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1.
A new synthesis of Mo2(CO)8(-PPh2)2 and W2(CO)8(-PPh2)2 by the reaction of molybdenum and tungsten hexacarbonyls with a tetraazamacrocyclic ligand containing —CH2PPh2 side chains, comprising cleavage of the phosphorus-methylene bond has been performed. The complexes have been investigated by magnetic and spectroscopic measurements and by single-crystal structure analyses. The structural characterization of a new polymorph of Mo2(CO)8(-PPh2)2 has been described.  相似文献   

2.
Mercury(II) halide complexes [HgX2(P(2-py)3)2] (X?=?Br (1), Cl (2)) and [HgX2(PPh(2-py)2)2] (X?=?Br (3), Cl (4)) containing P(2-py)3 and PPh(2-py)2 ligands (P(2-py)3 is tris(2-pyridyl)phosphine and PPh(2-py)2 is bis(2-pyridyl)phenylphosphine) were synthesized in nearly quantitative yield by reaction of corresponding mercury(II) halide and appropriate ligands. The synthesized complexes are fully characterized by elemental analysis, melting point determination, IR, 1H, and 31P-NMR spectroscopies. Furthermore, the crystal structure of [HgBr2(PPh(2-py)2)2] determined by X-ray diffraction is also reported.  相似文献   

3.
《Polyhedron》1999,18(26):3497-3504
The addition of pinacol to mixtures of titanium and cerium isopropoxides as well as the use of insoluble titanium and cerium pinacolate synthons was investigated as a route to M-Ce (M=Ti, Nb) species. Pinacol was able to promote the formation of mixed-metal species and the first Ce-Ti and Ce-Nb species namely Ce2Ti(pin)2(OPri)8 and [M2Ce23-O)2(μ,η2pin)4(OPri)6Hx] [M=Ti, x=2; M=Nb, x=0; pin=OCMe2-COMe2] were isolated and characterized by FT-IR and 1H NMR. The latter were also characterized by X-Ray diffraction. Their structures are based on a rhombus compressed along the M⋯M direction with 6-coordinated metals. The pinacolate moieties act as bridging-chelating ligands. The metal–oxygen bond lengths vary according to M–O(pin)<M-μ3–O<Mμ–O(pin)<Ce–OPri<Ce–μ3O.  相似文献   

4.
Well-dispersed roughly spherical nano-objects of the molecule-based superconductor κ-(BEDT-TTF)2Cu(NCS)2 have been prepared in an organic solution by using an easy synthetic route. Long alkyl-chain aconitate esters have been used as growth controlling agents. Nano-objects exhibiting sizes in the 35–120 nm range are made of aggregated individual smaller nanoparticles ranging from 3 to 10 nm. Nanoparticle powders have been studied by X-ray diffraction, high resolution electron microscopy and atomic force microscopy in the conductivity mode.  相似文献   

5.
The dependence of the properties of mixed ligand [Ni(II)(2)L(μ-O(2)CR)](+) complexes (where L(2-) represents a 24-membered macrocyclic hexaamine-dithiophenolato ligand) on the basicity of the carboxylato coligands has been examined. For this purpose 19 different [Ni(II)(2)L(μ-O(2)CR)](+) complexes (2-20) incorporating carboxylates with pK(b) values in the range 9 to 14 have been prepared by the reaction of [Ni(II)(2)L(μ-Cl)](+) (1) and the respective sodium or triethylammonium carboxylates. The resulting carboxylato complexes, isolated as ClO(4)(-) or BPh(4)(-) salts, have been fully characterized by elemental analyses, IR, UV/vis spectroscopy, and X-ray crystallography. The possibility of accessing the [Ni(II)(2)L(μ-O(2)CR)](+) complexes by carboxylate exchange reactions has also been examined. The main findings are as follows: (i) Substitution reactions between 1 and NaO(2)CR are not affected by the basicity or the steric hindrance of the carboxylate. (ii) Complexes 2-20 form an isostructural series of bisoctahedral [Ni(II)(2)L(μ-O(2)CR)](+) compounds with a N(3)Ni(μ-SR)(2)(μ-O(2)CR)NiN(3) core. (iii) They are readily identified by their ν(as)(CO) and ν(s)(CO) stretching vibration bands in the ranges 1684-1576 cm(-1) and 1428-1348 cm(-1), respectively. (iv) The spin-allowed (3)A(2g) → (3)T(2g) (ν(1)) transition of the NiOS(2)N(3) chromophore is steadily red-shifted by about 7.5 nm per pK(b) unit with increasing pK(b) of the carboxylate ion. (v) The less basic the carboxylate ion, the more stable the complex. The stability difference across the series, estimated from the difference of the individual ligand field stabilization energies (LFSE), amounts to about 4.2 kJ/mol [Δ(LFSE)(2,18)]. (vi) The "second-sphere stabilization" of the nickel complexes is not reflected in the electronic absorption spectra, as these forces are aligned perpendicularly to the Ni-O bonds. (vii) Coordination of a basic carboxylate donor to the [Ni(II)(2)L](2+) fragment weakens its Ni-N and Ni-S bonds. This bond weakening is reflected in small but significant bond length changes. (viii) The [Ni(II)(2)L(μ-O(2)CR)](+) complexes are relatively inert to carboxylate exchange reactions, except for the formato complex [Ni(II)(2)L(μ-O(2)CH)](+) (8), which reacts with both more and less basic carboxylato ligands.  相似文献   

6.
Tetrapalladium clusters containing dppa or dppa and dppm bridging ligands were prepared by condensation of dinuclear units. Reaction of [Pd2Cl2(-dppa)2] with [Cu(PPh3)]PF6 (generated in situ in THF) yielded [Pd4(-Cl)2(-dppa)4] (PF6)2 (4) in a virtually quantitative yield but [Pd4(-Cl)2(-dppm)2(-dppa)2] (PF6)2 (6) was best prepared in CH2Cl2 from [Pd2Cl2(-dppm)2] and [Pd2(MeCN)2(-dppa)2](PF6)2 (2). The structure of 6·2(CH3)2CO·2H2O was determined by X-ray diffraction. It consists of a planar, centrosymmetric 10-membered ring structure. The four bridging diphosphine ligands are of two types: two dppa ligands support the Pd Pd bonds [2.6055(4) Å], whereas the two dppm ligands bridge between two palladium atoms separated by 3.722(4) Å, which are also bridged by a chloride ligand.  相似文献   

7.
Thioselenohalide complexes Mo2(μ-S2)2Cl6(SeCl2)2 (I), Mo2(μ-S2)2Br6(SeBr2)2 (II), and W2(μ-S2)2Br6(SeBr2)2 (III) were synthesized by the reactions of corresponding metal halides or carbonyls or molybdenum metal with excesses of S2 X 2+Se2 X 2 mixtures. The complex W2(μ-S2)2Cl6(SeCl2)2 (IV) was obtained by an exchange reaction between (III) and excess of Se2Cl2. Coordination of the neutral SeX 2 ligands to thiohalidesM 2(μ-S2)2 X 6 results in higher thermal stability, and suggests the possibility to synthesize SeX 2 complexes of the unstable parent tungsten thiohalides. An unusual oxidative addition reaction of (I) was detected: {fx27-1} Both (I) and (IV) were characterized by X-ray crystal structure analysis. They are isostructural and form discrete molecules. Bridging S 2 2? ligands are coordinated perpendicularly to the metal-metal bond;d(M?M)=2.8066 Å and 2.793 Å for I and IV, respectively. Nonequivalence of chlorine atoms which are bound to the metal atom, relate to nonequivalence of halogen atoms in the complexesM 2(μ?S2)2 X 8 2? . Chlorine atomstrans to SeCl2 ligands form short bonds with the metal; the corresponding35Cl NQR frequency is increased. The selenium dichloride ligand is ambidentate. The selenium atom binds as a donor to the metal and as an acceptor to two chlorine atoms which are also bound covalently to the same metal atom.  相似文献   

8.
Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.  相似文献   

9.
The behavior of [Fe(2) (CO)(4) (κ(2) -PNP(R) )(μ-pdt)] (PNP(R) =(Ph(2) PCH(2) )(2) NR, R=Me (1), Ph (2); pdt=S(CH(2) )(3) S) in the presence of acids is investigated experimentally and theoretically (using density functional theory) in order to determine the mechanisms of the proton reduction steps supported by these complexes, and to assess the role of the PNP(R) appended base in these processes for different redox states of the metal centers. The nature of the R substituent of the nitrogen base does not substantially affect the course of the protonation of the neutral complex by CF(3) SO(3) H or CH(3) SO(3) H; the cation with a bridging hydride ligand, 1?μH(+) (R=Me) or 2?μH(+) (R=Ph) is obtained rapidly. Only 1?μH(+) can be protonated at the nitrogen atom of the PNP chelate by HBF(4) ?Et(2) O or CF(3) SO(3) H, which results in a positive shift of the proton reduction by approximately 0.15?V. The theoretical study demonstrates that in this process, dihydrogen can be released from a η(2) -H(2) species in the Fe(I) Fe(II) state. When R=Ph, the bridging hydride cation 2?μH(+) cannot be protonated at the amine function by HBF(4) ?Et(2) O or CF(3) SO(3) H, and protonation at the N atom of the one-electron reduced analogue is also less favored than that of a S atom of the partially de-coordinated dithiolate bridge. In this situation, proton reduction occurs at the potential of the bridging hydride cation, 2?μH(+) . The rate constants of the overall proton reduction processes are small for both complexes 1 and 2 (k(obs) ≈4-7?s(-1) ) because of the slow intramolecular proton migration and H(2) release steps identified by the theoretical study.  相似文献   

10.

The novel transition metal saccharinate complexes of triethanolamine (TEA) have been synthesized and characterized by elemental analyses, magnetic moments, UV-Vis and IR spectra. Mn(II), Co(II), Ni(II), Zn(II), Cd(II) and Hg(II) form mononuclear complexes of [M(TEA)2](SAC)2, where SAC is the saccharinate ion, while the Cu(II) complex is dimeric. The TEA ligand acts as a tridentate N,O,O'-donor ligand and one ethanol group is not involved in coordination. The SAC ion does not coordinate to the metal ions and is present as the counter-ion in the Mn(II), Co(II), Ni(II), Zn(II), Cd(II) and Hg(II) complexes, but coordinates to the Cu(II) ion as a monodentate ligand. The crystal structures of the [Co(TEA)2](SAC)2 and [Cu2(μ-TEA)2(SAC)2]·2(CH3OH) complexes were determined by single crystal x-ray diffraction. The Co(II) ion has a distorted octahedral coordination by two TEA ligands. The Cu(II) complex crystallizes as a dimethanol solvate and has doubly alkoxo-bridged centrosymmetric dimeric molecules involving two tridentate triethanolaminate (deprotonated TEA) and two monodentate SAC ligands. The geometry of each Cu(II) ion is a distorted square pyramid. Both crystal structures are stabilized by hydrogen bonds to form a three-dimensional network.  相似文献   

11.
Abstarct The Cp)2Ni2Fe(CO)33-C2H2) and Cp)2Ni2Fe(CO)33-C2H2) (B) complexes have been synthesized and spectroscopically characterized. An accurate X-ray study and a comparison with related structures shows that the substituents of the alkyne ligands exert considerable effects on the bonding parameters.Crystal data for complex A, monoclinic space group P21/n,a = 8.418(1),b = 15.779(2),c = 14,493(1) Å, = 91.64(1)°,Z = 4, 2753 observed reflections,R = 0.022; crystal data for complex B, monoclinic space group C2/c,a = 16.2189(7),b = 7.445(3),c = 25.745(5) Å, = 103.74(3),Z=8, 1853 observed reflections,R = 0.051.  相似文献   

12.
The cluster anion [HRu3(CO)11]- (1) reacts with dicyclohexylphosphine in THF solution to give the anionic derivative [HRu3(CO)8(PCy2)2]- (2), protonation of which yields the neutral cluster H2Ru3(CO)8(PCy2)2 (3) and, in the presence of excess phosphine, HRu3(CO)7(PCy2)3 (4). In protic methanol as reaction medium, the reaction of 1 with HPCy2 gives directly the neutral complex H2Ru3(CO)6(PCy2)2(HPCy2)2 (5), together with 4. The single-crystal structure X-ray analysis of 3 shows a closed triangular Ru3 framework. The electron count is in accordance with the EAN rule, but the structure analysis of 5 reveals an open, almost linear Ru3 skeleton, which is electron-deficient with respect to the EAN rule.  相似文献   

13.
Photoelectron spectra of (CO2)nH2O? (2≤n≤8) and (CO2)n(H2O) 2 ? (1≤n≤2) were measured at the photon energy of 3.49 eV. The spectra show unresolved broad features, which are approximated by Gaussians. The vertical detachment energies (VDEs) were determined as a function of the cluster size. For (CO2)nH2O?, the VDE-n plots exhibit a sharp discontinuity between n=3 and 4; the VDE value is ≈3.5 eV at n=3, while it drops down abruptly to 2.59 eV at n=4. This discontinuity in VDE is ascribed to "core switching" at n=4; a C2O 4 ? dimer anion forms the core of (CO2)nH2O? for n≤3, while a monomer CO 2 ? is the core for n≥4. The (CO2)2(H2O) 2 ? ion has a VDE of 2.33 eV, indicating the presence of a CO 2 ? monomer core in the binary clusters containing two H2O molecules.  相似文献   

14.
Treatment of [Cy2P(CH2OH)2]Cl with MeNH2 in the presence of Et3N affords a high yield of the phosphine (Cy2PCH2)2NMe (1) (dcpam) which has been characterised by a single crystal X-ray structure. Treatment of [PtX2(COD)], (COD=cyclo-octa-1,5-diene, X= Cl or I) with (1) affords the platinum complexes [PtX2{(Cy2PCH2)2NMe}] (2). The chloride complex, (2a), reacts with t-BuNC to afford [PtCl(t-BuNC)-{(Cy2PCH2)2NMe}]Cl (3) and treatment of (2a) with 2-mercapto-1-methylimidazole affords [Pt{SCN(Me)CHCH=N(Me)}{Cy2PCH2)2NMe}]Cl (5). The reaction of (2a) with 2-acetamidoacrylic acid in the presence of silver(I) oxide affords the carbon bonded isomer (8a) only whereas a similar reaction using [PtCl2{Ph2P-(CH2)3PPh2}] affords a mixture of the azaallyl complex (7) and the carbon bonded isomer (8b) which can be separated by fractional crystallisation. The crystal structures of PtX2{(Cy2PCH2)2NMe}] are also reported.  相似文献   

15.
We report ab initio spectroscopic constants for the recently identified 1(5)Π(g) state of C(2) [P. Bornhauser, Y. Sych, G. Knopp, T. Gerber, and P. P. Radi, J. Chem. Phys. 134, 044302 (2011)]. The calculations are performed at the multi-reference configuration interaction level of theory with Davidson's correction using aug-cc-pV6Z basis sets and include core-valence correlation and relativistic corrections obtained with quadruple-zeta bases. Such treatment accurately reproduces the experimentally observed constants of the a(3)Π(u) and other states. Thus, we expect our calculated ω(e) value for the 1(5)Π(g) state to be within a few cm(-1), and rotational constants to be within 0.1% of experiment. Agreement with available spectroscopic data is excellent, with the calculations strongly suggesting that the 1(5)Π(g) vibrational level observed by Bornhauser et al. is v = 0.  相似文献   

16.
《Chemical physics letters》2002,350(5-6):650-655
The dissociative photodetachment dynamics of (SO2)3 were studied by photoelectron–photofragment coincidence spectroscopy at 258 nm. Correlation between the photoelectron and photofragment translational energies was observed as previously seen in the dimer system, implying the presence of a dimer core. The three-body dissociation dynamics of (SO2)3 after photodetachment are consistent with a dimer core solvated by a spectator SO2 molecule with a broad distribution in initial geometry.  相似文献   

17.
New 2-(2-di- and tetrahydrothienyl)benzimidazole compounds were prepared by the ring closure reactions of 2-(mercaptomethyl)benzimidazole1,2 (1) and α,β-unsaturated compounds activated with electron-withdrawing groups.  相似文献   

18.
IntroductionThecontroleddesignofsolid-statearchitecturesandcrystalengineeringhascurrentlybeenrecognizedasoneofthemostimportan...  相似文献   

19.
Several potentially tridentate pyridyl and phenolic Schiff bases (apRen and HhapRen, respectively) were derived from the condensation reactions of 2-acetylpyridine (ap) and 2'-hydroxyacetophenone (Hhap), respectively, with N-R-ethylenediamine (RNHCH(2)CH(2)NH(2), Ren; R = H, Me or Et) and complexed in situ with iron(II) or iron(III), as dictated by the nature of the ligand donor set, to generate the six-coordinate iron compounds [Fe(II)(apRen)(2)]X(2) (R = H, Me; X(-) = ClO(4)(-), BPh(4)(-), PF(6)(-)) and [Fe(III)(hapRen)(2)]X (R = Me, Et; X(-) = ClO(4)(-), BPh(4)(-)). Single-crystal X-ray analyses of [Fe(II)(apRen)(2)](ClO(4))(2) (R = H, Me) revealed a pseudo-octahedral geometry about the ferrous ion with the Fe(II)-N bond distances (1.896-2.041 ?) pointing to the (1)A(1) (d(π)(6)) ground state; the existence of this spin state was corroborated by magnetic susceptibility measurements and M?ssbauer spectroscopy. In contrast, the X-ray structure of the phenolate complex [Fe(III)(hapMen)(2)]ClO(4), determined at 100 K, demonstrated stabilization of the ferric state; the compression of the coordinate bonds at the metal center is in accord with the (2)T(2) (d(π)(5)) ground state. Magnetic susceptibility measurements along with EPR and M?ssbauer spectroscopic techniques have shown that the iron(III) complexes are spin-crossover (SCO) materials. The spin transition within the [Fe(III)N(4)O(2)](+) chromophore was modulated with alkyl substituents to afford two-step and one-step (6)A(1) ? (2)T(2) transformations in [Fe(III)(hapMen)(2)]ClO(4) and [Fe(III)(hapEen)(2)]ClO(4), respectively. Previously, none of the X-salRen- and X-sal(2)trien-based ferric spin-crossover compounds exhibited a stepwise transition. The optical spectra of the LS iron(II) and SCO iron(III) complexes display intense d(π) → p(π)* and p(π) → d(π) CT visible absorptions, respectively, which account for the spectacular color differences. All the complexes are redox-active; as expected, the one-electron oxidative process in the divalent compounds occurs at higher redox potentials than does the reverse process in the trivalent compounds. The cyclic voltammograms of the latter compounds reveal irreversible electrochemical generation of the phenoxyl radical. Finally, the H(2)salen-type quadridentate ketimine H(2)hapen complexed with an equivalent amount of iron(III) to afford the μ-oxo-monobridged dinuclear complex [{Fe(III)(hapen)}(2)(μ-O)] exhibiting a distorted square-pyramidal geometry at the metal centers and considerable antiferromagnetic coupling of spins (J ≈ -99 cm(-1)).  相似文献   

20.
The reaction of anhydrous SmCl3 with two equivalents of lithium N,N′-diisopropyl-N″-bis(trimethylsilyl)guanidinate in THF afforded the [{(Me3Si)2NC(NPri)2}2SmCl]2 complex (1) in 82% yield. Analogous reactions with YCl3 and GdCl3 produced the ate-complexes { (Me3Si)2NC(NPri)2}2Ln(µ-Cl)2Li(THF)2 (Ln = Y (2) and Gd (3)). The structures of complexes 1 and 2 were established by X-ray diffraction. The reaction of complex 1 with NaBH4 in hexane (20 °C) followed by treatment with dimethoxyethane yielded the unexpected product, { (Me3Si)2NC(NPri)2}Sm(µ3-BH4)2(DME) (5). X-ray diffraction study showed that both borohydride ligands in complex 5 are tridentate.  相似文献   

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