Oxidative addition of different electrophiles with rhodium(I) carbonyl complexes of unsymmetrical phosphine–phosphine monoselenide ligands

Dimeric chlorobridge complex [Rh(CO)₂Cl]₂ reacts with two equivalents of a series of unsymmetrical phosphine–phosphine monoselenide ligands, Ph₂P(CH₂)_nP(Se)Ph₂ {n = 1( a ), 2( b ), 3( c ), 4( d )}to form chelate complex [Rh(CO)Cl(P∩Se)] ( 1a ) {P∩Se = η²‐(P,Se) coordinated} and non‐chelate complexes [Rh(CO)₂Cl(P～Se)] ( 1b–d ) {P～Se = η¹‐(P) coordinated}. The complexes 1 undergo oxidative addition reactions with different electrophiles such as CH₃I, C₂H₅I, C₆H₅CH₂Cl and I₂ to produce Rh(III) complexes of the type [Rh(COR)ClX(P∩Se)] {where R = ? C₂H₅ ( 2a ), X = I; R = ? CH₂C₆H₅ ( 3a ), X = Cl}, [Rh(CO)ClI₂(P∩Se)] ( 4a ), [Rh(CO)(COCH₃)ClI(P～Se)] ( 5b–d ), [Rh(CO)(COH₅)ClI‐(P～Se)] ( 6b–d ), [Rh(CO)(COCH₂C₆H₅)Cl₂(P～Se)] ( 7b–d ) and [Rh(CO)ClI₂(P～Se)] ( 8b–d ). The kinetic study of the oxidative addition (OA) reactions of the complexes 1 with CH₃I and C₂H₅I reveals a single stage kinetics. The rate of OA of the complexes varies with the length of the ligand backbone and follows the order 1a > 1b > 1c > 1d . The CH₃I reacts with the different complexes at a rate 10–100 times faster than the C₂H₅I. The catalytic activity of complexes 1b–d for carbonylation of methanol is evaluated and a higher turnover number (TON) is obtained compared with that of the well‐known commercial species [Rh(CO)₂I₂]^?. Copyright © 2006 John Wiley & Sons, Ltd.     

A modular design of metal catalysts for the transfer hydrogenation of aromatic ketones

The ability of transition metal catalysts to add or remove hydrogen from organic substrates by transfer hydrogenation is a valuable synthetic tool. Towards a series of novel metal complexes with a P―NH ligand, [Ph₂PNHCH₂―C₄H₃O] derived from furfurylamine were synthesized. Reaction of [Ph₂PNHCH₂―C₄H₃O] 1 with [Ru(η⁶‐p‐cymene)(μ‐Cl)Cl]₂, [Ru(η⁶‐benzene)(μ‐Cl)Cl]₂, [Rh(μ‐Cl)(cod)]₂ and [Ir(η⁵‐C₅Me₅)(μ‐Cl)Cl]₂ gave a range of new monodentate complexes [Ru(Ph₂PNHCH₂―C₄H₃O)(η⁶‐p‐cymene)Cl₂] 2 , [Ru(Ph₂PNHCH₂―C₄H₃O)(η⁶‐benzene)Cl₂] 3 , [Rh(Ph₂PNHCH₂‐C₄H₃O)(cod)Cl] 4 , and [Ir(Ph₂PNHCH₂‐C₄H₃0)(η⁵‐C₅Me₅)Cl₂] 5 , respectively. All new complexes were fully characterized by analytical and spectroscopic methods. ³¹P‐{¹H} NMR, distortionless enhancement by polarization transfer (DEPT) or ¹H‐¹³C heteronuclear correlation (HETCOR) experiments were used to confirm the spectral assignments. Following activation by KOH, compounds 1 , 2 , 3 , 4 catalyzed the transfer hydrogenation of acetophenone derivatives to 1‐phenylethanol derivatives in the presence of iso‐PrOH as the hydrogen source. Notably [Ru(Ph₂PNHCH₂‐C₄H₃O)(η⁶‐benzene)Cl₂] 3 acts as an excellent catalyst, giving the corresponding alcohols in 98–99% yield in 20 min at 82°C (time of flight ≤ 297 h^?1) for the transfer hydrogenation reaction in comparison to analogous rhodium or iridium complexes. Copyright © 2012 John Wiley & Sons, Ltd.     

Chemie polyfunktioneller Moleküle. 82. Neue Rhodium(I)-Chelatkomplexe mit N,N-Bis(diphenylphosphino)alkyl- und -arylaminen

Chemistry of Polyfunctional Molecules. 82. New Rhodium(1) Chelate Complexes with N,N-Bis(diphenylphosphino) alkyl- and -arylamines . [Rh(μ-Cl)(CO)₂]₂ ( 1 ) reacts with (Ph₂P)₂NR (2, a: R = C₆H₅, b: R = p-C₆H₄CH₃) in a molar ratio of 1:2 to give the square plane, ionic complexes [Rh{(PH₂P)₂NR}₂] [cis-Rh(CO)₂Cl₂] ( 3a, b ). By the reactions of [Rh(μ-Cl)(C₈H₁₂)]₂(C₈H₁₂ = 1.5-Cyclooctadiene) (4) with (Ph₂P)₂NR ( 2a–d ) (c: R = CH₃, d: R = C₂H₅) in the molar ratios of 1:4 the square plane 1:1 electrolytes [Rh{(Ph₂P)₂NR}₂]Cl ( 5a–d ) are obtained. Upon treatment of 5a–d in dichloromethane with CO the complexes [Rh(CO){(Ph₂P)₂NR}₂]Cl ( 6a–d ) are formed. They are only stable in solution and in CO atmosphere and were identified by infrared spectroscopy. The new complexes have been characterized, as far as possible, by conductometry, IR; FIR, Raman, ³¹P-NMR, and ¹H-NMR spectra.     

Applications of transition metal complexes containing aminophosphine ligand to transfer hydrogenation of ketones

Hydrogen transfer reduction processes are attracting increasing interest from synthetic chemists in view of their operational simplicity. Reaction of [Ph₂PNHCH₂‐C₄H₃S] with [Ru(η⁶‐benzene)(µ‐Cl)Cl]₂, [Rh(µ‐Cl)(cod)]₂ and [Ir(η⁵‐C₅Me₅)(µ‐Cl)Cl]₂ gave a range of new monodendate complexes [Ru(Ph₂PNHCH₂‐C₄H₃S)(η⁶‐benzene)Cl₂], 1, [Rh(Ph₂PNHCH₂‐C₄H₃S)(cod)Cl], 2, and [Ir(Ph₂PNHCH₂‐C₄H₃S)(η⁵‐C₅Me₅)Cl₂], 3, respectively. All new complexes were fully characterized by analytical and spectroscopic methods. ¹H? ³¹P NMR, ¹H? ¹³C HETCOR or ¹H? ¹H COSY correlation experiments were used to confirm the spectral assignments. 1–3 are suitable catalyst precursors for the transfer hydrogenation of acetophenone derivatives. Notably [Ru(Ph₂PNHCH₂‐C₄H₃S)(η⁶‐benzene)Cl₂], 1, acts as an excellent catalyst, giving the corresponding alcohols in 98–99% yields in 30 min at 82 °C (TOF ≤200 h^?1) for the transfer hydrogenation reaction in comparison to analogous rhodium or iridium complexes. This transfer hydrogenation is characterized by low reversibility under these conditions. Copyright © 2011 John Wiley & Sons, Ltd.     

Azametalla-closo-dodecaboranes

The azaborate K₂[nido-NB₁₀H₁₁] is gained from nido-NB₁₀H₁₃ and K[BHEt₃] in a 1:2 ratio. The anion [NB₁₀H₁₁]^2?, which is isoelectronic with [C₂B₉H₁₁]^2?, reacts with [{η⁶-(C₆R₆) · RuCl₂}₂] (R = H, Me), [{η⁵-(C₅Me₅)RhCl₂}₂], or [Ni(PPh₃)₂Cl₂] to give the azametalla-closo-dodecaboranes MNB₁₀H₁₁ with M = (C₆Me₆)Ru ( 2 ), (C₆H₆)Ru ( 3 ), (C₅Me₅)Rh ( 4 ), and (Ph₃P)₂Ni ( 5 ), respectively. The azametallaborane K[Co(NB₁₀H₁₁)₂] ( 6 ), which contains a sandwich-type coordinated Co atom, is formed from K₂[NB₁₀H₁₁] and CoCl₂. The structure of 2 · CH₂Cl₂ was determined by X-ray diffraction. The products 2 – 6 can be derived from the icosahedral anion [B₁₂H₁₂]^2? on replacing a BH^2? moiety by the isoelectronic nitrene NH and a BH moiety by the isolobal metal-complex fragment M. The N atom is six-coordinated in the cluster skeletons 2 – 6 .     

Enantioselective transfer hydrogenation of pro-chiral ketones catalyzed by novel ruthenium and iridium complexes of well-designed phosphinite ligand

Abstract

The interaction of [Ru(η⁶-arene)(μ-Cl)Cl]₂ and Ir(η⁵-C₅Me₅)(μ-Cl)Cl]₂ with a new Ionic Liquid-based phosphinite ligand, [(Ph₂PO)-C₆H₉N₂Ph]Cl, (2) gave [Ru((Ph₂PO)-C₆H₉N₂Ph)(η⁶-p-cymene)Cl₂]Cl (3), [Ru((Ph₂PO)-C₆H₉N₂Ph)(benzene)Cl₂]Cl (4) and [Ir((Ph₂PO)-C₆H₉N₂Ph)(C₅Me₅)Cl₂]Cl (5), complexes. All the compounds were characterized by a combination of multinuclear NMR and IR spectroscopy as well as elemental analysis. Furthermore, the Ru(II) and Ir(III) catalysts were applied to asymmetric transfer hydrogenation of acetophenone derivatives using 2-propanol as a hydrogen source. The results showed that the corresponding alcohols could be obtained with good activity (up to 55% ee and 99% conversion) under mild conditions. Notably, [Ir((Ph₂PO)-C₆H₉N₂Ph)(C₅Me₅)Cl₂]Cl (5) is more active than the other analogous complexes in the transfer hydrogenation (up to 81% ee).     

Olefin complexes of rhodium(I) containing the ligands but-3-enyldiphenylphosphine and diphenylpent-4-enylphosphine

But-3-enyldiphenylphosphine (mbp) and diphenylpent-4-enylphosphine (mpp) react with Rh₂Cl₂(C₂H₄)₄ (molar ratio $\text{2}\text{1}$ to form the four coordinate dimeric complexes Rh₂Cl₂(mbp)₂ and Rh₂Cl₂(mpp)₂ respectively, while but-3-enyldiphenylphosphine reacts with Rh₂Cl₂(C₂H₄)₄ (molar ratio $\text{4}\text{1}$) to form RhCl(mbp)₂, a five coordinate complex in the solid state. The dimers further react with sodium tetraphenylborate to give the π-bonded tetraphenylborate complexes Rh[mbp][C₆H₅)₄B] and Rh[i-mpp][(C₆H₅)₄B] where i-mpp = (C₆H₅)₂P(CH₂CH₂CHCHCH₃). RhCl(CO)(mbp)₂ reacts with sodium tetraphenylborate to form the five coordinate cationic complex [Rh(CO)(mbp)₂][(C₆H₅)₄B]. Both RhCl(CO)(mbp)₂ and RhCl(mbp)₂ react with hydrogen in methanol saturating the olefin to form RhCl[CO][(C₆H₅)₂P(C₄H₉)]₂ and Rh₂Cl₂[(C₆H₅)₂P(C₄H₉)]₂ respectively.     

Synthesis and characterization of heterometallic Rh/Ru complexes supported by 1,2-dichalcogenolato-o-carborane ligands

The 16-electron half-sandwich complexes Cp^∗Rh[E₂C₂(B₁₀H₁₀)] (E = S, 1a; Se, 1b) react with [Ru(COD)Cl₂]_x under different conditions to give different types of heterometallic complexes. When the reactions were carried out in THF for 24 h, the binuclear Rh/Ru complexes [Cp^∗Rh(μ-Cl)₂(COD)Ru][E₂C₂(B₁₀H₁₀)] (E = S, 2a; Se, 2b) bridged by two Cl atoms and the binuclear Rh/Rh complexes (Cp^∗Rh)₂[E₂C₂(B₁₀H₁₀)] (E = S, 3a; Se, 3b) with direct Rh-Rh bond can be isolated in moderate yields. [Ru(COD)Cl₂] fragments in 2a and 2b have inserted into the Rh-E bond. If the [Ru(COD)Cl₂]_x was reacted with 1a in the presence of K₂CO₃ in methanol solution, the product [Cp^∗Rh(COD)]Ru[S₂C₂(B₁₀H₁₀]] (4a), K[(μ-Cl)(μ-OCH₃)Ru(COD)]₄ (5a) and 3a were obtained. The B(3)-H activation in complex 4a was found. However, when the reaction between 1b and [Ru(COD)Cl₂]_x was carried out in excessive NaHCO₃, the carborane cage opened products {Cp^∗Rh[S₂C₂(B₉H₁₀)]}Ru(COD) (6b), {Cp^∗Rh[S₂C₂(B₉H₉)]}Ru(COD)(OCH₃) (7b) and 3b were obtained. All complexes were fully characterized by their IR, ¹H NMR and elemental analyses. The molecular structures of 2a, 2b, 3b, 4a, 5a, and 7b have been determined by X-ray crystallography.     

Organometallic ruthenium, rhodium and iridium complexes containing a P-bound thiophene-2-(N-diphenylphosphino)methylamine ligand: Synthesis, molecular structure and catalytic activity

Reaction of Ph₂PNHCH₂-C₄H₃S with [Ru(η⁶-p-cymene)(μ-Cl)Cl]₂, [Ru(η⁶-benzene)(μ-Cl)Cl]₂, [Rh(μ-Cl)(cod)]₂ and [Ir(η⁵-C₅Me₅)(μ-Cl)Cl]₂ yields complexes [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-p-cymene)Cl₂], 1, [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2, [Rh(Ph₂PNHCH₂-C₄H₃S)(cod)Cl], 3 and [Ir(Ph₂PNHCH₂-C₄H₃S)(η⁵-C₅Me₅)Cl₂], 4, respectively. All complexes were isolated from the reaction solution and fully characterized by analytical and spectroscopic methods. The structure of [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2 was also determined by single crystal X-ray diffraction. 1-4 are suitable precursors forming highly active catalyst in the transfer hydrogenation of a variety of simple ketones. Notably, the catalysts obtained by using the ruthenium complexes [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-p-cymene)Cl₂], 1 and [Ru(Ph₂PNHCH₂-C₄H₃S)(η⁶-benzene)Cl₂], 2 are much more active in the transfer hydrogenation converting the carbonyls to the corresponding alcohols in 98-99% yields (TOF ≤ 200 h⁻¹) in comparison to analogous rhodium and iridium complexes.     

Chemie polyfunktioneller Moleküle. 97. Beiträge zur Komplexchemie des Lithium-bis(diphenylphosphino)amids,des Bis(diphenylphosphino)amins und des Tris(diphenylphosphino)amins

Chemistry of Polyfunctional Molecules. 97. Contributions to the Coordination Chemistry of Lithium-bis(diphenylphosphino)amide, Bis(diphenylphosphino)amine, and Tris(diphenyl-phosphino)amine (Ph₂P)₂NLi ( 1 ) forms with AuCl(PPh₃) the already known complex [Au(Ph₂P)₂N]₂ ( 2 ), which now has been proved by mass spectroscopy to possess the postulated dimeric structure. 2 gives with HCl, HClO₄, and HBF₄ the new compounds [ClAu(Ph₂P)₂NH]₂ ( 3a ) and [Au(Ph₂P)₂NH…?X]₂ [X = ClO₄ ( 3b ), BF₄ ( 3c )]. In analogy the neutral complex Fe(C₅H₅)(CO)(Ph₂P)₂N ( 5 ) os obtained from FeCl(C₅H₅)(CO)₂ and 1. 5 reacts with HCl to [Fe(C₅H₅)(CO)(Ph₂P)₂NH…?Cl] ( 6a ). The last one can also be prepared by direct reaction of FeCl(C₅H₅)(CO)₂ with (Ph₂P)₂NH ( 4 ). In the same way FeBr(C₅H₅)(CO)₂ reacts with 4 yielding [Fe(C₅H₅)(CO)(Ph₂P)₂NH…?Br] ( 6b ), which leads under metathesis with NH₄PF₆ to [Fe(C₅H₅)(CO)(Ph₂P)₂NH]PF₆ ( 6c ). With PdCl₂(NCPh)₂ the ligand 1 forms Pd[(Ph₂P)₂N]₂ ( 7 ), which also can be synthesized in another way, but is now for the first time characterized in a spectroscopically detailed manner. Cr(CO)₄(Ph₂P)₂NPPh₂ reacts with AuCl(CO) to Cr(CO)₄(Ph₂P)₂NPPh₂AuCl ( 8 ). This compound gives with Cr(CO)₄(Ph₂P)₂NLi the trimetallic complex (OC)₄Cr(Ph₂P)₂NPPh₂AuN(PPh₂)₂Cr(CO)₄ ( 9 ). (Ph₂P)₃N ( 10 ) yields with AuCl(CO) in the molar ratio of 1:3 the compound [ClAuPh₂P]₃N ( 11 ).     

Polymerization of propadiene. III. Catalyst systems based on various rhodium (I) complexes

The polymerization of propadiene to 1,2-polyallene by various Rh(I) based catalysts is described and discussed. Also the interrelations between these Rh(I) complexes are discussed and an overall reaction scheme is given. A mechanism is put forward in which the formation of a common intermediate from propadiene and different Rh(I) complexes is the rate determining step. It is found that the activity decreases in the order: cis-Rh(CO)₂P(C₆H₅)₃Cl > [Rh(CO)₂Cl]₂ > Rh(CO)₃Cl. The complexes Rh[P(C₆H₅)₃]₂(CO)Cl and Rh[P(C₆H₅)₃]₃Cl proved to be inactive in the polymerization of propadiene.     

Konkurrierende bildung von heterometall-zweikern-komplexen mit μ-CCHPh und μ-ηPsu1,η3-CHCPhCO-brückenliganden bei der reaktion von C5H5Rh(PhCCH)PPri3 MIT Fe2(CO)9

The alkyne complex C₅H₅Rh(PhCCH)PPrⁱ₃ reacts wit Fe₂(CO)₉ to form two isomeric dinuclear products, C₅H₅(PPrⁱ₃)Rh(μ-CCHPh)(μ-CO)Fe(CO)₃ and C₅H₅(PPrⁱ₃)Rh(μ-η¹,η³-CHCPhCO)Fe(CO)₃. The X-ray crystal structure of the latter has been determined.     

Transition‐Metal‐Mediated Cleavage of Fluoro‐Silanes under Mild Conditions

Si?F bond cleavage of fluoro‐silanes was achieved by transition‐metal complexes under mild and neutral conditions. The Iridium‐hydride complex [Ir(H)(CO)(PPh₃)₃] was found to readily break the Si?F bond of the diphosphine‐ difluorosilane {(o‐Ph₂P)C₆H₄}₂Si(F)₂ to afford a silyl complex [{[o‐(iPh₂P)C₆H₄]₂(F)Si}Ir(CO)(PPh₃)] and HF. Density functional theory calculations disclose a reaction mechanism in which a hypervalent silicon species with a dative Ir→Si interaction plays a crucial role. The Ir→Si interaction changes the character of the H on the Ir from hydridic to protic, and makes the F on Si more anionic, leading to the formation of H^δ+???F^δ? interaction. Then the Si?F and Ir?H bonds are readily broken to afford the silyl complex and HF through σ‐bond metathesis. Furthermore, the analogous rhodium complex [Rh(H)(CO)(PPh₃)₃] was found to promote the cleavage of the Si?F bond of the triphosphine‐monofluorosilane {(o‐Ph₂P)C₆H₄}₃Si(F) even at ambient temperature.     

An unusual oxidative addition-ligand elimination reaction. Preparation and structure of RhCl2(PMe2Ph)2(C3Ph3)

The sym-triphenylcyclopropenium cation (C₃Ph₃⁺) stabilized as the Cl^? or PF₆^? salt, undergoes facile reactions at room temperature with trans-Rh(CO)Cl(PMe₂Ph)₂ to produce complexes which result from the oxidative cleavage of the ring and decarbonylation of the organometallic reactant. The product of the C₃Ph₃⁺Cl^? reaction has been fully characterized by X-ray analysis and is shown to be RhCl₂(PMe₂Ph)₂(C₃Ph₃).     

7‐{Di­phenyl­[(tri­phenyl­phos­phine)­aurio]­phos­phine(1+)‐P}‐8‐methyl‐7,8‐dicarba‐nido‐undecaborate(1–) dichloro­methane hemi­solvate

The title compound, 7‐[(Ph₂P)Au(PPh₃)]‐8‐(CH₃)‐7,8‐nido‐C₂B₉H₁₀]·­0.5CH₂Cl₂ or [Au(C₁₅H₂₃B₉P)­(C₁₈H₁₅P)]·­0.5CH₂Cl₂, is the first reported gold derivative of the ligand [7‐­(Ph₂P)‐8‐(CH₃)‐7,8‐nido‐C₂B₉H₁₀]^?. It has a mono­nuclear structure with the gold centre in an essentially linear coordination [P—Au—P 174.041 (15)°]. The open C₂B₃ face contains one H atom that is strongly bonded to the central B atom and semi‐bridging to a neighbouring B atom [B—H distances 1.070 (16) and 1.45 (3) Å].     

Ligating properties of thionitrosoamines: III. Carbonyl complexes of rhodium(I) and rhodium(III) containing N-thionitrosodimethylamine

Me₂NNS reacts with [Rh(CO)₂Cl]₂ to produce the complex cis-Rh(SNNMe₂)(CO)₂Cl (1). The latter undergoes reversible CO substitution by Me₂NNS to give the complex trans-Rh(SNNMe₂)₂(CO)Cl (2a). Complexes 1 and 2a, in solution lose CO and Me₂NSS, respectively, to give the complex trans-(μ-Cl)₂[Rh(SNNMe₂)(CO)]₂ (3). Complex 1 can also be prepared by bubbling CO through a CH₂Cl₂ solution of Rh(SNNMe₂)(diene)Cl (diene = 1,5-cyclooctadiene (4a), norbornadiene (4b)) obtained by a bridge-splitting reaction of Me₂NNS with [Rh(diene)Cl]₂. 1 and 2a react with EPh₃ (E = P, As, Sb) to give the complexes trans-Rh(EPh₃)₂(CO)Cl. The complexes trans-Rh(E′Ph₃)₂(CO)X (X = Cl, E′ = As, Sb; X = Br, NCS, E′ = As) undergo reversible E′Ph₃ displacement upon treatment with Me₂NNS to give the complexes trans-Rh(SNNMe₂)₂(CO)X (X = Cl (2a), Br (2b), NCS (2c)). Oxidative additions of Br₂, I₂, or HgCl₂ to 2a produce stable adducts, while the reaction of 2a with CH₃I gives an inseparable mixture of the adduct Rh(SNNMe₂)₂(CO)(CH₃)ClI and the acetyl derivative Rh(SNNMe₂)₂(CH₃CO)ClI. A mixture of the acetyl derivative (μ-Cl)₂[Rh(SNNMe₂)(CH₃CO)I]₂ and the adduct (μ-Cl)₂[Rh(SNNMe₂)(CO)(CH₃)I]₂ is obtained by treating 1 with CH₃I. The IR spectra of all the compounds are consistent with S-coordination of Me₂NNS. Because of the restricted rotation around the NN bond, the ¹H NMR spectra of the new compounds exhibit two quadruplets in the range 3.5–4.3δ when ⁴J(HH) = 0.7–0.5 Hz. When ⁴J(HH) < 0.5 Hz, the perturbing effect of the quadrupolar relaxation of the ¹⁴N nucleus obscures the spin-spin coupling and two broad signals are observed in the range 3.6–4δ.     

Synthesis and characterization of transition metal complexes of a new bidentate ligand {2-(diphenylphosphino)ethyl}benzylamine

A new bidentate ligand {2-(diphenylphosphino)ethyl}benzylamine(DPEBA) was synthesized and characterized based on the IR, mass and ¹H, ¹³C and ³¹P NMR spectra. Various complexes of platinum group metal ions and Ni(II) and Co(II) ions with the ligand were synthesized. Reaction of RuCl₂(PPh₃)₃ or RuCl₂(Me₂SO)₄ with the ligand DPEBA, resulted in formation of a penta-coordinate, Ru(II) species of the composition [RuCl(DPEBA)₂]Cl. Carbonylation of [RuCl(DPEBA)₂]Cl gave an octahedral carbonyl complex of the type [RuCl(CO)(DPEBA)₂]Cl. The reaction of RuCl₃·3H₂O or RuCl₃(AsPh₃)₂MeOH with a twofold excess of the ligand gave an octahedral Ru(III) cationic species [Ru(DPEBA)₂Cl₂]Cl. Carbonylation of the Ru(III) complex gave rise to a carbonyl complex [RuCl(CO)(DPEBA)₂]Cl₂. The ligand DPEBA reacts with cobalt(II) chloride in methanol to give the 1 : 1 complex [Co(DPEBA)Cl₂]. A series of Rh(I) complexes [Rh(DPEBA)₂Cl], [ RhCl(CO)(DPEBA)] and [Rh(DPEBA)₂]Cl were synthesized by the reaction of DPEBA with RhCl(PPh₃)₃, RhCl(CO)(PPh₃)₂ and [Rh(COD)Cl]₂, respectively. Reaction of [Ir(COD)Cl]₂ and IrCl(CO)(PPh₃)₂ with the ligand DPEBA, gave the square-planar complexes [Ir(DPBA)₂]Cl and [Ir(DPEBA)(CO)Cl], respectively. Octahedral cationic complexes of the type [M(DPEBA)₂Cl₂]Cl (M = Rh(III), Ir(III)) were synthesized by the reaction of the ligand DPEBA and rhodium and iridium trichlorides. Reaction of NiCl₂·6H₂O with DPEBA in 1 : 2 molar equivalents, in boiling butanol gave an octahedral neutral complex [Ni(DPEBA)₂Cl₂] which readily rearranges to the square-planar complex [Ni(DPEBA)₂]Cl₂ in methanol. Reaction of Pd(II) and Pt(II) chlorides with DPEBA gave square-planar, cationic complexes of the type [M(DPEBA)₂Cl]Cl (M = Pd, Pt). All the complexes were characterized on the basis of their analytical and spectral data.     

Reactions of Thiocarbamoyl compounds with vaska complexes: mechanism and stereochemistry

Bis(dimethylthiocarbamoyl)sulfide, (Me₂NCS)₂S, reacts with (PH₃P)₂MCOCl complexes giving ionic species [Ph₃PM(η²-CSNMe₂)(S₂CNMe₂)CO]X (M = Rh, Ir; X = Cl, PF₆) as kinetic products. On standing solution, [Ph₃PRh(η²-CSNMe₂)(S₂CNMe₂)CO]Cl is slowly transformed into the thermodynamic product Ph₃PRh(η²-CSNMe₂)S₂CNMe₂)Cl. The known reactions of Vaska-type complexes with Me₂NCSCl to give [trans-(Ph₃P)₂Ir(η²-CSNMe₂)COCl]Cl and trans-(Ph₃P)₂Rh(η²-CSNMe₂)Cl₂ probably follow a similar course. (PH₃P)RuNOCl reacts with (Me₂NCS)₂S and Me₂NCSCl in the same way as (Ph₃P)₂IrCOCl, but reacts with (Me₂NCS)₂NPh to give [trans-(Ph₃P)₂Ru(η²-CSNMe₂)NOCl]PF₆. The mechanism and stereochemistry of these reactions are discussed. Reactions were monitored by NMR spectroscopy in an attempt to identify intermediate η¹-thiocarboxamido complexes, but no such species could be detected.     

Cyclopentadienyl- and pentamethylcyclopentadienyl-rhodium(III) complexes containing isocyanide ligands

The complexes [(η⁵-C₅H₅)RhCl₂]₂ and [(η⁵-C₅Me₅)RhCl₂]₂ react with stoichiometric amounts of isocyanide ligands L to give (η⁵-C₅H₅)RhLCl₂ and (η⁵-C₅Me₅)RhLCl₂ (L = CNC₆H₁₁, CNC₆H₄CH₃-p); an excess of ligand L reacts further with (η⁵-C₅Me₅)RhLCl₂ to give the cationic complex [(η⁵-C₅Me₅)RhL₂Cl]⁺ which was isolated as tetraphenylborate salt. The cationic complexes [(η⁵-C₅Me₅)RhL(PPh₃)Cl]⁺ and [(η⁵-C₅Me₅)Rh(Ph₂PC₂H₄PPh₂)Cl]⁺ were obtained in the reaction of (η⁵-C₅Me₅)RhLCl₂ with PPh₃ and Ph₂PC₂H₄PPh₂ respectively. Unidentified solids which do not contain the cyclopentadienyl moiety were obtained in the analogous reactions of (η⁵-C₅H₅)RhLCl₂ with an excess of isocyanide or of tertiary phosphine.The complexes (η⁵-C₅H₅)Rh(CNC₆H₁₁)Cl₂ and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)Cl₂ react with SCN^? or SeCN^? giving the corresponding dithiocyanate or diselenocyanate derivatives in which the pseudohalogen groups are S- or Se-bonded to the metal atom. The analogous reactions with C₆Cl₅MgCl gave the chiral complexes (η⁵-C₅H₅)Rh(CNC₆H₁₁)(C₆Cl₅)Cl and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)(C₆Cl₅)Cl.The potentially chelating anion Ph₂PSS^? reacts with (η⁵-C₅H₅)Rh(CNC₆H_n11)Cl₂ and (η⁵-C₅Me₅)Rh(CNC₆H₁₁)Cl₂ to give (η⁵-C₅H₅)Rh(CNC₆H¹¹)(SSPPh₃)Cl and (η⁵-C₅Me₅)Rh(CNC₆H¹¹)(SSPPh₂)Cl in which the dithio ligand acts as monodentate; these compounds react with MeI or EtI to give the dihalide derivatives and the esters Ph₂PSSMe and PSSEt. The complex [(η⁵-C₅Me₅)Rh(CNC₆H₁₁)(SSPPh₂)]Cl was obtained by refluxing a benzene solution of the corresponding neutral complex; the cyclopentadienyl derivative failed to give the analogous chelate complex.The complexes (η⁵-C₅H₅)RhLCl₂, (η⁵-C₅Me₅)RhLCl₂ and [(η⁵-C₅Me₅)RhL₂Cl]⁺ (L = CNC₆H₁₁) were found to be unreactive towards amines.     

Synthesis and Structure of a New Type of Chiral Organoiron and Organoruthenium Complexes

The synthesis of 36 [Fe(CO)₂L¹(η⁴-diene)], three [Fe(CO)₂L¹(η⁴-encne)], and five [Ru(CO)₂L¹(η⁴-diene)] complexes (L¹ = Ph₃P, Et₃P, (EtO)₃P, (MeO)₃p, C₆H₁₁NC) by thermal, selective CO ligand displacement in the corresponding tricarbonyl precursor complexes is described. In a second step, photochemical CO displacement by another phosphorus ligand L² leads to a new type of η⁴-diene complexes with a centre of chirality at the metal atom (Fe, Ru). 23 Fe and three Ru complexes of this type have been prepared and characterized. In the case of complexes with unsymmetrical dienes, racemic diastereoisomers are formed which can be separated by chromatographic methods. The molecular structures of [Fe(CO)(Ph₃P)((MeO)₃P)(buta-1,3-diene)] ( 52 ), [Fe(CO)(Ph₃P)((MeO)₃P)(isoprene)] ( 58 ) and [Fe(CO)(Et₃P)(EtO)₃P(hexa-2,4-dienal)] ( 62a ) were determined by X-ray diffraction. All complexes were investigated by ¹³C-, ³¹P- and, in part, ¹H-NMR spectroscopy. At low temperatures, conformational isomers (rotamers) can be differentiated which probably arise from ψ rotation at the coordinated metal centre.