There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

The relatively small diffuse function-augmented basis set, 3-21+G, is shown to describe anion geometries and proton affinities adequately. The diffuse sp orbital exponents are recommended for general use to augment larger basis sets.

Efficient diffuse function‐augmented basis sets for anion calculations. III. The 3‐21+G basis set for first‐row elements, Li–F

A. Water Exchange 2326 B. Proton Exchange 2327 C. Electronic Relaxation 2327 D. Relaxivity 2331 E. Outerand Second-Sphere Relaxivity 2334 F. Methods of Improving Relaxivity 2336 V. Macromolecular Conjugates 2336 A. Introduction 2336 B. General Conjugation Methods 2336 C. Synthetic Linear Polymers 2336 D. Synthetic Dendrimer-Based Agents 2338 E. Naturally Occurring Polymers (Proteins, Polysaccharides, and Nucleic Acids) 2339

https://mriquestions.com/uploads/3/4/5/7/34572113/lauffer_1999_review.pdf

Gadolinium(III) Chelates as MRI Contrast Agents: Structure, Dynamics, and Applications

I. Introduction: Conceptual vs Fundamental andComputational Aspects of DFT1793II. Fundamental and Computational Aspects of DFT 1795A. The Basics of DFT: The Hohenberg−KohnTheorems1795B. DFT as a Tool for Calculating Atomic andMolecular Properties: The Kohn−ShamEquations1796C. Electronic Chemical Potential andElectronegativity: Bridging Computational andConceptual DFT1797III. DFT-Based Concepts and Principles 1798A. General Scheme: Nalewajski’s ChargeSensitivity Analysis1798B. Concepts and Their Calculation 18001. Electronegativity and the ElectronicChemical Potential18002. Global Hardness and Softness 18023. The Electronic Fukui Function, LocalSoftness, and Softness Kernel18074. Local Hardness and Hardness Kernel 18135. The Molecular Shape FunctionsSimilarity 18146. The Nuclear Fukui Function and ItsDerivatives18167. Spin-Polarized Generalizations 18198. Solvent Effects 18209. Time Evolution of Reactivity Indices 1821C. Principles 18221. Sanderson’s Electronegativity EqualizationPrinciple18222. Pearson’s Hard and Soft Acids andBases Principle18253. The Maximum Hardness Principle 1829IV. Applications 1833A. Atoms and Functional Groups 1833B. Molecular Properties 18381. Dipole Moment, Hardness, Softness, andRelated Properties18382. Conformation 18403. Aromaticity 1840C. Reactivity 18421. Introduction 18422. Comparison of Intramolecular ReactivitySequences18443. Comparison of Intermolecular ReactivitySequences18494. Excited States 1857D. Clusters and Catalysis 1858V. Conclusions 1860VI. Glossary of Most Important Symbols andAcronyms1860VII. Acknowledgments 1861VIII. Note Added in Proof 1862IX. References 1865

/pdf/conceptual-density-functional-theory-btz9wwrxv9.pdf

Conceptual density functional theory.

Asymmetric enamine catalysis.

/pdf/alternative-descriptions-of-the-c23-pbcl2-c37-co2si-b8b-ixwqsx6zcz.pdf

Alternative descriptions of the C23 (PbCl2), C37 (Co2Si), B8b (Ni2In) and related structure types

Lysine crotonylation (Kcr) is a histone post-translational modification that is implicated in numerous epigenetic pathways and diseases. Recognition of Kcr by YEATS domains has been proposed to occur through intermolecular amide-π and alkene-π interactions, but little is known about the driving force of these key interactions. Herein, we probed the recognition of lysine crotonylation and acetylation by the AF9 YEATS domain through incorporation of noncanonical Phe analogs with distinct electrostatics at two positions. We found that amide-π interactions between AF9 and acyllysines are electrostatically tunable, with electron-rich rings providing more favorable interactions. This differs from trends in amide-heteroarene interactions and provides insightful information for therapeutic design. Additionally, we report for the first time that CH-π interactions at Phe28 directly contribute to AF9's recognition of acyllysines, illuminating differences among YEATS domains, as this residue is not highly conserved but has been shown to impart selectivity for specific post-translational modification.

More Than π-π-π Stacking: Contribution of Amide-π and CH-π Interactions to Crotonyllysine Binding by the AF9 YEATS Domain.

Medium-ring lactones are synthetically challenging due to unfavorable energetics involved in cyclization. We have discovered a thioesterase enzyme DcsB, from the decarestrictine C1 (1) biosynthetic pathway, that efficiently performs medium-ring lactonizations. DcsB shows broad substrate promiscuity toward linear substrates that vary in lengths and substituents, and is a potential biocatalyst for lactonization. X-ray crystal structure and computational analyses provide insights into the molecular basis of catalysis.

A Polyketide Cyclase That Forms Medium-Ring Lactones.

Amphidynamic crystals, which possess crystallinity and support dynamic behaviours, are very well suited to the exploration of emergent phenomena that result from the coupling on the dynamic moieties. Here, dipolar rotors have been embedded in a crystalline metal–organic framework. The material consists of Zn(ii) nodes and two types of ditopic bicyclo[2.2.2]octane-based linkers—one that coordinates to the Zn clusters through two 1,4-aza moieties, and a difluoro-functionalized derivative (the dipolar rotor) that coordinates through linked 1,4-dicarboxylate groups instead. Upon cooling, these linkers collectively order as a result of correlated dipole–dipole interactions. Variable-temperature, frequency-dependent dielectric measurements revealed a transition temperature Tc = 100 K, when a rapidly rotating, dipole-disordered, paraelectric phase transformed into an ordered, antiferroelectric one in which the dipole moments of the rotating linkers largely cancelled each other. Monte Carlo simulations on a two-dimensional rotary lattice showed a ground state with an Ising symmetry and the effects of dipole–lattice and dipole–dipole interactions. A metal–organic framework (MOF) has been prepared that features dynamic rotors embedded within its crystalline lattice. The dipolar F2-functionalized carboxylate linkers—rapidly rotating at room temperature—show correlated behaviour upon cooling, converting the paraelectric MOF into an ordered antiferroelectric one below 100 K.

K. N. Houk

Papers

Alternative descriptions of the C23 (PbCl2), C37 (Co2Si), B8b (Ni2In) and related structure types

More Than π-π-π Stacking: Contribution of Amide-π and CH-π Interactions to Crotonyllysine Binding by the AF9 YEATS Domain.

A Polyketide Cyclase That Forms Medium-Ring Lactones.

Dipolar order in an amphidynamic crystalline metal–organic framework through reorienting linkers

Toward ferromagnetic materials: prediction of a triplet ground state for heterocyclic polyacenes