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1.
The thermal and photochemical reactions of CpRe(PPh 3) 2H 4 and CpRe(PPh 3)H 4 (Cp = η5-C 5H 5) with PMe 3, P( p-tolyl) 3, PMe 2Ph, DMPE, DPPE, DPPM, CO, 2,6-xylylisocyanide and ethylene have been examined. While CpRe(PPh 3) 2H 2 is thermally inert, it will undergo photochemical substitution of one or two PPh 3 ligands. With ethylene, substitution is followed by insertion of the olefin into the C-H bond of benzene, giving ethylbenzene. CpRe(PPh 3)H 4 undergoes thermal loss of PPh 3, which leads to substituted products of the type CpRe(L) H 4. Photochemically, reductive elimination of dihydrogen occurs preferentially. The complex trans-CpRe(DMPE)H 2 was structurally characterized, crystallizing in the monoclinic space group P2 1/ n (No. 14) with a = 6.249(6), b = 16.671(8), c = 13.867(7) Å, β = 92.11(6)°, V = 1443.7(2.9) Å and Z = 4. The complex trans-CpRe(PMe 2Ph) 2H 2 was structurally characterized, crystallizing in the monoclinic space group P2 1/ n (No. 14) with a = 7.467(3), b = 23.874(14), c = 11.798(6) Å, β = 100.16(4)°, V = 2070.2(3.4) Å 3 and Z = 4. 相似文献
2.
Three novel methylene bridged binuclear iron(II) complexes: (R,R′ = i-C 3H 7 (6); R = i-C 3H 7, R′ = CH 3 (7); R,R′ = CH 3 (8))} have been synthesized. Activated by Al( i-Bu) 3, complex 6 shows very poor activity for the polymerization of ethylene at one bar ethylene pressure, whereas, 7 and 8 exhibit much higher activity than mononuclear iron catalysts {[ArNC(Me)C 5H 3N(Me)CNAr′]FeCl 2 (Ar,Ar′ = 2,6-C 6H 3- i-Pr (9); Ar = 2,6-C 6H 3- i-Pr 2, Ar′ = 2,6-C 6H 3–Me 2 (10); Ar,Ar′ = 2,6-C 6H 3–Me 2 (11))}. The molecular weight ( Mw) of PE produced by 7 and 8 are in the range 13.2–46.0 × 10 4 and much higher than those produced by mononuclear iron catalysts 9 and 10. GPC results demonstrate that 7 and 8 yield PE with a broad/bimodal molecular weight distribution (MWD). In contrast, 9 and 10 yield PE with relatively narrow and unimodal MWD (4.26 and 3.55). Elevating the temperature and Al/Fe molar ratio will narrow the MWD of PE. 相似文献
3.
Copper(I) complexes with {Cu(μ 2-S)N} 4 and {Cu(μ 3-S)N} 12 core portions of butterfly-shaped or double wheel architectures have been isolated in the reaction of Cu(I) with the Schiff base ligand C 6H 4(CHNC 6H 4S) 2, “ iso-abt”, under different conditions. containing the tetranuclear electroneutral complex is formed by the reaction of CuI in acetonitrilic solution and recrystallization from DMF, whereas containing dodecanuclear wheels is accessible starting from CuBF 4. Complexes 2 and 4 represent the first examples of cyclic complexes with the same overall stoichiometry but different ring sizes. The ligand induces two different coordination environments around copper(I) by switching between μ 2- and μ 3-sulfur bridging modes. 相似文献
4.
Cp #2Yb (Cp #=C 5H 4(CH 2) 2NMe 2) has been obtained by reaction of YbI 2(THF) 2 with 2 equiv. of C 5H 4(CH 2CH 2NMe 2)K in THF. The X-ray structure analysis shows a bent structure with intramolecular coordination of both nitrogen atoms to ytterbium. The reaction of C 60-fullerene with Cp #2Yb leads to the formation of the fullerenide derivative [Cp #2Yb] 2C 60, which shows an ESR signal in the solid state and in THF solution at room temperature (solid: Δ H = 50 G, G = 1.9992; solution: Δ H = 10 G, G = 2.0001) and a magnetic moment of 3.6 BM. The lutetium fullerenides CpLu(C 60)(DME) (3) and Cp *Lu(C 60)(DME)(C 6H 5CH 3) (4), (Cp = η 5−C 5H 5, Cp * = η 5−C 5Me 5), were obtained by reaction of C 60 with CpLu(C 10H 8) (DME) and Cp *Lu(C 10H 8) (DME) in toluene. Both complexes are paramagnetic (μ eff = 1.4 and 0.9 BM) and exhibit temperature-dependent ESR signals (293 K: g = 1.992 and 2.0002 respectively). 相似文献
5.
The synthesis and characterization of a ferrocenyl-derived tridentate ligand, ferrocenyltris((methylthio)methyl)borate (FcTtP −), and its representative metal complexes, [(FcTt)Cu] 4 and [FcTt] 2M (M = Fe, Co and Ni), are reported. The M = Fe complex exhibits spin-crossover behavior with a μeff = 1.19 μ B at 25°C. The low-spin Co(II) derivative (1.88 μ B) exhibits a characteristic axial electron paramagnetic resonance (EPR) spectrum, gav = 2.13, A = 53 G and A¦ = 43 G. The [FcTt] 2M complexes display reversible two-electron redox processes assigned to ligand-centered events about 200 mV negative of the ferrocene-ferrocenium couple. [(FcTt)Cu] 4 and [FcTt] 2Ni have been characterized by X-ray diffraction. X-ray data for [(FcTt)Cu] 4: monoclinic space group C2/ c, with a = 24.3747(3) Å, b = 20.0857(2) Å, c = 17.2747(4) Å, β = 95.843(1)°, V = 8413.5(3) Å 3, and Z = 4; [FcTt] 2Ni: monoclinic space group C2/ c, with a = 12.6220(3) Å, b = 11.6002(3) Å, c = 25.0125(7) Å, β = 94.067(1)°, V = 3653.1(2) Å 3, and Z = 4. 相似文献
6.
The complex [Et 4N][W(CO) 5OMe] (1) has been prepared from the reaction of the photochemically generated W(CO) 5THF adduct and [Et 4N][OH] in methanol. Complex 1 was shown to undergo rapid CO dissociation in THF to quantitatively provide the dimeric dianion, [W(CO) 4OMe] 22−. The resulting THF insoluble salt [Et 4N] 2[W(CO) 4OMe] 2 (2) has been structurally characterized by X-ray crystallography, with the doubly bridging methoxide ligands being in an anti configuration. Complex 2 was found to subsequently react with excess methoxide ligand in a THF slurry to afford the face-sharing octahedron complex [Et 4N] 3[W 2(CO) 6(OMe) 3] (3) which contains three doubly bridging methoxide groups. In the absence of excess methoxide ligand complex 2 cleanly yields the tetrameric complex [Et 4N] 4[W(CO) 3OMe] 4 (4) which has been structurally characterized as a cubane-like arrangement with triply bridging μ3-methoxide groups and W(CO) 3 units. Although complex 3 was not characterized in the solid state, the closely related glycolate derivative [Et 4N] 3[W 2(CO) 6(OCH 2CH 2OH) 3] (5) was synthesized and its structure determined by X-ray crystallography. The trianions of complex 5 are linked in the crystal lattice by strong intermolecular hydrogen bonds. Crystal data for 2: space group P2 1/ n, a = 7.696(2), b = 22.019(4), c = 9.714(2) Å, β = 92.22(3)°, Z = 4, R = 6.43%. Crystal data for 4: space group Fddd, a = 12.433(9), b = 24.01(2), c = 39.29(3) Å, Z = 8, R = 8.13%. Crystal data for 5: space group P2 12 12 1, a = 11.43(2), b = 12.91(1), c = 29.85(6) Å, Z = 8, R = 8.29%. Finally, the rate of CO ligand dissociation in the closely related aryloxide derivatives [Et 4N][W(CO) 5OR] (R = C 6H 5 and 3,5-F 2C 6H 3) were measured to be 2.15 × 10 −2 and 1.31 × 10 −3 s −1, respectively, in THF solution at 5°C. Hence, the value of the rate constant of 2.15 × 10 −2 s −1 establishes a lower limit for the first-order rate constant for CO loss in the W(CO) 5OMe − anion, since the methoxide ligand is a better π-donating group than phenoxide. 相似文献
7.
New mixed metal complexes SrCu 2(O 2CR) 3(bdmap) 3 (R = CF 3 (1a), CH 3 (1b)) and a new dinuclear bismuth complex Bi 2(O 2CCH 3) 4(bdmap) 2(H 2O) (2) have been synthesized. Their crystal structures have been determined by single-crystal X-ray diffraction analyses. Thermal decomposition behaviors of these complexes have been examined by TGA and X-ray powder diffraction analyses. While compound 1a decomposes to SrF 2 and CuO at about 380°C, compound 1b decomposes to the corresponding oxides above 800°C. Compound 2 decomposes cleanly to Bi 2O 3 at 330°C. The magnetism of 1a was examined by the measurement of susceptibility from 5–300 K. Theoretical fitting for the susceptibility data revealed that 1a is an antiferromagnetically coupled system with g = 2.012(7), −2 J = 34.0(8) cm −1. Crystal data for 1a: C 27H 51N 6O 9F 9Cu 2Sr/THF, monoclinic space group P2 1/ m, A = 10.708(6), B = 15.20(1), C = 15.404(7) Å, β = 107.94(4)°, V = 2386(2) Å 3, Z = 2; for 1b: C 27H 60N 6O 9Cu 2Sr/THF, orthorhombic space group Pbcn, A = 19.164(9), B = 26.829(8), C = 17.240(9) Å, V = 8864(5) Å 3, Z = 8; for 2: C 22H 48O 11N 4Bi 2, monoclinic space group P2 1/ c, A = 17.614(9), B = 10.741(3), C = 18.910(7) Å, β = 109.99(3)°, V = 3362(2) Å 3, Z = 4. 相似文献
8.
Reaction of RuCl(η 5-C 5H 5( pTol-DAB) with AgOTf (OTf = CF 3SO 3) in CH 2Cl 2 or THF and subsequent addition of L′ (L′ = ethene (a), dimethyl fumarate (b), fumaronitrile (c) or CO (d) led to the ionic complexes [Ru(η 5-C 5H 5)( pTol-DAB)(L′)][OTf] 2a, 2b and 2d and [Ru(η 5-C 5H 5)( pTol-DAB)(fumarontrile- N)][OTf] 5c. With the use of resonance Raman spectroscopy, the intense absorption bands of the complexes have been assigned to MLCT transitions to the iPr-DAB ligand. The X-ray structure determination of [Ru(η 5-C 5H 5)( pTol-DAB)(η 2-ethene)][CF 3SO 3] (2a) has been carried out. Crystal data for 2a: monoclinic, space group P2 1/ n with A = 10.840(1), b = 16.639(1), C = 14.463(2) Å, β = 109.6(1)°, V = 2465.6(5) Å 3, Z = 4. Complex 2a has a piano stool structure, with the Cp ring η 5-bonded, the pTol-DAB ligand σN, σN′ bonded (Ru-N distances 2.052(4) and 2.055(4) Å), and the ethene η 2-bonded to the ruthenium center (Ru-C distances 2.217(9) and 2.206(8) Å). The C = C bond of the ethene is almost coplanar with the plane of the Cp ring, and the angle between the plane of the Cp ring and the double of the ethene is 1.8(0.2)°. The reaction of [RuCl(η 5-C 5H 5)(PPh) 3 with AgOTf and ligands L′ = a and d led to [Ru(η 5-C 5H 5)(PPh 3) 2(L′)]OTf] (3a) and (3d), respectively. By variable temperature NMR spectroscopy the rottional barrier of ethene (a), dimethyl fumarate (b and fumaronitrile (c) in complexes [Ru(η 5-C 5H 5)(L 2)(η 2-alkene][OTf] with L 2 = iPr-DAB (a, 1b, 1c), pTol-DAB (2a, 2b) and L = PPh 3 (3a) was determined. For 1a, 1b and 2b the barrier is 41.5±0.5, 62±1 and 59±1 kJ mol −1, respectively. The intermediate exchange could not be reached for 1c, and the Δ G# was estimated to be at least 61 kJ mol −. For 2a and 3a the slow exchange could not be reached. The rotational barrier for 2a was estimated to be 40 kJ mol −. The rotational barier for methyl propiolate (HC≡CC(O)OCH 3) (k) in complex [Ru(η 5-C 5H 5)(iPr-DAB) η 2-HC≡CC(O)OCH 3)][OTf] (1 k) is 45.3±0.2 kJ mol −1. The collected data show that the barrier of rotational of the alkene in complexes 1a, 2a, 1b, 2b and 1c does not correlate with the strength of the metal-alkene interaction in the ground state. 相似文献
9.
The phosphinoalkenes Ph 2P(CH 2) nCH=CH 2 ( n= 1, 2, 3) and phosphinoalkynes Ph 2P(CH 2) n C≡CR (R = H, N = 2, 3; R = CH 3, N = 1) have been prepared and reacted with the dirhodium complex (η−C 5H 5) 2Rh 2(μ−CO) (μ−η 2−CF 3C 2CF 3). Six new complexes of the type (ν−C 5H 5) 2(Rh 2(CO) (μ−η 1:η 1−CF 3C 2CF 3)L, where L is a P-coordinated phosphinoalkene, or phosphinoalkyne have been isolated and fully characterized; the carbonyl and phosphine ligands are predominantly trans on the Rh---Rh bond, but there is spectroscopic evidence that a small amount of the cis-isomer is formed also. Treatment of the dirhodium-phosphinoalkene complexes with (η−CH 3C 5H 4)Mn(CO) 2thf resulted in coordination of the manganese to the alkene function. The Rh 2---Mn complex [(η−C 5H 5) 2Rh 2(CO) (μ−η 1:η 1−CF 3C 2CF 3) {Ph 2P(CH 2) 3CH=CH 2} (η−CH 3C 5H 4)Mn(CO) 2] was fully characterized. Simi treatment of the dirhodium-phosphinoalkyne complexes with Co 2(CO) 8 resulted in the coordination of Co 2(CO) 6 to the alkyne function. The Rh 2---Co 2 complex [(η−C 5H 5) 2Rh 2(CO) (μ−η 1:η 1−CF 3C 2CF 3) {Ph 2PCH 2C≡CCH 3}Co 2(CO) 2], C 37H 25Co 2F 6O 7PRh 2, was fully characteriz spectroscopically, and the molecular structure of this complex was determined by a single crystal X-ray diffraction study. It is triclinic, space group
( Ci1, No. 2) with a = 18.454(6), B = 11.418(3), C = 10.124(3) Å, = 112.16(2), β = 102.34(3), γ = 91.62(3)°, Z = 2. Conventional R on | F| was 0.052 fo observed ( I > 3σ( I)) reflections. The Rh 2 and Co 2 parts of the molecule are distinct, the carbonyl and phosphine are mutually trans on the Rh---Rh bond, and the orientations of the alkynes are parallel for Rh 2 and perpendicular for Co 2. Attempts to induce Rh 2Co 2 cluster formation were unsuccessful. 相似文献
10.
A new method has been developed for the preparation of nitroaryl transition metal complexes using copper(II) nitrate in the presence of acetic anhydride (Menke conditions) to directly nitrate an aryl group which is already σ-bound to a transition metal centre. Under these conditions ruthenium(II) aryl complexes of the type:
(where R 1=R 2=H; R 1=H, R 2=CH 3; R 1=CH 3, R 2=H) react to yield three distinct types of nitroaryl-containing products (I–III). The preparation and characterisation of these compounds are described. X-ray crystallographic data for one example of each of the three types of compound, are also reported. The compounds that have been studied crystallographically are Ru(C6H4NO2-4)(η2-O2CCH3)(CO)(PPh3)2 (1a), C45H37NO5P2Ru·(CH2Cl2)0.5, a = 20.254(5), b=19.437(8), c=22.629(3) Å, β=115.390(10)°, monoclinic, space group C2/c, Z=8; Ru(C6H4N[O]O-2)- Cl(CO)(PPh3)2 (4a), C43H34ClNO3P2Ru, a=9.331(3), b=12.443(2), c=16.346(3) Å, =82.81(2), β=85.03(2), γ=74.76(2)°, triclinic, space group P
, Z=2; Ru(C6H2CH3-2,NO2-4,N[O]O-6)Cl(CO)(PPh3)2 (5b), C44H35Cl- N2O5P2Ru·(CH2Cl2)2, a=19.497(3), b=14.502(3), c=19.340(5) Å, β=122.79(1)°, monoclinic, space group Cc, Z=4. 相似文献
11.
Reactions of [Rh(COD)Cl] 2 with the ligand RN(PX 2) 2 (1: R = C 6H 5; X = OC 6H 5) give mono- or disubstituted complexes of the type [Rh 2(COD)Cl 2{ν 2−C 6H 5N(P(OC 6H 5) 2) 2}] or [RhCl{ν 2−C 6H 5 N(P(OC 6H 5) 2) 2 }] 2 depending on the reaction conditions. Reaction of 1 with [Rh(CO) 2Cl] 2 gives the symmetric binuclear complex, [Rh(CO)Cl{μ−C 6H 5N(P(OC 6H 5) 2) 2} 2, whereas the same reaction with 2 (R = CH 3; X = OC 6H 5) leads to the formation of an asymmetric complex of the type [Rh(CO)(μ−CO)Cl{μ−CH 3N(P(OC 6H 5) 2) 2} 2 containing both terminal and bridging CO groups. Interestingly the reaction of 3 (R = C 6H 5, X = OC 6H 4Br− p with either [Rh(COD)Cl] 2 or [Rh(CO) 2Cl] 2 leads only to the formation of the chlorine bridged binuclear complex, [RhCl{ν 2−C 6H 5N(P(OC 6H 4Br− p) 2) 2}] 2. The structural elucidation of the complexes was carried out by elemental analyses, IR and 31P NMR spectroscopic data. 相似文献
12.
Metathesis of [(η 3:η 3−C 10H 16)Ru(Cl) (μ−Cl)] 2 (1) with [R 3P) (Cl)M(μ-Cl)] 2 (M = Pd, Pt), [Me 2NCH 2C 6H 4Pd(μ-Cl)] 2 and [(OC) 2Rh(μ-Cl)] 2 affords the heterobimetallic chloro bridged complexes (η 3:η 3-C 10H 16) (Cl)Ru(μ-Cl) 2M(PR 3)(Cl) (M = Pd, Pt), (η 3:η 3-C 10H 16) (Cl)Ru(μ-Cl) 2PdC 6H 4CH 2NMe 2 and (η 3:η 3-C 10H 16) (Cl)Ru(μ-Cl) 2Rh(CO) 2, respectively. Complex 1 reacts with [Cp *M(Cl) (μ-Cl)] 2 (M = Rh, Ir), [ p-cymene Ru(Cl) (μ-Cl] 2 and [(Cy 3P)Cu(μ-Cl)] 2 to give an equilibrium of the heterobimetallic complexes and of educts. The structures of (η 3:η 3-C 10H 16)Ru(μ-Cl) 2Pd(PR 3) (Cl) ( R = Et, Bu) and of one diastereoisomer of (η 3:η 3-C 10H 16)Ru(μ-Cl) 2IrCp *(Cl) were determined by X-ray diffraction. 相似文献
13.
The observation of homolytic S---CH 3 bond cleavage in (Ph 2P( o-C 6H 4)SCH 3) 2Ni 0 under photochemical conditions has prompted further investigation of nickel(0) complexes and their stability. Tetradentate P 2S′ 2 donor ligands (S′ = thioether type S donor) with aromatic rings incorporated into the P to S links, Ph 2P( o-C 6H 4)S(CH 2) 3S( o-C 6H 4)PPh 2 (arom-PSSP), or the S to S links, Ph 2P(CH 2) 2SCH 2( o-C 6H 4)CH 2S(CH 2) 2PPh 2 (PS-xy-SP), have been used to form four-coordinate, square planar nickel(II) complexes, [(arom-PSSP)Ni](BF 4) 2 (2) and [(PS-xy-SP)Ni](BF 4) 2 (3). The bidentate and tetradentate ligands, Ph 2P( o-C 6H 4)SCH 2CH 3 (arom-PSEt) and Ph 2P(CH 2) 2S(CH 2) 3S(CH 2) 2PPh 2 (PSSP), give similar complexes, [(arom-PSEt) 2Ni](BF 4) 2 (1) and [(PSSP)Ni](BF 4) 2 (4), respectively. Cyclic voltammograms of the Ni 11 complexes in CH 3CN show two reversible redox events assigned to
and
. The one-electron reduction product produced by stoichiometric amounts of Cp 2Co can be characterized by EPR. At 100 K rhombic signals show hyperfine coupling to two phosphorus atoms. Complete bulk chemical reduction of complexes 1, 2, 3 and 4 with Na/Hg amalgam provided the corresponding nickel(0) complexes 1 R, 2 R, 3 R and 4 R which were isolated as red solutions or solids characterized by magnetic resonance properties and reaction products. Photolysis of these nickel(0) complexes leads to S-dealkylation to produce alkyl radicals and dithiolate nickel(II) complexes. Complex 3 crystallized in the monoclinic space group P2t/ c with a=20.740(5), B=9.879(3), C=17.801(4) åA, ß=92.59(2)°, V=3644(2) Å 3 and Z=4; complex 4: P2 1/ c with A=13.815(4), B=13.815(4), C=15.457(5) åA, V=3365.4(14) Å 3 and Z=4. 相似文献
14.
Unsymmetrical di(phosphine) ligands (dpp) 2Rop (1a, b = bis(diphenylphosphino)-2-alkyl-3-oxapropane (alkyl = methyl and ethyl)) and (dpp) 2oCy (1c = trans-2-diphenylphosphinocyclohexyl diphenylphosphinite) and their Pt(II) dichloride complexes, PtCl 2((dpp) 2mop) (2a), PtCl 2((dpp) 2eop) (2b) and PtCl 2((dpp) 2oCy) (2c), have been synthesized and characterized by NMR spectroscopy. The crystal structures of 2b and 2c show that the geometry about the platinum centers is square planar. In 2b, the metal and di(phosphine) ligand chelate ring are in a chair conformation, whereas in 2c, the chelate ring conformation is a skewed boat. Initial reaction of sodium borohydride with 2a, b, c yields the monohydride monochloride complexes PtHCl((dpp) 2mop) (5a), PtHCl((dpp) 2eop) (5b) and PtHCl((dpp) 2oCy) (5c). At longer reaction times, fluxional dimeric species are obtained, [PtH((dpp) 2mop)] 2 (4a), [PtH((dpp) 2eop)] 2 (4b) and [PtH((dpp) 2oCy)] 2 (4c),and in the case of 4c two different isomers exist. The dihydride complexes PtH 2((dpp) 2mop) (3a), PtH 2((dpp) 2eop) (3b) and PtH 2((dpp) 2oCy) (3c), are prepared by further reaction of NaBH 4 and 2. Hydrogen cycling is facile in the dihydride complexes 3a, b, c, and oxidative addition of H 2 proceeds in a pairwise manner as determined by the observation of parahydrogen induced polarization (PHIP) in the 1H NMR spectra. The reductive elimination of H 2 is also shown to be concerted by reaction of dihydride complexes with D 2. Crystal data: 2b (C 30H 32Cl 6OP 2Pt), monoclinic, space group P2 1/ c (No. 14), a = 13.7040(1), b = 11.3430(7), c = 21.3880(9) Å, β = 97.923(9)°, V = 3292.9(2) Å 3 and Z = 4; 2c (C 30H 30Cl 2OP 2Pt), monoclinic, space group P2 1 (No. 4), a = 11.7360(2), b = 8.4311(2), c = 14.2789(2) Å, β = 101.290(1)°, V = 1385.52(4) Å 3 and Z = 2. 相似文献
15.
Using thermal and photochemical methods a series of new chromium complexes has been prepared: (ν 6- p-C 6H 4F 2)Cr(CO) 3; (ν 6-C 6H 5CF 3)Cr(CO) 3; [ m-C 6H 4(CF 3) 2]Cr(CO) 3; (ν 6-C 6H 5F)Cr(CO) 2H(SiCl 3); (ν 6-C 6H 5F)Cr(CO) 2(SiCl 3) 2; ( p-C 6H 4F 2)Cr(CO) 2-H(SiCl 3); (C 6H 5CF 3)Cr(CO) 2H(SiCl 3( p-C 6H 4F 2)Cr(CO) 2(SiCl 3) 2; C 6H 5CF 3)Cr(CO) 2(SiCl 3) 2; [ m-C 6H 4(CF 3) 2]Cr(CO) 2-H(SiCl 3); [ m-C 6H 4(CF 3) 2]Cr(CO) 2(SiCl 3) 2. Two compounds were structurally characterized by X-ray diffraction. These data combined with IR and 1H NMR have allowed assessment of some of the electronic and steric effects. The Cr-arene bond is considerably longer in the Cr(II) derivatives than in the Cr(0) species. Also the Cr center, as might be expected, is less electron rich in the Cr(II) dicarbonyl disilyl derivatives. The ν 6- p-C 6H 4F 2 ligands are slightly folded so that the C---F carbons are moved further away from the Cr center. Comparison of structural and electronic effects is made with a series of similar chromium compounds reported in the literature. These new (arene)Cr(II) derivatives possess more labile ν 6-arene ligands, which promise a rich chemistry at the chromium center. 相似文献
16.
Four complexes of the type [Cu 4I 4(CH 3CN) 2(L) 2], L = aniline derivative: Cu 4I 4(CH 3CN) 2(2,6-dimethylaniline) 2 (I), triclinic,
, a = 12.449(3), B = 14.108(6), C = 10.606(4) Å, = 73.46(3), β = 95.00(2), γ = 73.42(3)°, V = 1682.3(10) Å 3; Cu 4I 4(CH 3CN) 2( o-ethylaniline) 2 (II), triclinic, , V = 1734.0(8) Å 3; Cu 4I 4(CH 3CN) 2(6-ethyl- o-toluidine) 2 (III), orthorhombic, Pnam, a = 14.976(6), b = 21.187(6), C = 12.545(2) Å, V = 3980.7(2) Å 3; Cu 4I 4(CH 3CN) 2( p-anisidine) 2 (IV), monoclinic, A2/ a, A = 20.032(10), B = 7.863(1), C = 18.715(9) Å, β = 101.56(4)°, V = 2888.0(2) Å 3; were examined by single crystal X-ray diffraction. Complexes I and II have no internal symmetry elements, III has an internal mirror and IV has a two-fold axis. Ab initio calculations based on the atomic positional parameters of complexes containing the three types of symmetry elements reveal HOMO orbitals to be dominated by the p orbitals of the iodine atoms whereas the LUMO orbitals contain major contributions from copper based p orbitals. 相似文献
17.
The reactions of the polysulfur and selenium cationic clusters S 82+ and Se 82+ with various iron carbonyls were investigated. Several new chalcogen containing iron carbonyl cluster cations were isolated, depending on the nature of the counteranion. In the presence of SbF 6− as a counterion, the cluster [Fe 3(E 2) 2(CO) 10] [SbF 6] 2·SO 2 (E = S, Se) could be isolated from the reaction of E 82+ and excess iron carbonyl. The cluster is a picnic-basket shaped molecule of two iron centers linked by two Se 2 groups, with the whole fragment capped by an Fe(CO) 4 group. Crystallographic data for C 10O 12Fe 3Se 4Sb 2F 12S (I): space group monoclinic P2 1/ c, A = 11.810(9), b = 24.023(6), c = 10.853(7) Å, β = 107.15(5)°, V = 2942(3) Å 3, Z = 4, R = 0.0426, Rw = 0.0503. When Sb 2F 11− is present as the counterion, or Se 4[Sb 2F 11] 2 is used as the cluster cation source, a different cluster can be isolated, which has the formula [Fe 4(Se 2) 3(CO) 12] [SbF 6] 2·3SO 2. The dication contains two Fe 2Se 2 fragments bridged by an Se 2 group. Crystallographic data for C 12O 18Fe 4Se 6Sb 2F 12S 3 (III): space group triclinic
, b = 18.400(9), C = 10.253(4) Å, = 93.10(4), β = 103.74(3), γ = 93.98(3)°, V = 1995(1) Å 3, Z = 2, R = 0.0328, Rw = 0.0325. The CO stretches in the IR spectrum all show a large shift to higher wavenumbers, suggesting almost no τ backbonding from the metals. This also correlates with the observed bond distances. All the compounds are extremely sensitive to air and water, and readily lose SO 2 when removed from the solvent. Thus all the crystals were handled at −100°C. The clusters seem to be either insoluble or unstable in all solvents investigated. 相似文献
18.
The reactions of [(H 5C 6) 3P] 2ReH 6− with (CH 3CN) 3Cr(CO) 3, (diglyme)Mo(CO) 3 or (C 3H 7CN) 3W(CO) 3 led to the formation of [(H 5C 6) 3P] 2ReH 6M(CO) 3− (M = Cr, Mo, W) complexes. These have been characterized by IR and NMR spectroscopies, as well as elemental analyses. A single crystal X-ray diffraction study has also been carried out for the M = Cr complex as a K(18-crown-6) + salt. The complex crystallizes as a THF monosolvate in the monoclinic space group P2 1/ n with a = 22.323(6), B = 9.523(2), C = 27.502(5) Å, β = 104.98(2) 0 and V = 5648 Å 3 for Z = 4. The Re---Cr separation is 2.5745(12) Å, and the two phosphine ligands are oriented unsymmetrically. Although the hydride ligands were not found, the presence of three bridging hydrides and a dodecahedral coordination geometry about rhenium could be inferred. Low temperature 1H and 31P NMR spectroscopic studies did not reveal the low symmetry of the solid state structure. 相似文献
19.
The aqueous chemistry of vanadium with physiologically relevant ligands constitutes a subject of burgeoning research, extending from bacterial metalloenzymic functions to human-health physiology. Vanadium, in the form of VCl 3 and V 2O 5, reacted expediently with citric acid, in a 1:2 molar ratio in water at pH4, and, in the presence of various cations, afforded crystalline materials bearing the general formula (Cat) 2[V 2O 4(C 6H 6O 7) 2]· nH 2O (A) (Cat +=Na +, NH 4 +, n=2; Me 4N +, K +, n=4). Exploration of the reactivity of A toward H 2O 2 yielded the peroxo-containing complexes (Cat) 2[V 2O 2(O 2) 2(C 6H 6O 7) 2]·2H 2O (B) (Cat +=K +, NH 4 +). Both classes of compounds were characterized analytically and spectroscopically. The X-ray structures of complexes A and B emphasize the exceptional stability of the dimeric rhombic unit V V 2O 2, which is retained upon H 2O 2 reaction, and the preserved mode of coordination of the citrate ligand as a doubly deprotonated moiety. In these complexes, typical six and eight coordination numbers were observed for the Na + and K + counter-ions, respectively. The variety of synthetic approaches leading to A, along with the stepwise and direct assembly and isolation of peroxo-compounds (B), denotes the significance of reaction pathways and intermediates in vanadium(III–V)–citrate synthetic chemistry. Hence, a systematic investigation of reactivity modes in aqueous vanadium–citrate systems emerges as a crucial tool for the establishment of chemical interconnectivity among low MW complex species, potentially participating in the intricate biodistribution of that metal ion in biological fluids. 相似文献
20.
The interaction of 1,3,5-triamino-1,3,5-trideoxy- cis-inositol (taci) and its N-methylated derivative 1,3,5-trideoxy-1,3,5-tris(dimethylamino)- cis-inositol (tdci) with the incomplete [Mo 3S 4] 4+ cube and the heterometallic [Mo 3S 4Cu] 4+ cube have been investigated by X-ray analysis. The crystal structures of [Mo 3S 4(taci+ rmC 3H 6O-H 2O) 3-4H]·2OH 2O (1a, rhombohedral, space group R32, A = 15.964(3), C = 40.59(1) Å, Z = 6), [Mo 3S 4(tdci) 3]Br 4·9.5EtOH·5H 2O (2a, triclinic, space group and [CuBrMo 3S 4(tdci) 3]Br 3·11 H 2O·EtOH (3a, monoclinic, space group P2,/ n, A = 14.887(3), B = 22.570(4), C = 21.974(5) Å, β = 98.54(2)°, Z = 4) revealed andN-N-O and an N-O-O coordination mode for taci and tdci, respectively. In 1a, taci is coordinated as an anion with deprotonated oxygen and nitrogen donors. In addition, the non-coordinating amino group reacted with one equivalent; of acetone, forming a Schiff base condensation product. For 2a, short Mo---O bonds and high p Ka values (compared to the aqua ion [Mo 3S 4(H 2O) 9] 4+) indicate the formation of a zwitterionic form of the tdci ligand with coordinated alkoxo groups and peripheral dimethylammonium groups. No significant differences were found for the structural properties of the Mo-tdci fragment in 2a and 3a. The coordination modes of taci and tdci, as observed in the solid state, are in agreement with the previously reported solution structures, established by NMR spectroscopy. They are attributed to the specific steric requirements of the two ligands and to a pronounced preference of the [Mo 3(μS) 3(μ 3S)] 4+ core to coordinate a nitrogen donor trans to μ 3S. 相似文献
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