THF Complexes Research Articles

Synthesis and Characterization of Ether Adducts of Thorium Tetrahydroborate Th(BH4)4 and Chemical Vapor Deposition of Thorium Boride Thin Films.

Treating ThCl4 with LiBH4 in various ethereal solvents affords the adducts Th(BH4)4(Et2O)2, Th(BH4)4(thf)2, and Th(BH4)4(dme) (thf = tetrahydrofuran and dme = 1,2-dimethoxyethane). The structures of these three compounds have been established by single-crystal X-ray diffraction: if the tetrahydroborate groups are considered as occupying one coordination site, the Et2O and thf complexes adopt trans-octahedral coordination geometries, whereas the dme complex exhibits a cis-octahedral structure. All four BH4- ligands in each compound are tridentate, rendering each thorium center 14-coordinate. The Th···B distances range from 2.64 to 2.67 Å, and the Th-O bond lengths are 2.47-2.52 Å. We propose that crystals of Th(BH4)4(thf)2 are isomorphous with those of U(BH4)4(thf)2, but owing to pseudosymmetry the latter was reported in a unit cell that was too small by a factor of 2. IR spectra and 1H and 11B NMR data are reported as well. All three adducts are volatile, subliming readily at 60 °C and 10-4 Torr, making them potentially useful as precursors for the chemical vapor deposition (CVD) of thin films of thorium boride. Passage of Th(BH4)4(Et2O)2 over glass, Si(100), and aluminum substrates heated to 350 °C yields amorphous films of approximate stoichiometry ThB2; films deposited from Th(BH4)4(thf)2 have stoichiometries closer to ThB2.5 and contain some oxygen. Auger, XPS, XRD, and SEM studies of these films are reported.

Triphosphines-containing ruthenium-acetato complexes: Synthesis, characterization, DFT, mer/fac isomerization and formic acid dehydrogenation

The triphosphines-containing ruthenium-acetato complexes [RuCl(κ2-OAc)(triphos)] (2) and the new analogue synthesized in our research group [RuCl(κ2-OAc)(etp)] (1) (triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane or etp = bis[2-(diphenylphosphino)ethyl]phenylphosphine) were evaluated as pre-catalyst for the dehydrogenation of formic acid (FA). Complex [RuCl(κ2-OAc)(etp)] (1) was fully characterized by 1H, 13C and 31P{1H} NMR, vibrational spectroscopy, elemental analysis and X-ray diffraction. The electrochemical behavior of 1 and 2 was checked by cyclic voltammetry. DFT calculations for 1, 2 and for the two isomers of 1 (1′ and 1”) were performed and discussed. Due to the linear nature of etp ligand, three isomeric forms for [RuCl(κ2-OAc)(etp)] (1′ and 1”) are possible and were observed. Both complexes were active for the decomposition of FA, in three solvents (MeOH, THF and iPrOH), at 80 °C, leading solely to formation of CO2 and H2. In THF both complexes achieved quantitative conversions (in times up to 125 min) and final TOF’s up to 833 h−1, for complex 1.

Metallogeny of the Zoujiashan uranium deposit in the Mesozoic Xiangshan volcanic-intrusive complex, southeast China: Insights from chemical compositions of hydrothermal apatite and metal elements of individual fluid inclusions

The Zoujiashan U deposit in the Mesozoic Xiangshan volcanic-intrusive complex is one of the largest volcanic-related type U deposits in China. Chemical composition of hydrothermal apatite and metal contents in individual fluid inclusions of quartz and fluorite are investigated in order to understand the precipitation mechanism of U and to further constrain the origin of U and ore-forming fluids of the Zoujiashan deposit. Illitization, hematitization, and U mineralization successively occurred within rhyolite and porphyritic lava. Three types of hydrothermal apatite are identified. Apatite Type 1 (Ap1) and apatite Type 2 (Ap2) are both euhedral-subhedral crystals found in hematitization zone, while only Ap2 shows evident irregular chemical zoning along its rims. Apatite Type 3 (Ap3) occurs as anhedral aggregates closely associated with U-minerals in U ore veins, implying synchronous precipitation of Ap3 and U ores. Comparable chemical compositions of Ap1 and cores of Ap2, including similar high Cl content, indicate both of them were precipitated from a Cl-rich fluid that induced hematitization. The elevated F contents of Ap3 and rims of Ap2 implies that a F-rich fluid was involved and altered Ap2 during the main stage of U deposition. Ap1 and cores of Ap2 have lower Mn contents than Ap3 and rims of Ap2, indicating an oxidized character for the Cl-rich fluid and a reducing character for the F-rich fluid.Metal contents of fluid inclusions in fluorite and quartz occurring in U ores suggest that two end-members of fluids, including a U-rich and a U-poor, were involved in the main stage of U mineralization. Mixing between these two fluids led to the deposition of U- and Th-minerals through oxidation-reduction reactions and destabilization of Th-F complexes, respectively. The U-rich fluid is depleted in Th and Sr compared with the U-poor fluid. Based on comparison of chemical compositions of apatite and fluid inclusions, we suggest that the Cl-rich fluid precipitating Ap1 and Ap2 corresponds to the U-rich end-member fluid, while the F-rich fluid precipitating Ap3 represents a mixture between the two end-members. The high U (12.7–58.5 ppm) in the U-rich end-member fluid is in agreement with a relatively high oxygen fugacity and a surface-derived origin. The U-poor end-member fluid has lower Rb/Cs than the U-rich end-member and the unaltered host rocks, indicating the U-poor fluid was derived from a mantle wedge that experienced addition of Cs by fluids generated from the devolatilization of the subducted paleo-Pacific slab.

Can THF hydrogen bond to glycine as strong as water?

Hydrogen bond complexation between glycine and THF and between glycine and water involving four lowest-energy glycine conformers have been studied. The complexes have been investigated in the gas phase at the ab initio molecular orbital theory (MP2) with aug-cc-pVDZ basis set and density functional theory (B3LYP) with aug-cc-pVTZ basis set. Bader’s theory of atoms in molecules (AIM), natural bond orbital (NBO), and symmetry adapted perturbation theory (SAPT) analyses are employed to elucidate the interaction characteristics in the complexes. The premise that the hydrogen bond donor ability of the O–H group of the carboxyl group dominates the interaction between glycine and THF and between glycine and water is confirmed. It is found that in comparison with water, THF binds more strongly to glycine. The quantum studies indicate that contribution of N–H···O and C–H···O hydrogen bonds in the complexes, although lower in magnitude to O–H···O interactions, play an important role in the stability of complexes. The blue and red shifts in the stretching frequencies of the hydrogen bond donors X–H (X = O, C, N) have also been related to stabilization energies. Decomposition of the stabilization energy based on the SAPT method clearly indicates the dominant role of the electrostatic interactions in all the complexes under study; however, induction and dispersion interaction terms are relatively higher in glycine–THF complexes.

Hydrogenation of imines catalyzed by trisphosphine-substituted molybdenum and tungsten nitrosyl hydrides and co-catalytic acid.

Hydride complexes Mo,W(CO)(NO)H(mer-etp(i)p) (iPr2PCH2CH2)2PPh=etp(i)p) (2 a,b(syn), syn and anti of NO and Ph(etp(i)p) orientions) were prepared and probed in imine hydrogenations together with co-catalytic [H(Et2O)2][B(C6F5)4] (140 °C, 60 bar H2). 2 a,b(syn) were obtained via reduction of syn/anti-Mo,W(NO)Cl3(mer-etp(i)p) and syn,anti-Mo,W(NO)(CO)Cl(mer-etp(i)p). [H(Et2O)2][B(C6F5)4] in THF converted the hydrides into THF complexes syn-[Mo,W(NO)(CO)(etp(i)p)(THF)][B(C6F5)4]. Combinations of the p-substituents of aryl imines p-R(1)C6H4CH=N-p-C6H4R(2) (R(1),R(2)=H,F,Cl,OMe,α-Np) were hydrogenated to amines (maximum initial TOFs of 1960 h(-1) (2 a(syn)) and 740 h(-1) (2 b(syn)) for N-(4-methoxybenzylidene)aniline). An 'ionic hydrogenation' mechanism based on linear Hammett plots (ρ=-10.5, p-substitution on the C-side and ρ=0.86, p-substitution on the N-side), iminium intermediates, linear P(H2) dependence, and DKIE=1.38 is proposed. Heterolytic splitting of H2 followed by 'proton before hydride' transfers are the steps in the ionic mechanism where H2 ligand addition is rate limiting.

Rapid and Efficient Procedure for the Synthesis of Group 3 Metal Tris[bis(dimethylsilyl)amide] THF Complexes

An expedient method for the synthesis of group 3 metal tris[bis(dimethylsilyl)amide] THF complexes from the corresponding tris[bis(trimethylsilyl)amide]s is described. Advantages of this technique over previous methods include short reaction times, simple workup, and near-quantitative yields that require only commercially available reagents.

Thermal analysis and phase behavior of poly(styrene-co-4-vinylpyridine)/poly(styrene-co-acrylic acid) mixtures

Due to the presence of specific interactions that occurred between poly(styrene-co-4-vinylpyridine) and poly(styrene-co-acrylic acid), novel materials as blends or interpolymer complexes of enhanced thermal stability were elaborated by simply mixing these copolymers and varying their initial blend composition in tetrahydrofuran or butan-2-one.The observed glass transition temperature-composition behaviors of miscible blends of these copolymers, cast from THF or interpolymer complexes obtained in butan-2-one, were analyzed according to Kwei and BCKV approaches that described well the experimental data of these systems, though better fits were obtained with the BCKV approach. A good fit of the S-shaped Tg-composition behavior, was obtained using Brostow's approach only.The presence of specific interactions within these materials was evidenced by FTIR spectroscopy. The thermal stability of all elaborated materials was analyzed by thermogravimetry.

The Features of Interaction of Bis(4, 6‐di‐tert‐butyl‐N‐(2, 6‐diisopropylphenyl)‐o‐amidophenolato)tin(IV) with Bromine and Iodine

AbstractThe oxidation of tin(IV) bis‐amidophenolate (APiPr)2Sn·THF (I) by bromine and iodine leads to the formation of monoradical mixed‐ligand complexes (APiPr)(ISQiPr)SnBr·THF (II) and (APiPr)(ISQiPr)SnI·THF (III) or diradical complexes (ISQiPr)2SnBr2 (IV) and (ISQiPr)2SnI2 (V), respectively [APiPr = dianion 4, 6‐di‐tert‐butyl‐N‐(2, 6‐diisopropylphenyl)‐o‐amidophenolate; ISQiPr = radical‐anion 4, 6‐di‐tert‐butyl‐N‐(2, 6‐diisopropylphenyl)‐o‐iminobenzosemiquinone], depending on the molar ratio of reagents (2:1 or 1:1). According to EPR data for compounds II and III, the unpaired electron is delocalized between both organic ligands. The EPR spectrum of IV in toluene matrix at 130 K is typical for diradical species with S = 1 with parameters D = 530 G, E = 105 G. The mixed‐ligand complexes II and III are unstable and undergo to symmetrization leading to formation of IV or V. The molecular structures of IV and V are determined by X‐ray analysis.

Lanthanide N,N-Dimethylaminodiboranates as a New Class of Highly Volatile Chemical Vapor Deposition Precursors

New lanthanide N,N-dimethylaminodiboranate (DMADB) complexes of stoichiometry Ln(H(3)BNMe(2)BH(3))(3) and Ln(H(3)BNMe(2)BH(3))(3)(thf) have been prepared, where Ln = yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, and lutetium, except that isolation of the desolvated complexes proved difficult for Eu and Yb. The tetrahydrofuran (thf) complexes are all monomeric, and most of them adopt 13-coordinate structures in which each DMADB group chelates to the metal center by means of four B-H···Ln bridges (each BH(3) group is κ(2)H; i.e., forms two B-H···Ln interactions). For the smallest three lanthanides, Tm, Yb, and Lu, the metal center is 12 coordinate because one of the DMADB groups chelates to the metal center by means of only three B-H···Ln bridges. The structures of the base-free Ln(H(3)BNMe(2)BH(3))(3) complexes are highly dependent on the size of the lanthanide ions: as the ionic radius decreases, the coordination number decreases from 14 (Pr) to 13 (Sm) to 12 (Dy, Y, Er). The 14-coordinate complexes are polymeric: each metal center is bound to two chelating DMADB ligands and to two "ends" of two ligands that bridge in a Ln(κ(3)H-H(3)BNMe(2)BH(3)-κ(3)H)Ln fashion. In the 13-coordinate complexes, all three DMADB ligands are chelating, but the metal atom is also coordinated to one hydrogen atom from an adjacent molecule. The 12-coordinate complexes adopt a dinuclear structure in which each metal center is bound to two chelating DMADB ligands and to two ends of two ligands that bridge in a Ln(κ(2)H-H(3)BNMe(2)BH(3)-κ(2)H)Ln fashion. The complexes react with water, and the partial hydrolysis product [La(H(3)BNMe(2)BH(3))(2)(OH)](4) adopts a structure in which the lanthanum and oxygen atoms form a distorted cube; each lanthanum atom is connected to three bridging hydroxyl groups and to two chelating DMADB ligands. One B-H bond of each chelating DMADB ligand forms a bridge to an adjacent metal center. Field ionization MS data, melting and decomposition points, thermogravimetric data, and NMR data, including an analysis of the paramagnetic lanthanide induced shifts (LIS), are reported for all of the complexes. The Ln(H(3)BNMe(2)BH(3))(3) compounds, which are highly volatile and sublime at temperatures as low as 65 °C in vacuum, are suitable for use as chemical vapor deposition (CVD) and atomic layer deposition (ALD) precursors to thin films.

Lanthanoid and Alkaline Earth Complexes Involving New Substituted Pyrazolates

From the pyrazoles 3,5-di-(2′-furanyl)pyrazole (fu2pzH), 3-phenyl-5-(2′-thienyl)pyrazole (PhtpzH) and 3-(2′-furanyl)-5-(2′′-naphthyl)pyrazole (funappzH), a range of alkaline earth and lanthanoid pyrazolate complexes has been prepared by redox transmetallation/protolysis reactions between free metals, Hg(C6F5)2 and the pyrazoles, by reaction of I2‐activated metals with the pyrazoles, and in one case by a similar reaction of unactivated metal, in the donor solvents tetrahydrofuran (thf) and 1,2-dimethoxyethane (dme). Thus the divalent [Ca(Phtpz)2(thf)4], [Ba(Phtpz)2(thf)4] and [Ca(funappz)2(thf)4]·(thf) complexes, the heteroleptic [Yb(Phtpz)I(thf)4] and the trivalent [La(fu2pz)3(thf)3]·2thf complex have been prepared and structurally characterized, as well as the dme complexes [Yb(Phtpz)2(dme)2] and [Eu(Phtpz)3(dme)2]. Highlights include the first trans-[LnII(pz)I(thf)4] complex, a rare transoid [Ln(pz)2(dme)2] complex and a complex with both chelating and unidentate dme. In all cases, the Phtpz complexes exhibit pronounced positional disorder of the 2-thienyl and phenyl groups in the solid state, as do the two polymorphs of the parent pyrazole.

Low-coordinate rare-earth complexes of the asymmetric 2,4-di-tert-butylphenolate ligand prepared by redox transmetallation/protolysis reactions, and their reactivity towards ring-opening polymerisation

New trivalent lanthanoid aryloxide complexes have been prepared by redox transmetallation/protolysis (rtp) reactions using 2,4-di-tert-butylphenol (dbpH). Mononuclear octahedral complexes from tetrahydrofuran (thf) were of the type [Ln(dbp)(3)(thf)(3)] (Ln = La (1), Pr (2), Nd (3), Gd (4), Er (5)). The lanthanoid contraction results in the rather subtle change in stereochemistry from meridional (La, Pr, Nd, Gd) to facial (Er). An analogous reaction with neodymium in dimethoxyethane (dme), resulted in the isolation of the seven coordinate [Nd(dbp)(3)(dme)(2)] (6), and this is comparable with the thf complexes in terms of steric crowding. Dinuclear complexes of the type [Ln(2)(dbp)(6)(thf)(2)], (Ln = Nd (7), Er (8)) were obtained when 1 and 5 were recrystallised from toluene. These dimeric complexes contain two bridging and four terminal phenolates, as well as a single coordinated molecule of thf at each metal. A similar structural motif was observed for the products when the reaction was performed in diethyl ether, and in the absence of a solvent, yielding [Nd(2)(dbp)(6)(Et(2)O)(2)] (9) and [Nd(2)(dbp)(6)(dbpH)(2)] (10) respectively. Complexes 3 and 4 alone were efficient but poorly-controlled initiators for the ROP of rac-lactide, but with an excess of BnOH as a co-initiator they showed features consistent with immortal polymerisation. Use of BnNH(2) led to well-controlled, amine-initiated immortal ROP of rac-lactide, only the second report of this type of process for a group 3 or lanthanoid system.

Synthesis and Molecular Structures of Phenylamides of Magnesium, Calcium, Strontium, and Barium − From Molecular to Polymeric Structures

Several preparative procedures for the synthesis of the THF complexes of the alkaline earth metal bis(phenylamides) of Mg (1), Ca (2), Sr (3), and Ba (4) are presented such as metalation of aniline with strontium and barium, metathesis reactions of MI2 with KN(H)Ph, and metalation of aniline with arylcalcium compounds or dialkylmagnesium. The THF content of these compounds is rather low and an increasing aggregation is observed with the size of the metal atom. Thus, tetrameric [(THF)2Ca{mu-N(H)Ph}2]4 (2) and polymeric [(THF)2Sr{mu-N(H)Ph}2]infinity and {[(THF)2Ba{mu-N(H)Ph}2]2[(THF)Ba{mu-N(H)Ph}2]2}infinity show six-coordinate metal atoms with increasing interactions to the pi systems of the phenyl groups with increasing the radius of the alkaline earth metal atom.

Reinvestigation of the reaction of strontium and barium with iodobenzene and molecular structure of the heavy Grignard reagent [((thf) 2BaPh 2) 4 · (thf)BaO] with an oxygen-centered square Ba 5 pyramid

The direct synthesis of activated strontium and barium with iodobenzene in THF yields the corresponding THF complexes of phenylstrontium and phenylbarium iodide, respectively, which dismutate into the homoleptic compounds MPh 2 and MI 2. Already at low temperatures ether cleavage reactions take place and from this reaction, the oxygen-centered cage [((thf) 2BaPh 2) 4 · (thf)BaO] was isolated and its molecular structure determined.

Pseudooctahedral complexes of vanadium(III): electronic structure investigation by magnetic and electronic spectroscopy.

A variety of physical methods has been used to probe the non-Kramers, S = 1, V(III) ion in two types of pseudooctahedral complexes: V(acac)(3), where acac = anion of 2,4-pentanedione, and VX(3)(thf)(3), where thf = tetrahydrofuran and X = Cl and Br. These methods include tunable frequency and high-field electron paramagnetic resonance (HFEPR) spectroscopy (using frequencies of approximately 95-700 GHz and fields up to 25 T) in conjunction with electronic absorption, magnetic circular dichroism (MCD), and variable-temperature variable-field MCD (VTVH-MCD) spectroscopies. Variable-temperature magnetic susceptibility and field-dependent magnetization measurements were also performed. All measurements were conducted on complexes in the solid state (powder or mull samples). The field versus sub-THz wave quantum energy dependence of observed HFEPR resonances yielded the following spin Hamiltonian parameters for V(acac)(3): D = +7.470(1) cm(-1); E = +1.916(1) cm(-1); g(x) = 1.833(4); g(y) = 1.72(2); g(z) = 2.03(2). For VCl(3)(thf)(3), HFEPR detected a single zero-field transition at 15.8 cm(-1) (474 GHz), which was insufficient to determine the complete set of spin Hamiltonian parameters. For VBr(3)(thf)(3), however, a particularly rich data set was obtained using tunable-frequency HFEPR, and analysis of this data set gave the folowing: D = -16.162(6) cm(-1); E = -3.694(4) cm(-1); g(x) = 1.86(1); g(y) = 1.90(1); g(z) = 1.710(4). Analysis of the VTVH-MCD data gave spin Hamiltonian parameters in good agreement with those determined by HFEPR for both V(acac)(3) and VBr(3)(thf)(3) and in rough agreement with the estimate for VCl(3)(thf)(3) (D approximately 10 cm(-1), |E/D| approximately 0.18), together with the finding that the value of D is negative for both thf complexes. The electronic structures of these V(III) complexes are discussed in terms of their molecular structures and the electronic transitions observed by electronic absorption and MCD spectroscopies.

Trivalent lanthanide compounds with fluorinated thiolate ligands: Ln-F dative interactions vary with Ln and solvent.

The fluorinated tris-thiolate compounds Ln(SC(6)F(5))(3) can be isolated as THF, pyridine, or DME coordination complexes. In THF, the larger Ce forms dimeric [(THF)(3)Ce(SC(6)F(5))(3)](2) (1) with bridging thiolate ligands, while the smaller lanthanides (Ln = Ho (2), Er (3)) form monometallic (THF)(3)Ln(SC(6)F(5))(3) compounds. There is a tendency for fluoride to coordinate to Ln throughout the lanthanide series (Ce-Er). The cerium compound 1 contains a pair of bridging thiolates connecting two eight-coordinate Ce(III) ions. Of the two terminal thiolates, only one exhibits a distinct Ce-F bond. In contrast, the Ho derivative (THF)(3)Ho(SC(6)F(5))(3) is a molecular compound in the solid state, with two monodentate thiolates and one thiolate that again coordinates through both S and F atoms. Incorporation of a stronger Lewis base reduces but does not necessarily eliminate the tendency to form Ln-F bonds. Structural characterization of the eight-coordinate (pyridine)(4)Sm(SC(6)F(5))(3) (4) reveals a single, clearly defined Ln-F interaction, while in (pyridine)(4)Yb(SC(6)F(5))(3) (5) there are no Yb-F bonds. In the structure of (DME)(2)Er(SC(6)F(5))(3) (6) the DME ligands completely displace F from the Er coordination sphere.

Complexes of heteroscorpionate trispyrazolylborate anionic ligands: Part II. The X-ray crystallographic and 1H NMR studies on thiocyanato[hydrobis(3-phenylpyrazolyl)(3,5-di- tert-butylpyrazolyl)borato]cobalt(II) and thiocyanato[hydrobis(3-phenyl,5-methylpyrazolyl)(3-methyl,5-phenylylpyrazolyl)borato]cobalt(II) complexes

Synthesis of two heteroscorpionate tris(pyrazolyl)borate anionic ligands (Tp′) was described; the sterically demanding [hydrobis(3-phenylpyrazolyl)(3,5-di- tert-butylpyrazolyl)borate] − obtained by condensation of KBH 4 with 3-phenylpyrazole and 3,5-di- tert-butylpyrazole and [hydrobis(3-phenyl,5-methylpyrazolyl)(3-methyl, 5-phenylylpyrazolyl)borate] − formed in similar reaction between NaBH 4 and 3(5)-methyl,5(3)-phenylpyrazole. The ligands were converted into tetracoordinate [HB(3,5-di- tBupz)(3-Phpz) 2]Co(NCS) and pentacoordinate [HB(3-Me,5-Phpz)(3-Ph,5-Mepz) 2]Co(NCS)(THF)·THF complexes, which molecular structures were determined by X-ray crystallographic method. The reactivity of high-spin cobalt(II) complexes was studied by the 1H NMR spectroscopy in solution. The reactive [HB(3-Me,5-Phpz)(3-Ph,5-Mepz) 2]Co(NCS) complex readily underwent conversions into pentacoordinate [HB(3-Me,5-Phpz)(3-Ph,5-Mepz) 2]Co(OOCCH(OH)CH 3) and hexacoordinate [HB(3-Me,5-Phpz)(3-Ph,5-Mepz) 2]Co[HB(pz) 3] complexes.

Reaction of Grignard Compounds with 4-Chloro-2-methyl-3-butyn-2-ol in Diethyl Ether Equivalents.

Reactions of RMgX·THF complexes with 4-chloro-2-methyl-3-butyn-2-ol in aromatic hydrocarbons were studied. The complexes formed by arylmagnesium halides require the presence of anisole for the reaction to occur. 4-Chloro-2-methyl-3-butyn-2-ol can be synthesized by reaction of 2-methyl-3-butyn-2-ol with sodium hypochloride in the two-phase system water-benzene.

Photolytic Ring-Opening Polymerization of Phosphorus-Bridged [1]Ferrocenophane Coordinating to an Organometallic Fragment

Manganese and tungsten complexes bearing a strained phosphorus-bridged [1]ferrocenophane were prepared by reaction of their appropriate THF complexes with (1,1‘-ferrocenediyl)phenylphosphine (1). The monomer complexes [Mn(η5-C5H4R)(CO)2(1)] (R = Me, H) and [W(CO)5(1)] thus obtained were found to undergo a ring-opening polymerization (ROP) upon irradiation with UV−vis light for 10 min in THF or acetonitrile. Because they polymerize in the same manner as the free ligand 1, with the metallic fragment intact, the photopolymerization reaction is considered applicable to a variety of organometallic fragments bearing 1 as a ligand.

Organotransition metal modified sugars 14. Activation of sugar-based alkynols at a metal carbonyl template: a metal vinyl carbene functionalization of carbohydrates and non-conventional route to organometallic disaccharides

Abstract Chromium and tungsten alkenyl carbene modified carbohydrates have been synthesized by activation of sugar-based propargylic alcohols with pentacarbonyl–THF complexes followed by addition of methanol. This method has also been exploited in disaccharide synthesis. Higher functionalized carbohydrate skeletons are accessible by Diels–Alder and Michael-type addition reactions.

Synthesis and Solution Behavior of (Tetraisopropylcyclopentadienyl)calcium Acetylide Complexes. Molecular Structure of {[(C3H7)4C5H]Ca(μ-C⋮CPh)(thf)}2

The reaction of (Cp4i)Ca[N(SiMe3)2](thf) (Cp4i = (i-Pr)4C5H) (1) with several terminal alkynes HC⋮CR in either toluene or hexanes produces the corresponding calcium acetylide complexes (Cp4i)Ca[C⋮CR](thf) (2) (R = Ph (2a), Fc (2b), SiMe3 (2c), Si(i-Pr)3 (2d), SiPh3 (2e)) in good yield. The (Cp4i)Ca[C⋮CR](thf) complexes do not react with excess alkyne. (Cp4i)Ca[C⋮CPh](thf) crystallizes from toluene as an acetylide-bridged dimer, [(Cp4i)Ca[μ-C⋮CPh)(thf)]2·C7H8, with a pentahapto [Cp4i]- ligand and a terminal THF ligand on each calcium. The calcium−carbon bond distances for the bridging [C⋮CPh]- ligands are 2.551(8) and 2.521(7) A; the average Ca−C(ring) bond distance is 2.713(15) A. As with other (Cp4i)CaX(thf)n complexes, the (Cp4i)Ca[C⋮CR](thf) compounds are kinetically stabilized against disproportionation in the solid state and in THF solution; (Cp4i)Ca[C⋮CSi(i-Pr)3](thf) is also indefinitely stable in aromatic solutions. Slow but substantial dissociation of the THF ligand in (Cp4i)Ca[C⋮CR](thf) (R = Ph...