Clusteraufbau durch Photolyse von R3PAuN3. VIII. Synthese und Kristallstruktur von [(Ph3PAu)5Mo(CO)4]PF6 · CH2Cl2 und (Ph3PAu)3Co(CO)3

Cluster Synthesis by Photolysis of R₃PAuN₃. VIII. Synthesis and Crystal Structure of [(Ph₃PAu)₅Mo(CO)₄]PF₆ · CH₂Cl₂ and (Ph₃PAu)₃Co(CO)₃ Photolysis of a mixture of Ph₂PAuN₃ and Mo(CO)₆ in THF yields [(Ph₃PAu)₅Mo(CO)₄]⁺ (1), which can be crystallized from CH₂Cl₂/diisopropylether as orange 1 · PF₆ · CH₂Cl₂ with the space group P2₁/c and a = 1681.4(5), b = 2215.6(12), c = 2761.5(9) pm, β = 91.54(3)°, Z = 4. The Au₅Mo center of cluster 1 forms a capped trigonal bipyramid with the Mo atom in equatorial position and almost equal Mo? Au distances between 279.9(5) and 284.6(7) pm to all five Au atoms. The Au? Au distances range from 272.2(4) to 301.3(4) pm. The Mo(CO)₄ group causes three v(C0) at 1975, 1915 and 1890cm^?1. Reaction of Ph₃PAuCo(CO)₄ with Ph₃PAuPF₆ affords the known cluster cation [(Ph₃PAu)₄Co(CO)₃]⁺ in high yield. It can be degraded with C1^? to the neutral cluster (Ph₃PAu)₃Co(CO)₃ (2). 2 forms air stable, yellow crystals with the space group P2₁/n and a = 1359.4(4), b = 2041.0(5), c = 1853.2(6)pm, β = 91.47(1)°, Z = 4. The Au₃Co core of 2 has a tetrahedral structure with distances Co? Au between 250.4(1) and 254.0(2) pm and Au? Au between 279.5(1) and 285.1(1) pm. v(C0) are observed at 1963, 1905 and 1891 cm^?1. Reaction of 2 with [(Ph₃PAu)₄Co(CO)₃]⁺ yields the condensed cluster [(Ph₃PAu)₆AuCo₂(CO)₆]⁺.     

1,8‐Bis[(dimethoxy)phosphino]naphthalene: A New Bis‐phosphonite Ligand with a Rigid C3‐Backbone and Unexpected Reaction Chemistry

1,8‐Bis[(diethylamino)phosphino]naphthalene ( 1 ) reacted with dry methanol in dichloromethane to form the new bis‐phosphonite ligand 1,8‐bis[(dimethoxy)phosphino]naphthalene (dmeopn, 2 ). By oxidation of 2 with H₂O₂ · (H₂N)₂C(:O) the corresponding bis‐phosphonate, 1,8‐bis[(dimethoxy)phosphoryl]naphthalene ( 3 ), was obtained quantitatively. Reaction of 3 with phosphorus trichloride unexpectedly furnished a 2.4 : 1 mixture of the bis‐phosphonate anhydrides rac‐ and meso‐1,3‐dimethoxy‐1,3‐dioxo‐2,3‐dihydro‐1,3‐diphospha‐2‐oxaphenalene (rac‐ 4 and meso‐ 4 ) from which rac‐ 4 could be fractionally crystallised. The bis‐phosphonite 2 behaved as a normal bidentate chelate ligand towards Mo⁰ and Pd^II, and furnished the complexes [(dmeopn)Mo(CO)₄] ( 5 ) and [(dmeopn)PdCl₂] ( 6 ) when treated with [(nor)Mo(CO)₄] or [(cod)PdCl₂] (nor = norbornadiene, cod = cycloocta‐1,8‐diene). Attempts to prepare 1,8‐diphosphinonaphthalene ( 7 ) by reducing 2 or 3 with LiAlH₄ or LiAlH₄/TMSCl (1 : 1) (TMSCl = trimethyl chlorosilane) in THF led to inseparable mixtures of phosphorus‐containing products. Compounds 2 – 6 were characterised by ¹H‐, ¹³C‐, and ³¹P‐NMR spectroscopy, IR spectroscopy, mass spectrometry and elemental analysis. X‐ray crystal structure analyses were carried out for the bis‐phosphonate anhydride rac‐ 4 and the palladium(II) complex 6 . The geometry of compound rac‐ 4 , in which the phosphorus atoms are connected by an oxygen atom, reveals a relief of strain from the bis‐phosphine 1 , whereas the 1,8‐P,P′‐naphthalenediyl group in 6 is surprisingly distorted; the P atoms are displaced from the naphthalene best plane by –46.7 and 54.5 pm.     

Synthesis and spectroscopic properties of selenolato- and tellurolato-bridged dimolybdenum(MoMo) complexes [(η5-MeCp)Mo(CO)(μ-EPh)]2 (E = Se,Te)

UV irradiation of the diphenylchalcogenides Ph₂Se₂ or Ph₂Te₂ in the presence of [(η⁵-MeCp)Mo(CO)₃]₂ induces rapid reaction to give the double μ-EPh bridged compounds [(η⁵-MeCp)Mo(CO)₂(μ-EPh)]₂. Subsequent decarbonylation by mild thermolysis in vacuo gives [(η⁵-MeCp)Mo(CO)(μ-SePh)]₂ or [(η⁵-MeCp)Mo(CO)(μ-TePh)₂ in good yields. The new compounds were characterized by elemental analysis, infrared and mass spectra. The mixed Se/ Te bridged complex [(η⁵-MeCp)Mo₂(Co)₄(μ-SePh)(μ-TePh)] was not obtained by UV irradiation of [(η⁵-MeCp)Mo(CO)₃]₂ in the presence of a mixture of Ph₂Se₂ and Ph₂Te₂.     

Molybdenum(0) and Tungsten(0) Complexes with P,S and P,Se Monooxidized Bis(phosphanyl)amine Ligands

Reactions of monooxidized thioyl and selenoyl bis(phosphanyl)amine ligands C₁₀H₇‐1‐N(P(E)Ph₂)(PPh₂) [E = S ( 1 ), Se ( 2 )] with Mo(CO)₄(pip)₂ and W(CO)₄(cod) afforded the complexes [M(CO)₄{ 1 ‐κ²P,S}] [M = Mo ( 3 ), W ( 4 )] and [M(CO)₄{ 2 ‐κ²P,Se}] [M = Mo ( 5 ), W ( 6 )]. Complexes 3 – 6 were characterized by multinuclear NMR (¹H, ¹³C, ³¹P, and ⁷⁷Se NMR) and IR spectroscopy. Crystal‐structure determinations were carried out on 3 , 5 , and 6 , which represent the first examples of structurally characterized complexes of such ligands with group‐6 metal carbonyls.     

Synthesis and Spectra of Cationic Bis(tertiary phosphine) derivatives of cycloheptatrienyliummolybdenum and cyclopentadienyliron complexes

Reaction of [(η-C₇H₇)Mo(CO)₃][PF₆] and [(η-C₅H₅)Fe(CO)₂CH₃CN][PF₆] with ditertiary phosphine ligands afforded products of three types; the monosubstituted complexes [(Ring)M(CO)₂Ph₂P(CH₂)_nPPh₂][PF₆] (Ring = η-C₇H₇, M = Mo, N = 1; Ring = η-C₅H₅, M = Fe, N = 1 and 2), the chelated complexes [(Ring)M(CO)Ph₂P(CH₂)_nPPh₂][PF₆] (Ring = η-C₇H₇, M = Mo, N = 1 and 2; Ring = η-C₅H₅, M = Fe, N = 1 and 2), and the dinuclear complex [{(η-C₇H₇)Mo(CO)₂}₂ -μ- Ph₂PCH₂CH₂PPh₂][(PF₆)₂]. Spectroscopic properties, including ³¹P NMR, are reported.     

New Heteronuclear Bridged Borylene Complexes That Were Derived from [{Cp*CoCl}2] and Mono‐Metal?Carbonyl Fragments

The synthesis, structural characterization, and reactivity of new bridged borylene complexes are reported. The reaction of [{Cp*CoCl}₂] with LiBH₄ ? THF at ?70 °C, followed by treatment with [M(CO)₃(MeCN)₃] (M=W, Mo, and Cr) under mild conditions, yielded heteronuclear triply bridged borylene complexes, [(μ₃‐BH)(Cp*Co)₂(μ‐CO)M(CO)₅] ( 1 – 3 ; 1 : M=W, 2 : M=Mo, 3 : M=Cr). During the syntheses of complexes 1 – 3 , capped‐octahedral cluster [(Cp*Co)₂(μ‐H)(BH)₄{Co(CO)₂}] ( 4 ) was also isolated in good yield. Complexes 1 – 3 are isoelectronic and isostructural to [(μ₃‐BH)(Cp*RuCO)₂(μ‐CO){Fe(CO)₃}] ( 5 ) and [(μ₃‐BH)(Cp*RuCO)₂(μ‐H)(μ‐CO){Mn(CO)₃}] ( 6 ), with a trigonal‐pyramidal geometry in which the μ₃‐BH ligand occupies the apical vertex. To test the reactivity of these borylene complexes towards bis‐phosphine ligands, the room‐temperature photolysis of complexes 1 – 3 , 5 , 6 , and [{(μ₃‐BH)(Cp*Ru)Fe(CO)₃}₂(μ‐CO)] ( 7 ) was carried out. Most of these complexes led to decomposition, although photolysis of complex 7 with [Ph₂P(CH₂)_nPPh₂] (n=1–3) yielded complexes 9 – 11 , [3,4‐(Ph₂P(CH₂)_nPPh₂)‐closo‐1,2,3,4‐Ru₂Fe₂(BH)₂] ( 9 : n=1, 10 : n=2, 11 : n=3). Quantum‐chemical calculations by using DFT methods were carried out on compounds 1 – 3 and 9 – 11 and showed reasonable agreement with the experimentally obtained structural parameters, that is, large HOMO–LUMO gaps, in accordance with the high stabilities of these complexes, and NMR chemical shifts that accurately reflected the experimentally observed resonances. All of the new compounds were characterized in solution by using mass spectrometry, IR spectroscopy, and ¹H, ¹³C, and ¹¹B NMR spectroscopy and their structural types were unequivocally established by crystallographic analysis of complexes 1 , 2 , 4 , 9 , and 10 .     

Interconversion of Molybdenum Imido and Amido Complexes by Proton‐Coupled Electron Transfer

Interconversion of the molybdenum amido [(^PhTpy)(PPh₂Me)₂Mo(NHtBuAr)][BArF²⁴] (^PhTpy=4′‐Ph‐2,2′,6′,2“‐terpyridine; tBuAr=4‐tert‐butyl‐C₆H₄; ArF²⁴=(C₆H₃‐3,5‐(CF₃)₂)₄) and imido [(^PhTpy)(PPh₂Me)₂Mo(NtBuAr)][BArF²⁴] complexes has been accomplished by proton‐coupled electron transfer. The 2,4,6‐tri‐tert‐butylphenoxyl radical was used as an oxidant and the non‐classical ammine complex [(^PhTpy)(PPh₂Me)₂Mo(NH₃)][BArF²⁴] as the reductant. The N?H bond dissociation free energy (BDFE) of the amido N?H bond formed and cleaved in the sequence was experimentally bracketed between 45.8 and 52.3 kcal mol^?1, in agreement with a DFT‐computed value of 48 kcal mol^?1. The N?H BDFE in combination with electrochemical data eliminate proton transfer as the first step in the N?H bond‐forming sequence and favor initial electron transfer or concerted pathways.     

Ligand Substitution Reactions on Aquapentachloro‐ and Hexachloroplatinic Acid — Synthesis and Characterization of Tetrachloroplatinum(IV) Complexes with Heterocyclic N,N Donors

Reactions of aquapentachloroplatinic acid, (H₃O)[PtCl₅(H₂O)]·2(18C6)·6H₂O ( 1 ) (18C6 = 18‐crown‐6), and H₂[PtCl₆]·6H₂O ( 2 ) with heterocyclic N, N donors (2, 2′‐bipyridine, bpy; 4, 4′‐di‐tert‐butyl‐2, 2′‐bipyridine, tBu₂bpy; 1, 10‐phenanthroline, phen; 4, 7‐diphenyl‐1, 10‐phenanthroline, Ph₂phen; 2, 2′‐bipyrimidine, bpym) afforded with ligand substitution platinum(IV) complexes [PtCl₄(N∩N)] (N∩N = bpy, 3a ; tBu₂bpy, 3b ; Ph₂phen, 5 ; bpym, 7 ) and/or with protonation of N, N donor yielding (R₂phenH)₂[PtCl₆] (R = H, 4a ; Ph, 4b ) and (bpymH)⁺ ( 8 ). With UV irradiation Ph₂phen and bpym reacted with reduction yielding platinum(II) complexes [PtCl₂(N∩N)] (N∩N = Ph₂phen, 6 ; bpym, 9 ). Identities of all complexes were established by microanalysis as well as by NMR (¹H, ¹³C, ¹⁹⁵Pt) and IR spectroscopic investigations. Molecular structures of [PtCl₄(bpym)]·MeOH ( 7 ) and [PtCl₂(Ph₂phen)] ( 6 ) were determined by X‐ray diffraction analyses. Differences in reactivity of bpy/bpym and phen ligands are discussed in terms of calculated structures of complexes [PtCl₅(N∩N)]^— with monodentately bound N, N ligands (N∩N = bpy, 10a ; phen, 10b ; bpym, 10c ).     

Addition des O'Donnell Reagenzes [Ph2C=NCHCO2Me]– an π-koordinierte,ungesättigte Kohlenwasserstoffe in [(C6H7)Fe(CO)3]+, [(C7H9)Fe(CO)3]+, [(C7H7)M(CO)3]+ (M = Cr,Mo) und [(C2H4)Re(CO)5]+. α-Aminosäuren mit metallorganischen Seitenketten

Metal Complexes of Biologically Important Ligands. CXVII [1] Addition of the O'Donnell Reagent [Ph₂C=NCHCO₂Me]^– to Coordinated, Unsaturated Hydrocarbons of [(C₆H₇)Fe(CO)₃]⁺, [C₇H₉Fe(CO)₃]⁺, [(C₇H₇)M(CO)₃]⁺ (M = Cr, Mo), and [(C₂H₄)Re(CO)₅]⁺. α-Amino Acids with Organometallic Side Chains The addition of [Ph₂C=NCHCO₂Me]^– to [(C₆H₇)Fe(CO)₃]⁺, [(C₇H₉)Fe(CO)₃]⁺, [(C₇H₇)M(CO)₃]⁺ (M = Cr, Mo) and [(C₂H₄)Re(CO)₅]⁺ gives derivatives of α-amino acids with organometallic side chains. The structure of [(η⁴-C₆H₇)CH(N=CPh₂)CO₂Me]Fe(CO)₃ was determined by X-ray diffraction. From the adduct of [Ph₂C=NCHCO₂Me]^– and [(C₇H₇)Mo(CO)₃]⁺ the Schiff base of a new unnatural α-amino acid, Ph₂C=NCH(C₇H₇)CO₂Me, was obtained.     

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).     

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.     

Untersuchungen zur P–P‐Bindungsknüpfung in der Koordinationssphäre von Übergangsmetallen

Investigations of P–P Bond Formation Reactions in the Coordination Sphere of Transition Metals The reaction of [CpW(CO)₃]^– with PCl₃ leads to the transition metal substituted dichlorphosphines [{CpW(CO)₃}PCl₂] ( 1 ) and [{Cp(CO)₃W}PCl₂{WCl(CO)₂Cp}] ( 2 ). The X‐ray structure of 2 reveals the Lewis acid/base character of this compound. Reactions of 1 and [Cr(CO)₅Cp*PCl₂], respectively, with metalates of the type [M(CO)₃Cp′]^– (M′ = Mo, W; Cp′ = η⁵‐C₅H₄tBu) afford the cyclo‐P₃ complexes [(η³‐P₃)MCp′(CO)₃] ( 3 ) (M = W) and ( 4 ) (M = Mo) and the compounds [(μ,η²‐P₂{Cr(CO)₅}₂){Mo(CO)₂Cp}₂] ( 5 ) and [{μ₃‐PW(CO)₃Cp′}{W(CO)₂Cp′}₂] ( 6 ), respectively. Complex 6 possesses a planar homoleptic W₃P moiety revealing delocalised multiple bonds within the W₂P‐subunit. Reducing [(CO)₅WPCl₃] with magnesium leads to the formation of the phosphinidene complex [{(CO)₅W}₂PCl], whereas the reduction of [CpW(CO)₃PCl₂] ( 1 ) with magnesium yields the cyclo‐P₃ complex 3 together with P₄ phosphorus.     

Heterokuban‐Cluster‐Verbindungen (NEt4){Y=M[(μ3‐S)Re(CO)3]3(μ3‐E)} (M = W oder Mo,Y = O oder S,E = S oder Se): Strukturen,Spektroskopie und Elektrochemie

Heterocubane Cluster Compounds (NEt₄){Y=M[(μ₃‐S)Re(CO)₃]₃(μ₃‐E)} (M = W or Mo, Y = O or S, E = S or Se): Structures, Spectroscopy, and Electrochemistry Thiometallates [MS₄]^2– (M = Mo, W) or [WOS₃]^2– react with Re(CO)₅(O₃SCF₃) and Li₂E (E = S or Se) to yield the following compounds which were structurally characterized: (NEt₄){S=W[(μ₃‐S)Re(CO)₃]₃(μ₃‐S)}(NEt₄) ( 1 ), (NEt₄){O/S=W[(μ₃‐S)Re(CO)₃](μ₃‐S)}(NEt₄) ( 1 / 2 ), (mixed crystals), (NEt₄){S=W[(μ₃‐S)Re(CO)₃]₃(μ₃‐Se)}(NEt₄) ( 3 ) and (NEt₄){S=Mo[(μ₃‐S)Re(CO)₃]₃(μ₃‐S)}(NEt₄) ( 4 ). The heterocubane anions 1 – 4 contain electron‐rich centers such as rhenium(I) or sulfide whereas molybdenum(VI) or tungsten(VI) act as acceptor sites. Accordingly, the absorption spectra show long‐wavelength metal‐to‐ligand charge transfer transitions, and cyclic voltammetry reveals a quasi‐reversible reduction of the clusters. Although both six‐coordinate rhenium(I) and four‐coordinate metal(VI) centers are present in the clusters there is no evidence for significant metal‐to‐metal charge transfer interaction.     

Synthese,Struktur und Reaktivität von η3‐1,2‐Diphosphaallylkomplexen sowie von [{(η5‐C5H5)(CO)2W–Co(CO)3}{μ‐AsCH(SiMe3)2}(μ‐CO)]

Syntheses, Structure and Reactivity of η³‐1,2‐Diphosphaallyl Complexes and [{(η⁵‐C₅H₅)(CO)₂W–Co(CO)₃}{μ‐AsCH(SiMe₃)₂}(μ‐CO)] Reaction of ClP=C(SiMe₂iPr)₂ ( 3 ) with Na[Mo(CO)₃(η⁵‐C₅H₅)] afforded the phosphavinylidene complex [(η⁵‐C₅H₅)(CO)₂Mo=P=C(SiMe₂iPr)₂] ( 4 ) which in situ was converted into the η¹‐1,2‐diphosphaallyl complex [η⁵‐(C₅H₅)(CO)₂Mo{η³‐tBuPPC(SiMe₂iPr)₂] ( 6 ) by treatment with the phosphaalkene tBuP=C(NMe₂)₂. The chloroarsanyl complexes [(η⁵‐C₅H₅)(CO)₃M–As(Cl)CH(SiMe₃)₂] [where M = Mo ( 9 ); M = W ( 10 )] resulted from the reaction of Na[M(CO)₃(η⁵‐C₅H₅)] (M = Mo, W) with Cl₂AsCH(SiMe₃)₂. The tungsten derivative 10 and Na[Co(CO)₄] underwent reaction to give the dinuclear μ‐arsinidene complex [(η⁵‐C₅H₅)(CO)₂W–Co(CO)₃{μ‐AsCH(SiMe₃)₂}(μ‐CO)] ( 11 ). Treatment of [(η⁵‐C₅H₅)(CO)₂Mo{η³‐tBuPPC(SiMe₃)₂}] ( 1 ) with an equimolar amount of ethereal HBF₄ gave rise to a 85/15 mixture of the saline complexes [(η⁵‐C₅H₅)(CO)₂Mo{η²‐tBu(H)P–P(F)CH(SiMe₃)₂}]BF₄ ( 18 ) and [Cp(CO)₂Mo{F₂PCH(SiMe₃)₂}(tBuPH₂)]BF₄ ( 19 ) by HF‐addition to the PC bond of the η³‐diphosphaallyl ligand and subsequent protonation ( 18 ) and/or scission of the PP bond by the acid ( 19 ). Consistently 19 was the sole product when 1 was allowed to react with an excess of ethereal HBF₄. The products 6 , 9 , 10 , 11 , 18 and 19 were characterized by means of spectroscopy (IR, ¹H‐, ¹³C{¹H}‐, ³¹P{¹H}‐NMR, MS). Moreover, the molecular structures of 6 , 11 and 18 were determined by X‐ray diffraction analysis.     

Modified cyclopentadienyl molybdenum compounds with enhanced cytotoxic activity towards MOLT‐4 leukaemia cells

A series of new cyclopentadienyl molybdenum compounds bearing substituted phenanthroline ligands [(η⁵‐C₅H₄CH₂C₆H₄X‐4)Mo(CO)₂(^N,NL)][BF₄] (X = F, Cl, Br; ^N,NL = phen, 5‐NH₂‐phen, 4,7‐Ph₂‐phen) was prepared and characterized using infrared and NMR spectroscopies. Crystal structures of [(η⁵‐C₅H₄CH₂C₆H₄F‐4)Mo(CO)₂(NCMe)₂][BF₄], [(η⁵‐C₅H₄CH₂C₆H₄X‐4)Mo(CO)₂(phen)][BF₄] (X = F, Cl, Br) and [(η⁵‐C₅H₄CH₂C₆H₄Cl‐4)Mo(CO)₂(4,7‐Ph₂‐phen)][BF₄]⋅(4,7‐Ph₂‐phen)⋅HBF₄ were determined using X‐ray diffraction analysis. Biological studies revealed a strong cytotoxic effect of the chelating ligands. Although the cytostatic effect of the halogen in the side chain of the cyclopentadienyl ring is negligible, it could be used for future post‐modification of these types of cytotoxic active molybdenum‐based compounds.     

The preparation of Cr(O), Mo(O), W(O), Re(I), Rh(I), Mo(II) and Pd(II) complexes of N-diphenylphosphinopyrrole and -2,5-dimethylpyrrole

The complexes trans-[(LP)₂Cr(CO)₄], cis-[(LP)₂Mo(CO)₄], trans-[(LM)₂W(CO)₄], [(LM)Mo(CO)₅], cis-[(LM)Re(CO)₄Br], [(LP)₂Mo(CO)₂Br₂], [(LM)₂Rh(CO)Cl] and trans-[(LM)₂PdCl₂] (LP = N-(diphenylphosphino)pyrrole; LM = N-(diphenylphosphin-2,5-dimethylpyrrole) have been prepared. Structural assignments were based upon IR data. LP resembles Ph₃P in coordinating ability, while LM is a poorer ligand. The successive replacement of Ph in Ph₃P by the pyrrolyl moiety causes a decrease in the donor properties of the phosphorus centre.     

Synthesen und Kristallstrukturen von [(t-Bu4Sb4)Fe(CO)4], [(t-Bu4Sb4)Mo(CO)5] und [(t-Bu3Sb4)Mo(η5-C5Me5)(CO)3]

Syntheses and Crystal Structures of [( t -Bu₄Sb₄)Fe(CO)₄], [( t -Bu₄Sb₄)Mo(CO)₅], and [( t -Bu₃Sb₄)Mo(η⁵-C₅Me₅)(CO)₃] t-Bu₄Sb₄ reacts with Fe₂(CO)₉ to form [(t-Bu₄Sb₄)Fe(CO)₄] ( 1 ). [(t-Bu₄Sb₄)Mo(CO)₅] ( 2 ) is formed from (thf)Mo(CO)₅ and t-Bu₄Sb₄. [(t-Bu₃Sb₄)Mo(η⁵-C₅Me₅)(CO)₃] ( 3 ) is a product of the reaction of t-Bu₄Sb₄ with [(η⁵-C₅Me₅)Mo(CO)₃]₂. The crystal structures of 1–3 are reported.     

Synthesis and Basic Coordination Properties of Side‐chain Functionalized Bis‐phosphonio‐benzophospholides

Salts containing bis‐phosphonio‐benzophospholide cations 2 a – d with an additional donor site in one of the phosphonio‐moieties were synthesized either via quaternisation of the Ph₂P moiety in the neutral phosphonio‐benzophospholide 3 , or via ring‐closure of the functionalized bis‐phosphonium ion 6 . The Ph₂P‐substituted cation 2 d formed chelate complexes [M(k²P,P′‐ 2 d )(CO)_n]⁺ with M(CO)_n = Ni(CO)₂, Fe(CO)₃, Cr(CO)₄. In the latter case, competition between formation of the chelate and a complex [Cr(kP‐ 2 d )₂(CO)₄]²⁺ was observed, and interpreted as a consequence of antagonism between the stabilizing chelate effect and destabilizing ligand–ligand repulsions. The formation of stable Pd^II and Pt^II complexes of 2 d suggests that the chelate effect may also overcome the kinetic inhibition which so far prevented isolation of complexes of these metals with bis‐phosphonio‐benzophospholides. The newly synthesized ligands and complexes were characterized by spectroscopic data, and an X‐ray crystal structure analysis of 2 a [Br]. The reactivity of chelate complexes towards Ph₃P indicates that the ring phosphorus atom is a weaker donor than the pendant Ph₂P‐group.     

Synthesis and characterizations of N,N′‐bis(diphenylphosphino)‐2‐(aminomethyl)aniline derivatives: application of a palladium(II) complex as pre‐catalyst in Heck and Suzuki cross‐coupling reactions

The reaction of 2‐(aminomethyl)aniline with 2 equivalents of PPh₂Cl in the presence of Et₃N, proceeds in CH₂Cl₂ to give N,N′‐bis(diphenylphosphino)‐2‐(aminomethyl)aniline 1 in good yield. Oxidation of 1 with aqueous H₂O₂, elemental sulfur or gray selenium gave the corresponding oxide, sulfide and selenide dichalcogenides [Ph₂P(E)NHC₆H₄CH₂NHP(E)Ph₂] (E: O, 2a; S, 2b; Se, 2c), respectively. The reaction of [Ph₂PNHC₆H₄CH₂NHPPh₂] with PdCl₂(cod), PtCl₂(cod) and [Cu(MeCN)₄]PF₆ gave the corresponding chelate complexes, PdCl₂1, PtCl₂1 and [Cu(1)₂]PF₆. The new compounds were fully characterized by NMR, IR spectroscopy and elemental analysis. The catalytic activity of the Pd(II) complex was tested in the Suzuki coupling and Heck reactions. The Pd(II) complex catalyzes the Suzuki coupling and Heck reaction, affording biphenyls and stilbenes respectively, in good yields. Copyright © 2009 John Wiley & Sons, Ltd.     

Trans Influence of Triphenylstibine: Crystal Structures of cis‐[PtBr2(SbPh3)2], trans‐[PtBr(Ph)(SbPh3)2], [NMe4][PtBr3(SbPh3)], and cis‐[PtBr2(SbPh3)(PPh3)]

The work reports the unexpected reaction of diphenyldibromo antimonates (III) with PtCl₂ and cis‐[PtCl₂(PPh₃)₂]. The reaction gives triphenylstibine containing Pt^II complexes viz. cis‐[PtBr₂(SbPh₃)₂] ( 1 ), trans‐[[PtBr(Ph)(SbPh₃)₂] ( 2 ), [NMe₄][PtBr₃(SbPh₃)] ( 3 ), and cis‐[PtBr₂(PPh₃)(SbPh₃)] ( 4 ). All the complexes were characterised by elemental analyses, IR, Raman, ¹⁹⁵Pt NMR, FAB mass spectroscopy and X‐ray crystallography. A plausible mechanism via the phenyl migration is proposed for the formation of these complexes. The average Pt–Br distance in 1 is 2.456(2) Å, in 2 2.496 Å(trans to Ph) while in 3 it is 2.476 Å (trans to Sb) implying a comparable trans influence of Ph₃Sb and Ph₃P.