共查询到20条相似文献,搜索用时 15 毫秒
1.
Dixon FM Masar MS Doan PE Farrell JR Arnold FP Mirkin CA Incarvito CD Zakharov LN Rheingold AL 《Inorganic chemistry》2003,42(10):3245-3255
The ligand 1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene, 3, was used to synthesize a mononuclear Rh(II) complex [(eta(1):eta(6):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh][PF(6)](2), 6+, in a two-legged piano-stool geometry. The structural and electronic properties of this novel complex including a single-crystal EPR analysis are reported. The complex can be cleanly interconverted with its Rh(I) form, allowing for a comparison of the structural properties and reactivity of both oxidation states. The Rh(I) form 6 reacts with CO, tert-butyl isocyanide, and acetonitrile to form a series of 15-membered mononuclear cyclophanes [(eta(1):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh(CO)(3)][PF(6)] (8), [(eta(1):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh(CNC(CH(3))(3))(2)][PF(6)] (10), and [(eta(1):eta(1)-1,4-bis[4-(diphenylphosphino)butyl]-2,3,5,6-tetramethylbenzene)Rh(CO)(CH(3)CN)][PF(6)] (11). The Rh(II) complex 6+ reacts with the same small molecules, but over shorter periods of time, to form the same Rh(I) products. In addition, a model two-legged piano-stool complex [(eta(1):eta(6):eta(1)-1,4-bis[3-(diphenylphosphino)propoxy]-2,3,5,6-tetramethylbenzene)Rh][B(C(6)F(5))(4)], 5, has been synthesized and characterized for comparison purposes. The solid-state structures of complexes 5, 6, 6+, and 11 are reported. Structure data for 5: triclinic; P(-)1; a = 10.1587(7) A; b = 11.5228(8) A; c = 17.2381(12) A; alpha = 96.4379(13) degrees; beta = 91.1870(12) degrees; gamma = 106.1470(13) degrees; Z = 2. 6: triclinic; P(-)1; a = 11.1934(5) A; b = 12.4807(6) A; c = 16.1771(7) A; alpha = 81.935(7) degrees; beta = 89.943(1) degrees; gamma = 78.292(1) degrees; Z = 2. 6+: monoclinic; P2(1)/n; a = 11.9371(18) A; b = 32.401(5) A; c = 12.782(2) A; beta = 102.890(3) degrees; Z = 4. 11: triclinic; P(-)1; a = 13.5476(7) A; b = 13.8306(7) A; c = 14.9948(8) A; alpha = 74.551(1) degrees; beta = 73.895(1) degrees; gamma = 66.046(1) degrees; Z = 2. 相似文献
2.
Potassium 2,5-di-tert-butyl-3,4-dimethylphospholide K(dtp) (9) was synthesised in 45 % yield from commercially available starting materials by using zirconacyclopentadiene chemistry. Reaction of the K salt of this bulky anion and of the previously described potassium 2,5-bis(trimethylsilyl)-3,4-dimethylphospholide K(dsp) (8) with SmI(2) in diethyl ether afforded the homoleptic samarium(II) complexes 7 and 6, respectively, whose solid-state structures, [[Sm(dtp)(2)](2)] (7 a) and [[Sm(dsp)(2)](2)] (6 a), are dimeric owing to coordination of the phosphorus lone pairs to samarium, as shown by X-ray crystallography. Reaction of 8 with TmI(2) in diethyl ether afforded [Tm(dsp)(2)(Et(2)O)], which could not be desolvated without decomposition. In contrast, the coordinated ether group of the solvate [Tm(dtp)(2)(Et(2)O)], obtained from 9 and TmI(2), could easily be removed by evaporation of the solvent and extraction with pentane at room temperature, and the monomer [Tm(dtp)(2)] (5) could be isolated and was characterised by X-ray crystallography. Presumably, steric crowding in 5 is too high for dimerisation to occur. Compound 5, the first Tm(II) homoleptic sandwich complex, is remarkably stable at room temperature in solution and did not noticeably react with nitrogen, in sharp contrast with other thulium(II) species. As expected, 5, 6 and 7 all reacted with azobenzene to give the trivalent complexes [Tm(dtp)(2)(N(2)Ph(2))] (13), [Sm(dsp)(2)(N(2)Ph(2))], (14) and [Sm(dtp)(2)(N(2)Ph(2))] (15), respectively; 13 and 14 were characterised by X-ray crystallography. Complex 5 immediately reacted with triphenylphosphane sulfide at room temperature to give [[Tm(dtp)(2)](2)(mu-S)] (16), which was characterised by X-ray crystallography, whereas samarium(II) complexes 6 and 7 did not noticeably react with Ph(3)PS over 24 h under the same conditions. 相似文献
3.
Hanne Therese Bonge 《Tetrahedron letters》2010,51(41):5378-5937
A computational study on a range of Rh(II) carbenoids shows how carbenoid stability and cyclopropanation diastereoselectivity can be affected by certain properties of the carbenoid substituents. The results of the study imply that substituents capable of π-interactions are stabilising and cis-directing, and that the trans-directing abilities are affected by steric effects as well as the polarity of carbonyl groups. 相似文献
4.
5.
The water exchange on [Ru(CO)(H2O-eq)4(H2O-ax)](tos)2 (1), [Ru(CO)2(H2O-eq)2(H2O-ax)2](tos)2 (2), and [Ru(CO)3(H2O)3](ClO4)2 (3), the 17O exchange between the bulk water and the carbonyl oxygens have been studied by 17O NMR spectroscopy, and the X-ray crystallographic structures of 1 and 2 have been determined. The water exchange of equatorially and axially coordinated water molecules on 1 and 2 follow an Id mechanism and are characterized by keq298 (s-1), delta H++ (kJ/mol), and delta S++ (J/(mol K)) of (2.54 +/- 0.05) x 10(-6), 111.6 +/- 0.4, and 22.4 +/- 1 (1-eq); (3.54 +/- 0.02) x 10(-2) and 81 (1-ax); (1.58 +/- 0.14) x 10(-7), 120.3 +/- 2, and 28.4 +/- 4 (2-eq); and (4.53 +/- 0.08) x 10(-4), 97.9 +/- 1, and 19.3 +/- 3 (2-ax). The observed reactivities correlate with the strength of the Ru-OH2 bonds, as expressed by their length obtained by X-ray studies: 2.079 (1-eq), 2.140 (1-ax), 2.073 (2-eq), and 2.110 (2-ax) A. 3 is strongly acidic witha pKa of -0.14 at 262 K. Therefore, the acid-dependent water exchange can take place through 3 or Ru(CO)3(H2O)3OH+ with an estimated keq298 of 10(-4)/10(-3) s-1 and kOH262 of 0.053 +/- 0.006 s-1. The 17O exchange rate between the bulk water and the carbonyl oxygens increases from 1 to 2 to 3. For 1 an upper limit of 10(-8) s-1 was estimated. For 2, no acid dependence of kRuCO between 0.1 and 1 m Htos was observed. At 312.6 K, in 0.1 and 1 m Htos, kRuCO = (1.18 +/- 0.03) x 10(-4). For the tricarbonyl complex, the exchange can proceed through 3 or Ru(CO)3(H2O)2OH+ with kRuCO and kRuOHCO of, respectively, 0.003 +/- 0.002 and 0.024 +/- 0.003 s-1, with a ruthenacarboxylic acid intermediate. 相似文献
6.
Mononuclear copper(II) methoxide complexes supported by N(3)S(thioether) chelate ligands having two internal hydrogen bond donors have been prepared, comprehensively characterized, and evaluated for hydrolytic reactivity. 相似文献
7.
Hassan Hadadzadeh Ghobad Mansouri Ali RezvaniHamid R. Khavasi Brian W. SkeltonMohamed Makha Faramarz Rostami Charati 《Polyhedron》2011,30(15):2535-2543
Three mononuclear polypyridyl complexes of Ni(II), [Ni(Ph2phen)3](PF6)2·CH3CN (1), [Ni(dpa)2(phen)](PF6)2 (2) and [Ni(bpy)3](PF6)2 (3), where Ph2phen is 4,7-diphenyl-1,10-phenanthroline, dpa is 2,2′-dipyridylamine, bpy is 2,2′-bipyridine, and phen is 1,10-phenanthroline, were prepared and their solid state structures determined by single-crystal X-ray crystallography. The structural determination shows that the coordination geometry around the Ni(II) center is a distorted octahedron in each complex. The investigation of synthesis procedure and crystallographic data of complex 3 indicates the spontaneous resolution of supramolecular chirality. A careful inspection of the packing pattern in the lattice of each complex reveals that non-covalent interactions of two different types, viz. C-H?F and C-H?π interactions, are active in the lattice. The packing structures of 1-3 also show that the rings of the polypyridyl ligands, Ph2phen, dpa, bpy, and phen, are not located face-to-face and can not interact through π-π interactions. Cyclic voltammetry data of 1 and 3 show that the Ni(III/II) reduction couple is quasi-reversible and this reduction becomes progressively more difficult on passing from bpy to Ph2phen, while complex 2 shows an irreversible behavior with the peak-to-peak separation of about 500 mV. Magnetic susceptibility data derived from paramagnetic NMR revealed effective magnetic moments of 3.12 BM for 1, 3.27 BM for 2, and 3.14 for 3 at room temperature. 相似文献
8.
9.
Tadeusz Wilczewski 《Journal of organometallic chemistry》1982,224(1):C1-C4
Ruthenium and osmium complexes of the type CpMX(PPh3)L (M = Ru; X = Cl, H, S2COC10H19, S2COMe; L & PPh3 and PHPh2; M = Os, X = Cl, Br, I, H, D, xanthogenate, dithiocarbamate, BPh4, L = PPh3). The compound CpOsCl(PPh3)2 is readily soluble in MeOH and in the solution the cation [CpOs(PPh3)2]+ is present. Upon addition of NaBPh4 a white compound CpOs(PPh3)2BPh4 immediately precipitates, which can not be solved in MeOH, contrary to the behaviour of the corresponding ruthenium compound. 相似文献
10.
Jeffery SP Green KN Rampersad MV Reibenspies JH Darensbourg MY 《Dalton transactions (Cambridge, England : 2003)》2006,(35):4244-4252
Three molecular structures are reported which utilize the NiN(2)S(2) ligands -, (bis(mercaptoethyl)diazacyclooctane)nickel and -', bis(mercaptoethyl)diazacycloheptane)nickel, as metallodithiolate ligands to rhodium in oxidation states i, ii and iii. For the Rh(I) complex, the NiN(2)S(2) unit behaves as a bidentate ligand to a square planar Rh(I)(CO)(PPh(3))(+) moiety with a hinge or dihedral angle (defined as the intersection of NiN(2)S(2) and S(2)Rh(C)(P) planes) of 115 degrees . Supported by -' ligands, the Rh(II) oxidation state occurs in a dirhodium C(4) paddlewheel complex wherein four NiN(2)S(2) units serve as bidentate bridging ligands to two singly-bonded Rh(II) ions at 2.893(8) A apart. A compilation of the remarkable range of M-M distances in paddlewheel complexes which use NiN(2)S(2) complexes as paddles is presented. The Rh(III) state is found as a tetrametallic [Rh(-')(3)](3+) cluster, roughly shaped like a boat propeller and structurally similar to tris(bipyridine)metal complexes. 相似文献
11.
Summary Manganese(II) complexes of bis(2-benzimidazolylmethyl) ether (DGB), bis(2-benzimidazolylmethyl) sulphide (TGB) and the n-butyl derivative of DGB (BDGB) were prepared and characterised. The solution e.p.r. spectrum of [Mn(TGB)Cl2] in DMF at 143 K is commensurate with an axially distorted monomeric manganese(II) complex, room temperature magnetic moment
(6.04 B.M.) per manganese(II) atom being in the range found for other d5 monomeric manganese(II) complexes. The solution e.p.r. spectrum of [Mn(BDGB)Cl2]-2H2O in DMF at 143 K indicates the presence of two equivalent manganese(II) ions coupled by an exchange interaction, fostered
by bridging chlorides. Evidence for this is provided by a nearly isotropic 11 line hyperfine structure of 55Mn, with a coupling constant 45 ± 5G. Contact-shifted 1H n.m.r. data also supports an exchange coupled dimeric manganese complex. The room temperature magnetic moment, 5.64 B.M.,
per manganese(II) indicates quenching of the magnetic moment below that of monomeric manganese(II) ion. The [Mn(DGB)Cl2]·H2O complex exhibits a magnetic moment of 6.02 B.M. per manganese, indicating a monomeric manganese complex. E.p.r. data of
the complex diluted in an analogous Zn-DGB complex (1∶20) correlates well for D = 0.22cm−1 and λ ∼- 0.267. The [Mn(DGB)-(C1O4)2] and [Mn(BDGB)(ClO4)2] complexes, diluted in analogous Zn-DGB and Zn-BDGB complexes (1∶20), show a strong single e.p.r. line at g
eff ∼- 2. The complexes have low magnetic moments; 4.44 B.M./Mn and 4.39 B.M./Mn, at room temperature. 相似文献
12.
New chelate bis-heterocyclic-carbene complexes of Rh(I) and Rh(III) have been obtained and fully characterized. The molecular structures of the new species have been determined. The synthesis of the compounds starts from the bisimidazolium precursors, which are deprotonated with NEt(3) under mild reaction conditions, leading to coordination to the Rh complex. The Rh(III) compounds are generated from Rh(I) and [Rh(II)](2) species, although there is no apparent oxidizing agent in the reaction media. 相似文献
13.
Summary Reactivity trends are reported for aquation of tris(5-nitro-1,10-phenanthroline)iron(II) in ternary H2O-t-BuOH-polyethyleneglycol (PEG400) solvent media. Wavelengths of maximum absorption for the lowest energy charge-transfer band of dicyanobis(2-acetylpyridineoximato)-iron(II) are reported for the same series of ternary solvent mixtures. There is no overall correlation of rate constants with wavelength shifts, indicating that solvation effects in the two systems are not directly related.On leave from the Faculty of Science, Assiut University, Sohag, Egypt. 相似文献
14.
Dempsey JL Winkler JR Gray HB 《Dalton transactions (Cambridge, England : 2003)》2011,40(40):10633-10636
Powerful reductants [Os(II)(NH(3))(5)L](2+) (L = OH(2), CH(3)CN) can be generated upon ultraviolet excitation of relatively inert [Os(II)(NH(3))(5)(N(2))](2+) in aqueous and acetonitrile solutions. Reactions of photogenerated Os(II) complexes with methyl viologen to form methyl viologen radical cation and [Os(III)(NH(3))(5)L](3+) were monitored by transient absorption spectroscopy. Rate constants range from 4.9 × 10(4) M(-1) s(-1) in acetonitrile solution to 3.2 × 10(7) (pH 3) and 2.5 × 10(8) M(-1) s(-1) (pH 12) in aqueous media. Photogeneration of five-coordinate Os(II) complexes opens the way for mechanistic investigations of activation/reduction of CO(2) and other relatively inert molecules. 相似文献
15.
Montag M Leitus G Shimon LJ Ben-David Y Milstein D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2007,13(32):9043-9055
Reaction of the aryl-monophosphine ligand alpha(2)-(diisopropylphosphino)isodurene (1) with the Rh(I) precursor [Rh(coe)(2)(acetone)(2)]BF(4) (coe=cyclooctene) in different solvents yielded complexes of all three common oxidation states of rhodium, depending on the solvent used. When the reaction was carried out in methanol a cyclometalated, solvent-stabilized Rh(III) alkyl-hydride complex (2) was obtained. However, when the reaction was carried out in acetone or dichloromethane a dinuclear eta(6)-arene Rh(II) complex (5) was obtained in the absence of added redox reagents. Moreover, when acetonitrile was added to a solution of either the Rh(II) or Rh(III) complexes, a new solvent-stabilized, noncyclometalated Rh(I) complex (6) was obtained. In this report we describe the different complexes, which were fully characterized, and probe the processes behind the remarkable solvent effect observed. 相似文献
16.
Sciarone TJ Nijhuis CA Meetsma A Hessen B 《Dalton transactions (Cambridge, England : 2003)》2006,(41):4896-4904
The mono(amidinate) iron(ii) ferrate complex [{PhC(NAr)(2)}FeCl(micro-Cl)Li(THF)(3)] (1, Ar = 2,6-iPr(2)C(6)H(3)) was prepared and was found to undergo ligand redistribution in non-coordinating solvents to give the homoleptic [{PhC(NAr)(2)}(2)Fe] (2) as the only isolable product. Reaction of with alkylating agents also induces this redistribution, but the presence of pyridine allows isolation of the four-coordinate 14 VE monoalkyl complex [{PhC(NAr)(2)}FeCH(2)SiMe(3)(py)] (4). Generation of the 12 VE alkyl via pyridine abstraction from 4 by B(C(6)F(5))(3) again induced ligand redistribution. Attempts to trap a 12 VE alkyl species with CO led to the isolation of a dimeric Fe(0)-Li-ferrate complex (3) with a carbamoyl ligand, derived from CO insertion into the iron-amidinate bond. 相似文献
17.
18.
A. S. Novikov A. I. Dement’ev Yu. N. Medvedev 《Russian Journal of Inorganic Chemistry》2013,58(3):320-330
The mechanism of 1,3-dipolar cycloaddition of nitrone (CH2=N(Me)O) to methylisonitrile coordinated to Rh(I) and Rh(III) in the [RhCl(PH3)(CNMe)2] and [RhCl3(PH3)(CNMe)2] complexes has been studied by quantum-chemical methods. The molecular and electronic structures of the cycloaddition products, the nature of transition states, the mechanism of reactions, their kinetic and thermodynamic parameters, and the solvent effect have been described. The reactions occur via the concerted strongly asynchronous mechanism involving the formation of a five-membered cyclic transition state. The use of rhodium complexes as reagents leads to a noticeable decrease in the activation barriers of the processes under consideration and an increase in the magnitudes of energy effects of the reactions. It has been demonstrated that the Rh(III) complexes are better activators of the cycloaddition of nitrone to isonitrile than the Rh(I) complex. The calculations predict that in the case of the Rh(I) complexes, only one isonitrile ligand can be involved in cycloaddition of nitrone, whereas the use of the Rh(III) complexes enables the participation of both ligands. The solvation effects inhibit the reactions. 相似文献
19.
Pantcheva Ivayla N. Stambolyiska Radoslava D. Petkov Nikolay N. Tadjer Alia V. Simova Svetlana D. Stoyanova Radostina K. Kukeva Rositza R. Dorkov Petar D. 《Transition Metal Chemistry》2022,47(1):67-76
Transition Metal Chemistry - The 16-membered macrolide antibiotics tylosin (HTyl) and tilmicosin (HTilm) react with Cu(II) to form isostructural mononuclear complexes of composition [CuL2]... 相似文献
20.
Charmant JP Fan C Norman NC Pringle PG 《Dalton transactions (Cambridge, England : 2003)》2007,(1):114-123
The reaction between [Pt(nbe)3] (nbe=norbornene), two equivalents of the phosphines PPh3, PMePh2 or PMe2Ph and 1 equivalent of BCl3 affords the platinum dichloroboryl species [PtCl(BCl2)(PPh3)2], [PtCl(BCl2)(PMePh2)2] and [PtCl(BCl2)(PMe2Ph)2]. All three complexes were characterised by X-ray crystallography and reveal that the boryl group lies trans to the chloride. With PMe3 as the phosphine, the complex [PtCl(BCl2)(PMe3)2] is isolated in high yield as a white crystalline powder although crystals suitable for X-ray crystallography were not obtained. Crystals were obtained of a product shown by X-ray crystallography to be the unusual dinuclear species [Pt2(BCl2)2(PMe3)4(micro-Cl)][BCl4] which reveals an arrangement in which two square planar platinum(II) centres are linked by a single bridging chloride which is trans to a BCl2 group on each platinum centre. The reaction of [PtCl(BCl2)(PMe3)2] with NEt3 or pyridine (py) affords the adducts [PtCl{BCl2(NEt3)}(PMe3)2] and [PtCl{BCl2(py)}(PMe3)2], respectively, both characterised spectroscopically. The reaction between [PtCl(BCl2)(PMe3)2] and either 4 equivalents of NHEt2 or piperidine (pipH) results in the mono-substituted boryl species [PtCl{BCl(NEt2)}(PMe3)2] and [PtCl{BCl(pip)}(PMe3)2], respectively, the former characterised by X-ray crystallography. Treatment of either [PtCl(BCl2)(PMe3)2] (in the presence of excess NEt3) or [PtCl{BCl(NEt2)}(PMe3)2] with catechol affords the B(cat) (cat=catecholate) derivative [PtCl{B(cat)}(PMe3)2] which is also formed in the reaction between [Pt(PMe3)4] and ClB(cat) and also from the slow decomposition of [Pt{B(cat)}2(PMe3)2] in dichloromethane over a period of months. The compound [Pt{B(cat)}2(PMe3)2] was prepared from the reaction between [Pt(PMe3)4] and B2(cat)2. 相似文献