Rhodium(I) carbonyl complexes with sulphur and nitrogen donor ligands

Summary Rhodium(I) carbonyl complexes, namely [Rh(CO)₂ClL] where L = thiourea (Tu), 1,3-diphenyl-2-thiourea (DTu), dithizone (Dtz), indole (Id), 3-chloropyridine (Clpy), 3-hydroxypyridine (HOpy), 3-methylpyridine (Mepy), 2,5-dimethylpyridine (Me₂py) or 2,5-dichloropyridine (Cl₂py)] were prepared. [Rh(CO)₂Cl(Clpy)₂] has also been isolated. In the (Tu) complex, (C-S) occurs at ca. 710cm^-1, indicating the presence of a metal-sulphur bond. The carbonyl stretching frequencies in [Rh (CO)₂ClL] and [Rh(CO)₂CIL₂] occur at ca. 2100–1990 and 1830–1800 cm^-1, respectively. PPh₃ reacts with the complexes to form trans-[Rh(CO)Cl(PPh₃)₂]. The complexes were characterized by elemental analyses, conductivity measurements and by their i.r. spectra.     

Platinum,iridium and rhodium complexes with substituted bis-(diphenylphosphino)methane ligands Ph2PCH(R)PPh2 (R = Me,Ph or SiMe3)

Substituted phosphines of the type Ph₂PCH(R)PPh₂ and their Pt^II complexes [PtX₂{Ph₂PCH(R)PPh₂}] (R = Me, Ph or SiMe₃; X = halide) were prepared. Treatment of [PtCl₂(NCBu^t)₂] with Ph₂PCH(SiMe₃)-PPh₂ gave [PtCl₂(Ph₂PCH₂PPh₂)], while treatment with Ph₂PCH(Ph)PPh₂ gave [Pt{Ph₂PCH(Ph)PPh₂}₂]Cl₂. Reaction of p-MeC₆H₄C≡CLi or PhC≡CLi with [PtX₂{Ph₂PCH(Me)PPh₂}] gave [Pt(C≡CC₆H₄Me-p)₂-{Ph₂PCH(Me)PPh₂}] (X = I) and [Pt{Ph₂PC(Me)PPh₂}₂](X = Cl),while reaction of p-MeC₆H₄C≡CLi with [Pt{Ph₂PCH(Ph)PPh₂}₂]Cl₂ gave [Pt{Ph₂PC(Ph)PPh₂}₂]. The platinum complexes [PtMe₂(dpmMe)] or [Pt(CH₂)₄(dpmMe)] fail to undergo ring-opening on treatment with one equivalent of dpmMe [dpmMe = Ph₂PCH(Me)PPh₂]. Treatment of [Ir(CO)Cl(PPh₃)₂] with two equivalents of dpmMe gave [Ir(CO)(dpmMe)₂]Cl. The PF₆ salt was also prepared. Treatment of [Ir(CO)(dpmMe)₂]Cl with [Cu(C≡CPh)₂], [AgCl(PPh₃)] or [AuCl(PPh₃)] failed to give heterobimetallic complexes. Attempts to prepare the dinuclear rhodium complex [Rh₂(CO)₃(μ-Cl)(dpmMe)₂]BPh₄ using a procedure similar to that employed for an analogous dpm (dpm = Ph₂PCH₂PPh₂) complex were unsuccessful. Instead, the mononuclear complex [Rh(CO)(dpmMe)₂]BPh₄ was obtained. The corresponding chloride and PF₆ salts were also prepared. Attempts to prepare [Rh(CO)(dpmMe)₂]Cl in CHCl₃ gave [RhHCl(dpmMe)₂]Cl. Recrystallization of [Rh(CO)(dpmMe)₂]BPh₄ from CHCl₃/EtOH gave [RhO₂(dpmMe)₂]BPh₄. Treatment of [Rh(CO)₂Cl₂]₂ with one equivalent of dpmMe per Rh atom gave two compounds, [Rh(CO)(dpmMe)₂]Cl and a dinuclear complex that undergoes exchange at room temperature between two formulae: [Rh₂(CO)₂(μ-Cl)(μ-CO)(dpmMe)₂]Cl and [Rh₂(CO)₂-(μ-Cl)(dpmMe)₂]Cl. This revised version was published online in June 2006 with corrections to the Cover Date.     

Carbonylrhodium complexes of pyridine ligands and their catalytic activity towards carbonylation of methanol

The cis‐[Rh(CO)₂ClL] (1) complexes, where L = 2‐methylpyridine (a), 3‐methylpyridine (b), 4‐methylpyridine (c), 2‐phenylpyridine (d), 3‐phenylpyridine (e), 4‐phenylpyridine (f), undergo oxidative addition reactions with various electrophiles, like CH₃I, C₂H₅I, C₆H₅CH₂Cl or I₂, to yield complexes of the types [Rh(CO)(COR)ClXL] (2) (where R = CH₃ (i), C₂H₅ (ii), X = I; R = C₆H₅CH₂ (iii), X = Cl) or [Rh(CO)ClI₂L] (3) and [Rh(CO)₂ClI₂L] (4). The pseudo‐first‐order rate constants of CH₃I addition with complexes 1 containing pyridine (g) and 2‐substituted pyridine (a and d) ligands were found to follow the order pyridine >2‐methylpyridine >2‐phenylpyridine. The catalytic activity of complexes 1 containing different pyridine ligands (a–g) on carbonylation of methanol was studied and, in general, a higher turnover number was obtained compared with that of the well‐known species [Rh(CO)₂I₂]^?. Copyright © 2002 John Wiley & Sons, Ltd.     

Ruthenium and rhodium nitrosyl complexes containing dichalcogenoimidodiphosphinate ligands

Interaction of [Ru(NO)Cl₃(PPh₃)₂] with K[N(R₂PS)₂] in refluxing N,N-dimethylformamide afforded trans-[Ru(NO)Cl{N(R₂PS)₂}₂] (R = Ph (1), Prⁱ (2)). Reaction of [Ru(NO)Cl₃(PPh₃)₂] with K[N(Ph₂PSe)₂] led to formation of a mixture of trans-[Ru(NO)Cl{N(Ph₂PSe)₂}₂] (3) and trans-[Ru(NO)Cl{N(Ph₂PSe)₂}{Ph₂P(Se)NPPh₂}] (4). Reaction of Ru(NO)Cl₃ · xH₂O with K[N(Ph₂PO)₂] afforded cis-[Ru(NO)(Cl){N(Ph₂PO)₂}₂] (5). Treatment of [Rh(NO)Cl₂(PPh₃)₂] with K[N(R₂PQ)₂] gave Rh(NO){N(R₂PQ)₂}₂] (R = Ph, Q = S (6) or Se (7); R = Prⁱ, Q = S (8) or Se (9)). Protonation of 8 with HBF₄ led to formation of trans-[Rh(NO)Cl{HN(Prⁱ₂PS)₂}₂][BF₄]₂ (10). X-ray diffraction studies revealed that the nitrosyl ligands in 2 and 4 are linear, whereas that in 9 is bent with the Rh–N–O bond angle of 125.7(3)°.     

Rhodium(I) carbonyl complexes of ether‐phosphine ligands and their reactivity

The reactions of dimeric complex [Rh(CO)₂Cl]₂ with hemilabile ether‐phosphine ligands Ph₂P(CH₂) _nOR [n = 1, R = CH₃ (a); n = 2, R = C₂H₅ (b)] yield cis‐[Rh(CO)₂Cl(P ～ O)] (1) [P ～ O = η ¹‐(P) coordinated]. Halide abstraction reactions of 1 with AgClO₄ produce cis‐[Rh(CO)₂(P ∩ O)]ClO₄ (2) [P ∩ O = η ²‐(P,O)chelated]. Oxidative addition reactions of 1 with CH₃I and I₂ give rhodium(III) complexes [Rh(CO)(COCH₃)ClI(P ∩ O)] (3) and [Rh(CO)ClI₂(P ∩ O)] (4) respectively. The complexes have been characterized by elemental analyses, IR, ¹H, ¹³C and ³¹P NMR spectroscopy. The catalytic activity of 1 for carbonylation of methanol is higher than that of the well‐known [Rh(CO)₂I₂]^? species. Copyright © 2002 John Wiley & Sons, Ltd.     

Ligating properties of tertiary phosphine/arsine sulphides or selenides—VI. Addition compounds of zinc(II), cadmium(II) and mercury(II) with sulphides or selenides of triphenyl- and tri- -tolylphosphines and 1,3-trimethylenebis (diphenylphosphine)

Post-transition elements react with ligands, triphenylphosphine sulphide or selenide (Ph₃PS or Ph₃PSe), tri-p-tolylphosphine sulphide or selenide (T₃PS or T₃PSe) and 1,3-trimethylenebis-(diphenylphosphine sulphide or selenide) (PDPS or PDPSe) in suitable organic solvents forming complexes of compositions: MX₂. L(M = Zn, X = I, L = all except Ph₃PS: M = Cd, X = I, L = T₃PS, T₃PSe, M = Hg, L = T₃PSe, X = Cl, Br, I); ZnI₂·2Ph₃PS, Hg(NO₃)₂·2Ph₃PS, CdBr₂·3T₃PSe and 3Hg(NO₃)₂·4Ph₃PSe. All these have been characterized through elemental analyses, ir spectra (4000−200 cm⁻¹) and molar conductance (nitrobenzene). Complexes are essentially nonelectrolytes. Tetrahedral structures have been assigned to all except a 1 : 3 complex which has been assigned a bridged octahedral structure.     

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.     

Rhodium(I) carbonyl complexes with heterocyclic and nonheterocyclic nitrogen-donor ligands

Summary Complexes of the [Rh(N-N)(CO)₂][RhCl₂(CO)₂], [Rh(N-N)(CO)₂]BF₄ and Rh(N-N)(CO)₂Cl types where (N-N) = 2,9-dimethyl-1,10-phenanthroline (Me₂Phen), 4,7-diphenyl-1,10-phenanthroline (Ph₂Phen), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (Me₂2Ph₂Phen) or 2,2-biquinoline (biq), have been prepared and investigated. Benzidine (benz) ando-tolidine (tol) also form complexes of the first type. The complexes of the first two types behave as 11 electrolytes. While Ph₂Phen forms the four coordinate monocarbonyl Rh(Ph₂Phen)(CO)Cl complex, benzo(f)-quinoline (Q) yields the Rh(CO)₂ (Q)Cl compound. Triphenyl-phosphine and triphenylarsine react with the above complexes to form the well knowntrans-Rh(CO)ClL₂ where L = PPh₃ or AsPh₃. The i.r. and u.v.-visible spectra of the compounds are discussed.     

A novel reaction producing the rhodium(I) complexes with π-coordinated tetraphenylborate anion, (π-PhBPh3). X-ray study of [Rh(PPh3)2(π-PhBPh3)]

Treating the complexes [Rh(TFA)(PPh₃)₂], [Rh(HFA)(PPh₃)₂], and [Rh(TFA)(Cod)] (TFA - trifluoroacetylacetonate, HFA - hexafluoroacetylacetonate, Cod - 1,5 cyclooctadiene) with an excess of NaBPh₄ in acetonitrile yields the rhodium(I) complexes with coordinated [BPh₄]⁻ anion, [Rh(PPh₃)₂(π-PhBPh₃)] · 2MeCN (I) and [Rh(Cod)(π-PhBPh₃)] (II). The reactions present a new example of β-diketonate ligand replacement. The ¹H, ³¹P, and ¹¹B NMR spectra of I and II are discussed. [Rh(PPh₃)₂(π-PhBPh₃)] has been characterized by single crystal X-ray analysis.     

Schiff Base Complexes of Rhodium(I) with Tridentate N-Methyl-S-methyldithiocarbazate Ligands

Schiff bases derived from the condensation of β-diketones with N-methyl-S-methyldithiocarbazates yield cis dicarbonyl complexes Rh(CO)₂ (Schiff) on reaction with [Rh(μ-Cl)(CO)₂]₂. Those derived from aromatic aldehydes form trans dicarbonyl complexes. These complexes with excess of triphenylphosphine give only Rh(CO)(PPh₃)(Schiff). cis-1,5-cyclooctadiene (COD) reacts with cis dicarbonyl complexes to yield the carbonyl-free product Rh(COD)(Schiff); similar reactions have not been observed in the case of trans-dicarbonyl complexes. Oxidative addition of bromine to these complexes yields dibromo derivative in which the Schiff base acts as bidentate chelate. Rh(PPh₃)₂(Schiff) complexes have been obtained from the reaction of above Schiff bases with Rh(PPh₃)₃Cl. The structures of these new complexes have been determined based on IR and ¹H NMR spectra.     

Platinum group metal functionalized phosphine complexes. Part 2. Phosphinoamide rhodium(I), iridium(I), palladium(II) and platinum(II) complexes

Summary Rhodium(I), iridium(I), palladium(II) and platinum(II) complexes of the phosphinoamide ligands, Ph₂PCH₂CONHR (R = H, HDPA; Me, MDPA; Ph, PDPA) were prepared and characterized by using conductivity data, i.r., ¹H and ³¹P(H) n.m.r. spectral data. Reaction of the ligands with MCl(PPh₃)₃ and MCl(CO)(PPh₃)₂ (M = Rh, Ir) in CH₂Cl₂ under reflux lead to the formation of MCl(PPh₃)₂ [Ph₂PCH₂C(O)NHR] and MCl(CO)(PPh₃)[Ph₂PCH₂–C(O)HNR] respectively. The reaction of either K₂MCl₄ or cis-MCl₂(PPh₃)₂ affords complexes of the type cis-MCl₂[Ph₂PCH₂C(O)NHR]₂ (M = Pd, Pt). A similar product results even from the reaction of phosphinoamides with cis-platin. Possible structures are proposed for the complexes based on their physicochemical data     

Metal complexes in inorganic matrices,Part II. CO reactions of chloro(carbonyl)(phosphine)rhodium complexes in a silica gel matrix

Summary Materials obtained by polycondensation of [Rh(CO)ClL₂] [L=PPh₂CH₂CH₂Si(OEt)₃] with tetraethoxysilane (TEOS) irreversibly take up CO to give monomeric or dimeric [cis-Rh(CO)₂ClL']: (L'=PPh₂CH₂CH₂SiO_3/2·xSiO₂) (2). The polymeric metal complex (2) is also obtained by CO treatment of [Rh₂(CO)₂Cl₂L'₂] (4) or by polycondensation ofin-situ prepared (monomeric or dimeric) [Rh(CO)₂ClL] with TEOS. Unlike comparable complexes in solution,(2) is extremely stable in respect to CO loss, even at higher temperatures andin vacuo.Part I of this series, ref. (1).     

Synthesis and characterization of new Rh complexes bearing CO, PPh3 and chelating P,O- or Se,Se-ligands: Application to hydroformylation of styrene

The complexes [Rh(CO)(PPh₃){Ph₂PNP(O)Ph₂-P,O}] (3), [Rh(CO)₂{Ph₂P(Se)NP(Se)Ph₂-Se,Se′}] (5), and [Rh(CO)(PPh₃){Ph₂P(Se)NP(Se)Ph₂-Se,Se′}] (6), were synthesised by stepwise reactions of CO and PPh₃ with [Rh(cod){Ph₂PNP(O)Ph₂-P,O}] (2) and [Rh(cod){Ph₂P(Se)NP(Se)Ph₂-Se,Se′}] (4), respectively. The complexes 3, 5 and 6 have been studied by IR, as well as ¹H and ³¹P NMR spectroscopy. The ν(CO) bands of complexes 3 and 6 appear at approximately 1960 cm⁻¹, indicating high electron density at the Rh^I centre. The structure of complexes 3 and 6 has been determined by X-ray crystallography, and the ³¹P NMR chemical shifts have been resolved via low temperature NMR experiments. Both complexes exhibit square planar geometry around the metal centre, with the five-membered ring of complex 3 being almost planar, and the six-membered ring of complex 6 adopting a slightly distorted boat conformation. The C-O bond of the carbonyl ligand is relatively weak in both complexes, due to strong π-back donation from the electron rich Rh^I centre. The catalytic activity of the complexes 2, 3 and 6 in the hydroformylation of styrene has been investigated. Complexes 2 and 3 showed satisfactory catalytic properties, whereas complex 6 had effectively no catalytic activity.     

The chemistry of hetero-allene and -allylic derivatives with rhodium and iridium III. Elimination of hetero-allene molecules from rhodium(I)-hetero-allylic-phosphine complexes. The first complex with η2-coordinated Ph2PS−

Carbon monoxide causes elimination of the hetero-allene molecules ptolNNptol and PhNCO in Rh(PPh₃)₂[Ph₂PC(Nptol)Nptol] and Rh(PPh₃)₂[Ph₂PC(NPh)O], respectively. The resulting complex in both cases is [Rh(CO)₂(PPh₂)(PPh₂)]_n.In the reaction of RhCl(PPh₃)₃ with Ph₂P(S)C(Nptol)NHptol or Ph₂P(S)C(O)NHPh in the presence of a base, a similar elimination occurs yielding the liberated heterocumulene and Rh(PPh₃)₂(SPPh₂). This complex is the first example of a specieswith a side-on coordinated Ph₂PS-moiety. We have also prepared this compound and other species, containing η₂SPPh₂, via direct interaction of RhCl(PPh₃)₃ and IrCl(PPh₃)₂(C₈H₁₄) with Ph₂P(S)H. Upon reaction with CO, the chelating PPh₂ group is displaced by CO to give complexes with an end-on coordinated Ph₂PS^? ligand.Finally, Rh(PPh₃)₂(SPPh₂) incorporates three moles of PhNCS, one by insertion and two by disproportionation, to yield Rh(PPh₃)(PhNC)(PhNCS₂)[Ph₂P(S)C(S)NPh].     

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.     

Rhodium(I) phosphine complexes containing bidentate unsaturated thio ligands: I. Synthesis and characterisation

The rhodium(I) complexes (Ph₃P)₂Rh(LL′), in which LL′ is an unsaturated chelate coordinating via L = S and L′ = N, O, P or S, have been prepared from RhCl(PPh₃)₃ by two routes.Direct substitution of one Ph₃P and Cl^? by the chelate anion gives (Ph₃P)₂Rh[Ph₂PC(S)S] (L = S, L′ = P). Oxidative addition of an NH bond followed by reductive elimination of HCl results in (Ph₃P)₂Rh[Me₂NC(S)NC(S)NMe₂] (L = S, L′ = S), (Ph₃P)₂Rh[PhNC(S)NMe₂] (L = S, L′ = N), (Ph₃P)₂Rh[Ph₂PC(S)NPh) (L = S, L′ = P) and (Ph₃P)₂Rh[Ph₂P(O)C(S)NPh] (L = S, L′ = O).Reaction of the complexes (Ph₃P)₂Rh(LL′) with CO gives (CO)(Ph₃P)Rh(LL′) with CO trans to the chelate donor atom with the lowest trans-influence. Pt(PPh₃)₄ reacts with Me₂NC(S)N(H)C(S)NMe₂ and HN(Ph)C(S)PPh₂, respectively, to give H(Ph₃P)Pt[Me₂NC(S)NC(S)NMe₂] (L = S, L′ = S) and H(Ph₃P)Pt[Ph₂PC(S)NPh] (L = S, L′ = P).The coordinating atoms and their configurations have been assigned by IR ³¹P NMR and ¹H NMR. Some trend in IR and ³¹P NMR paramaters are discussed.     

Synthesis of aurocyanide and auricyanide complexes of phosphines,phosphine sulfides and phosphine selenides,and their characterization by IR,far-IR,UV solution,and solid-state NMR spectroscopic methods

A series of aurocyanide and auricyanide complexes of phosphines, phosphine sulfides, and phosphine selenides were synthesized. These new complexes have the general formula [L _n Au(CN) _m ], where L could be Cy₃P, (2-CN-Et)₃P, Me₃PS, Et₃PS, Ph₃PS, Me₃PSe, or Ph₃PSe. Auricyanide was reacted with L at 1?:?2 ratio. Products were characterized using elemental analysis, melting point, UV, IR, far-IR solution, and solid-state NMR spectroscopy. Phosphine ligands cause gold(III) reduction to gold(I); less redox tendency was found for phosphine sulfides and phosphine selenides. Tri-coordinate complexes [L₂AuCN] were produced from phosphine ligands with gold-tetracyanide. IR and UV spectroscopic methods were used to identify gold oxidation state in the synthesized complexes.     

Oxorhenium(V) Complexes with 1,3,4‐Triphenyl‐1,2,4‐triazol‐5‐ylidene

Reactions of the oxorhenium(V) complexes [ReOX₃(PPh₃)₂] (X = Cl, Br) with the N‐heterocyclic carbene (NHC) 1,3,4‐triphenyl‐1,2,4‐triazol‐5‐ylidene (L^Ph) under mild conditions and in the presence of MeOH or water give [ReOX₂(Y)(PPh₃)(L^Ph)] complexes (X = Cl, Br; Y = OMe, OH). Attempted reactions of the carbene precursor 5‐methoxy‐1,3,4‐triphenyl‐4,5‐dihydro‐1H‐1,2,4‐triazole ( 1 ) with [ReOCl₃(PPh₃)₂] or [NBu₄][ReOCl₄] in boiling xylene resulted in protonation of the intermediately formed carbene and decomposition products such as [HL^Ph][ReOCl₄(OPPh₃)], [HL^Ph][ReOCl₄(OH₂)] or [HL^Ph][ReO₄] were isolated. The neutral [ReOX₂(Y)(PPh₃)(HL^Ph)] complexes are purple, airstable solids. The bulky NHC ligands coordinate monodentate and in cis‐position to PPh₃. The relatively long Re–C bond lengths of approximate 2.1Å indicate metal‐carbon single bonds.     

Hemilabile Phosphonate-Phoshane Complexes of Rhodium and Iridium -Synthesis and Catalytical Properties

Abstract

New phosphonate-phosphane ligands la-d¹ were converted into the Rh and Ir complexes 2a-d and 3a-c. The open-chain Rh complexes 2a-d are more effective catalysts for liquid-phase MeOH-carbonylation with respect to known bisphosphane and phosphane-monoxide phosphane complexes [Rh(CO)L₁]_n, [Rh(cod)L₂] (L₁: Ph₂P(CH₂)₂PPh₂, Ph₂P(CH₂)₃PPh₂; L₂: Ph₂P(CH₂)₂PPh₂).     

Synthese und Struktur chiraler Heterometallatetrahedrane des Typs [Re2(M1PPh3)(M2PPh3)(μ‐PCy2)(CO)7C≡CPh] (M1 = Ag,Au; M2 = Cu,Ag, Au)

Syntheses and Structure of Chiral Metallatetrahedron Complexes of the Type [Re₂(M¹PPh₃)(M²PPh₃)(μ‐PCy₂)(CO)₇C≡CPh] (M¹ = Ag, Au; M² = Cu, Ag, Au) From the reaction of Li[Re₂(μ‐H)(μ‐PCy₂)(CO)₇(C(Ph)O)] ( 1 ) with Ph₃AuC≡CPh both benzaldehyde and the trinuclear complex Li[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇C≡CPh] ( 2a ) were obtained in high yield. The complex anion was isolated as its PPh₄‐salt 2b . The latter reacts with coinage metal complexes PPh₃M²Cl [M² = Cu, Ag, Au] to give chiral heterometallatetrahedranes of the general formula [Re₂(AuPPh₃)(M²PPh₃)(μ‐PCy₂)(CO)₇C≡CPh] (M² = Cu 3a , Ag 3b , Au 3c ). The corresponding complex [Re₂(AgPPh₃)₂(μ‐PCy₂)(CO)₇C≡CPh] ( 3d ) is obtained from the reaction of [Re₂(AgPPh₃)₂(μ‐PCy₂)(CO)₇Cl] ( 4 ) with LiC≡CPh. 3d undergoes a metathesis reaction in the presence of PPh₃CuCl giving [Re₂(AgPPh₃)(CuPPh₃)(μ‐PCy₂)(CO)₇C≡CPh] ( 3e ) and PPh₃AgCl. Analogous metathesis reactions are observed when 3c is reacted with PPh₃AgCl or PPh₃CuCl giving 3a or 3b , respectively. The reaction of 1 with PPh₃AuCl gives benzaldehyde and Li[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇Cl] ( 5a ) which upon reaction with PhLi forms the trinuclear complex Li[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇Ph] ( 6a ). Again this complex was isolated as its PPh₄‐salt 6b . In contrast to 2b , 6b reacts with one equivalent of Ph₃PAuCl by transmetalation to give Ph₃PAuPh and PPh₄[Re₂(AuPPh₃)(μ‐PCy₂)(CO)₇Cl] ( 5b ). The X‐ray structures of the compounds 3a , 3b , 3e and 4 are reported.