共查询到20条相似文献,搜索用时 31 毫秒
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Hans‐Christian Bttcher Marion Graf Kurt Merzweiler Christoph Wagner 《无机化学与普通化学杂志》2001,627(12):2657-2662
Activation of Carbon Disulfide on Triruthenium Clusters: Synthesis and X‐Ray Crystal Structure Analysis of [Ru3(CO)5(μ‐H)2(μ‐PCy2)(μ‐Ph2PCH2PPh2){μ‐η2‐PCy2C(S)}(μ3‐S)] and [Ru3(CO)5(CS)(μ‐H)(μ‐PtBu2)(μ‐PCy2)2(μ3‐S)] [Ru3(CO)6(μ‐H)2(μ‐PCy2)2(μ‐dppm)] ( 1 ) (dppm = Ph2PCH2PPh2) reacts under mild conditions with CS2 and yields by oxidative decarbonylation and insertion of CS into one phosphido bridge the opened 50 VE‐cluster [Ru3(CO)5(μ‐H)2(μ‐PCy2)(μ‐dppm){μ‐η2‐PCy2C(S)}(μ3‐S)] ( 2 ) with only two M–M bonds. The compound 2 crystallizes in the triclinic space group P 1 with a = 19.093(3), b = 12.2883(12), c = 20.098(3) Å; α = 84.65(3), β = 77.21(3), γ = 81.87(3)° and V = 2790.7(11) Å3. The reaction of [Ru3(CO)7(μ‐H)(μ‐PtBu2)(μ‐PCy2)2] ( 3 ) with CS2 in refluxing toluene affords the 50 VE‐cluster [Ru3(CO)5(CS)(μ‐H)(μ‐PtBu2)(μ‐PCy2)2(μ3‐S)] ( 4 ). The compound cristallizes in the monoclinic space group P 21/a with a = 19.093(3), b = 12.2883(12), c = 20.098(3) Å; β = 104.223(16)° and V = 4570.9(10) Å3. Although in the solid state structure one elongated Ru–Ru bond has been found the complex 4 can be considered by means of the 31P‐NMR data as an electron‐rich metal cluster. 相似文献
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The preparation of three new N‐Fmoc‐protected (Fmoc=[(9H‐fluoren‐9‐yl)methoxy]carbonyl) β2‐homoamino acids with proteinogenic side chains (from Ile, Tyr, and Met) is described, the key step being a diastereoselective amidomethylation of the corresponding Ti‐enolates of 3‐acyl‐4‐isopropyl‐5,5‐diphenyloxazolidin‐2‐ones with CbzNHCH2OMe/TiCl4 (Cbz=(benzyloxy)carbonyl) in yields of 60–70% and with diastereoselectivities of >90%. Removal of the chiral auxiliary with LiOH or NaOH gives the N‐Cbz‐protected β‐amino acids, which were subjected to an N‐Cbz/N‐Fmoc (Fmoc=[(9H‐fluoren‐9‐yl)methoxy]carbonyl) protective‐group exchange. The method is suitable for large‐scale preparation of Fmoc‐β2hXaa‐OH for solid‐phase syntheses of β‐peptides. The Fmoc‐amino acids and all compounds leading to them have been fully characterized by melting points, optical rotations, IR, 1H‐ and 13C‐NMR, and mass spectra, as well as by elemental analyses. 相似文献
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Hans‐Christian Bttcher Mauricio Fernandez Marion Graf Kurt Merzweiler Christoph Wagner 《无机化学与普通化学杂志》2002,628(11):2247-2248
Activation of Carbon Disulfide on Triruthenium Clusters: Synthesis and X‐Ray Crystal Structure Analysis of [Ru3(CO)4(μ‐PCy2)2(μ‐Ph2PCH2PPh2)(μ3‐S){μ3‐η2‐CSC(S)S}] [Ru3(CO)4(μ‐H)3(μ‐PCy2)3(μ‐dppm)] ( 2 ) (dppm = Ph2PCH2PPh2) reacts with CS2 at room temperature and yields the open 50 valence electron cluster [Ru3(CO)4(μ‐PCy2)2(μ‐dppm)(μ3‐S){μ3‐η2‐CSC(S)S}] ( 3 ) containing the unusual μ3‐η2‐C2S3 mercaptocarbyne ligand. Compound 3 was characterized by single crystal X‐ray structure analysis. 相似文献
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The synthesis and single crystal X‐ray structure determination are reported for the 2,2′ : 6′,2″‐terpyridine (= tpy) adduct of bismuth(III) nitrate. The hydroxide‐bridged dimer [(η2‐NO3)2(tpy)Bi(μ‐OH)2Bi(tpy)(η2‐NO3)2] with nine‐coordinate geometry about Bi was the only isolable product from all crystallization attempts in varying ratios of Bi(NO3) : terpy.; [(η2‐NO3)2(tpy)Bi(μ‐OH)2Bi(tpy) · (η2‐NO3)2] is triclinic, P 1, a = 7.941(8), b = 10.732(9), c = 11.235(9) Å; α = 63.05(1), β = 85.01(1), γ = 79.26(1)°, Z = 1, dimer, R = 0.058 for N0 = 2319. 相似文献
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A series of monochalcogenide derivatives of the seco‐cubane [Sn3(μ2‐NHtBu)2(μ2‐NtBu)(μ3‐NtBu)] has been prepared and characterized by NMR and X‐ray crystallographic studies. These complexes exhibit different tin‐chalcogen bonding modes. In the case of the monotelluride, a terminal Sn=Te bond was observed in solution and in the solid state, whereas for the monosulfide, a μ2 bridging mode was adopted by the sulfur atoms. The monoselenide was found to employ both bonding modes in solution, although only the terminal Sn=Se bonding mode was structurally characterized. The complexes undergo chalcogen exchange between tin atoms in solution, and this process was studied by variable temperature NMR. 相似文献
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Hans‐Christian Bttcher Marion Graf Kurt Merzweiler Christoph Wagner 《无机化学与普通化学杂志》2001,627(5):903-908
Heterobinuclear Complexes: Synthesis and X‐ray Crystal Structures of [RuRh(μ‐CO)(CO)4(μ‐PtBu2)(tBu2PH)], [RuRh(μ‐CO)(CO)3(μ‐PtBu2)(μ‐Ph2PCH2PPh2)], and [CoRh(CO)4(μ‐H)(μ‐PtBu2)(tBu2PH)] [Ru3Rh(CO)7(μ3‐H)(μ‐PtBu2)2(tBu2PH)(μ‐Cl)2] ( 2 ) yields by cluster degradation under CO pressure as main product the heterobinuclear complex [RuRh(μ‐CO)(CO)4(μ‐PtBu2)(tBu2PH)] ( 4 ). The compound crystallizes in the orthorhombic space group Pcab with a = 15.6802(15), b = 28.953(3), c = 11.8419(19) Å and V = 5376.2(11) Å3. The reaction of 4 with dppm (Ph2PCH2PPh2) in THF at room temperature affords in good yields [RuRh(μ‐CO)(CO)3(μ‐PtBu2)(μ‐dppm)] ( 7 ). 7 crystallizes in the triclinic space group P 1 with a = 9.7503(19), b = 13.399(3), c = 15.823(3) Å and V = 1854.6 Å3. Moreover single crystals of [CoRh(CO)4(μ‐H)(μ‐PtBu2)(tBu2PH)] ( 9 ) could be obtained and the single‐crystal X‐ray structure analysis revealed that 9 crystallizes in the monoclinic space group P21/a with a = 11.611(2), b = 13.333(2), c = 18.186(3) Å and V = 2693.0(8) Å3. 相似文献
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Grald Lelais Peter Micuch Delphine Josien‐Lefebvre Francesco Rossi Dieter Seebach 《Helvetica chimica acta》2004,87(12):3131-3159
The Ser, Cys, and His side chains play decisive roles in the syntheses, structures, and functions of proteins and enzymes. For our structural and biomedical investigations of β‐peptides consisting of amino acids with proteinogenic side chains, we needed to have reliable preparative access to the title compounds. The two β3‐homoamino acid derivatives were obtained by Arndt–Eistert methodology from Boc‐His(Ts)‐OH and Fmoc‐Cys(PMB)‐OH (Schemes 2–4), with the side‐chain functional groups' reactivities requiring special precautions. The β2‐homoamino acids were prepared with the help of the chiral oxazolidinone auxiliary DIOZ by diastereoselective aldol additions of suitable Ti‐enolates to formaldehyde (generated in situ from trioxane) and subsequent functional‐group manipulations. These include OH→OtBu etherification (for β2hSer; Schemes 5 and 6), OH→STrt replacement (for β2hCys; Scheme 7), and CH2OH→CH2N3→CH2NH2 transformations (for β2hHis; Schemes 9–11). Including protection/deprotection/re‐protection reactions, it takes up to ten steps to obtain the enantiomerically pure target compounds from commercial precursors. Unsuccessful approaches, pitfalls, and optimization procedures are also discussed. The final products and the intermediate compounds are fully characterized by retention times (tR), melting points, optical rotations, HPLC on chiral columns, IR, 1H‐ and 13C‐NMR spectroscopy, mass spectrometry, elemental analyses, and (in some cases) by X‐ray crystal‐structure analysis. 相似文献
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Rafa Petrus Piotr Sobota 《Acta Crystallographica. Section C, Structural Chemistry》2012,68(10):m275-m280
The zinc alkoxide molecules in di‐μ3‐ethanolato‐diethyltetrakis(μ2‐2‐methyl‐4‐oxo‐4H‐pyran‐3‐olato‐κ3O3,O4:O3)tetrazinc(II), [Zn4(C2H5)2(C2H5O)2(C6H5O3)4], (I), and bis(μ3‐2‐ethoxyphenolato‐κ4O1,O2:O1:O1)bis(μ2‐2‐ethoxyphenolato‐κ3O1,O2:O1)bis(μ2‐2‐methyl‐4‐oxo‐4H‐pyran‐3‐olato‐κ3O3,O4:O3)bis(2‐methyl‐4‐oxo‐4H‐pyran‐3‐olato‐κ2O3,O4)tetrazinc(II) toluene disolvate, [Zn4(C6H5O3)4(C8H9O2)4]·2C7H8, (II), lie on crystallographic centres of inversion. The asymmetric units of (I) and (II) contain half of the tetrameric unit and additionally one molecule of toluene for (II). The ZnII atoms are four‐ and six‐coordinated in distorted tetrahedral and octahedral geometries for (I), and six‐coordinated in a distorted octahedral environment for (II). The ZnII atoms in both compounds are arranged in a defect dicubane Zn4O6 core structure composed of two EtZnO3 tetrahedra and ZnO6 octahedra for (I), and of four ZnO6 octahedra for (II), sharing common corners. The maltolate ligands exist mostly in a μ2‐bridging mode, while the guetholate ligands prefer a higher coordination mode and act as μ3‐ and μ2‐bridges. 相似文献
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Coordinatively Unsaturated Diruthenium Complexes: Synthesis and X‐ray Crystal Structures of [Ru2(CO)n(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] (n = 4; 5) and [Ru2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] The reaction of [Ru2(μ‐CO)(CO)5(μ‐H)(μ‐PtBu2)(tBu2PH)] ( 2 ) with dppm yields the dinuclear species [Ru2(μ‐CO)(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 3 ) (dppm = Ph2PCH2PPh2). Under thermal or photolytic conditions 3 loses very easily one carbonyl ligand and affords the corresponding electronically and coordinatively unsaturated complex [Ru2(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 4 ). 4 is also obtainable by an one‐pot synthesis from [Ru3(CO)12], an excess of tBu2PH and stoichiometric amounts of dppm via the formation of [Ru2(CO)4(μ‐H)(μ‐PtBu2)(tBu2PH)2] ( 1 ). 4 exhibits a Ru–Ru double bond which could be confirmed by addition of methylene to the dimetallacyclopropane [Ru2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 5 ). The molecular structures of 3 , 4 and 5 were determined by X‐ray crystal structure analyses. 相似文献
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Coordinatively Unsaturated Diiron Complexes: Synthesis and Crystal Structures of [Fe2(CO)4(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] and [Fe2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] [Fe2(μ‐CO)(CO)6(μ‐H)(μ‐PtBu2)] ( 1 ) reacts spontaneously with dppm (dppm = Ph2PCH2PPh2) to give [Fe2(μ‐CO)(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 2 c ). By thermolysis or photolysis, 2 c loses very easily one carbonyl ligand and yields the corresponding electronically and coordinatively unsaturated complex [Fe2(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 3 ). 3 exhibits a Fe–Fe double bond which could be confirmed by the addition of methylene to the corresponding dimetallacyclopropane [Fe2(CO)4(μ‐CH2)(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 4 ). The reaction of 1 with dppe (Ph2PC2H4PPh2) affords [Fe2(μ‐CO)(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppe)] ( 5 ). In contrast to the thermolysis of 2 c , yielding 3 , the heating of 5 in toluene leads rapidly to complete decomposition. The reaction of 1 with PPh3 yields [Fe2(CO)6(H)(μ‐PtBu2)(PPh3)] ( 6 a ), while with tBu2PH the compound [Fe2(μ‐CO)(CO)5(μ‐H)(μ‐PtBu2)(tBu2PH)] ( 6 b ) is formed. The thermolysis of 6 b affords [Fe2(CO)5(μ‐PtBu2)2] and the degradation products [Fe(CO)3(tBu2PH)2] and [Fe(CO)4(tBu2PH)]. The molecular structures of 3 , 4 and 6 b were determined by X‐ray crystal structure analyses. 相似文献
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Francois Gessier Laurent Schaeffer Thierry Kimmerlin Oliver Flgel Dieter Seebach 《Helvetica chimica acta》2005,88(8):2235-2250
The title compounds were prepared from valine‐derived N‐acylated oxazolidin‐2‐ones, 1 – 3, 7, 9 , by highly diastereoselective (≥ 90%) Mannich reaction (→ 4 – 6 ; Scheme 1) or aldol addition (→ 8 and 10 ; Scheme 2) of the corresponding Ti‐ or B‐enolates as the key step. The superiority of the ‘5,5‐diphenyl‐4‐isopropyl‐1,3‐oxazolidin‐2‐one’ (DIOZ) was demonstrated, once more, in these reactions and in subsequent transformations leading to various t‐Bu‐, Boc‐, Fmoc‐, and Cbz‐protected β2‐homoamino acid derivatives 11 – 23 (Schemes 3–6). The use of ω‐bromo‐acyl‐oxazolidinones 1 – 3 as starting materials turned out to open access to a variety of enantiomerically pure trifunctional and cyclic carboxylic‐acid derivatives. 相似文献
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Hans‐Christian Bttcher Marion Graf Kurt Merzweiler Christoph Wagner 《无机化学与普通化学杂志》2000,626(2):597-603
Coordinatively Unsaturated Diruthenium Complexes: Synthesis and X‐Ray Crystal Structures of [Ru2(CO)4(μ‐H)(μ‐S)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)], [Ru2(CO)4(μ‐X)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)] (X = Cl, S2CH) [Ru2(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 1 ) reacts in benzene with elemental sulfur to the addition product [Ru2(CO)4(μ‐H)(μ‐S)(μ‐PtBu2)(μ‐dppm)] ( 2 ) (dppm = Ph2PCH2PPh2). 2 is also obtained by reaction of 1 with ethylene sulfide. The reaction of 1 with carbon disulfide yields with insertion of the CS2 into the Ru2(μ‐H) bridge the dithioformato complex [Ru2(CO)4(μ‐S2CH)(μ‐PtBu2)(μ‐dppm)] ( 3 ). Furthermore, 1 reacts with [NO][BF4] to the complex salt [Ru2(CO)4(μ‐NO)(μ‐H)(μ‐PtBu2)(μ‐dppm)][BF4] ( 4 ), and reaction of 1 with CCl4 or CHCl3 affords spontaneously [Ru2(CO)4(μ‐Cl)(μ‐PtBu2)(μ‐dppm)] ( 5 ) in nearly quantitative yield. The molecular structures of 2 , 3 and 5 were confirmed by crystal structure analyses. 相似文献
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