A friend was making some starting materials and [they] allowed me to take some photos of these beautiful compounds. Bright colors are definitely among the top reasons to love inorganic chemistry.
Posts from an inorganic chemistry enthusiast!
Sunday, March 22, 2015
Saturday, March 21, 2015
Technetium Chemistry in the Fuel Cycle: Combining Basic and Applied Studies #chempaperaday 204
Technetium is the most mysterious element. In the middle of the d-block and yet radioactive. You can't just dig and find technetium (therefore the name). Despite all these difficulties, the isotope 99mTc is the "workhorse of diagnostic nuclear medicine." It is the byproduct of fission reactions of uranium isotopes in the reactors. Because, it requires special handling and other requirements, not every lab is lucky to study technetium chemistry. So, not much is known about it yet. All I know is that it makes nice bimetallic complexes with multiple Tc-Tc bonds. So, I was not much surprised to learn that "[on binary compounds]...only three species, TcF6, TcF5, and TcCl4, identified prior to 2008."
A few more details from the paper:
A few more details from the paper:
Because of its high fission production rate, the amount of technetium on Earth may ultimately exceed that of rhenium, its heavier congener.
In a typical light water nuclear reactor, 99Tc production is around 2 g/day for every 100 MW of thermal energy.
Technetium has a range of oxidation states, from 7+ to 1–, and its chemistry has considerable similarities to rhenium; e.g., it has extensive pentavalent chemistry.
The overall trends clearly demonstrate increasing technetium–technetium interactions with decreasing oxidation state.
A Half-Century of Nonclassical Organometallic Chemistry: A Personal Perspective #chempaperaday 203
The 100th #chempaperaday was "A millennial overview of transition metal chemistry" by F.A. Cotton. Interestingly enough, my 203rd paper is another great article by him.
In this article, he highlights a few selected areas of inorganic chemistry and obviously his contributions to these areas. In fact, he paved the way for several of these. When chemists just put their hands on an NMR instrument, he started to do VT experiments to study the fluctional behavior of several organometallic compounds. Incredible work. There is also a few pages on the iron dimer that I just posted, the discovery of agostic interactions, his proposal to use hapticity and so on.
"Prior to the report on ferrocene, no one worked in the field of transition metal organometallic chemistry because no one believed that there was any such field to work in."
Does cyclopentadienyl iron dicarbonyl dimer have a metal–metal bond? Who’s asking? #chempaperaday 202
A really nice article on why we should draw a bond between iron atoms in this complex. I presented this paper later to a group of people. I defended Jay Labinger's view and my own literature search and the evidence (homolytic cleaveage to give 17 electron radical species etc.) I saw made me think that we should draw a bond. If you like controversies and discussions on transition metal complexes like me, you will enjoy it.
I should note that the article has quotes from Galileo, poems from Dante and Pushkin. It is not very often you see these types of things in articles which made me like the article even more.
http://www.sciencedirect.com/science/article/pii/S0020169314002278
A few quotes:
I should note that the article has quotes from Galileo, poems from Dante and Pushkin. It is not very often you see these types of things in articles which made me like the article even more.
http://www.sciencedirect.com/science/article/pii/S0020169314002278
A few quotes:
..given Al Cotton’s intimate involvement with the history of both M–M bonds in general and Fp2 in particular – not to mention his fondness for engaging in polemics.
The latter argues against E. O. Fischer’s description: probably this constitutes Cotton’s first polemic in print!)
The metathesis reactions: from a historical perspective to recent developments #chempaperaday 201
A nice historical perspective of olefin metathesis and metathesis catalysts. The article was published in 2005. So, don't expect to see exciting new stuff like enantioselective ones.
I remember writing on metathesis before. So, let's add some new things that I learned.
I remember writing on metathesis before. So, let's add some new things that I learned.
"..the first observation of the metathesis of propene at high temperature was reported in 1931.
Schrock, then at Du Pont, tried to synthesize [Ta(CH2CMe3)5], which would not contain b-hydrogens and thus, according to this principle, should have been stable. Good luck smiles only on good scientists, and the expected compound did not form...led to the isolation of the first stable metal-alkylidene complex, [Ta(CH2CMe3)3(=CHCMe3)]."
"Exploration of Earth-Abundant Transition Metals (Fe, Co, and Ni) as Catalysts in Unreactive Chemical Bond Activations" #chempaperaday 200
This is a short article on Fe, Co and Ni catalysts towards C-O, C-C and C-H activation. My purpose to read this article was to see "what is out there" and see if I can learn a few new things. I want to point out a few important (at least for me) details in this article on the characteristic behaviors of these metals. As an inorganic chemist, I enjoyed these parts the most.
Fe : Let's repeat that it is the most abundant transition metal on earth.
Co : Like iron, it is cheap and abundant. But, in these type of bond activation reactions, Co catalysis "lagged greatly."
Ni : $1/g ! Unbelievable! The congeners of Ni; Pd($183/g), Pt($483/g)! Oxidative addition of Ni(0) or Ni(I) usually goes through SET processes. And as we can see from the beautiful periodic table, Ni is more nucleophilic as expected. The authors also claim that Ni is "the best metal to induce the C-O cleaveage of various O-based nucleophiles."
There are lots of examples of bond activations and catalytic cycles in the paper. I noticed an error in one of the figures:
Also, one of the authors was born in 1991 and he is a ""third year graduate student."
Fe : Let's repeat that it is the most abundant transition metal on earth.
Co : Like iron, it is cheap and abundant. But, in these type of bond activation reactions, Co catalysis "lagged greatly."
Ni : $1/g ! Unbelievable! The congeners of Ni; Pd($183/g), Pt($483/g)! Oxidative addition of Ni(0) or Ni(I) usually goes through SET processes. And as we can see from the beautiful periodic table, Ni is more nucleophilic as expected. The authors also claim that Ni is "the best metal to induce the C-O cleaveage of various O-based nucleophiles."
There are lots of examples of bond activations and catalytic cycles in the paper. I noticed an error in one of the figures:
Also, one of the authors was born in 1991 and he is a ""third year graduate student."
"A Nickel(II)–Sulfur-Based Radical-Ligand Complex as a Functional Model of Hydrogenase" and the "controversy" #chempaperaday 197-199
The first paper came out in 2010 and reported synthesis and characterization of a Ni(II)-dithiolene complex. The authors formulated the compound as NiII(L2−)(L−.)][PPh4] and claim that complex "shows strikingly similar EPR and reduction potential values to those observed with native Ni-containing hydrogenases." I should mention that CV of the compound was reported in MeCN. You can read the paper and ask questions, but the most interesting thing they did not provide a proton NMR spectrum for this paramagnetic compound. But, they assigned a signal at 4.1 ppm to a S-H. Interesting.
Anyway, shortly after a "comment" was published and proposed a new oxidation state assignment for the Ni atom and the ligand. A "Response" followed and honestly I don't think they added any new evidence or supporting argument for their own assignment.
I still think, they are worth reading.
Sunday, March 8, 2015
Book: The Violinist's Thumb
I got this book as a gift. As I read The Disappearing Spoon by the same author before, I was expecting it would be as entertaining and interesting as it was. I think this is a good book to read, but if you already know some about biology, genetics, genes and some evolution; I don't think you will learn much. I read it quickly and I liked it (3 stars). There are several interesting stories, but in my case, I knew most of them. Anyway, I still think it is worth reading since there are a lot of names and details. Also, you will have a lot to learn if you do not know much about science.
Friday, March 6, 2015
A Salute to My Colleague Yves Chauvin, 1930–2015 #chempaperaday 196
Olefin metathesis is one of the most important and useful chemical transformations. The earliest versions of this reaction involved using not well defined catalysts and the reaction mechanism was not understood. In 1971, Chauvin proposed a mechanism that is accepted as the actual mechanism of the reaction today.
Chauvin died on January 27. I have read about him before. But, I think this is the best article.
Here are a few quotes from him proving how good a scientist he was:
Here are a few quotes from him proving how good a scientist he was:
“If you want to find something new, look for something new!”
“Some people say that there is too much chemistry in our society. It is in fact the opposite: there is not enough chemistry, not enough understanding, not enough control of chemical reactions. Catalysis is the key for a better chemistry.”
Friday, February 20, 2015
Visible-Light-Driven CO2 Reduction with Carbon Nitride: Enhancing the Activity of Ruthenium Catalysts #chempaperaday 195
A carbon nitride and ruthenium complex system with 4 different Ru complexes are reported in this article. The authors state that these results are "the best values that have been reported for heterogeneous photocatalysts for CO2 reduction under visible-light irradiation to date." I am trying to design and synthesize homogeneous catalysts, but I always have great interest in heterogeneous systems.
Below you can see their CO2 reduction abilities.
The German Chemical Society (GDCh) and Nazi Germany #chempaperaday 194
For those interested in history of science and chemistry, this is a short and a good article.
"all sciences and engineering were involved in the planning of the war, but chemistry played a central role; hardly any area of the war effort was able to do without the help of chemistry, for example in the synthesis of gasoline, new polymeric materials, or the availability of explosives.
A simplified summary is that the DChG was a society for (inter)national researchers in academia, whereas the VDCh represented predominantly the German industrial chemists. The leading scientific
journal of the DChG was the Berichteder deutschen Chemischen Gesellschaft, whereas the top-tier journal of the VDCh was Angewandte Chemie."
I am glad to learn that a new book is coming very soon:
Chemiker im “Dritten Reich” –Die Deutsche Chemische Gesellschaft und der Verein Deutscher Chemiker im NS-Herrschaftsapparat
."
Thursday, February 19, 2015
Challenges and Opportunities in the Development of Organometallic Anticancer Drugs #chempaperaday 193
A very short review of organometallic anticancer compounds as "drugs" ending with possible 8 opportunities for chemists to design these types of compounds.
http://pubs.acs.org/doi/pdf/10.1021/om300373t
Sunday, February 15, 2015
One Hundred Years of the Fritz Haber Institute #chempaperaday 192
Fritz Haber Institute is one of the "sub" institutes of Max Planck Institute. Unless you are interested what they do, you probably have not heard of the institute. Since, I follow some of their research areas, I can say I know a some about the institute and in fact it would be an honor for me to work there one day in the future.
So I was really happy when I came across this paper about a month ago. It's a short history of the institute and the research within covering one hundred years. I am glad I read it because I was able to learn much more than I know about FHI. I did not know FHI had seven Nobel laureates for example.
Photo: Wikipedia
If you read the paper, you will learn how much the institute contributed to modern science especially in surface chemistry, heterogeneous catalysis and electron microscopy. I would like to highlight a few titles that were also related to FHI: gas masks, methane detector, allotropes of hydrogen, symmetry.
The fields of research explained by the paper are:
Gas-Phase Kinetics and Dynamics
Methane Detector
Haber-Born Cycle
Chemiluminescence
Combustion
Sttatistical Mechanics
The Franck-Hertz and the Compton Effects
Dispersion
Theoretical Chemistry
Molecular Beams
Physisorption
Colloid Chemistry
Electron Microscopy
Surface Science
[The] science research project of today is the temporary culmination of a very long, hard- fought struggle by a largely invisible community of our ancestors. Each of us may be standing on the shoulders of giants; more often we stand on the graves of our predecessors.
"In the words of the historian Fritz Stern, Haber' s Institute during the First World War became “ kind of forerunner of the Manhattan Project."
Gallium-Iron multiple bond controversy #chempaperaday 189-191
I have three papers starting with a report claiming that there is evidence for a Ga-Fe triple bond and they named it "ferrogallyne."
http://pubs.acs.org/doi/abs/10.1021/om970530c
As you can see the evidence for this so-called multiple bond was not so convincing. So, being an expert in multiple bonds, F.A. Cotton wrote his comments and concerns about this assignment. He explained his reasoning and suggested that there is also a dative bond between Ga and Fe.
http://pubs.acs.org/doi/abs/10.1021/om970971w
There was no reply from the original authors. So, this is unfortunate. I was able to find a computational paper on the issue. But, it's not the best paper to read on the subject. The authors simply say that the triple bond is a "pseudo-conflict" in this case because our bonding model is not "appropriate." Personally, I agree with Cotton and I think there should only be a Ga->Fe bond.
http://pubs.acs.org/doi/abs/10.1021/om970530c
As you can see the evidence for this so-called multiple bond was not so convincing. So, being an expert in multiple bonds, F.A. Cotton wrote his comments and concerns about this assignment. He explained his reasoning and suggested that there is also a dative bond between Ga and Fe.
http://pubs.acs.org/doi/abs/10.1021/om970971w
There was no reply from the original authors. So, this is unfortunate. I was able to find a computational paper on the issue. But, it's not the best paper to read on the subject. The authors simply say that the triple bond is a "pseudo-conflict" in this case because our bonding model is not "appropriate." Personally, I agree with Cotton and I think there should only be a Ga->Fe bond.
Sunday, February 8, 2015
Lewis Acidity of Organofluorophosphonium Salts #chempaperaday 187-188
The paper I read was "Lewis Acidity of Organofluorophosphonium Salts: Hydrodefluorination by a Saturated Acceptor that was published in Science. The second one is the "perspective" by F.Gabbai in the same issue.
Caputo, C. B.; Hounjet, L.
J.; Dobrovetsky, R.;
Stephan, D. W., Lewis Acidity of Organofluorophosphonium
Salts: Hydrodefluorination by a
Saturated Acceptor. Science 2013, 341 (6152), 1374-1377.
Gabbaï, F. P., Lewis Acids with a Difference. Science
2013, 341
(6152), 1348-1349.
I pretty much knew nothing about hydrodefluorination until I read these papers. Now I know some. Really difficult research but it's not very popular yet. So, there is a lot of opportunities in this area of research.
Whittlesey, M. K.; Peris, E., Catalytic Hydrodefluorination with
Late Transition Metal Complexes. ACS Catalysis 2014, 4 (9),
3152-3159
"Synthesis, Characterization, and Structures of a Persistent Aniline Radical Cation" and the controversy #chempaperaday 183-186
The recent controversy and discussion starts with the publication of the report of a stabilized aninile radical cation.
Here the authors claim that they were able to stabilize the radical cation and report x-ray structures, electrochemical studies and some EPR data.
Shortly after this paper, two comments appear:
Comment on “Synthesis,
Characterization, and Structures of Persistent Aniline Radical Cation”:
It Is a Protonated Aniline and Not an Aniline Radical Cation
and
Comment on “Synthesis,
Characterization, and Structures of a Persistent Aniline Radical
Cation”: A New Interpretation Is Necessary
The commenters try to replicate the experiments and they basically say that it is not an aniline radical. They have some detailed studies and explanations.
Finally, the original authors publish a reply to those two comments here:
Reply to Comments on “Synthesis, Characterization, and Structures of Persistent Aniline Radical Cation”
The problem with the "reply" is that they accept some of their "mistakes" and claim that they obtained the aniline radical cation. But, they can't really clarify some of the other concerns that the commenters pointed out.
Really interesting read.
Wednesday, January 28, 2015
Book: Regenesis: How Synthetic Biology Will Reinvent Nature and Ourselves
George Church is a great mind and scientist. I had the chance to listen to his talk in Museum of Science last year. So, when I saw the book by him, I didn't even hesitate one second. I knew it would be a great read. After reading it, I can say I was absolutely right. Whether you like biology or not, whether you know some biology or not, you should read the book. It is not only a book about synthetic biology and the future of it, it is also about humanity, the fate of humans and our society.
"Imagine a future in which human beings have become immune to all viruses, in which bacteria can custom-produce everyday items, like a drinking cup, or generate enough electricity to end oil dependency. Building a house would entail no more work than planting a seed in the ground. These scenarios may seem far-fetched, but pioneering geneticist George Church and science writer Ed Regis show that synthetic biology is bringing us ever closer to making such visions a reality. In Regenesis, Church and Regis explore the possibilities—and perils—of the emerging field of synthetic biology. Synthetic biology, in which living organisms are selectively altered by modifying substantial portions of their genomes, allows for the creation of entirely new species of organisms. Until now, nature has been the exclusive arbiter of life, death, and evolution; with synthetic biology, we now have the potential to write our own biological future. Indeed, as Church and Regis show, it even enables us to revisit crucial points in the evolution of life and, through synthetic biological techniques, choose different paths from those nature originally took. Such exploits will involve far more than just microbial tinkering. Full-blown genomic engineering will make possible incredible feats, from resurrecting woolly mammoths and other extinct organisms to creating mirror life forms with a molecular structure the opposite of our own. These technologies—far from the out-of-control nightmare depicted in science fiction—have the power to improve human and animal health, increase our intelligence, enhance our memory, and even extend our life span. A breathtaking look at the potential of this world-changing technology, Regenesis is nothing less than a guide to the future of life."
The above paragraph is straight from the Amazon webpage for the book. I had to quote it because I can't write anything better than that. It's an easy to read book so I am pretty sure anyone who has 3-4 hours on a weekend will easily finish reading it. You will not only learn how synthetic biology can change our future but also how important it has become in our lives without even realizing it. Moreover, if you want to be an entrepreneur in biotech there are tens of examples of them; how they were founded, how and why they succeeded (or didn't), the challenges and even future directions.
Before you look up for the definition of synthetic biology, let's see how George Church describes it:
"the science of selectively altering the genes of organisms to make them do things that they wouldn;t do in their original, natural, untouched state."
As usual, I have quotes :
"Creating a mirror world might give us a fresh lease on life, one free of disease and unwanted agricultural pest species.""...species that are lowest in diversity are most vulnerable to extinction.""Give me a selection, and I will change the world.""Multicellularity tends to come with a hard consequence-you give up your immortality.""...just as individuals respond differently to drugs and to pathogens, they also respond differently to information.""What should we do? Doing nothing, or doing what is traditional or natural, is not even close to a recipe for survival. If we choose tomorrow to behave in a way that our primitive ancestors did, nearly all of our 7 billion humans will die."
Alfred Werner's seminal 1910 paper on polynuclear cobalt complexes: What have we learnt since then?
Alfred Werner is one of my heroes in chemistry. He's probably in top 3 with Linus Pauling and Fritz Haber. I wrote posts about him before. Also here are two links about the controversy between him and Jorgensen:
But, he has some role on almost anything I write about inorganic chemistry since he is the founder of coordination chemistry and probably the most important chemist who showed people the importance and power of inorganic chemistry. What he did in his limited time (he died at the age of 53) and with his limited equipment is simply incredible. He left us hundreds of pages of publications, books and his legend.
Karl Wieghardt is among my scientific heroes and as I said before I hope I can work for him one day. Here is an interview with him that I posted before. So, I am extremely happy to hear him giving a talk about Alfred Werner. I will not spoil it for you, because I really want you to watch/listen to this presentation by him about Alfred Werner. Once again, I hope you will realize and share my thoughts about Alfred Werner. Because, as Werner's life, the presentation is also full of surprises. I am pretty sure you will learn many things about Werner that you haven't heard so far. I hope you enjoy it.
Saturday, January 17, 2015
The Principle of Membrane Fusion in the Cell (Nobel Lecture) #chempaperaday 182
I try to read as many Nobel lectures as possible. You can often find really important pieces in those successful scientists' life and career that might help you figure out a problem in your research or a way to approach the problem.
This Nobel lecture on membrane fusion by J.E. Rothman is among the best. Just like many other Nobel laureates, he also has an interesting and diverse background that helped him throughout his career.
According to him, "the key elements for breakthrough" are:
-an ideal working environment
-The choice of the right problem at the right time
-A unique way of approaching the problem-hard work and persistence to develop a method that works in the wake of many painful failures
-the right partner to attack the problem-stable research funding
"there is no process in biology that, at its very core, is not physical-chemical
in nature. As the direct consequence, we can expect that, in due course, all of
life—even human thought and emotion—will be understood as emergent from
physics and we will understand ourselves in health and in disease as complex,
organically composed self-determining machines. This is a perspective that may
frighten some, but it should not because it offers our species the best hope for
the long term."
-Seeks universal laws to explain all related processes on a common basis
-Formulates the simplest hypothesis to explain the facts
The simplest hypothesis:
-Intrinsic chemical specificity governs transport, not intracellular anatomy"
Here is the lecture slides :
Here is where I read the lecture:
Also here:
Saturday, January 3, 2015
Fritz Haber: The Damned Scientist - #chempaperaday 181
I couldn't help reading another article on Fritz Haber today.
Like every persont, he had a personal life and he made choices. All I am interested in him is his science and I admire his science.
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