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NNadir

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Gender: Male
Current location: New Jersey
Member since: 2002
Number of posts: 25,196

Journal Archives

Our power is on again.

Everything is right with the world.

For Father's day, my family bought me the video documentary Juice: How Electricity Explains the World, which is about life without electricity in Puerto Rico - for years after the Trumpers abandoned these Americans - and, sadly, Lebanon - Africa and elsewhere. I had the electricity to watch it.

It was pretty well done overall.

Of course I knew all about this, life without electricity, after Hurricane Sandy (during which I was pretty badly injured), but the reminder connected with the tropical storm this week in New Jersey was, um, um, for lack of a better term for it, "a useful reminder."

Like Taj Mahal used to sing, "You don't miss your water, until your well runs dry."

This Immigrant Who Trump Clearly Hates, Built an Innovative Scientific Tool Company in the US.

Every day I get pop up ads in various places for scientific instruments, whether at work or at home. I usually can learn something from them, but it is not possible to open them all.

Today's ad came from a company developing innovative devices that would have been much appreciated in an earlier part of my career; regrettably I have no need for rotary evaporators, although I have a certain nostalgia for the days when they were part of my daily life.

An immigrant to this country, from Ghana, has founded a company built around an improved rotary evaporator device.

George Adjabeng

About Our Founder

Born in Somanya, Ghana, George Adjabeng attended the University of Cape Coast in nearby Ghana for his undergraduate studies. Graduating in 2000, he received the Mendell Award for overall top chemistry student. In the fall of 2000, he moved to Brock University (St. Catharines, Canada) where he began his masters’ research with Professor Alfredo Capretta studying new and robust methodologies for palladium-catalyzed, cross-coupling reactions. There, he co-authored five internationally acclaimed articles. He left Brock in the fall of 2003 to pursue a medicinal chemistry career with Roche (Palo Alto, California). At Roche, his research was focused on infectious diseases where he co-authored two papers. In 2004, George left Roche to join GSK (Research Triangle Park, North Carolina) to pursue cancer drug research. He was awarded the Exceptional Science Award twice for making significant contributions to the discovery of new drugs. He was a discoverer and first inventor of the advanced melanoma drug, Tafinlar. His contributions on many more projects lead to the discovery of drugs, publications and many patents. In his research into infectious diseases, he independently invented a scaffold upon which a Hepatitis C Virus pan-genotype inhibitor drug was discovered. He left GSK in 2011 as a Senior Scientist and briefly held research positions at the National Institute of Health (NIH, Rockville, MD) and UNC Eshelman School of Pharmacy (Chapel Hill, NC) before venturing into entrepreneurship...

...During his MBA studies his entrepreneurial spirit was awakened and after graduating in 2010, he filed his first sole inventor patent titled Rotary Evaporator. Prior to this invention, George used rotary evaporators extensively in research for over a decade. George developed his first prototype in 2013, followed by the second prototype in 2014 and the customer-ready product the EcoChyll® in 2015. Today, he leads Ecodyst through its formative years in instrument design, engineering, manufacturing, finance, marketing, sales and customer relations.




Now you would need to have a shithole brain and an extremely primitive understanding of the world, a lousy education, and the moral level of a decomposed turnip to not appreciate Mr. Adjabeng.

Mr. Adjabeng has much of which to be proud, of course, of what he brought to his adopted country - may we be worthy of him - and it goes significantly beyond being such an idiot as to be proud of reciting "Person, Man, Woman, Camera, TV..."

The company: Ecodyst: Leading High Speed Solvent Recovery.

It is going to take a long time, a long time, before our country can erase the stain of Trumpist racism from our history.

Efficient, Reversible, and Selective Absorption of SO2 in an Emim-Cl Ionic Liquid Deep Eutectic.

The paper I'll discuss in this post is this one: Highly Efficient, Reversible, and Selective Absorption of SO2 in 1-Ethyl-3-methylimidazolium Chloride Plus Imidazole Deep Eutectic Solvents (Zi-Liang Li, Lin-Sen Zhou, Yue-Han Wei, Hai-Long Peng, and Kuan Huang, Ind. Eng. Chem. Res. 2020, 59, 30, 13696–13705).

Sulfur dioxide is a major pollutant from the combustion of dangerous fossil fuels as well as, albeit to a lesser extent, the combustion of "renewable" biomass. My interest in this paper is not connected with putting lipstick on the dangerous fossil fuel pig, nor as an endorsement of so called "renewable energy" which has proved to be, at enormous expense, yet another form of lipstick on the dangerous fossil fuel pig.

My interest is connected rather with a particular version of a thermochemical water splitting cycle, specifically, the sulfur iodine cycle which generates separate streams of hydrogen and oxygen. My considerations of thermochemical cycles has in recent years focused on other cycles, specifically those utilizing transition metals or cerium, a multivalent lanthanide, but it has always been the case that the sulfur iodine cycle - and some closely related cycles - have the advantage of requiring only fluid phases. An issue in the sulfur iodine cycle is that the oxygen generated may be contaminated with sulfur dioxide, limiting its use in oxyfuel combustion, and also suffering from reversibility. (The oxyfuel combustion of biomass under closed conditions - no smokestack - is a fairly straight forward path to recovering carbon dioxide from the atmosphere, and much safer than current procedures which are responsible for about half of the six to seven million air pollution deaths per year.)

The recent developments in ionic liquid approaches have renewed my interest in this cycle - although others offer different advantages.

These cycles are accessible by the use of clean energy, of which there is only one real form, nuclear energy. Because these cycles take place at relatively high temperatures, they also afford the achievement of high energy efficiency with managed heat flows, coming under the general rubric of "process intensification."

Anyway, from the introduction to the paper - artifacts of the translation of thoughts in Chinese to English text notwithstanding:

Sulfur dioxide (SO2) is an air contaminant that can be found in the tail gas of thermal power plants, sulfuric acid factories, and steel mills. It constitutes the major precursor of acid rain and may cause serious harm to the global environment if directly emitted into the atmosphere.(1,2) Therefore, the contents of SO2 in industrial tail gas should be strictly controlled. On the other hand, SO2 is very useful as the extractant, food additive, and raw material for the production of sulfur-containing chemicals.(3) Therefore, it is of great significance to eliminate and recycle SO2 from industrial tail gas.(4) At present, the most widely adopted method to capture SO2 from industrial tail gas is wet scrubbing, which utilizes absorbents such as organic solvents,(5) seawater(6) limestone slurry,(7) and aqueous ammonia.(8) However, these absorbents are associated with many shortcomings. For example, traditional organic solvents are highly volatile and may cause secondary pollution to the environment; seawater is abundant only in coastal areas and of relatively low efficiency for SO2 absorption; limestone slurry and aqueous ammonia are irreversible for SO2 absorption, leading to the waste of sulfur resource.

Given these shortcomings, developing new absorbents with low volatility, high efficiency, and good reversibility is highly demanded. Since there are many other components (e.g., N2 and CO2) in industrial tail gas, the developed absorbents should also exhibit high selectivity. To this end, ionic liquids (ILs) were proposed as promising candidates.(9−11) ILs are a class of organic molten salts and credited as “green solvents” owing to their negligible volatility. In addition, the properties of ILs can be easily tuned by tailoring the structures of ILs.(12−16) It is expected that highly efficient, reversible, and selective absorption of SO2 can be achieved in ILs. Within this regard, many functionalized ILs with excellent performance for SO2 capture have been developed by utilizing the electron-deficient and Lewis acidic property of SO2 molecules.


The authors combine two developments garnering a great deal of attention, the ionic liquids mentioned the text, and "deep eutectic solvents."

From the text:


Recently, deep eutectic solvents (DESs) started to attract considerable attention in gas separation research because they share similar features with ILs in terms of low volatility and tunable properties.(30,31) DESs are simple mixtures of hydrogen-bond acceptors (HBAs) and hydrogen-bond donors (HBDs). They have lower melting points than individual components because the hydrogen-bond interaction formed between HBAs and HBDs changes the electron distribution of molecules.(32) In comparison with ILs, DESs can be more easily prepared from commercial reagents, thus making them more intriguing from a practical perspective. Therefore, DESs are regarded as more promising candidates to achieve highly efficient, reversible, and selective absorption of SO2.


The authors add the very simple ionic liquid, ethylmethylimidazolium chloride, most often designated "emim chloride" imidazole, to imidazole, the chemical precursor to emim cations.

The structure of the emim chloride and imidazole are given in this figure:



The caption:

Scheme 1. Chemical Structures of [Emim]Cl and Imidazole


A table in the paper gives literature references for a number of other deep eutectic solvents utilized for the capture SO2.

Of more immediate relevance is a table of the showing viscosities as a function of composition, along with the decomposition temperatures of the mixtures.



The viscosities at room temperature (298K) are roughly equivalent, for the most dilute IL in imidazole, to that of, say, corn oil, only slightly higher. The supplementary data of the table gives the viscosities as a function of temperature, and near the temperature of regeneration reported in the paper which was around 353 K, about 20 K lower than the boiling point of water, the viscosities are quite low, not quite as low as that of water, but approaching it more closely. Note that the desorption temperature is only around 40 K lower than the decomposition temperatures of the deep eutectic solvent mixtures with the lowest concentrations of the emim-Cl. A mixture of SO2 and O2 gas from the thermal decomposition of sulfuric acid would emerge at much higher temperatures, but there is certainly an impetus to rapidly cool this gas mixture - most wisely in a process intensification setting - to prevent the rapid reoxidation of SO2 to SO3, the latter being the anhydride of sulfuric acid.

In the paper's experimental section it is noted that the viscosity is determined using a Brookfield viscometer, which is a widely used but considerably less sophisticated instrument than those provided by, say, Anton Paar, or TA instruments, which measure the full viscosity curves over a wide range of shear rates, but it is, at least illustrative.

No Arrhenius plot of the decomposition reaction is given, nor is the reaction clearly described, despite the fact that the regeneration (desorption) temperature is relatively close to that of the decomposition paper, but the paper does describe the behavior over multiple cycles, suggesting a fairly good stability:



The caption:

Figure 3. Solubilities of SO2 in [emim]Cl+imidazole (1:0.5) for ten consecutive absorption–desorption cycles (absorption condition, 313.2 K and ∼100 kPa; desorption condition, 353.2 K and ∼0.1 kPa for 2 h).


The reported concentrations of SO2 are quite high, approximately 15 mol/kg, which translates to over 900 grams of SO2/kg.

This data is, however, for the most viscous deep eutectic and concentrated with respect to the ionic liquid. Perhaps there are reasonable trade offs, which also seem necessary with respect to the time of regeneration.

This system is designed for the exhaust of dangerous fossil fuels, and thus the selectivity with respect to carbon dioxide and nitrogen gas are described, and not oxygen, but it is notable that the absorption depends on the lewis acidity of SO2, a property not generally associated with oxygen gas. This breakthrough graph from the paper shows the selectivity with respect to nitrogen and carbon dioxide, neither of which would be present in a sulfur iodine cycle decomposition gas:



Figure 6. Breakthrough curves for the absorption of SO2/CO2/N2 mixed gas (0.02/0.15/0.87 vol) in [emim]Cl+imidazole (1:0.5) at 298.2 K.


In an industrial setting, fast analysis might prove possible using simple IR techniques.



The caption:

Figure 11. FTIR spectra of [emim]Cl+imidazole (1:0.5) before and after SO2 absorption (black line, before SO2 absorption; red line, after SO2 absorption).


This quite an interesting little paper, I think, cheap and easy to synthesize reagents, readily accessible temperatures in a process intensification setting, and other features. In any case there is a long distance between an industrial sulfur-iodine cycle and the present day, but it could make for an interesting future in clean energy, the only sustainable form of which is nuclear energy.

I trust you are having a safe weekend and are enjoying life as much as is possible in these tragic times.

For what change in yourself do you hope when President Biden takes office?

Mine: I want to feel less bitter, less angry, and free of wishing cruel things on people, irrespective of how evil they are.

I don't like many of the things I think; and never knew they were in me.

The National Lung Matrix Trial of personalized therapy in lung cancer

The paper I'll discuss in this post is this one: The National Lung Matrix Trial of personalized therapy in lung cancer (Gary Middleton, Peter Fletcher, Sanjay Popat, Joshua Savage, Yvonne Summers, Alastair Greystoke, David Gilligan, Judith Cave, Noelle O’Rourke, Alison Brewster, Elizabeth Toy, James Spicer, Pooja Jain, Adam Dangoor, Melanie Mackean, Martin Forster, Amanda Farley, Dee Wherton, Manita Mehmi, Rowena Sharpe, Tara C. Mills, Maria Antonietta Cerone, Timothy A. Yap, Thomas B. K. Watkins, Emilia Lim, Charles Swanton & Lucinda Billingham, Nature 583, 807–812 (2020))

The authors are all from the UK, where everyone has died from having a single payer health care system, as well we know from the Pravda/Völkischer Beobachter of America, fair and balanced FOX News, the official mouthpiece of Dr. Trump and the chloroquine demon seed doctors, and official Jim Jones Memorial Koolaid Kure-all Klub (KKK).

Cancer, as most people know, is not actually one disease, and it turns out that even cancers in and of particular organs are not single diseases. For example, in breast cancer, there is ER+, PR+, HER2+ and triple negative. These are not equivalent diseases. My sister-in-law had ER+ cancer - I wept for joy when I found this out, of course, after finding out that she had cancer since ER+ is treatable - and her cancer proved quite treatable; she kept her breast and is 5 years into remission after surgical excision, chemotherapy and radiation therapy. Other types of breast cancer are far more problematic.

It gets deeper than that on a molecular biology level, and the use of automatic genetic testing has allowed for the development of targeted or "personalized" treatment. That is the subject of this paper.

My father, a smoker who used to joke about "cancer sticks" that he "needed" died from lung cancer. Perhaps in a personalized medicine word he might have survived longer; he was dead within a few months of diagnosis.

From the paper's introduction:

In the case of cancer treatment, stratified medicine is a therapeutic strategy whereby the genotype of a tumour is used to match the patient to an appropriate targeted therapy. This strategy was first realized for the treatment of NSCLC when mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) were identified as the molecular basis of the clinical responses observed in patients treated with the EGFR tyrosine kinase inhibitor gefitinib1. In NSCLC, the majority of targetable alterations tend to occur in the cancers of patients who have never smoked or who are former light smokers. In tobacco-associated lung adenocarcinoma (LUAD) there are few actionable aberrations, and in squamous-cell lung cancer (LUSC) there are no options for targeted therapy.

Here we report the current results of the ongoing National Lung Matrix Trial (NLMT), the largest national NSCLC umbrella study. NSCLC genotyping using next-generation sequencing (NGS) is used to stratify patients into one of 22 single-arm signal-of-activity studies, testing 8 different drugs (Fig. 1). Screening was performed on the 28-gene NGS panel from Cancer Research UK’s Stratified Medicine Programme (SMP2) (details provided in Methods). To embed the programme into National Health Service (NHS) practice, the majority of tumours sequenced were obtained from formalin-fixed paraffin-embedded material surplus to requirements of the diagnostic work-up. Aberrations in targeted genes were tiered for oncogenic relevance using published data: tier 1 or tier 2 aberrations were eligible for inclusion4.


There's that NHS practice note. Terrible, terrible, terrible, right Rush Limbaugh, you bag of physical tumors not quite as bad as the tumor you've been on our culture, you racist lump of cancer eaten lard. May you rot in hell with the other racists.

Sorry. Can't help myself.

Some graphics:



The caption:

Patients are stratified using the 28-gene NGS panel test results from SMP2, and the trial is currently testing 8 different targeted drugs (A–H) in 22 different actionable biomarker cohorts. The trial also includes a cohort of patients with no actionable aberrations (NA).




The caption:

he flow diagram shows the progress of patients through SMP2 and NLMT arms A–H as of 30 November 2019




The caption:

orest plots show Bayesian estimates and 95% credible intervals for true values of median PFS, DCB rate and OR rate. Purple is used to highlight estimates for which PFS is the primary outcome measure, with vertical lines showing a pre-specified clinically relevant target of a median PFS of 3 months. Green or blue is used to highlight estimates for which DCB and OR rates are co-primary outcome measures, with vertical lines showing pre-specified clinically relevant target rates of 40% or 30%, respectively. Cohorts that are closed to recruitment are represented by solid lines and those still open are represented by dashed lines. Bayesian estimates are the medians of the posterior probability distributions derived from the current data and minimally informative priors. Because the trial is ongoing and the follow-up is not complete (including in some closed cohorts), these estimates are subject to change as the trial continues.




The caption:



The caption:

a, Top, waterfall plot shows, for each patient, the best percentage change in sum of target lesion diameters according to RECIST v.1.1. Bars are coloured according to the patient’s smoking history. Patients who discontinued before assessment, or had a value greater than 100% were capped at 100%. Bottom, forest plots show Bayesian estimates (with 95% credible intervals) of OR rates, grouped according to the smoking history of the patients. b, As for a, but coloured and grouped according to the histology of the tumour.


The results of the study are ambiguous, reflecting the genetic complexity of cancers, particularly in this case, among smokers, but the work presents some pathways forward:

Pre-clinical work is essential to identify promising biomarker–drug combinations, but the models used must recapitulate the genomic context and evolutionary trajectory of the targeted genomic alteration. Tobacco-associated NSCLCs harbour many more clonal mutations compared with NSCLCs in non-smokers11, which increases the chance that other oncogenic drivers could co-exist with the targeted genomic aberration. Ongoing genomic instability driven largely by tobacco exposure, APOBEC and mitotic clock signatures12—combined with extensive somatic copy-number alterations (SCNAs)—may also lead to the rapid evolution of resistance. A reduction in clinical benefit with increasing cumulative smoking duration13 and higher complexity of the mutational landscape14 has been demonstrated in patients with EGFR mutations treated with EGFR tyrosine kinase inhibitors. Although we relied on extensive pre-clinical data to inform our biomarker–drug selections, a substantial amount of data was generated using models that lacked other genomic aberrations besides the targeted alteration. Genetically engineered mouse models of NSCLC have mutational burdens more than 100-fold lower than that of human disease15. Carcinogen-induced models have few SCNAs16. Non-malignant cells that are engineered to harbour single genomic aberrations (as used to select treated with AZD454717) fail to replicate genomic complexity. The results of targeting common SCNAs were disappointing. There was a stark difference in the activity of crizotinib in patients with cancers that harbour MET amplification compared with MET exon 14 mutations: the former is characterized by greater genomic instability and can be heterogeneous, the latter often occurs in non-smokers in cancers without concurrent driver mutations18. Chromosomal copy-number amplicons can encode multiple genes, all of which might subtly affect the phenotype. Using two genomic datasets—TCGA and TRACERx (tracking non-small cell lung cancer evolution through therapy)—we investigated whether this was the case with PIK3CA amplification. We found that there are indeed a substantial number of potential drivers that are co-amplified with PIK3CA and, furthermore, that there is considerable heterogeneity of amplicon size across individual tumours (Extended Data Figs. 5, 6).


Lung cancer, is usually a bad thing, but not always. Rush Limbaugh has it.

I happen to know it can be a very ugly way to die, and coldly and cruelly, without any sense of forgiveness, in his case all ugliness is merited.

Enjoy the rest of the weekend safely.





ACS Green Chemistry Institute Oilfield Chemistry Roundtable

I am a member, for decades, of the American Chemical Society, an organization I value highly.

But sometimes...

I am a regular reader of the journal Energy and Fuels, which is a journal which is largely devoted to the chemistry of dangerous fossil fuels, all of which I oppose.

The journal however does cover a fair amount of interesting papers on making "renewable biofuels" safe - something which as currently utilized they are not - and, in fairness, a number of papers on the topic of carbon capture, something which will be critical for future generations even in the absence of dangerous fossil fuel utilization, since they will need to clean up the waste my generation dumped on them in expressions of contempt.

Anyway here is the paper that led me to a deep sigh of grief, in the current issue of Energy and Fuels:

Grand Challenges and Opportunities for Greener Chemical Alternatives in Hydraulic Fracturing: A Perspective from the ACS Green Chemistry Institute Oilfield Chemistry Roundtable (David Harry, David Horton, Danny Durham, David J. C. Constable*, Simon Gaffney, Joseph Moore, Bridget Todd, and Isamir Martinez, Energy & Fuels 2020, 34, 7, 7837-7846 (Review))

Um...um...um...

One hears quite a bit from dumb shit anti-nukes raising the point about nuclear energy that "nobody knows what to do with the (so called) "waste," which they claim will last "thousands" or "millions" or "billions" of years depending on exactly how scientifically illiterate they are.

Since I have actually studied, for decades, the chemistry of used nuclear fuel, I can say that I personally know exactly what to do with every component of used nuclear fuel, all of which are in any case valuable, but in the minds of these people I am clearly "no one."

The number of these same people who raise the same point of whether anyone knows to do with dangerous fossil fuel waste is vanishingly close to zero.

In any case the difference between so called "nuclear waste" and dangerous fossil fuel waste is that dangerous fossil fuel waste kills people, millions of people per year and so called "nuclear waste," um, doesn't.

Whatever.

I am not going to dignify this paper with a reading. There is no such thing as "green" oil fields, or gas fields or coal fields, just there is no such thing as green so called "renewable energy," since the issue of electronic waste and heavy metal waste is challenging (for solar) and mining tailings, in particular coal mine tailings, represent intractable problems for the wind industry, which is 100% dependent on steel, and thus on coal, as well as copper and lanthanide mining.

The point I'm raising is the abuse of the word "green."

The last issue of Energy and Fuels featured a graphic of a wind turbine - which the public routinely in a completely rote manner calls "green," - even though wind energy is no such thing, and functions merely as a cloak for the gas industry. (The journal as far as I recall from going through it featured no articles on wind energy, which is just as well, unless it was raised obliquely with some silly reference to wind based hydrogen.)

The point is that we all abuse language, even members of the American Chemical Society, the professional organization of which I am a member, almost all members being scientists.

And when we abuse language, we abuse the future.

A word of warning.

I hope you're safe and well in these tragic times, and I wish you any small pleasures available to you.

...this isn't a Russian poem, this is not somewhere else but here, our country moving closer...

What Kind of Times Are These?

There's a place between two stands of trees where the grass grows uphill
and the old revolutionary road breaks off into shadows
near a meeting-house abandoned by the persecuted
who disappeared into those shadows.

I've walked there picking mushrooms at the edge of dread, but don't be fooled
this isn't a Russian poem, this is not somewhere else but here,
our country moving closer to its own truth and dread,
its own ways of making people disappear.

I won't tell you where the place is, the dark mesh of the woods
meeting the unmarked strip of light—
ghost-ridden crossroads, leafmold paradise:
I know already who wants to buy it, sell it, make it disappear.

And I won't tell you where it is, so why do I tell you
anything? Because you still listen, because in times like these
to have you listen at all, it's necessary
to talk about trees.


-Adrienne Rich (1929–2012)

In a way, it's wonderful that she did not have to live to see this.

There is young cowboy...

?t=236

New Alkaline-Earth Metal Fluoroiodates Exhibiting Large Birefringence and Short Ultraviolet Cutoff.

The paper I'll discuss in this post is this one: New Alkaline-Earth Metal Fluoroiodates Exhibiting Large Birefringence and Short Ultraviolet Cutoff Edge with Highly Polarizable (IO3F)2– Units (Minqiang Gai,§ Tinghao Tong,§ Ying Wang,§ Zhihua Yang, and Shilie Pan, Chem. Mater. 2020, 32, 13, 5723–5728)

Organohalide contamination of the air, hydrosphere and land is a very serious environmental issue. From my perspective, the best and least demanding approach to ameliorating this long term problem is high energy radiation.

The highest energy radiation readily available on Earth is gamma radiation, however in most matrices this high energy radiation is down converted to lower forms of energy, x-rays and high energy UV. The ability to control and direct, that is to focus, this high energy radiation is more problematic than it is with visible light, and thus materials that have the ability to refract UV radiation is certainly of interest.

This is why this paper caught my eye.

I won't spend a lot of time discussing it, but just offer a brief excerpt and a few pictures to give a feel for the paper, which is, in any case, relatively short.

As a representative phenomenon in nature, the polarized light has led to plenty of discoveries and applications in which birefringent materials are one of core functional materials to regulate the polarization of light.(1,2) Currently, birefringent crystals, laser crystals, and nonlinear optical (NLO) crystals are the three fundamental crystal devices in all-solid-state lasers. Nevertheless, the difficulty in designing birefringent crystal materials is how to construct excellent fundamental building blocks (FBB) and realize the desirable arrangement of the anionic groups to increase the polarizability anisotropy of materials. The halogen atoms are introduced into metal borates, phosphates, carbonates, silicates, iodates, etc.,(3−15) leading to afford many opportunities for discovering new compounds with rich structural and compositional diversities.(16) Some commercial birefringent materials (YVO4,(17) TiO2,(18) LiNbO3,(19) CaCO3,(20) MgF2,(21) α-BaB2O4 (α-BBO),(22) etc.) have been used widely in the near-infrared (NIR), visible, and ultraviolet (UV) regions. In view of structural chemistry, a main strategy for obtaining high optical anisotropy is to introduce the symmetric building units (SBU).(23−25) The triangular or planar structure group with p-conjugation is beneficial for large birefringence, including BO3, NO3, CO3, and C3N3O3.(26−32) Among these units, the coplanar BO3 groups are beneficial for having the large anisotropic polarizability...

...In this contribution, we reported one iodate Sr(IO3)2 (SIO) and two fluoroiodate compounds SrI2O5F2 (SIOF) and Ba(IO2F2)2 (BIOF). Among these compounds, SIOF and BIOF are the first reported cases in alkaline-earth metal fluoroiodates. It is noted that the (IO3F)2– units in fluoroiodates have not yet been reported. Interestingly, compared with the reported fluoroiodates, SIOF shows a large birefringence (cal. 0.203 at 532 nm) and its birefringence is about twice than that of SIO and BIOF. SIO, SIOF, and BIOF have short UV cutoff edges (255, 250, 230 nm) as well as good thermal stability. The mechanism of large birefringence source in SIOF and BIOF was discussed systematically...


Birefringent materials are materials that refract light - in this case UV light - differently - that is to a different degreen depending on orientation of the material with respect to beam path.

A few more comments from the paper about these properties:

In general, the birefringence is closely related to covalent behavior in the groups. Alkali and alkaline earth metal cations usually have weak covalency and make little direct contribution to the birefringence, such as Sr2+ and Ba2+. The total and partial density of states (TDOS and PDOS) of SIO, SIOF, and BIOF also reveal that the optical properties of above crystals are determined mainly by the anionic groups. The calculated frontier molecular orbital diagrams of (IO2F2)−, (IO3F)2–, (IOF4)−, (IO2F4)3–, (IO3)−, and (IO4)3– anionic groups from BIOF, SIOF, Cs(IOF4),(60) SbF5IF3O2,(62) SIO, and CsIO4(63) were investigated first by using the Gaussian 09 package at the LanL2DZ level without any structure optimization.(64) The presence of F atoms in the (IO3F)2– group, by the calculated frontier molecular orbital diagrams of the [IOF] and [IO] anionic groups, may cause the anisotropy of HOMO and LUMO, and this will affect the overall optical anisotropy of SIOF (Figure 2).


For most of my life, I've just thought of the fluoroiodates as potentially relevant materials to certain reprocessing schemes for used nuclear fuel and as, well, interesting curiosities. This paper points out I've been missing, overlooking, some things.

Some pictures from the text:



The caption:

Figure 1. Crystal structures of SIO, SIOF, and BIOF (a, b, c).




The caption:

Figure 2. Highest occupied molecular orbital (HOMO) and gaps from molecular orbitals of IO2F2, IO2F4, IO3, IO3F, IO4, and IOF4 units, respectively. Light blue and pink lines refer to the energy of the HOMO and lowest unoccupied molecular orbital (LUMO).




The caption:

Figure 3. (a) Calculated hyperpolarizabilities, HUMO–LUMO bandgaps, and static polarizability anisotropies of [IO] and [IOF] groups. (b, c) The reference axis of the minimum mean angle method in SIOF.


The conclusion:

In summary, we synthesized and characterized one iodate SIO and two alkaline-earth metal fluoroiodates SIOF and BIOF with large birefringences of 0.093, 0.18, and 0.092, respectively. These compounds exhibit short UV cutoff edges (255, 250, and 230 nm). The large birefringence in SIOF is mainly attributed to the highly polarizable (IO3F)2– anion groups through systematic analysis. Thus, we propose that the (IO3F)2– units may be a superior functional group to prompt us finding fabulous UV birefringent materials. These results indicate that the unexpectedly large birefringence of SIOF makes it to be a prospective UV birefringent material.


None of this means very much I suppose in the grand scheme of things, but I reflect on things of this nature thus: I often rail against what my generation has done to all future generations with terror and disgust. Irrespective of the fact that history will not forgive us, as some slight redeeming facet is that the world is left with all these tiny punctilios of knowledge that may be sign posts for the future to do what can be done to restore the world.

Being able to focus and move UV radiation certainly is something that may be of value.

I trust you are having a pleasant and safe summer evening in these very difficult times.


Rosalind Franklin was so much more than the 'wronged heroine' of DNA

An editorial in the current issue of Nature:

Rosalind Franklin was so much more than the ‘wronged heroine’ of DNA

It's open sourced, but some excerpts:

At the centre of Rosalind Franklin’s tombstone in London’s Willesden Jewish Cemetery is the word “scientist”. This is followed by the inscription, “Her research and discoveries on viruses remain of lasting benefit to mankind.”

As one of the twentieth century’s pre-eminent scientists, Franklin’s work has benefited all of humanity. The one-hundredth anniversary of her birth this month is prompting much reflection on her career and research contributions, not least Franklin’s catalytic role in unravelling the structure of DNA.

She is best known for an X-ray diffraction image that she and her graduate student Raymond Gosling published in 19531, which was key to the determination of the DNA double helix.

But Franklin’s remarkable work on DNA amounts to a fraction of her record and legacy. She was a tireless investigator of nature’s secrets, and worked across biology, chemistry and physics, with a focus on research that mattered to society. She made important advances in the science of coal and carbon, and she became an expert in the study of viruses that cause plant and human diseases. In essence, it is because of Franklin, her collaborators and successors, that today’s researchers are able to use tools such as DNA sequencing and X-ray crystallography to investigate viruses such as SARS-CoV-2...

...Franklin wanted to understand the porosity of coal, mainly to learn how to make it burn more efficiently. But, as Patricia Fara, a historian of science at the University of Cambridge, UK, points out, the porosity of coal was also a key factor in the effectiveness of Second World War gas masks, which contained activated-charcoal filters. As such, Franklin indirectly aided in the design of the personal protective equipment of her day...

...From coal, Franklin moved on to the study of viruses, which would fascinate her for the remainder of her life. During the 1950s, she spent five productive years at Birkbeck College in London using her X-ray skills to determine the structure of RNA in the tobacco mosaic virus (TMV), which attacks plants and destroys tobacco crops. The virus was discovered in the 1890s...

...With the structure of TMV resolved, Franklin set out to study other plant viruses blighting important agricultural crops, including the potato, turnip, tomato and pea. Then, in 1957, she pivoted again to begin studying the virus that causes polio, which is structurally similar to the turnip yellow mosaic virus. At the time, polio was a feared communicable disease. It has since been mostly eradicated, although cases linger in Pakistan and Afghanistan...

...In 1956, she was diagnosed with ovarian cancer, and she died two years later at the age of just 37. Her collaborators Aaron Klug and John Finch published the poliovirus structure the following year, dedicating the paper to her memory4. Klug would go on to be awarded the 1982 Nobel Prize in Chemistry for his work on elucidating the structure of viruses.


A broader story than the one you usually hear.
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