PMe₂Ph, PMePh₂ and PPh₃ to give [Mo(CO)₂(L³-κ¹P)(L)(η⁵-C₅H₅)]BF₄ (L=PMe₃ 10a; PMe₂Ph 10b; PMePh₂ 10c; PPh₃ 10d). No reaction was observed for the pentamethylcyclopentadienyl compounds 4b–6b with PMe₃, PMe₂Ph, PMePh₂ or PPh₃. These results are consistent with the displacement of the co-ordinated oxygen atom being influenced by the steric properties of the P,O-ligand, with PPh₃ displacing the keto group from L² but not from the bulkier L¹. In the reaction of [Mo(CO)₂(L²-κ²P,O)(η⁵-C₅H₅)]BF₄ (5a) with PMe₃ the phosphine does not displace the keto group, instead it acts as a base, with the only observed molybdenum-containing product being the enolate compound [Mo(CO)₂{PPh₂CHC(O)Ph-κ²P,O}(η⁵-C₅H₅)] 9. Compound 9 can also be formed from the reaction of 2a with BuLi or NEt₃, and a single crystal X-ray analysis has confirmed the enolate structure.     

Synthese,Struktur und Reaktivität des Ferrioarsaalkens [(η5‐C5Me5)(CO)2FeAs=C(Ph)NMe2]

Synthesis, Structure, and Reactivity of the Ferrioarsaalkene [(η⁵‐C₅Me₅)(CO)₂FeAs=C(Ph)NMe₂] Reaction of equimolar amounts of the carbenium iodide [Me₂N(Ph)CSMe]I and LiAs(SiMe₃)₂ · 1.5 THF afforded the thermolabile arsaalkene Me₃SiAs = C(Ph)NMe₂ ( 1 ), which in situ was converted into the black crystalline ferrioarsaalkene [(η⁵‐C₅Me₅)(CO)₂FeAs=C(Ph)NMe₂)] ( 2 ) by treatment with [(η⁵‐C₅Me₅)(CO)₂FeCl]. Compound 2 was protonated by ethereal HBF₄ to yield [(η⁵‐C₅Me₅)(CO)₂FeAs(H)C(Ph)NMe₂]BF₄ ( 3 ) and methylated by CF₃SO₃Me to give [(η⁵‐C₅Me₅)(CO)₂FeAs(Me)C(Ph)NMe₂]‐ SO₃CF₃ ( 4 ). [(η⁵‐C₅Me₅)(CO)₂FeAs[M(CO)_n]C(Ph)NMe₂] ( 5 : [M(CO)_n] = [Fe(CO)₄]; 6 : [Cr(CO)₅]) were isolated from the reaction of 2 with [Fe₂(CO)₉] or [{(Z)‐cyclooctene}Cr(CO)₅], respectively. Compounds 2 – 6 were characterized by means of elemental analyses and spectroscopy (IR, ¹H, ¹³C{¹H}‐NMR). The molecular structure of 2 was determined by X‐ray diffraction analysis.     

Cluster-containing carbon-rich molecules: Reactions of ruthenium cluster carbonyls with {Au(PR3)}2(μ-CCCC) (R = Ph, tol)

Complexes containing C₄ ligands attached to one or two AuRu₃ clusters by conventional σ, 2π interactions have been obtained from reactions between (R₃P)AuC≡CC≡CAu(PR₃) (R = Ph, tol) or Au(C≡CC≡CH){P(tol)₃} and either Ru₃(CO)₁₂, Ru₃(CO)₁₀(NCMe)₂ or Ru₃(μ-dppm)(CO)₁₀. The X-ray determined structures of {(R₃P)AuRu₃(CO)₉}₂(μ₃,η²:μ₃,η²-C₂C₂) [R = Ph (1) (three solvates), tol (2)], AuRu₃{μ₃,η²-C₂C≡CAu(PPh₃)}(CO)₉(PPh₃) (3) and {(Ph₃P)AuRu₃(μ-dppm)(CO)₇} (μ₃,η²:μ₃,η²-C₂C₂){Ru₃(μ-H)(μ-dppm)(CO)₇} (4) are reported.     

Reactions of (η6-diphenylacetylene) chromiumtricarbonyl complexes with polynuclear carbonyls I. Synthesis of Cr(CO)3(η6-diphenylacetylene) complex and its reaction with Co2(CO)8. Crystal and molecular structure of Cr(CO)3(η6:η2-diphenylacetylene)Co2(CO)6

The reaction of Cr(CO)₃(NH₃)₃ with diphenylacetylene affords as a main product the complex with Cr(CO)₃ moiety bound to a phenyl ring of diphenylacetylene; Cr(CO)₃(η⁶-PhC₂Ph) (I). Complex I readily reacts with Co₂(CO)₈ yielding the mixed metal complex Cr(CO)₃(η⁶:η²-PhC₂Ph)Co₂(CO)₆ (II). The reaction proceeds with retention of the Cr(CO)₃ (η⁶-arene) structural unit, the Co₂(CO)₆ fragment being bound to the triple bond of diphenylacetylene in μ₂,η²-mode. The structure of II was determined by single crystal X-ray analysis. The complex crystallizes in space group P2₁/c with unit cell parameters a 8.666(3) Å, b 18.046(3) Å, c 15.155(6) Å. β 97.57(3)°, V 2349(2) ų, Z = 4, D_x = 1.70 g/cm³. The structure was solved by direct methods and refined by full-matrix least-squares technique to R and R_w values of 0.032 and 0.034, respectively, for 3655 observed reflections. The data obtained show that two structural units in II, Cr(CO)₃(η⁶-Ph-) and Co₂(CO)₆(μ₂,η²-CC), are distorted due to steric repulsion between these metal carbonyl moieties. The Cr(CO)₃ fragment is shifted from the centre of the phenyl ring and slightly tilted with respect to the phenyl ring plane. The Co₂C₂ tetrahedron in the Co₂(CO)₆(μ₂,η²-CC) moiety is distorted in such a way that two of the four Co_iC_j bonds are elongated.     

1,3-Dipolar cycloaddition reaction of nitrone η6-(arene)chromium tricarbonyl complexes with styrene and η6-(styrene)chromium tricarbonyl

The products of 1,3-dipolar cycloaddition of the nitrone-type η⁶-(arene)chromium tricarbonyl complexes (CO)₃CrC₆H₅CH=N⁺(O^?)R, where R = Me, Ph, Bu^t, with styrene and η⁶-(styrene)chromium tricarbonyl were obtained and characterized by a combination of physicochemical methods. This type of reactions proceeded with very high regio- and stereoselectivity to exclusively form cis-2,3,5-tri-substituted isoxazolidines.     

Isomere η2-Acyl- und σ-Alkyl(carbonyl)-Komplexe von Molybdän und Wolfram. Eine Studie zum Bildungs-mechanismus,zur Isomerisierungsgeschwindigkeit und zur Steuerung der Gleichgewichtslage

η²-Acyl and σ-Alkyl(carbonyl) Coordination in Molybdenum and Tungsten Complexes: Synthesis and Studies of the Isomerization Equilibria and Kinetics The anionic molybdenum and tungsten complexes [L_RM(CO)₃]^? (L_R^? = [(C₅H₅)Co{P(O)R₂}₃]^?, R = OCH₃, OC₂H₅, O-i-C₃H₇; M = Mo, W) have been alkylated with the iodides R′ I, R′ = CH₃, C₂H₅, i-C₃H₇, and CH₂C₆H₅. The reactivity pattern of the alkylation is in accord with a S_N2 mechanism. Depending on M, R′, reaction temperature, and time the η-alkyl (carbonyl) compounds [L_RM(CO)₃R′] and/or the isomeric η²-acyl compounds [L_RM(CO)₂(η²-COR′)] can be obtained. 8 new σ-alkyl(carbonyl) compounds and 15 new η²-acyl compounds have been isolated and characterized. The ¹H NMR and the IR spectra give conclusive evidence that the σ-alkyl(carbonyl) compounds [L_RM(CO)₃R′] are formed as the primary products of the alkylation and that they isomerize partly or completely to give the η²-acyl compounds [L_RM(CO)₂(η²-COR′)]. The position of the equilibrium σ-alkyl(carbonyl)/η²-acyl is controlled by the steric demands of the groups R′ and the ligands L_R^?. The molybdenum compounds isomerize much more readily than the tungsten compounds. The rate constants of the isomerization processes [L_RMo(CO)₃CH₃] → [L_RMo(CO)₂(η²-COCH₃)], R = OCH₃, OC₂H₅, and O-i-C₃H₇, measured at 305 K in acetone-d₆, are 6–8 x 10^?3 s^?1.     

Preparation and Characterization of a Heteronuclear μ-Alkyne Complex; X-Ray Crystal Structure of MoCo(CO)4(PPh3){μ-HCCSiMe3)(η5-C5H5)

Reaction of MoCo(CO)₅(PPh₃)₂(η⁵-C₅H₅) (1a) with trimethylsilylacetylene in tetrahydrofuran at 58° C yielded two acetylene bridged heterobimetallic compounds, MoCo(CO)₄(PPh₃){μ-HC?CSiMe₃}(η⁵-C₅H₅) (4) and MoCo (CO)₅{μ-HC?CSiMe₃}(η⁵-C₅H₅)(5). (4) was characterized by mass, infrared, ¹H, ¹³C and ³¹P NMR spectra. The X-ray crystal structure of (4) was determined:triclinic, P-1, a=8.821(1) Å, b=11.315(3) Å, c=17.029(2) Å, α=70.73(1)°, β=78 .72(1)°, γ=86.10(2)°,V =1573.4(6) ų, Z=2, R = 3.92%,R_w = 6.06% for 4285 (F > 4σ (F)) observed reflections. The core of this molecule is a quasi-tetrahedron containing Mo, Co and two carbons of acetylene. The triphenylphosphine ligand is attached to cobalt rather than molybdenum center.     

Reactivity of unsaturated clusters. Phosphoruscarbon bond activation,hydrogen migration and acetylene interconversion in the reactions of 46-electron (H)Ru3(CO)9(μ-PPh2) with Ph2PCCR (R = Ph,But, Pri). X-ray structure of Ru3(CO)9(μ-PPh2)2(μ3-η2-HCCPh): a new type of 5-vertex, 7-skeletal pair cluster

Novel examples of PC bond activation under mild conditions are reported. The reactions of phosphinoalkynes Ph₂PCCR (R = Ph, Bu^t, Prⁱ) with the formally 46-electron cluster HRu₃(CO)₉(μ-PPh₂) result in PC bond cleavage, transfer of a phosphido group onto the cluster, and transfer of hydride to the acetylide. The new species Ru₃(CO)₇(μ-PPh₂)₂(μ₃-η²-HCCR), of which the derivative with R = Ph has been studied by X-ray diffraction, are representatives of a new class of μ₂-η²-| acetylene cluster with NIDO 5-vertex structures.