Our Future,Our Heritage. The Chemical Family Tree of Tetsuo Nozoe

Note from the Editor: When I was editing Tetsuo Nozoe's autobiography Seventy Years in Organic Chemistry in the late 1980s, I realized that the history of Japanese organic chemistry was not too well known in countries other than Japan. I urged Professor Nozoe to include the historical context of his life in his writings, and I was absolutely delighted that he did so. I also suggested that he publish a “Riko Majima Family Tree in Chemistry.” Majima was not only Nozoe's professor but, as detailed in Nozoe's autobiography and elsewhere in the literature, the father figure of Japanese organic chemistry. Nozoe was reluctant because to single‐out some chemical academics but not others in such a public manner could—would—prove embarrassing. But faithful to his profession, the obligations to history prevailed and Nozoe's autobiography contains the Majima Family Tree. We now skip ahead 25 years where we are immersed in the publication of the Nozoe Autograph Books (see: http://www.tcr.wiley‐vch.de/nozoe and this introductory essay: J. I. Seeman, Chem. Rec. 2012 , 12, 517–531). I find myself once again an editor studying in the life and legacies of Riko Majima and Tetsuo Nozoe. The “repeating experiences” of history have been felt once again! ² I asked Professors Ichiro Murata, Shô Itô, and Toyonobu Asao (who are Professor Nozoe's students and biographers) to follow Professor Nozoe's lead and provide his Family Tree in Chemistry. What follows is a reproduction of the Majima Family Tree as provided by Professor Nozoe along with the next generation Family Tree, that being the students of Tetsuo Nozoe's students who themselves became illustrious professors. —Jeffrey I. Seeman Guest Editor University of Richmond Richmond, Virginia 23173, USA E‐mail: jseeman@richmond.edu     

My Father,My Grandfather

Note from the Editor: It is with great pleasure and enthusiasm that I introduce this essay which accompanies the publication of the fourth segment of the Tetsuo Nozoe Autograph Books. In the conceptualization stages of this project—which shall appear in 15 consecutive issues of The Chemical Record as well as have a significant internet presence—I proposed to my colleagues Eva Wille and Brian Johnson that each segment be accompanied with a specially invited essay or perspective. This proposal was immediately and enthusiastically accepted. To both celebrate the life and warmth of Tetsuo Nozoe, I can hardly imagine a more appropriate essay than one written by two of his grandchildren and one of his own children! I thank the Masamune Family for their touching contribution to this project. The Nozoe Autograph Books and all the accompanying essays, including this essay, are open access for at least a three‐year period at: http://www.tcr.wiley‐vch.de/nozoe . Jeffrey I. Seeman Guest Editor, University of Richmond Richmond, Virginia 23173, USA     

The Nozoe Autograph Books: Why Sign Them? Why Publish Them? Why Read Them? Why Treasure Them? Personal and Professional Reflections

Note from the Editor: The Nozoe Autograph Books project involves the publication of the entire 1179 pages of Tetsuo Nozoe's autograph books in 15 consecutive issues of The Chemical Record. In the design of this project, three of us—Eva Wille, Brian Johnson and I—had a vision of bringing a wide range of experiences to our communities of readers. We also had an eye to the archival future. The final design included, with each of these issues of The Chemical Record, an essay that would provide context, novel content and especially enjoyable reading, to round out the project. In the 10 issues published to date, and in the others that will follow, the essays range from personal stories to perspectives in the areas of chemistry near and dear to the heart of Tetsuo Nozoe. Eva Wille's essay is particularly special. The daughter of a professor of chemistry of Nozoe's generation at the Ludwig‐Maximilians‐Universität München (Franz Wille, 1909—1986), Wille is a Ph.D. chemist herself, and for many years, has been and is a major figure in the world of scientific publishing. Thus, she has a unique perspective to share. Indeed, all of the authors of these essays have shared their very personal and professional perspectives, and we are thankful for all of them—and for Tetsuo Nozoe and the thousands of our friends and colleagues who signed his books. —Jeffrey I. Seeman Guest Editor University of Richmond Richmond, Virginia 23173, USA E‐mail: jseeman@richmond.edu     

Tetsuo Nozoe's “Autograph Books by Chemists 1953–1994”: An Essay

Note from the Editor: It is with special pleasure and a warm feeling of gratitude that I introduce Koji Nakanishi's essay which accompanies the publication of the fifth segment of the Tetsuo Nozoe Autograph Books. This project, “Bonding beyond Borders,” is a symbol of the ever‐increasing connectivity among the many members of the chemistry community. Both Nakanishi and Nozoe wrote autobiographies in the Profiles, Pathways and Dreams series that I edited from 1985 to 1997. I learned from their books how close they were as friends and as colleagues. My interest in publishing the Nozoe Autograph Books goes back many years but was stymied by the difficulty of finding a publisher. This interest was rekindled when, in 2006, Nakanishi told me about – and eventually lent me – a one volume specially printed commemorative collection of the Nozoe Autograph Books. At an ACS National meeting, I rushed to show this book to Eva Wille who could not put it down. This was the entry, the personal connection, that led to the publication of the Nozoe Autograph Books by Wiley‐VCH in The Chemical Record. This is another example of bonding, of enthusiasm and commitment, within our community. Jeffrey I. Seeman Guest Editor, University of Richmond Richmond, Virginia 23173, USA     

Extraordinary Transformations to Achieve the Synthesis of Remarkable Aromatic Compounds

Note from the Editor: When we walk around a sculpture, it can speak to us in many ways, sometimes quite differently from various view points. Central to Tetsuo Nozoe and the Nozoe Autograph Book project are novel aromatic compounds. Just look at nearly any page and such compounds jump out at us. We can categorize them in many ways. Their structures. Their physical properties. Their pharmacological and toxicological properties. Their commercial utilities. Their symmetry. Their size. In this essay, Graham Bodwell brings to us his analysis of the various ways in which some of the most remarkable of these compounds have been ingeniously synthesized. We are privileged to have Bodwell's vision and his sense of organization and beauty. Tetsuo Nozoe would have beamed! —Jeffrey I. Seeman Guest Editor University of Richmond Richmond, Virginia 23173, USA E‐mail: jseeman@richmond.edu     

Graphene Enhances the Shape Memory of Poly (acrylamide‐co‐acrylic acid) Grafted on Graphene

Acrylamide and acrylic acid are grafted on graphene by free‐radical polymerization to produce a series of graphene–poly(acrylamide‐co‐acrylic acid) hybrid materials with different contents of graphene. The materials demonstrate shape memory effect and self‐healing ability when the content of graphene is in the range of 10%–30% even though poly(acrylamide‐co‐acrylic acid) itself had poor shape memory ability. The permanent shape of the materials can be recovered well after 20 cycles of cut and self‐healing. The result is attributed to the hard–soft design that can combine nonreversible “cross‐link” by grafting copolymer on graphene and reversible “cross‐link” utilizing the “zipper effect” of poly(acrylamide‐co‐acrylic acid) to form or dissociate the hydrogen‐bond network stimulated by external heating.

     

B Values as a Sensitive Measure of Steric Effects

Someone who says “A” should be prepared to also say “B” : In contrast to cyclohexane model‐based A values, biphenyl model‐derived B values are powerful tools to quantify steric repulsion in and conformational behavior of ortho‐substituted aromatic compounds.

     

Organometallic Compounds of Titanium and Zirconium as Selective Nucleophilic Reagents in Organic Synthesis

The addition of carbanionic organometallic compounds (usually RLi or RMgX) to a carbonyl group—a key step in numerous syntheses—is not always straightforward. Depending on the substrate, various complications and problems may arise, but in many cases these can be remedied by addition of (RO)₃TiCl, (RO)₃ZrCl or (R₂N)₃TiX to the classic lithium and Grignard reagents. This usually leads to formation of stable organo-titanium and -zirconium compounds which react highly selectively with carbonyl groups. For example, CH₃Ti(OiPr)₃ reacts five orders of magnitude faster with benzaldehyde than with acetophenone at room temperature; reagents of the type RTi(OiPr)₃ add smoothly to nitro-, ido-, or cyano-subsituted benzaldehyde, and the reactions may be performed in chlorinated solvents or acetonitrile; the zirconium analogues have particularly low basicity and add in high yield to α- and β-tetralones or to substrates containing a nitroaldol group; the inclusion of chiral OR^* groups gives enantioselective reagents (up to 90% ee); allylic (RO₃)Ti- derivatives react only at the more highly substituted carbon atom and, in addition, react diastereoselectively (up to 98% ds) with unsymmetrical ketones. Finally, titanium reagents have also been found to effect novel transformations such as direct geminal dialkylation (C?O→CMe₂) and alkylative amination [C?O→CR(NR)]. The modification and finetuning (“taming”) of carbonyl reactivity obtainable by use of the new reagents is not dearly bought; starting materials are the cheap and harmless “titanates”, “zirconates” and the corresponding tetrachlorides.     

Concerning electronegativity as a basic elemental property and why the periodic table is usually represented in its medium form

Electronegativity, described by Linus Pauling described as “The power of an atom in a molecule to attract electrons to itself” (Pauling in The nature of the chemical bond, 3rd edn, Cornell University Press, Ithaca, p 88, 1960), is used to predict bond polarity. There are dozens of methods for empirically quantifying electronegativity including: the original thermochemical technique (Pauling in J Am Chem Soc 54:3570–3582, 1932), numerical averaging of the ionisation potential and electron affinity (Mulliken in J Chem Phys 2:782–784, 1934), effective nuclear charge and covalent radius analysis (Sanderson in J Chem Phys 23:2467, 1955) and the averaged successive ionisation energies of an element’s valence electrons (Martynov and Batsanov in Zhurnal Neorganicheskoi Khimii 5:3171–3175, 1980), etc. Indeed, there are such strong correlations between numerous atomic parameters—physical and chemical—that the term “electronegativity” integrates them into a single dimensionless number between 0.78 and 4.00 that can be used to predict/describe/model much of an element’s physical character and chemical behaviour. The design of the common and popular medium form of the periodic table is in large part determined by four quantum numbers and four associated rules. However, adding electronegativity completes the construction so that it displays the multi-parameter periodic law operating in two dimensions, down the groups and across the periods, with minimal ambiguity.     

Cover Picture: The Chemistry of Escapin: Identification and Quantification of the Components in the Complex Mixture Generated by an L‐Amino Acid Oxidase in the Defensive Secretion of the Sea Snail Aplysia californica (Chem. Eur. J. 7/2009)

Defensive chemicals such as the ink secretion of this marine gastropod mollusk—the sea hares Aplysia californica—are released following attacks from predators for protection. One might expect these secretions to be complex mixtures of products, given that they must work against a diversity of predators. In their Full Paper on page 1597 ff. , C. D. Derby et al. describe some of the chemical complexity of the ink of sea hares attributable to the enzyme “escapin”. Escapin is an L ‐amino acid oxidase that oxidatively deaminates its major substrate, L ‐lysine, to produce an equilibrium mixture of the molecules shown in this image. Photograph from Genny Anderson (Santa Barbara City College).

     

Polynomial multivariate least‐squares regression for modeling nonlinear data applied to in‐depth characterization of chromatographic resolution

Well‐established, linear multivariate calibration methods such as multivariate least‐squares regression (MLR), principal component regression (PCR), or partial least squares (PLS) have two limitations: (i) measured data must be linearly related to the response variables and (ii) predictor variables x_{n = 1, …, N} cannot be coupled to each other. For evaluation of nonlinear data, however, these restrictions need to be overcome and thus polynomial multivariate least‐squares regression (PMLR or “response surfaces”) has been introduced here. PMLR is based on multivariate least squares but incorporates all combinations of predictor variables up to a user‐selected polynomial order (e.g., including u or v = 0). Because of the inclusion of such coupled terms and their powers, PMLR models are better adapted to model nonlinear data and can help to enhance the prediction step's accuracy and precision. PMLR has been based on MLR because it facilitates—unlike PCR or PLS—a physical and chemical interpretation of the predictors. Hence, the origins and the relevance of nonlinear and/or coupled predictors can be investigated. The details of the PMLR algorithm and its implementation are presented along with a method for model optimization utilizing gradients of response surfaces. Newly developed PMLR models up to quintic order have been applied to predict a chromatograph's peak resolution as a function of six‐instrument parameters. It has been demonstrated that PMLR is better capable than MLR and PCR to describe these nonlinear and coupled instrument parameters. In addition, the novel software tool has been utilized for model optimization to determine instrument parameters, which result in the best chromatographic resolution. Copyright © 2011 John Wiley & Sons, Ltd.     

Quantum mechanical valence study of a bond-breaking–bond-forming process in triatomic systems

The recently introduced set of the quadratic, two-electron covalent and ionic valence indices is used to investigate the bond-breaking–bond-forming (BB-BF ) process in an atom exchange reaction between H₂ and X (X = H, F—I) as well as in the O₂—H system. Valence changes accompanying selected charge reorganizations are examined within the three-orbital model and valence diagrams for symmetric transition states (TS s) are given. The UHF valence data for Li₂O and CO₂ and the H—H—X, O—O—H, and O—H—O (ABC) TS s (collinear and angular) are reported and compared to valence data in the separated fragments limits (SFL ), AB and BC. The overall valence, ν(ABC), and the total (ionic plus covalent) diatomic valences, ν_AB and ν_BC, are used as measures of the overall bond-order in a concerted BB–BF reaction, to test the postulate of the bond-energy–bond-order (BEBO ) model. In collinear TS s of H₂X, ν ? ?1, i.e., one bonding electron pari, is found to be roughly preserved, whereas in the angular H₂X and in collinear O—H—O TS s, the effect of increased valence at the saddle-point is observed, relative to that of diatomic fragments (reactiants or products). For the angular O—O—H TS , a similar increase in | ν (ABC)| relative to both O₂ and OH SFL s is detected; smaller changes relative to the O₂ data are found in the collinear TS . This observation is in agreement with earlier predictions from the intersecting-state model. The relative diatomic valences, ν/ν and ν/ν, are shown to conserve the overall relative bond multiplicity around 1 in both collinear and angular TS s of the H₂—X systems. © 1994 John Wiley & Sons, Inc.     

Error analysis of variationally optimized upper- and lower-bound wave functions for H

Wave functions which are a linear combination of H-type elliptical orbitals are optimized to provide either an upper bound or a lower bound to the H ground state. For the latter, Temple's formula is used. Three criteria are considered to determine the relative accuracy of these wave functions: (i) energy (calculated versus exact eigenvalue); (ii) average error; and (iii) local energy. Although the lower-bound optimized wave functions obtained are the most accurate available for H from approximate wave functions, they are still inferior to the corresponding upper-bound wave functions by criteria (i) and (ii). In particular, using criterion (ii), it is shown numerically that the upper-bound functions are “correct to second order,” while the lower-bound functions are almost, but not quite, “correct to second order.” Despite this, the local energy analysis, criterion (iii), reveals that the lower-bound wave functions can be more accurate than the upper-bound functions in some regions of space, and hence give more accurate values for physical properties sensitive to these regions. Examples considered are the dipole–dipole and Fermi contact interactions.     

A simple preparation of stable,nonreactive surfaces for gas kinetic studies of reactions of hydrogen atoms

A quartz surface has been prepared for which γ, the mean collisional efficiency for removal of hydrogen atoms, is given by over the temperature range from 315 to 818 K. The preparation “cleans” the surface by contact with 10M aqueous NaOH for ? 15 hr and then deactivates it by contact with 10M aqueous HNO₃ for ?15 hr. The surface is stable and long-lived even after prolonged contact with air. Preliminary results show that a similar result can be obtained using Pyrex glass surfaces.     

Synthesis of Thermosensitive PNIPAM‐co‐MBAA Nanotubes by Atom Transfer Radical Polymerization within a Porous Membrane

Summary: Thermosensitive polymer nanotubes can be fabricated within an aminopropylsilane‐modified porous anodic aluminum oxide membrane by surface‐initiated atom transfer radical polymerization (ATRP) followed by template removal. DSC experiments prove that the synthesized PNIPAM‐co‐MBAA copolymer nanotubes have a reversible thermosensitive behavior. The temperature‐induced changes in dimension and shape of the nanotubes were studied by AFM in real time in an aqueous environment. It indicates that the nanotubes undergo a shape alteration from an “ellipse” to “circular” shape in water upon heating to LCST or above.

DSC curves of PNIPAM‐co‐MBAA nanotubes.     

Scope for Accessing the Chain Length Dependence of the Termination Rate Coefficient for Disparate Length Radicals in Acrylate Free Radical Polymerization

A method that utilizes reversible addition fragmentation chain transfer (RAFT) chemistry is evaluated on a theoretical basis to deduce the termination rate coefficient for disparate length radicals k in acrylate free radical polymerization, where s and l represent the arbitrary yet disparate chain lengths from either a “short” or “long” RAFT distribution. The method is based on a previously developed method for elucidation of k for the model monomer system styrene. The method was expanded to account for intramolecular chain transfer (i.e., the formation of mid-chain radicals via backbiting) and the free radical polymerization kinetic parameters of methyl acrylate. Simulations show that the method's predictive capability is sensitive to the polymerization rate's dependence on monomer concentration, i.e., the virtual monomer reaction order, which varies with the termination rate coefficient's value and chain length dependence. However, attaining the virtual monomer reaction order is a facile process and once known the method developed here that accounts for mid-chain radicals and virtual monomer reaction orders other than one seems robust enough to elucidate the chain length dependence of k for the more complex acrylate free radical polymerization.     

Density Functional Theory Investigation of the Alkyl–Alkyl Negishi Cross‐Coupling Reaction Catalyzed by N‐Heterocyclic Carbene (NHC)–Pd Complexes

Why bigger is better : A “steric wall” created by the N‐(2,6‐diisopropylphenyl) substituent on the bulky NHC ligand IPr (1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) guides the reactants to and from the Pd center through weak, fleeting (IPr)H–Pd interactions that help the oxidative addition intermediate escape “the anti‐trap”. The alternative “side” approach leads to transmetalation (the rate‐limiting step) for which a novel Pd–Zn interaction was identified.

     

“On‐Off” Multivalent Recognition: Degradable Dendrons for Temporary High‐Affinity DNA Binding

Now you bind it—now you don't! Chemical degradation of a dendritic scaffold allows multivalent interactions with DNA to be “switched off” as the multivalent array of ligands breaks down into smaller fragments, offering an approach by which a molecule can be temporarily endowed with high affinity for a biological target—an important concept in the development of new synthetic systems to intervene in biological pathways.

     

“Sandglass”‐Shaped Self‐Assembly of Coil–rod–coil Triblock Copolymer Containing Rigid Aniline‐Pentamer

The amphiphilic PEG_{1 500}‐b‐EM AP‐b‐PEG_{1 500} (EM PAP) triblock copolymer of poly(ethylene glycol) (PEG) and emeraldine aniline‐pentamer (EM AP) in its concentrated solution can self‐assemble into a special shape like “sandglass”, as observed by transmission electron microscopy (TEM), field emission scanning electron microscopy (ESEM) and atomic force microscopy (AFM). This “sandglass”‐shaped assembly is composed of several “rods” aggregated in the middle, with every “rod” being about 8 µm in length and 300 nm in diameter. We conclude that the special “sandglass”‐shaped assembly may come into being because of the inducement effect of the crystallization of EM AP segments, by studying electron diffraction (ED) results and wide‐angle X‐ray diffusion (WAXD) characterization of the EM PAP triblock copolymer.