The fascinating story of olefin (or alkene) metathesis (eq
1) began almost five decades ago, when Anderson and
Merckling reported the first carbon-carbon double-bond
rearrangement reaction in the titanium-catalyzed polymerization of norbornene. Nine years later, Banks and Bailey reported “a new disproportionation reaction . . . in which olefins are converted to homologues of shorter and longer carbon chains...”. In 1967, Calderon and co-workers named this metal-catalyzed redistribution of carbon-carbon double bonds olefin metathesis, from the Greek word “μeτάθeση”, which means change of position. These contributions have since served as the foundation for an amazing research field, and olefin metathesis currently represents a powerful transformation in chemical synthesis, attracting a vast amount of interest both in industry and academia.

https://core.ac.uk/download/pdf/4884240.pdf

Ruthenium-based heterocyclic carbene-coordinated olefin metathesis catalysts.

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

Large-scale applications of transition metal-catalyzed couplings for the synthesis of pharmaceuticals.

In recent years, olefin cross metathesis (CM) has emerged as a powerful and convenient synthetic technique in organic chemistry; however, as a general synthetic method, CM has been limited by the lack of predictability in product selectivity and stereoselectivity. Investigations into olefin cross metathesis with several classes of olefins, including substituted and functionalized styrenes, secondary allylic alcohols, tertiary allylic alcohols, and olefins with α-quaternary centers, have led to a general model useful for the prediction of product selectivity and stereoselectivity in cross metathesis. As a general ranking of olefin reactivity in CM, olefins can be categorized by their relative abilities to undergo homodimerization via cross metathesis and the susceptibility of their homodimers toward secondary metathesis reactions. When an olefin of high reactivity is reacted with an olefin of lower reactivity (sterically bulky, electron-deficient, etc.), selective cross metathesis can be achieved using fee...

A General Model for Selectivity in Olefin Cross Metathesis

A mean-field phase diagram for conformationally symmetric diblock melts using the standard Gaussian polymer model is presented. Our calculation, which traverses the weak- to strong-segregation regimes, is free of traditional approximations. Regions of stability are determined for disordered (DIS) melts and for ordered structures including lamellae (L), hexagonally packed cylinders (H), body-centered cubic spheres (QIm3m), close-packed spheres (CPS), and the bicontinuous cubic network with Ia3d symmetry (QIa3d). The CPS phase exists in narrow regions along the order−disorder transition for χN ≥ 17.67. Results suggest that the QIa3d phase is not stable above χN ∼ 60. Along the L/QIa3d phase boundaries, a hexagonally perforated lamellar (HPL) phase is found to be nearly stable. Our results for the bicontinuous Pn3m cubic (QPn3m) phase, known as the OBDD, indicate that it is an unstable structure in diblock melts. Earlier approximation schemes used to examine mean-field behavior are reviewed, and compa...

Unifying Weak- and Strong-Segregation Block Copolymer Theories

Resist compositions that can be used in immersion lithography without the use of an additional topcoat are disclosed. The resist compositions comprise a photoresist polymer, at least one photoacid generator, a solvent; and a self-topcoating resist additive. A method of forming a patterned material layer on a substrate using the resist composition is also disclosed.

Self-topcoating resist for photolithography

/pdf/a-general-model-for-selectivity-in-olefin-cross-metathesis-3osm95int1.pdf

A General Model for Selectivity in Olefin Cross Metathesis.

A Method. The method includes forming a substructure, on a substrate, including a feature having a sidewall of a first material and a bottom surface of a second material. Applying a solution including two immiscible polymers and third material to the substructure. The immiscible polymers include a first and second polymer. A selective chemical affinity of the first polymer for the material is greater than a selective chemical affinity of the second polymer for the material. The first polymer is segregated from the second polymer. The first polymer selectively migrates to the at least one sidewall, resulting in the first polymer being disposed between the at least one sidewall and the second polymer. The first polymer is selectively removed. The second polymer remains, resulting in forming structures including the substructure, the third material, and the second polymer. The substructure has a pattern. The pattern is transferred to the substrate.

Aligning polymer films

Methods are disclosed for reducing the number of defects in a directed self-assembled structure formed on a guiding pre-pattern (e.g., a chemical pre-pattern) on a substrate. A first layer comprising a first self-assembly material is applied onto the guiding pre-pattern, with the first self-assembly material forming domains whose alignment and orientation are directed by the guiding pre-pattern; as a result, a first self-assembled structure is formed. The first self-assembled structure is washed away, and a second layer comprising a second self-assembly material is then applied. The second self-assembly material forms a second self-assembled structure having fewer defects than the first self-assembled structure.

Methods of reducing defects in directed self-assembled structures

The invention provides novel organometallic complexes useful as olefin metathesis catalysts. The complexes have an N-heterocyclic carbene ligand and a chelating carbene ligand associated with a Group 8 transition metal center. The molecular structure of the complexes can be altered so as to provide a substantial latency period. The complexes are particularly useful in catalyzing ring closing metathesis of acyclic olefins and ring opening metathesis polymerization of cyclic olefins.

Daniel P. Sanders

Papers

Self-topcoating resist for photolithography

A General Model for Selectivity in Olefin Cross Metathesis.

Aligning polymer films

Methods of reducing defects in directed self-assembled structures

Latent, high-activity olefin metathesis catalysts containing an n-heterocyclic carbene ligand