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1.
[Fe2sb‐CO)(CO)3(NO)(μ‐PtBu2)(μ‐Ph2PCH2PPh2)]: Synthesis, X‐ray Crystal Structure and Isomerization Na[Fe2(μ‐CO)(CO)6(μ‐PtBu2)] ( 1 ) reacts with [NO][BF4] at —60 °C in THF to the nitrosyl complex [Fe2(CO)6(NO)(μ‐PtBu2)] ( 2 ). The subsequent reaction of 2 with phosphanes (L) under mild conditions affords the complexes [Fe2(CO)5(NO)L(μ‐PtBu2)], L = PPh3, ( 3a ); η‐dppm (dppm = Ph2PCH2PPh2), ( 3b ). In this case the phosphane substitutes one carbonyl ligand at the iron tetracarbonyl fragment in 2 , which was confirmed by the X‐ray crystal structure analysis of 3a . In solution 3b loses one CO ligand very easily to give dppm as bridging ligand on the Fe‐Fe bond. The thus formed compound [Fe2(CO)4(NO)(μ‐PtBu2)(μ‐dppm)] ( 4 ) occurs in solution in different solvents and over a wide temperature range as a mixture of the two isomers [Fe2sb‐CO)(CO)3(NO)(μ‐PtBu2)(μ‐dppm)] ( 4a ) and [Fe2(CO)4(μ‐NO)(μ‐PtBu2)(μ‐dppm)] ( 4b ). 4a was unambiguously characterized by single‐crystal X‐ray structure analysis while 4b was confirmed both by NMR investigations in solution as well as by means of DFT calculations. Furthermore, the spontaneous reaction of [Fe2(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 5 ) with NO at —60 °C in toluene yields a complicated mixture of products containing [Fe2(μ‐CO)(CO)4(μ‐H)(μ‐PtBu2)(μ‐dppm)] ( 6 ) as main product beside the isomers 4a and 4b occuring in very low yields.  相似文献   

2.
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   

3.
The synthesis and crystallographic characterization of a complex possessing a well‐defined {2Fe3S(μ‐H)} core gives access to a paramagnetic bridging hydride with retention of the core geometry. Chemistry of this 35‐electron species within the confines of a thin‐layer FTIR spectro‐electrochemistry cell provides evidence for a unprecedented super‐reduced FeI(μ‐H)FeI intermediate.  相似文献   

4.
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   

5.
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   

6.
The reaction of Na2[Fe(CO)4] with Br2CF2 in n‐pentane generates a mixture of the compounds (CO)3Fe(μ‐CO)3–n(μ‐CF2)nFe(CO)3 ( 2 , n = 2; 3 , n = 1) in low yields with 3 as the main product. 3 is obtained free from 2 by reacting Br2CF2 with Na2[Fe2(CO)8]. The non‐isolable monomeric complex (CO)4Fe=CF2 ( 1 ) can probably considered as the precursor for 2 . 3 reacts with PPh3 with replacement of two CO ligands to form Fe2(CO)6(μ‐CF2)(PPh3)2 ( 4 ). The complexes 2 – 4 were characterized by single crystal X‐ray diffraction. While the structure of 2 is strictly similar to that of Fe2(CO)9, the structure of 3 can better be described as a resulting from superposition of the two enantiomers 3 a and 3 b with two semibridging CO groups. Quantum chemical DFT calculations for the series (CO)3Fe(μCO)3–n(μ‐CF2)nFe(CO)3 (n = 0, 1, 2, 3) as well as for the corresponding (μ‐CH2) derivatives indicate that the progressively larger σ donor and π acceptor properties for the bridging ligands, in the order CO < CF2 < CH2, favor a stronger Fe–Fe bond.  相似文献   

7.
The chemistry of [Fe]‐hydrogenase has attracted significant interest due to its ability to activate molecular hydrogen. The intriguing properties of this enzyme have prompted the synthesis of numerous small molecule mimics aimed at activating H2. Despite considerable effort, a majority of these compounds remain nonfunctional for hydrogenation reactions. By using a recently synthesized model as an entry point, seven biomimetic complexes have been examined through DFT computations to probe the influence of ligand environment on the ability of a mimic to bind and split H2. One mimic, featuring a bidentate diphosphine group incorporating an internal nitrogen base, was found to have particularly attractive energetics, prompting a study of the role played by the proton/hydride acceptor necessary to complete the catalytic cycle. Computations revealed an experimentally accessible energetic pathway involving a benzaldehyde proton/hydride acceptor and the most promising catalyst.  相似文献   

8.
A new nanostructured coordination polymer of divalent lead with the ligand 2,9‐dimethyl‐1,10‐phenanthroline (dmp), [Pb(dmp)(μ‐N3)(μ‐NO3)]n ( 1 ), was synthesized by sonochemical methods. The polymer was characterized by scanning electron microscopy, X‐ray powder diffraction, IR, 1H NMR, and 13C NMR spectroscopy, and elemental analyses. Compound 1 was structurally characterized by single‐crystal X‐ray diffraction. The single‐crystal analysis shows that the coordination number of PbII ions is seven, (PbN4O3) has a “stereo‐chemically active” electron lone pair, and the coordination sphere is hemidirected. The chains interact with each other through π–π stacking interactions to create a 3D framework. The structure of the title complex was optimized by density functional calculations. The calculated structural parameters and the IR spectrum of the title complex are in agreement with the crystal structure.  相似文献   

9.
Understanding the electronic properties of single peptides is not only of fundamental importance, but it is also paramount to the realization of peptide‐based molecular electronic components. Electrochemical and theoretical studies are reported on two β‐strand‐based peptides, one with its backbone constrained with a triazole‐containing tether introduced by Huisgen cycloaddition (peptide 1 ) and the other a direct linear analogue (peptide 2 ). Density functional theory (DFT) and non‐equilibrium Green’s function were used to investigate conductance in molecular junctions containing peptides 3 and 4 (analogues of 1 and 2 ). Although the peptides share a common β‐strand conformation, they display vastly different electronic transport properties due to the presence (or absence) of the side‐bridge constraint and the associated effect on backbone rigidity. These studies reveal that the electron transfer rate constants of 1 and 2 , and the conductance calculated for 3 and 4 , differ by approximately one order of magnitude, thus providing two distinctly different conductance states and what is essentially a molecular switch. A definitive correlation of electrochemical measurements and molecular junction conductance simulations is demonstrated using two different charge transfer techniques. This study furthers our understanding of the electronic properties of peptides at the molecular level, which provides an opportunity to fine‐tune their molecular orbital energies through suitable structural manipulation.  相似文献   

10.
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)23‐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)23‐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   

11.
A trinuclear linear Mo-Fe-Mo dialkyldithiocarbamate complex [Et4N] { [ Me2dtcMoO (μ-S)2 ]2Fe} has been obtained and structurally characterized, which contains two Me2dtcMoO-(μ-S)2 units coordinated to a central tetrahedral Fe atom. A comparison of the structural parameters indicates the metal oxidation states of 2Mo(v) Fe(III). The 1H NMR shows chemical shifts of Me2dtc ligands at 5 10.14 and 8 9.40 with the intensity ratio of 1:1. The cyclic voltammogram displays a reversible couple at - 1.41 V/ - 1.36 V responsible for 1-/2-anions of the complex and an irreversible oxidation at 0.5 V, which seems to show the apparent lack of stability for its neutral species (Me2dtcMoOS2)2Fe.  相似文献   

12.
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   

13.
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)73‐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   

14.
A series of nickel complexes with nuclearity ranging from Ni3 to Ni6 have been obtained by treatment of a variety of nickel salts with the 2‐pyridylcyanoxime ligand. The reported compounds have as a common structural feature the triangular arrangement of nickel cations bridged by a central μ3‐oxo/alkoxo ligand. These compounds are simultaneously the first nickel derivatives of the 2‐pyridylcyanoxime ligand and the first examples of isolated, μ3‐O triangular pyridyloximate nickel complexes. Magnetic measurements reveal antiferromagnetic interactions promoted by the μ3‐O and oximato superexchange pathways and comparison of the experimental structural and magnetic data with DFT calculations give an in‐depth explanation of the factors that determine the magnetic interaction in this kind of system.  相似文献   

15.
Phthalocyanine compounds of novel type based on a bridged bis‐ligand, denoted “intracavity” complexes, have been prepared. Complexation of clamshell ligand 1,1′‐[benzene‐1,2‐diylbis(methanediyloxy)]bis[9(10),16(17),23(24)‐tri‐tert‐butylphthalocyanine] (clam,tBuPc2H4, 1 ) with lanthanide(III) salts [Ln(acac)3] ? n H2O (Ln=Eu, Dy, Lu; acetylacetonate) led to formation of double‐deckers clam,tBuPc2Ln ( 2 a – c ). Formation of high molecular weight oligophthalocyanine complexes was demonstrated as well. The presence of an intramolecular covalent bridge affecting the relative arrangement of macrocycles was shown to result in specific physicochemical properties. A combination of UV/Vis/NIR and NMR spectroscopy, MALDI‐TOF mass‐spectrometry, cyclic voltammetry, and spectroelectrochemistry provided unambiguous characterization of the freshly prepared bis‐phthalocyanines, and also revealed intrinsic peculiarities in the structure–property relationship, which were supported by theoretical calculations. Unexpected NMR activity of the paramagnetic dysprosium complex 2 b in the neutral π‐radical form was observed and examined as well.  相似文献   

16.
17.
Two new compounds, FcCHNC6H4COOH ( 1 ) and FcCHNCH2CH2OH ( 2 ) (Fc=C5H4FeC5H5), have been synthesized and characterized by elemental analyses, IR and 1H NMR spectroscopy, and ESI‐MS. Attempt has been made to explain their quasi‐reversible redox behavior evidenced by cyclic voltammetry using density functional theory (DFT) calculations. Light‐harvesting properties of both the compounds and also the starting material, FcCHO ( 3 ), have been studied using these compounds as photosensitizers in TiO2‐based dye‐sensitized solar cells having either a propylene carbonate‐based electrolyte or ionic liquid electrolyte, namely, 1‐propyl‐3‐methyl imidazolium iodide (PMII). Long‐term stability of the photocurrent output of the cell using compound 1 as photosensitizer has been monitored periodically over 1400 h.  相似文献   

18.
The title compound, [Zn(SiF6)(C12H8N2)2]·CH3OH, contains a neutral heteroleptic tris‐chelate ZnII complex, viz. [Zn(SiF6)(phen)2] (phen is 1,10‐phenanthroline), exhibiting approximate molecular C2 point‐group symmetry. The ZnII cation adopts a severely distorted octahedral coordination. As far as can be ascertained, the title complex represents the first structurally characterized example of a ZnII complex bearing a bidentate‐bound hexafluorosilicate ligand. A density functional theory study of the isolated [Zn(SiF6)(phen)2] complex was undertaken to reveal the influence of crystal packing on the molecular structure of the complex. In the crystal structure, the methanol solvent molecule forms a hydrogen bond to one F atom of the hexafluorosilicate ligand. The hydrogen‐bonded assemblies so formed are tightly packed in the crystal, as indicated by a high packing coefficient (74.1%).  相似文献   

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