Darstellung,Eigenschaften und Molekülstrukturen von Komplexen des versteiften dreizähnigen Chelatliganden N,N′-Bis(diphenylphosphino)-2, 6-diaminopyridin mit MII - und M0-Übergangsmetallen [MII = Ni,Pd, Pt; M0 = Cr,Mo, W]

Preparation, Properties, and Molecular Structures of a Rigid Tridentate Chelate Ligand N, N′-Bis(diphenylphosphino)-2, 6-diaminopyridine with M^II and M⁰ Transition Metals [M^II = Ni, Pd, Pt; M⁰ = Cr, Mo, W] The reaction of chlorophenylphosphane and 2, 6-Diaminopyridine give N, N′-Bis-(diphenylphosphino)-2, 6-diaminopyridine (PNP). Two types of complexes [M(PNP)Cl]Cl · L (M = Ni, L = H₂O; M = Pd, L = C₂H₅OH; M = Pt) and mer-[M(PNP)(CO)₃] · 2 THF (M = Cr, Mo, W) have been prepared using PNP. These coordination compounds have been characterized by means of i.r., u.v., ³¹P and ¹H n.m.r. measurements. The determination of the molecular structure of the two triclinic substances mer-[Mo(PNP)(CO)₃] · 2 THF and [Ni(PNP)Cl]Cl · H₂O show that the octahedral Mo(d⁶) and the square planar nickel (d⁸) compounds contain a nearly planar tridentate chelate ring system (two fused five-membered rings of the type ) in which the observed bond distances are in accordance with a π electron delocalization effect. The observed gram susceptibility of the diamagnetic Ni(d⁸) compound remains unchanged between 293 and 410 K. The relative activation property for a homogenous catalytic standard hydrogenation reaction of styrene to ethylbenzene decreases in series of catalysts of type [M(PNP)Cl]Cl · L with M^II = Ni > Pd > Pt.     

Alternativ-Liganden. VIII. Chelatkomplexe des Typs M(CO)4(Me2XGeMe2CH2X′Me2) (M = Cr,Mo, W; X,X′ = N,P, As; Me = CH3)

Chelate Complexes of the Type M(CO)₄(Me₂XGeMe₂CH₂X′Me₂) (M) = Cr, Mo, W; X, X′ = N, P, As; Me = CH₃) The ligands (Me₂)XGeMe₂CH₂X′Me₂ (M) = Cr, Mo, W) react with M(CO)₄norbor (norbor = Norbornadiene) (M = Cr, Mo, W) yielding the chelate complexes M(CO)₄(Me)₂XGeMe₂CH₂X′Me₂). compounds of low thermal stability are formed with the ligands (Me₂NGeMe₂CH₂X′Me₂ because of the weak donor ability of the GeNMe₂ group and with Me₂AsGeMe₂CH₂NMe₂ caused by strong steric ring tension. The new compounds are characterized by analytical and spectroscopic (n.m.r., i.r., m.s.) investigations.     

Synthese und Molekülstruktur von [Li(THF)4][{(CO)4Mo}2(μ-PPh2)(μ-PPh2PPh2)]: Die erste Verbindung mit einem 1,3-Dimetalla-cyclopentaphosphan-Gerüst

Synthesis and Molecular Structure of [Li(THF)₄][{(CO)₄Mo}₂(μ-PPh₂)(μ-PPh₂PPh₂)]: The First Compound with an 1,3-Dimetalla-cyclopentaphosphane Ring [Mo(CO)₄(NBD)] (NBD = norbornadiene) reacts with LiPPh₂ and PPh₂PPh₂ in THF at –80 °C to give [Li(THF)₄][{(CO)₄Mo}₂(μ-PPh₂)(μ-PPh₂PPh₂)] ( 1 ). 1 exhibits an A₂X coupling pattern in the ³¹P NMR spectrum. A crystal structure determination showed the presence of bridging phosphanido (PPh₂) and diphosphane ligands (PPh₂PPh₂). The central Mo₂P₃ five-membered ring adopts a half-chair conformation and thus resembles an inorganic cyclopentane.     

Reactions of 1,8-bis(diphenylphosphino)naphthalene with Os3(CO)12: C-H and C-P bond cleavage reactions

Reactions of Os₃(CO)₁₂ with 1,8-bis(diphenylphosphino)naphthalene (dppn) are described. Crystallographically characterised complexes isolated from a reaction carried out in refluxing toluene are Os₃(μ-H)₂{μ-PPh₂(nap)PPh(C₆H₄)}₂(CO)₆ (1), Os₃(μ-H){μ₃-PPh₂(nap)PPh(C₆H₄)}(CO)₈ (2) and Os₂(μ-PPh₂){μ-PPh₂(nap)}(CO)₅ (3) (nap=1,8-C₁₀H₆), while at r.t. in the presence of ONMe₃, only Os₃(CO)₁₁{PPh₂(1-C₁₀H₇)} (4) was isolated. While 1 and 2 contain ligands formed by metallation of a Ph group of dppn, as found also in complexes obtained from dppn and Ru₃(CO)₁₂, ligands in 3 and 4 are formed by cleavage of a P-nap bond, not found in the Ru series.     

Dinuclear group VIB metal carbonyl complexes bridged by bis(diphenylphosphino)alkanes

Reactions of the intermediate W(CO)₅THF, generated photochemically from W(CO)₆ in THF, with Ph₂P(CH₂) _n PPh₂ [ = PP; n = 2 (dppe), 4 (dppb), 6 (dpph), 10 (dppd)] at room temperature in THF solutions gave exclusively bimetallic complexes of the (CO)₅WPPW(CO)₅ type. In addition, complexes bridged by diphosphine ligands of the (CO)₄(pip)MPPM(pip)(CO)₄ type (pip = piperidine; M = Mo, W) were prepared by stirring the (CO)₄M(pip)₂ complexes with bis(diphenylphosphino)alkanes in CH₂Cl₂ solution at ambient temperatures. These new bis(diphenylphosphino)alkane-bridged complexes were characterized by i.r., ¹H- and ³¹P-n.m.r. spectroscopies, as well as by elemental analysis.     

Reaktivität der M-M-mehrfachbindung in metallcarbonyl-derivaten: VII. Aktivierung von carbodiimiden durch [η-C5H5(CO)2Mo]2 als μ(η1:η2) ligand unter erhalt der Mo—Mo-Dreifachbindung

The reaction of Cp(CO)₂MoMo(CO)₂Cp (Cp = η-C₅H₅) with an excess of carbodiimides RN=C=NR′ results in the substitution of two carbonyl groups to give the new asymmetrically bridged complexes Cp₂(CO)₂Mo₂μ(η¹:η²-RN=C=NR′) with Cp₂(CO)₄Mo₂μ(η¹:η²-CNR) complexes as by products.     

Some Aryl Substituted Metal Phosphorus Double Bonded Complexes C5R5 (CO)2 M=PR′2 (R=H,CH3; M=Mo,W)

Abstract

The attempt to generate the metal-phosphorus double bonded system Cp(CO)₂M=PPh₂ (M=Mo, W) (4a,b) via thermal or photochemical decarbonylation of Cp(CO)₃M-PPh₂ (la,b) leads to the formation of hydrido-phosphido-bridged complexes (μ2-H) (μ2-PPh₂)[M(CO)₂Cp]₂ (2a,b).     

Alternativ-Liganden. XXVI [1]. M(CO)4L-Komplexe (M  Cr,Mo, W) der Chelatliganden Me2ESiMe2(CH2)2E′Me2 (Me  CH3; E  P,As; E′  N,P, As)

Alternative Ligands. XXVI. M(CO)₄ L-Complexes (M ? Cr, Mo, W) of the Chelating Ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ (Me ? CH₃; E ? P, As; E′ ? N, P, As) The reaction of M(CO)₄NBD (NBD = norbornadiene; M ? Cr, Mo, W) with the ligands Me₂ESiMe₂(CH₂)₂E′ Me₂ yields the chelate complexes (CO)₄M[Me₂ESiMe₂]) for E,E′ ? P, As, but not for E and /or E′ ? N. The NSi group is not suited for coordination because of strong (p-d)π-interaction. In the case of the ligands with E ? P or As and E′ ? N chelate complexes can be detected in the reaction mixture, but isolable products are complexes with two ligands coordinated via the E donor group. The new compounds are characterized by analytical and spectroscopic (IR, NMR, MS) investigations. The spectroscopic data are also used to deduce the coordinating properties of the ligands. X-ray diffraction studies of the molybdenum complexes (CO)₄Mo[Me₂ESiMe₂(CH₂)₂AsMe ₂] (E ? P, As) in accord with the observed coordination effects show only small differences between SiE and CE donor functions. Attempts to use the ligands Me₂ESiMe₂(CH₂)₂AsMe₂ (E ? P, As) for the preparation of Fe(CO)₃L complexes result in the fission of the SiE bonds and the formation of the binuclear systems Fe₂(CO)₆(EMe₂)₂ (E ? P, As) together with the disilane derivative [Me₂Si(CH₂)₂AsMe₂]₂.     

Photochemical reactions of M(CO)6 (M = Cr,Mo, W) with Ph2P(S)P(S)Ph2

New complexes {M(CO)₄[Ph₂P(S)P(S)Ph₂]} (M = Cr, Mo and W), (1a)–(3a), [(1a), M = Cr; (2a), M = Mo; (3a), M = W] and {M₂(CO)₁₀[-Ph₂P(S)P(S)Ph₂]} (M = Cr, Mo, W), [(1b)–(3b) [(1b), M = Cr; (2b), M = Mo; (3b), M = W]] have been prepared by the photochemical reaction of M(CO)₆ with Ph₂P(S)P(S)Ph₂ and characterized by elemental analyses, f.t.-i.r. and ³¹P-(¹H)-n.m.r. spectroscopy and by FAB-mass spectrometry. The spectra suggest cis-chelate bidentate coordination of the ligand in {M(CO)₄[Ph₂P(S)P(S)Ph₂]} and cis-bridging bidentate coordination of the ligand between two metals in (M = Cr, Mo and W).     

Tetracarbonyl group 6 complexes containing secondary and tertiary phosphines

The mixed ligand tetracarbonyl derivatives, cis-M(CO)₄(PPh₂H)(PPh₃) (M  Cr, Mo, W) and cis-W(CO)₄(PPh₂H)(L) (L  PEt₃, PEt₂Ph, PEtPh₂) have been prepared from the reaction of M(CO)₅PPh₂H with L in THF in the presence of potassium t-butoxide. These reactions are accompanied in most instances by the formation of [W(CO)₅PPh₂]⁻, [(OC)₅M(μ-PPh₂)M(CO)₅]⁻, [(OC)₅M(μ-PPh₂)-M(CO)₄(PPh₂H)]⁻, [(OC)₄M(μ-PPh₂)₂M(CO)₄]²⁻, (OC)₄M(μ-PPh₂)₂M(CO)₄, and cis-M(CO)₄(PPh₂H)₂.     

Heterometallatom-Koordinationsverbindungen Re2(μ-PPh2)2[mer-(CO)3]2-trans-[InX2(H2O)]2 und neue halogenhaltige drei- und vierkernige Rheniumcluster aus Reaktionen zwischen Re2[μ-PPh2)2(CO)8] und InX3 (X = Cl,Br, I)

Heterometallic Coordination Compounds Re₂(μ-PPh₂)₂[mer-(CO)₃]₂-trans-[InX₂(H₂O)]₂ and New Halogene Containing Three- and Four-Nuclear Rhenium Clusters from Reactions between Re₂(μ-PPh₂)₂(CO)₈ and InX₃ (X = Cl, Br, I) In sealed glass tubes equimolar amounts of Re₂(μ-PPh₂)₂(CO)₈ and InX₃ (X = Cl, Br, I) were reacted in the presence of xylene at 220°C to two types of products. The first type comprised the heterometallic coordination compounds Re₂(μ-PPh₂)₂(CO)₆[InX₂(H₂O)]₂ (X = Cl, Br, I) (yield 60%), and the second halogene containing rhenium complexes Re₃(μ₃-H)(μ₃-X)(μ-PPh₂)₃(CO)₆ (unsaturated three-membered metal ring with 46 VE) and Re₄(μ-H)(μ-X)(μ-PPh₂)₄(μ₄-PPh)(CO)₈ and additionally those substances as cis-IRe(CO)₄(PPh₂H), Re₂(μ-PPh₂)(μ-X)(CO)₈ (X = Cl, Br), Re₂(μ-I)₂[μ-(PPh₂)₂O](CO)₆ and Re₄(μ-Cl)₂(μ-PPh₂)₄(μ₄-PPh)(CO)₈ (four-membered metal ring with 66 VE with three Re? Re bonds) which have been observed in one or two of the three reaction systems. A proposal of the reaction course is discussed. The single X-ray analysis of Re₂(μ-PPh₂)₂[mer(CO)₃]₂-trans[InI₂(H₂O)]₂ · 2 Me₂CO shows for the two fold phosphido bridged dirhenium molecular fragment with 34 VE a Re? Re bond of 294.6(1) pm. From two possible transpositions of both In? Re bond vectors, the one found advantageously has sterical reasons. The average In? Re single bond length is 271.1(1) pm. The corresponding determination of the unsaturated three-membered ring compound Re₃(μ₃-H) (μ₃-Cl)(μ-PPh₂)₃(CO)₆ showed three Re? Re bond lenghts of comparable size, of which the mean value of 281.9(1) pm was significantly shortened by π electron delocalization effect compared to that of a saturated phosphido bridged three-membered rhenium ring compound. As it was recognized by further comparison, the structural data of the common molecular fragments in the three examined three-membered rhenium ring clusters (X = Cl, Br, I) are not dependent on the different kind of halogeno ligand atoms. Finally, the crystal structure determination of the substance Re₄(μ-H)(μ-Br)(μ-PPh₂)₄(μ₄-PPh)(CO)₈ shows the presence of square-pyramidal Re₄(μ₄-P) atomic arrangement, of which the planar basic plane has a sequence of up- and downwards orientated four diphenylphosphido bridging groups. The four measured Re? Re single bond lengths (mean value 302.7(3) pm change with the different kind of bridging atoms. The structural features observed are compared with those of a corresponding iodine derivative.     

Highly reduced organometallics: XI. Formal derivatives of the tricarbonylmetallates (6-) of chromium,molybdenum and tungsten

Reduction of W(CO)₃(PMTA) (PMTA = 1,1,4,7,7-pentamethyldiethylenetriamine) by six equivalents of potassium metal in liquid ammonia provides an incompletely characterized highly reduced carbonyltungstate ion which reacts with several electrophiles to provide derivatives containing only tungsten tricarbonyl units. These include W(CO)₃(NH₃)₃, [W₃(CO)₉(μ-OC₂H₅)(μ₃-OC₂H₅)₂]^3-, HW(CO)₃(SnPh₃)₃^2- and the unusual [(Ph₃Sn)₂{(Ph₂Sn)₂OEt}W(CO)₃]^?. The latter compound results from an unprecedented phenyl-tin cleavage in the reaction of triphenyltin chloride and the highly reduced carbonyltungstate ion. Triphenyltin derivatives of the unknown M(CO)₃^6- (M = Cr, Mo and W) have also been prepared by reacting M(CO)₃(SnPh₃)₃^3- with Brønsted acids and Ph₃SnCl. From these reactions the previously unknown HM(CO)₃(SnPh₃)₃^2- (M = Cr, Mo and W) and M(CO)₃(Ph₃Sn)₄^2- (M = Mo and W) have been isolated and characterized. The latter are the first compounds containing more than three triphenyltin units attached to one transition metal.     

Übergangsmetallphosphidokomplexe. XIII. P-funktionelle phosphidoverbrückte Heterozweikernkomplexe mit und ohne Metall-Metall-Bindung; P(SiMe3)2-verbrückte cp(CO)xFe-Derivate

Transition Metal Phosphido Complexes. XIII. P-functional Phosphido-Bridged Heterobimetallic Complexes with and without a Metal-Metal Bond; P(SiMe₃)₂-Bridged cp(CO)_xFe Derivatives cp(CO)₂FeP(SiMe₃)₂ 1 reacts with the carbonyl nitrosyl complexes Co(CO)₃(NO), Fe(CO)₂(NO)₂,Mn(CO)(NO)₃ substituting a CO ligand and with the THF complexes M′(CO)₅THF(M′ = Cr, Mo, W), Mncp(CO)₂THF MnMecp(CO)₂ which can be obtained in solution substituting the THF ligand to give the phosphido-bridged bimetallic complexes cp(CO)₂Fe[μ-P(SiMe₃)₂]M′L_m 2 (M′L_m = Co(CO)₂(NO) b , Fe(CO)(NO)₂ c , Mn(NO)₃ d , Cr(CO)₅ f , Mo(CO)₅ g , W(CO)₅ h , Mncp(CO)₂ i , MnMecp(CO)₂ j ). Solutions of Li(Me₃Si)₂PM′L_m 4e–l (M′L_m = Fe(CO)₄ e , Crcp(CO)(NO) k , Vcp(CO)₃ l ) are available by a selective cleavage reaction of a Si? P bond in the complexes (Me₃Si)₃PM′L_m 3e–l using n-BuLi. Reactions of cp(CO)₂FeBr with 4e–l give the bimetallic complexes 2e–l . The open-chain complexes 2c, 2f, 2h–k undergo a photochemical decarbonylation reaction to form the phosphido-bridged bimetallic complexes cp(CO)Fe[μ-CO, μ-P(SiMe₃)₂]M′L_m?1(Fe-M′) 5 (M′L_m?1 = Fe(NO)₂ c , Cr(CO)₄ f , W(CO)₄ h , Mncp(CO) i , MnMecp(CO) j , Crcp(NO) k ) containing a metal-metal bond. Equilibria between various isomers can partially be observed in solutions of the complexes 5. I.R., N.M.R., and mass spectral data are reported.     

Binuclear 2,2′-bipyrimidine complexes derived from chromium,molybdenum and tungsten carbonyls

Reaction of 2,2′-bipyrimidine (bpym) with [Mo(CO)₄(diene)] gives [Mo(CO)₄(bpym)], which will react with [M(CO)₄(diene)] to form [MoM(CO)₈(bpym)] (M = Cr, Mo, W). The bipyrimidine complexes are characterised by microanalysis and spectroscopy (IR, ¹H and ¹³C NMR, UV/vis). Reduction of [Mo₂(CO)₈(bpym)] produces an anion in which the unpaired electron is localised on the bridging bpym ligand.     

New Bimetallics of Mo and W with Metallocene,Metal Carbonyl and Bridging PPh2 or ‘Cp’PPh2 Units

Ring substituted (R=^tBu, SiMe₃) metallocene dichlorides undergo a nucleophilic substitution on one of the two rings upon the action of LiPPh₂M'(CO)_x salts with the formation of chloro-hydrido complexes [C₅H₃(R)PPh₂M'(CO)_x](C₅H₄R)M(H)Cl. Their UV irradiation leads to the chloro-bridged M(μ-Cl)M' separable diastereoisomers. Use of the ansa-metal-locene dichlorides [Me₂X(C₅H₄)₂MCl₂] (X=Si or C) allowed the access to the new bridging system [M(μ-PPh₂, μ-Cl)M′] (M=Mo, W ; M'=W).     

The syntheses and coordination properties of M(CO)3X(DAB) (M = Mn,Re; X = Cl,Br, I; DAB = 1,4-diazabutadiene)

M(CO)₅X (M = Mn, Re; X = Cl, Br, I) reacts with DAB (1,4-diazabutadiene = R₁N=C(R₂)C(R₂)′=NR′₁) to give M(CO)₃X(DAB). The ¹H, ¹³C NMR and IR spectra indicate that the facial isomer is formed exclusively. A comparison of the ¹³C NMR spectra of M(CO)₃X(DAB) (M = Mn, Re; X = Cl, Br, I; DAB = glyoxalbis-t-butylimine, glyoxyalbisisopropylimine) and the related M(CO)₄DAB complexes (M = Cr, Mo, W) with Fe(CO)₃DAB complexes shows that the charge density on the ligands is comparable in both types of d⁶ metal complexes but is slightly different in the Fe-d⁸ complexes. The effect of the DAB substituents on the carbonyl stretching frequencies is in agreement with the A′(cis) > A″ (cis) > A′(trans) band ordering.Mn(CO)₃Cl(t-BuNCHCHNt-Bu) reacts with AgBF₄ under a CO atmosphere yielding [Mn(CO)₄(t-BuNCHCHN-t-Bu)]BF₄. The cationic complex is isoelectronic with M(CO)₄(t-BuNCHCHNt-Bu) (M = Cr, Mo, W).     

Synthesis, characterization and electrochemical studies of the heterometallic diclusters [{Fe2(μ-CO)(CO)6(μ-PPh2)Au}2(diphosphine)] (diphosphine=dppm, dppip, dppe, dppp)

Treatment of [(ClAu)₂(diphosphine)] {diphosphine=bis(diphenylphosphino)methane (dppm), bis(diphenylphosphino)isopropane (dppip), 1,2-bis(diphenylphosphino)ethane (dppe), 1,3-bis(diphenylphosphino)propane (dppp)} with two equivalents of the anion [Fe₂(μ-CO)(CO)₆(μ-PPh₂)]⁻ in the presence of TlBF₄ gives the new heterometallic diclusters [{Fe₂(μ-CO)(CO)₆(μ-PPh₂)Au}₂(diphosphine)] that have been isolated and characterized. Their ³¹P-NMR spectra show different patterns as a function of the diphosphine ligand. The electrochemical behavior of these compounds has been investigated and compared with that of the mono- [Fe₂(μ-CO)(CO)₆(μ-PPh₂)(μ-AuPPh₃)] and tricluster [{Fe₂(μ-CO)(CO)₆(μ-PPh₂)Au}₃(triphos)] derivatives.     

Perfluormethyl-Element-Liganden. Reaktionen der Metallhydride π-C5H5(CO)3 MH (M = Cr,Mo, W) mit Organoelement-Elementverbindungen des Typs R2EER2 und RE′ E′ R (E = As; E′ = S,Se; R = CH3 CF3)

Perfluoromethyl Element Ligands. XXX. Reactions of the Metal Hydridesπ-C₅H₅(CO)₃MH (M = Cr, Mo, W) with Organoelement-Element Compounds of the Type R₂ EER₂ and RE′ ′E ′R (E = P, As; E′ = S, Se; R = CH₃, CF₃) Cleavage reactions of R₂EER₂ and RE′E′R, respectively, (E = P, As; E′ = S, Se; R = CH₃, CF₃) with complexes π-C₅H₅(CO)₃MH (M = Cr, Mo, W) are used (a) to prepare known and novel complex subsituted phosphanes, arsanes, sulfanes, or selanes π-C₅H₅(CO)₃MER₂ (I) and π-C₅H₅(CO)₃ME′R (II), respectively, (b) to study the reactivity trends as a function of E, E′, R, and M (see Inhaltsübersicht). The tendency observed for the formation of the binuclear complexes [π-C₅H₅(CO)₂MER₂]₂ and [π-C₅H₅(CO)₂ME′R]₂, respectively, in following reactions of I and II increases in the series W ? Mo ≤ Cr and SeCF₃ < As(CF₃)₂ < SCF₃ ≈ P(CF₃)₂ < SeMe < AsMe₂ ?; PMe₂ ≈ SMe.     

The synthesis of and nuclear magnetic resonance strudies on bimetallic chromium(0), or molybdenum(0) carbonyl complexes containing bridging trans-Ph2PCHCHPPh2 ligands: Crystal structure of [Mo2(CO)8(μ-trans-PH2PCHCHPPh2)2]

The trans-PH₂PCH=CHPPh₂ (t-dppe)-bridged bimetallic 10-membered ring complexes [M₂(CO)₈(μ-t0dppe)₂] (M = Cr or MO) have been synthesized by treatment of the metal hexacarbonyl with one equivalent of t-dppe at elevated temperature. the fluxional process in the Mo(μ-t-dppe) Mo ring has been studied by variable temperature ¹³P-{¹H} NMR spectroscopy and is characterised by a change from an A₄ spin system at +20°C to an AA′BB′ system at −100°C. The bimetallic complex [Mo₂(CO)₆(μ-tdppe)₃] has been prepared and ¹³P-{¹H} NMR studies indicate that in solution all four phosphorus nuclei are equivalent, even at −115°C. Attempts to prepare related heterobimetallic complexes are also described. Crystals of [Mo₂(CO)₈(μ-trans-Ph₂PCH=CHPPh₂)₂] are monoclinic, space group P2₁/a, with a 2020.2(5), b 1423.1(5), c 2145.1(5) pm, β 113.95(2)°, and Z = 4; final R factor 0.0465 for 5668 observed reflections. The structure shows two [Mo(CO)₄] moieties linked by two trans-dppe bridges to give a 10-membered Mo₂P₄C₄ ring.