A new generation of simple methylidene complexes has been prepared by reactions excited group 4−6 transition metal atoms with methyl halides and methane in solid argon. These CH2MHX (X = F, Cl, Br, I) CH2MH2 exhibit agostic bonding effects CH2 MH2 distortion. The proceed through the CH3MX insertion product followed α-H transfer on an potential energy surface. higher valence 6 metals sustains a second to form CH⋮MH2X (M Mo, W, X H, Br) methylidyne complexes, electron capture 5 Nb, Ta, gives...

Multiconfigurational quantum chemical methods (complete active space self-consistent field (CASSCF)/second-order perturbation theory (CASPT2)) have been used to study the agostic interaction between metal atom and H(C) in methylidene dihydride complexes H2MCH2, where M is a second row transition or actinide atoms Th U. The geometry of some these highly irregular due formation three center bond CH···M, electrons CH are delocalized onto empty half orbitals d- f-type on metal. No expected when...

Reactions of laser-ablated Pt atoms with CH4 and C2H6 produce CH3−PtH CH3CH2−PtH via oxidative C−H insertion show that the atom is an effective agent. The methylidene CH2═PtH2 also detected in methane experiments. Methyl fluoride, CH3F, on other hand, yields as well C−F products (CH2F−PtH CH3−PtF). CH3−PtF molecule exists photochemical equilibrium agostic CH2(H)−PtF isomer matrix, which unique for product, CH2═PtHF appears to participate rearrangement process. Moreover, CHF═PtHCl, CHF═PtHF,...

Reaction of laser-ablated Zr with CH4 (13CH4, CD4, and CH2D2) in excess neon during condensation at 5 K forms CH2ZrH2, the simplest alkylidene hydride complex, which is identified by infrared absorptions 1581.0, 1546.2, 757.0, 634.5 cm-1. Density functional theory electronic structure calculations using a large basis set polarization functions predict C1 symmetry agostic C−H- - -Zr bonding distance 2.300 Å. Identification CH2ZrH2 methylidene complex confirmed an excellent match calculated...

The photoreversible system of titanium methylidene and methyltitanium fluoride complexes has been formed by the reaction methyl laser-ablated Ti atoms isolated in a solid argon matrix. There are two major groups absorptions based on broad-band irradiation annealing behavior. increase group I is accompanied decrease II photolysis with UV light (240 nm < λ 380 nm) reverse visible (λ > 530 nm). CH2TiHF CH3−TiF responsible for these absorptions, photochemical interconversion occurs via α-H...

Laser-ablated titanium atoms react with methane to form the insertion product CH3TiH, which undergoes a reversible photochemical α-H transfer give methylidene complex CH2TiH2. On annealing second activation occurs produce (CH3)2TiH2. These molecules are identified from matrix infrared spectra by isotopic substitution (CH4, 13CH4, CD4, CH2D2) and comparison DFT frequency calculations. The computed planar structure for singlet ground-state CH2TiH2 shows CH2 distortion evidence agostic bonding...

Reaction of laser-ablated Mo atoms with CH(4) in excess argon forms the CH(3)-MoH, CH(2)=MoH(2), and CH(triple bond)MoH(3) molecules, which are identified from infrared spectra by isotopic substitution density functional theory frequency calculations. These simple methyl, methylidene, methylidyne molybdenum hydride molecules reversibly interconverted alpha-H transfers upon visible ultraviolet irradiations. The methylidene dihydride CH(2)=MoH(2) exhibits CH(2) MoH(2) distortion agostic...

Laser-ablated Cr, Mo, and W atoms react with di-, tri-, tetrahalomethanes to form XC⋮MX3 (M = W; X H, F, Cl) methylidyne molecules as major products. Dihalomethanes also give a minor yield of CH2MX2 methylidenes. The electronic state bonding changes in the CH2CrCl2, CH2CrFCl, CH2−CrF2 methylidene series, but Mo counterparts are calculated be triplet molecules. Identifications these new carbon−metal multiple bond species made through isotopic substitution (D, 13C) frequency calculations using...

Methane activation by laser-ablated, excited Group 11 metal atoms has been carried out, leading to generation of CH3–MH, CH3–M, and CH3–MH−, which are identified in the product infrared spectra on basis isotopic shifts correlation with DFT calculated frequencies. The products reveal that C–H insertion Au, Ag, Cu readily occurs, subsequent hydride-detachment or electron addition also follows. Each type similar photochemical properties regardless metal. computed energies facile hydride...

A photoreversible transition-metal methylidene system has been formed for the first time by reaction of methyl fluoride and laser-ablated Zr atoms, isolated in solid argon, investigated means infrared spectroscopy. Four different groups absorptions are characterized on basis behaviors upon broad-band irradiation sample annealing. Growth Group I is accompanied demise II with visible light (lambda > 530 nm) vice versa UV (240 < lambda 380 nm). The complex CH(2)=ZrHF responsible Groups either...

Methane activation reactions with group 3 metal atoms find that Sc, Y, and La are just as effective other early transition metals. Two primary products, CH3−MH CH2−MH2, identified for each from the matrix IR spectra. The single insertion product becomes more favorable increasing atomic mass of metal, opposite general trend observed systems. C−M bond lengths CH2−MH2 comparable to other, on basis electronic structure calculations, methylidene dihydride complex is symmetrical without agostic...

Laser-ablated hafnium atoms react with methane to form the methylidene complex CH2HfH2. The activation of a second CH4 molecule forms (CH3)2HfH2 particularly on sample annealing. These molecules are identified from infrared spectra by isotopic substitution (CH4, 13CH4, CD4, CH2D2) and comparison DFT frequency calculations. computed structure for singlet ground state CH2HfH2 shows CH2 HfH2 distortion evidence agostic bonding (angle H−C−Hf, 95.6°), which is more stable than symmetrical...

Laser-ablated W atoms react with CH4 in excess argon to form the CH3-WH, CH2=WH2, and CH[triple bond]WH3 molecules increasing yield this order of product stability. These are identified from matrix infrared spectra by isotopic substitution. Tungsten methylidene methylidyne hydride reversibly interconverted alpha-H transfers upon visible ultraviolet irradiations. Matrix DFT/B3LYP calculations show that is a stable molecule C3v symmetry, but other levels theory were required describe agostic...

Platinum atoms react with tetrachlorofluoromethanes upon laser-ablation and ultraviolet irradiation to form dihalomethylidene platinum dihalide complexes, CX(2)=PtX(2). These new molecules are identified from carbon-13 chlorine isotopic shifts, displacements in functional group frequencies as is replaced fluorine, comparison calculated by density theory. The PtC bond lengths here, 1.810 1.816 A, shorter than analogous measured earlier for Pt(II) carbene complexes (1.943-1.950 A). computed...

Reactions of laser-ablated Fe atoms with halomethanes and ethane have been investigated through matrix infrared spectra density functional calculations. Only insertion complexes are identified from reactions methyl fluoride ethane, parallel to the previously observed complex CH3−FeH photochemical reaction methane. However, also forms methylidene α-X migration in products di-, tri-, tetrahalomethanes. Calculated structures show no agostic distortion these complexes. an interesting elongation...

Rhenium carbyne complexes (HC identical with ReH 3, HC 2X, ReHX 2, [X = F, Cl, and Br] CH 3C 3) are produced by reactions of laser-ablated Re atoms methane, methyl halides, methylene ethane via oxidative C-H(X) insertion alpha-hydrogen migration in favor the carbon-metal triple bond. The stabilities relative to other possible products predicted DFT calculations. diagnostic methylidyne C-H stretching absorptions 3 its mono- dihalo derivatives observed on blue sides precursor bands, frequency...

Reactions of laser-ablated group 4 transition-metal atoms with acetylene have been carried out. The ethynyl metal hydrides (HC[triple bond]C-MH) and corresponding pi complexes (M-eta(2)-(C2H2)) are identified in the matrix infrared spectra. observed M-H C-M stretching absorptions show that oxidative C-H insertion readily occurs during codeposition photolysis afterward. from complex, on other hand, relatively weak original deposition spectrum but increase dramatically process annealing....

Simple Os carbyne complexes (HC≡OsH3, HC≡OsH2F, HC≡OsH2Cl, HC≡OsH2Br, and CH3C≡OsH3) are produced in reactions of laser-ablated atoms with small alkanes methyl halides via oxidative C−H insertion α-hydrogen migration. The diagnostic methylidyne C—H stretching absorptions HC≡OsH3 its halide derivatives observed about 200 cm−1 above the precursor bands, frequencies consistent s character hybridization bond. all have computed Cs structures, particularly CH3C≡OsH3 two equivalent shorter one...

A combined computational and experimental investigation provides evidence that excited thorium uranium atoms activate ethane to form the vinyl metal trihydride, metallacyclopropane dihydride, ethylidene dihydride for latter complex inserted ethyl hydride uranium. These products are trapped in solid argon identified through deuterium isotopic substitution vibrational frequencies calculated by density functional theory. Comparisons made with group 4 methane reaction products. Numerous...

Laser-ablated lanthanide metal atoms were condensed with CH(2)F(2) in excess argon at 6 K or neon 4 K. New infrared absorption bands are assigned to the oxidative addition product methylene difluorides on basis of deuterium substitution and vibrational frequency calculations density functional theory (DFT). Two dominant absorptions 500 cm(-1) region identified as lanthanide-fluoride stretching modes for this very strong absorption. The predominantly lanthanide-carbon follow a similar trend...

The η2-M(NC)-CH3, CH3-MNC, and CH2═M(H)NC complexes are observed in the matrix IR spectra from reactions of laser-ablated Th U atoms with acetonitrile. These actinide products line those group 4–6 metals acetonitrile, they again most stable steps previously proposed reaction path. N-coordination methylidyne (M←NCCH3 HCM(H)2NC) not probably due to their high energies. methylidenes show agostic distortion, nitrile π-complexes (η2-M(NC)-CH3) support strong back-donations π*-orbitals. NBO...

Laser ablated Ti, Zr, and Hf atoms react with phosphine during condensation in excess argon or neon at 4 K to form metal hydride insertion phosphides (H2P-MH) dihydride phosphinidenes (HP═MH2) phosphorus double bonds, which are characterized by their intense metal-hydride stretching frequencies. Both products formed spontaneously on annealing the solid matrix samples, suggests that both relaxed from initial higher energy M-PH3 intermediate complex, is not observed. B3LYP (DFT) calculations...

Methane activation by group 5 transition-metal atoms in excess argon and the matrix infrared spectra of reaction products have been investigated. Vanadium forms only monohydrido methyl complex (CH3-VH) with CH4 upon irradiation. On other hand, heavier metals form hydride methylidene dihydride complexes (CH3-MH CH2=MH2) along methylidyne trihydride anion (CHMH3-). The neutral products, particularly complex, increase markedly on irradiation whereas anionic product depletes UV or addition a...