Photochemische Reaktionen von Cyclopentadienylbis(ethen)rhodium mit Benzolderivaten

Photochemical Reactions of Cyclopentadienylbis(ethene)rhodium with Benzene Derivatives During UV irradiation of [CpRh(C₂H₄)₂] ( 1 ) (Cp = η⁵‐C₅H₅) in hexane in the presence of hexamethylbenzene the di‐ and trinuclear arene bridged complexes [(CpRh)₂(μ‐η³ : η³‐C₆Me₆)] ( 3 ) and [(CpRh)₃(μ₃‐η² : η² : η²‐C₆Me₆)] ( 4 ) are formed besides known [CpRh(η⁴‐C₆Me₆)] ( 2 ). It was shown by a separate experiment that 3 besides small amounts of 4 is formed by attack of photochemically from 1 arising CpRh fragments at the free double bond of the η⁴‐bonded benzene ring in 2 . Irradiation of 1 in the presence of diphenyl (C₁₂H₁₀) affords the compounds [(CpRh)₂(μ‐η³ : η³‐C₁₂H₁₀)] ( 5 ) and [(CpRh)₃(μ₃‐η² : η² : η²‐C₁₂H₁₀)] ( 6 ) as analogues of 3 and 4 , in the presence of triptycene (C₂₀H₁₄) only [(CpRh)₂(μ‐η³ : η³‐C₂₀H₁₄)] ( 7 ) is obtained; the bridging in 5 , 6 , and 7 always occurs via the same six‐membered ring of the corresponding ligand system. During the photochemical reaction of 1 in the presence of styrene (C₈H₈) substitution of the ethene ligands by the vinyl groups with formation of [CpRh(C₂H₄)(η²‐C₈H₈)] ( 8 ) and known [CpRh(η²‐C₈H₈)₂] ( 9 ) is observed exclusively. The new complexes were characterized analytically and spectroscopically, in the case of 3 also by X‐ray structure analysis.     

Zweikernige silylenverbrückte Cyclopentadienylrhodiumbis(ethen)-Komplexe,photochemische Reaktion mit Benzolderivaten und selektiver Einschluß von Methylcyclopentan in das Kristallgitter von [Me2Si{3-But-C5H3Rh(C2H4)2}2]

Dinuclear Silylene Bridged Cyclopentadienylrhodiumbis(ethene) Complexes, Photochemical Reaction with Benzene Derivatives, and Selective Inclusion of Methylcyclopentane into the Crystal Lattice of [Me₂Si{3-Bu^t-C₅H₃Rh(C₂H₄)₂}₂] By reaction of [{(C₂H₄)₂RhCl}₂] with Na₂[Me₂Si(C₅H₄)₂] or with Li₂[Me₂Si(3-Bu^t-C₅H₃)₂] in THF the dinuclear silylene bridged complexes [Me₂Si{C₅H₄Rh(C₂H₄)₂}₂] 1 and [Me₂Si{3-Bu^t-C₅H₃Rh(C₂H₄)₂}₂] 2 , respectively, were synthesized. Due to the asymmetric substitution of the five-membered rings and their hindered rotation around the Si? C axes, 2 is formed as three isomers. The X-ray structure analysis of 2 obtained from hexane reveals the selective inclusion of methylcyclopentane, the content of which in the solvent is about 17%, into the crystal lattice. UV irradiation of 1 in hexane in the presence of benzene causes elimination of the ethene ligands yielding the μ-η³:η³ benzene complex [Me₂Si(C₅H₄Rh₂)₂C₆H₆] which cannot be separated from unreacted 1 . However, separation is possible in case of the hexamethylbenzene compound 4 analogous with 3 .     

Das Tris(cyclopentadienyl)methylsilan-Trianion – ein neues Ligandensystem und Komplexbildung mit Rhodium

The Tris(cyclopentadienyl)methylsilane Trianion – a New Ligand System and Complex Formation with Rhodium Starting from MeSiCl₃ the title compound was synthesized by two steps as the virtually insoluble trithallium salt ( 1 ). Reaction of 1 with [(C₂H₄)₂RhCl]₂ in pentane gives {MeSi[C₅H₄Rh(C₂H₄)₂]₃} ( 2 ). Under UV irradiation of 2 in pentane in the presence of benzene only two [C₅H₄Rh(C₂H₄)₂] units of 2 react with loss of ethene and formation of the μ-η³ : η³ benzene compound {MeSi[(C₅H₄Rh)₂(C₆H₆)][C₅H₄Rh(C₂H₄)₂]} ( 3 ). The novel complexes 2 and 3 were characterized spectroscopically and by X-ray structure analysis.     

Die Kristallstrukturen von Me3SiI · β-Picolin und Me3SiI · γ-Picolin Vergleich der Lewis-Basen Pyridin, β-Picolin und γ-Picolin

The Crystal Structure of Me₃SiI · β-Picoline and Me₃SiI · γ-Picoline A Comparison between the Lewis-Bases Pyridine, β-Picoline, and γ-Picoline The reaction of Iodinetrimethylsilane with β- und γ-Picoline (Pic) leads to solid 1 : 1 compounds Me₃SiI · β-Picoline 1 , Me₃SiI · γ-Picoline 2. The reaction was performed at room temperature. Yellow single crystals were obtained by sublimation. Single crystal X-ray investigations confirm that both compounds are ionic [Me₃SiPic]⁺I^?. The comparison of β-Picoline with γ-Picoline and Pyridine (Py) demonstrates that the presence of a methyl group and also its position has no significant influence on the Si? N bond length in compound 1, 2 and on the adduct Me₃SiI · Py.     

Komplexchemie P-reicher Phosphane und Silylphosphane. XI [1]. Bildung,Reaktionen und Strukturen von Chromcarbonylkomplexen aus Reaktionen von Li(THF)2[η2-(tBu2P)2P] mit Cr(CO)5 · THF und Cr(CO)4 · NBD

Transition Metal Complexes of P-rich Phosphanes and Silylphosphanes. XI. Formation, Reactions, and Structures of Chromium Carbonyl Complexes from Reactions of Li(THF)₂[η₂-(^tBu₂P)₂P] with Cr(CO)₅ · THF and Cr(CO)₄ · NBD Reactions of Li(THF)₂[η²-(^tBu₂P)₂P] 1 with Cr(CO)₅ · THF yield Li(THF)₂Et₂O[Cr(CO)₄{η²-(^tBu₂P)₂P}η¹-Cr(CO)₅] 2 and the compounds [Cr(CO)₄{η²-(^tBu₂P)₂PH}] 3 , [Cr(CO)₅{η¹-(^tBu₂P)₂PH}] 4 , (^tBu₂P)₂PH 5 and ^tBu₂PH · Cr(CO)₅ 6 . The formation of 3, 4, 5 and 6 is due to byproducts coming from the synthesis of 1. 2 reacts with CH₃COOH under formation of 3 . After addition of 12-crown-4 1 with NBD · Cr(CO)₄ in THF forms Li(12-crown-4)₂[Cr(CO)₄-{η²-(^tBu₂P)₂P}] 7 (yellow crystals). 7 reacts with CH₃COOH to 3 – which regenerates 7 with LiBu – with Cr(CO)₅THF to compound 2 , with NBD · Cr(CO)₄ in THF to 2 and 3 (ratio 1 : 1). With EtBr, 7 forms [Cr(CO)₄{η²-(^tBu₂P)₂PEt}] 8 , and [Cr(CO)₄{η²-(^tBu₂P)₂PBr}] 9 with BrCH₂? CH₂Br. The compounds were characterized by means of ¹H, ¹³C, ³¹P, ⁷Li NMR spectroscopy, IR spectroscopy, elementary analysis, mass spectra, and 2, 3 and 4 additionally by means of X-ray diffraction analysis. 2 crystallizes in the space group P1 with 2 formula units in the elementary cell; a = 10.137(9), b = 15.295(12), c = 15.897(14) Å; α = 101.82(7), β = 91.65(7), γ = 98.99(7)°; 3 crystallizes in the space group P2_t/n with 4 molecules in the elementary unit; a = 11.914(6), b = 15.217(10), c = 14.534(10) Å; α = 90, β = 103.56(5), γ = 90°. 4 : space group P1 with 2 molecules in the elementary unit; a = 8.844(4), b = 12.291(6), c = 14.411(7) Å, α = 66.55(2), β = 89.27(2), γ = 71.44(2)°.     

Syntheses,and Crystal Structures of Indium Complexes with η2‐Piperidinyldithiocarbamate and η2‐Pyridine‐2‐Thionate Containing Ligands: Structures of [In(η2‐S2CNC5H10)3] and [In(η2‐pyS)3]

The η²‐thio‐indium complexes [In(η²‐thio)₃] (thio = S₂CNC₅H₁₀, 2 ; SNC₄H₄, (pyridine‐2‐thionate, pyS, 3 ) and [In(η²‐pyS)₂(η²‐acac)], 4 , (acac: acetylacetonate) are prepared by reacting the tris(η²‐acac)indium complex [In(η²‐acac)₃], 1 with HS₂CNC₅H₁₀, pySH, and pySH with ratios of 1:3, 1:3, and 1:2 in dichloromethane at room temperature, respectively. All of these complexes are identified by spectroscopic methods and complexes 2 and 3 are determined by single‐crystal X‐ray diffraction. Crystal data for 2 : space group, C2/c with a = 13.5489(8) Å, b = 12.1821(7) Å, c = 16.0893(10) Å, β = 101.654(1)°, V = 2600.9(3) ų, and Z = 4. The structure was refined to R = 0.033 and Rw = 0.086; Crystal data for 3 : space group, P2₁ with a = 8.8064 (6) Å, b = 11.7047 (8) Å, c = 9.4046 (7) Å, β = 114.78 (1)°, V = 880.13(11) ų, and Z = 2. The structure was refined to R = 0.030 and Rw = 0.061. The geometry around the metal atom of the two complexes is a trigonal prismatic coordination. The piperidinyldithiocarbamate and pyridine‐2‐thionate ligands, respectively, coordinate to the indium metal center through the two sulfur atoms and one sulfur and one nitrogen atoms, respectively. The short C‐N bond length in the range of 1.322(4)–1.381(6) Å in 2 and C‐S bond length in the range of 1.715(2)–1.753(6) Å in 2 and 3 , respectively, indicate considerable partial double bond character.     

Reaktionen des [η2-{P–PtBu2}Pt(PPh3)2] und [η2-{P–PtBu2}Pt(dppe)] mit Metallcarbonylen. Bildung von [η2-{(CO)5M · PPtBu2}Pt(PPh3)2] (M = Cr,W) und [η2-{(CO)5Cr · PPtBu2}Pt(dppe)]

Coordination Chemistry of P-rich Phosphanes and Silylphosphanes. XVI [1] Reactions of [g²-{P–P^tBu₂}Pt(PPh₃)₂] and [g²-{P–P^tBu₂}Pt(dppe)] with Metal Carbonyls. Formation of [g²-{(CO)₅M · PP^tBu₂}Pt(PPh₃)₂] (M = Cr, W) and [g²-{(CO)₅Cr · PP^tBu₂}Pt(dppe)] [η²-{P–P^tBu₂}Pt(PPh₃)₂] 4 reacts with M(CO)₅ · THF (M = Cr, W) by adding the M(CO)₅ group to the phosphinophosphinidene ligand yielding [η²-{(CO)₅Cr · PP^tBu₂}Pt(PPh₃)₂] 1 , or [η²-{(CO)₅W · PP^tBu₂}Pt(PPh₃)₂] 2 , respectively. Similarly, [η²-{P–P^tBu₂}Pt(dppe)] 5 yields [η²-{(CO)₅Cr · PP^tBu₂}Pt(dppe)] 3 . Compounds 1 , 2 and 3 are characterized by their ¹H- and ³¹P-NMR spectra, for 2 and 3 also crystal structure determinations were performed. 2 crystallizes in the monoclinic space group P2₁/n (no. 14) with a = 1422.7(1) pm, b = 1509.3(1) pm, c = 2262.4(2) pm, β = 103.669(9)°. 3 crystallizes in the triclinic space group P1 (no. 2) with a = 1064.55(9) pm, b = 1149.9(1) pm, c = 1693.2(1) pm, α = 88.020(8)°, β = 72.524(7)°, γ = 85.850(8)°.     

Synthesis and Nucleophilic Addition Reactions of Tricarbonyl[η5‐2‐(phenylthio)hexadienyl]iron Hexafluorophosphate

3‐Phenylthio‐3‐sulfolene ( 1 ) was readily converted to a C‐5 substituted product 2 , which upon thermolysis and complexation with Fe₂(CO)₉ gave (η⁴‐diene)iron complexes 3a and 3b . Treatment of 3a and 3b with aq. HPF₆ and Ac₂O provided the title compound 5 , which reacted regio‐ and stereospecifically with some nucleophiles to give the addition products 3b and 7 .     

2, 4‐Dimethylpenta‐1, 3‐dien‐ und 2, 4‐Dimethylpentadienyl‐Komplexe des Rhodiums und Iridiums

2, 4‐Dimethylpenta‐1, 3‐diene and 2, 4‐Dimethylpentadienyl Complexes of Rhodium and Iridium The complexes [(η⁴‐C₇H₁₂)RhCl]₂ ( 1 ) (C₇H₁₂ = 2, 4‐dimethylpenta‐1, 3‐diene) and [(η⁴‐C₇H₁₂)₂IrCl] ( 2 ) were obtained by interaction of C₇H₁₂ with [(η²‐C₂H₄)₂RhCl]₂ and [(η²‐cyclooctene)₂IrCl]₂, respectively. The reaction of 1 or 2 with CpTl (Cp = η⁵‐C₅H₅) yields the compounds [CpM(η⁴‐C₇H₁₂)] ( 3a : M = Rh; 3b : M = Ir). The hydride abstraction at the pentadiene ligand of 3a , b with Ph₃CBF₄ proceeds differently depending on the solvent. In acetone or THF the “half‐open” metallocenium complexes [CpM(η⁵‐C₇H₁₁)]BF₄ ( 4a : M = Rh; 4b : M = Ir) are obtained exclusively. In dichloromethane mixtures are produced which additionally contain the species [(η⁵‐C₇H₁₁)M(η⁵‐C₅H₄CPh₃)]BF₄ ( 5a : M = Rh; 5b : M = Ir) formed by electrophilic substitution at the Cp ring, as well as the η³‐2, 4‐dimethylpentenyl compound [(η³‐C₇H₁₃)Rh{η⁵‐C₅H₃(CPh₃)₂}]BF₄ ( 6 ). By interaction of 2, 4‐dimethylpentadienyl potassium with 1 or 2 the complexes [(η⁴‐C₇H₁₂)M(η⁵‐C₇H₁₁)] ( 7a : M = Rh; 7b : M = Ir) are generated which show dynamic behaviour in solution; however, attempts to synthesize the “open” metallocenium cations [(η⁵‐C₇H₁₁)₂M]⁺ by hydride abstraction from 7a , b failed. The new compounds were characterized by elemental analysis and spectroscopically, 4b and 5a also by X‐ray structure analysis.     

Chloro(η6‐p‐cymene)(phosphoramidite)ruthenium(II), a 16‐Electron Fragment Stabilized by an η2‐Aryl–Metal Interaction,and Its Use in Asymmetric Cyclopropanation

Chloride abstraction from the half‐sandwich complexes [RuCl₂(η⁶‐p‐cymene)(P*‐κP)] ( 2a : P* = (S_a,R,R)‐ 1a = (1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐1‐phenylethyl)]phosphoramidite; 2b : P* = (S_a,R,R)‐ 1b = (1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl bis[(1R)‐(1‐(1‐naphthalen‐1‐yl)ethyl]phosphoramidite) with (Et₃O)[PF₆] or Tl[PF₆] gives the cationic, 18‐electron complexes dichloro(η⁶‐p‐cymene){(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐phenyl]ethyl}[(1R)‐1‐phenylethyl]phosphoramidite‐κP}ruthenium(II) hexafluorophosphate ( 3a ) and [Ru(S)]‐dichloro(η⁶‐p‐cymene){(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl {(1R)‐1‐[(1,2‐η)‐naphthalen‐1‐yl]ethyl}[(1R)‐1‐(naphthalen‐1‐yl)ethyl]phosphoramidite‐κP)ruthenium(II) hexafluorophosphate ( 3b ), which feature the η²‐coordination of one aryl substituent of the phosphoramidite ligand, as indicated by ¹H‐, ¹³C‐, and ³¹P‐NMR spectroscopy and confirmed by an X‐ray study of 3b . Additionally, the dissociation of p‐cymene from 2a and 3a gives dichloro{(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐(1‐(η⁶‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP)ruthenium(II) ( 4a ) and di‐μ‐chlorobis{(1S_a)‐[1,1′‐binaphthalene]‐2,2′‐diyl [(1R)‐1‐(η⁶‐phenyl)ethyl][(1R)‐1‐phenylethyl]phosphoramidite‐κP}diruthenium(II) bis(hexafluorophosphate) ( 5a ), respectively, in which one phenyl group of the N‐substituents is η⁶‐coordinated to the Ru‐center. Complexes 3a and 3b catalyze the asymmetric cyclopropanation of α‐methylstyrene with ethyl diazoacetate with up to 86 and 87% ee for the cis‐ and the trans‐isomers, respectively.     

Organotransition-Metal Complexes of Multidentate Ligands 6. Electronic and Steric Influences on the Formation of η2-Acyl Complexes

Three new η²-acyl complexes, TMo(CO)₂(η²-COR) (T = Tp', Tp'; R= Me, Buⁿ; Tp' = hydridotris(3,5-dimethyl-pyrazol-1-yl)borate; Tp' = hydridotris(3,4,5-trimethylpyrazol-l-yl)borate) prepared from the corresponding alkyl iodides, RI, and the anions, TMo(CO)^?₃. The preparation of Et₄N⁺Tp Mo(CO)₃^? is also described. Using solution IR spectra to monitor the reactions between RI and TMo(CO)₃^?, it was found that Tp'Mo(CO)₂(η²-COMe) was formed more readily than Tp'Mo(CO)₂(η²-COMe) which was obtained more easily than Tp'Mo(CO)₂(η²-COBuⁿ). This finding suggests that the mechanism is probably an ionic substitution rather than a radical mechanism. The different times required for the complete conversion from the anions to TMo(CO)₂(η²-COR) is rationalized in terms of the electronic and steric influences of T and RI.     

1,1′-Disubstituierte Titanocen-dithiolen-Chelate des Typs (η5-Me3EC5H4)2Ti(S2C2R2) (E = C,Si, Ge)

1,1′-Disubstituted Titanocene Dithiolene Chelates of Type (η⁵-Me₃EC₅H₄)₂Ti(S₂C₂R₂) (E = C, Si, Ge) Reaction of the titanocene dichlorides (η⁵-Me₃EC₅H₄)₂TiCl₂ (E = C, 1a ; E = Si, 1b ; E = Ge, 1c ) with the 1,2-dithiolates (NaS)₂C₂H₂, (NaS)₂C₂(CN)₂ or (LiS)₂C₆H₃Me-4 gave the new titanocene dithiolene chelates (η⁵-Me₃EC₅H₄)₂Ti(S₂C₂H₂) ( 2a–c ), (η⁵-Me₃EC₅H₄)₂Ti[S₂C₂(CN)₂] ( 3a–c ) and (η⁵-Me₃EC₅H₄)₂Ti(S₂C₆H₃Me-4) ( 4a–c ). These have been characterized by ¹H NMR, IR, and mass spectroscopy, and have been compared with the unsubstituted η⁵-C₅H₅ analogues 2d, 3d and 4d . Activation energies for the chelate ring inversion in solution of 2a–c, 3a–d and 4a–c have been estimated by temperature-dependent ¹H NMR spectroscopy.     

Conformation of a terminally protected βγ hybrid dipeptide Boc‐Ant‐Gpn‐OMe stabilized by C6/C7 hydrogen bonds

The hybrid βγ dipeptide, methyl 2‐[1‐({2‐[(tert‐butoxycarbonyl)amino]benzamido}methyl)cyclohexyl]acetate (Boc‐Ant‐Gpn‐OMe), C₂₂H₃₂N₂O₅, adopts a folded conformation stabilized by intramolecular six‐ (C₆) and seven‐membered (C₇) hydrogen‐bonded rings, together with weak C—H...O and C—H...π interactions, resulting in a ribbon‐like structure.     

Niob- und Tantalkomplexe mit P2- und P4-Liganden

Niobium and Tantalum Complexes with P₂ and P₄ Ligands The photolysis of [Cp″Ta(CO)₄] 1 (Cp″ = C₅H₃^tBu₂?1,3) and P₄ affords Cp″(CO)₂Ta(η⁴?P₄) 2 , [{Cp″(CO)Ta}₂(m??η^2:2?P₂)₂] 3 and [Cp₃″(CO)₃Ta₃(P₂)₂] 4 . In a photochemical reaction 2 and [Cp*Nb(CO)₄] 5 form [{Cp*(CO)Nb}{Cp″(CO)Ta}(m??η^2:2?P₂)₂] 6 and [{Cp*(CO)₂Nb} {Cp*Nb}{Cp″(CO)Ta}(m?₃?η^2:1:1?P₂)₂] 7 , a compound with the novel m?₃?η^2:2:1?P₂-coordination mode. The reaction of 2 and [Cp*Co(C₂H₄)₂] 8 leads to [{Cp*Co} {Cp″(CO)Ta}(m??η^2:2?P₂)₂] 9 , a heteronuclear complex with an ?early”? and a ?late”? transition metal. Complexes 2, 3, 7 and 9 have been further characterized by X-ray structure analyses.     

Stereoselectivity in Diphos Addition to Molybdenum Complex with Pyridine‐2‐thionate (pyS) and η3‐Methallyl Coordinated Ligands

The conformational isomers endo‐ and exo‐[Mo{η³‐C₃H₄(CH₃)}(η²‐pyS)(CO)(η²‐diphos)] (diphos: dppm = {bis(diphenylphosphino)methane}, 2 ; dppe = {1,2‐bis(diphenylphosphino)ethane}, 3 ) are prepared by reacting the double‐bridged pyridine‐2‐thionate (pyS) complex [Mo{η³‐C₃H₄(CH₃)}(CO)₂]₂(η¹:η²:μ‐pyS)₂, 1 with diphos in refluxing acetonitrile. Stereoselectivity of the methallyl, C₃H₄(CH₃), ligand improves the formation of the exo‐conformation of 2 and 3 . Orientations and spectroscopy of these complexes are discussed.     

Synthesis and Crystal Structure of [Nd(η6‐1, 3, 5‐C6H3Me3)‐(AlCl4)3](C6H6) and Structural Comparison of Ln(η6‐arene)‐(AlCl4)3

Reaction of Ndcl₃ with AlCl₃ and mesitylene in benzene gives complex [Nd(η⁶‐1, 3, 5‐C₆H₃Me₃)‐(AlCl₄)₃](C₆H₆) (1) which was characterized by elemental analysis, IR spectra, MS and X‐ray diffractions. The X‐ray determination indicates that 1 has a distorted pentagonal bipyramidal geometry and crystallizes in the monoclinic, space group P2₁/n with a = 0.9586(2), b = 1.1717(5), c = 2.8966(7) nm, β = 90.85 (2)°, V = 3.2529 (6) nm³,D_c= 1.573 g/cm³, Z = 4. A comparison of bond parameters for all the reported Ln (η⁶‐Ar) (AlCl₄)₃ complexes indicates that the bond distance of La? C is shortened with the increasing of methyl group on benzene and with the decreasing of radius of lanthanide ions.     

Zum Einfluß der PR3‐Liganden auf Bildung und Eigenschaften der Phosphinophosphiniden‐Komplexe [{η2‐tBu2P–P}Pt(PR3)2] und [{η2‐tBu2P1–P2}Pt(P3R3)(P4R′3)]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes XXI The Influence of the PR₃ Ligands on Formation and Properties of the Phosphinophosphinidene Complexes [{η²‐^tBu₂P–P}Pt(PR₃)₂] and [{η²‐^tBu₂P¹–P²}Pt(P³R₃)(P⁴R′₃)] (R₃P)₂PtCl₂ and C₂H₄ yield the compounds [{η²‐C₂H₄}Pt(PR₃)₂] (PR₃ = PMe₃, PEt₃, PPhEt₂, PPh₂Et, PPh₂Me, PPh₂ⁱPr, PPh₂^tBu and P(p‐Tol)₃); which react with ^tBu₂P–P=PMe^tBu₂ to give the phosphinophosphinidene complexes [{η²‐^tBu₂P–P}Pt(PMe₃)₂], [{η²‐^tBu₂P–P}Pt(PEt₃)₂], [{η²‐^tBu₂P–P}Pt(PPhEt₂)₂], [{η²‐^tBu₂P–P}Pt(PPh₂Et)₂], [{η²‐^tBu₂P–P}Pt(PPh₂Me)₂], [{η²‐^tBu₂P–P}Pt(PPh₂ⁱPr], [{η²‐^tBu₂P–P}Pt(PPh₂^tBu)₂] and [{η²‐^tBu₂P–P}Pt(P(p‐Tol)₃)₂]. [{η²‐^tBu₂P–P}Pt(PPh₃)₂] reacts with PMe₃ and PEt₃ as well as with ^tBu₂PMe, PⁱPr₃ and P(c‐Hex)₃ by substituting one PPh₃ ligand to give [{η²‐^tBu₂P¹–P²}Pt(P³Me₃)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Ph₃)(P⁴Me₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Et₃)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³Me^tBu₂)(P⁴Ph₃)], [{η²‐^tBu₂P¹–P²}Pt(P³ⁱPr₃)(P⁴Ph₃)] and [{η²‐^tBu₂P¹–P²}Pt(P³(c‐Hex)₃)(P⁴Ph₃)]. With ^tBu₂PMe, [{η²‐^tBu₂P–P}Pt(P(p‐Tol)₃)₂] forms [{η²‐^tBu₂P¹–P²}Pt(P³Me^tBu₂)(P⁴(p‐Tol)₃)]. The NMR data of the compounds are given and discussed with respect to the influence of the PR₃ ligands.     

Synthesis of propyl O-(α-L-rhamnopyranosyl)-(1→3)-[2,4-di-O-(2s-methylbutyryl)-α-L-rhamnopyranosyl]-(1→2)=(3-O-acetyl-β-D-glucopyranosyl)-(1→2)-βp-D-fucopyranoside,the tetrasaccharide moiety of Tricolorin A

Propyl O-(α-L-rhamnopyranosyl)-(1→3)-[2,4di-O-(2s-methylbutyryl)-α-L-rhamnopyranosyl]-(1→2)-(3-O-acetyl-β-glucopyranosyl)-(1→2)-β-D-fucopyranoside (1), the tetrasaccharide moiety of Ricolorin A, was synthesized in total 23 steps with a longest linear sequence of 10 steps, and overall yield of 3.7% from D-Glucose. The isomerization of the dioxolane-type benzylidene in the prance of NIS/AgOTf was observed. Tetrasaccharide 1 exhibited no activity against the cultured P388 cell as Tricolorin A did.