Cellular interactions of platinum drugs #chempaperaday 232

This is a 2012 review paper and a really good summary on the fate of platinum drugs in model systems and in cells. 

While we know that cisplatin completely cures testicular cancer and is very effective in a few other cancer types, the mechanism of action is still not really known. It is also not known why it is so selective against testicular cancer. The article made me really realize how little we know about cisplatin and other platinum anticancer drugs. There are tens of cellular targets and it is still not understood what happens to cisplatin when it enters the cell. In fact, only 1% of cisplatin ends up binding to DNA. There is still so much work to do to answer these questions and develop better drugs. I hope I can help one day.

The Phenomenon of the Styrian Arsenic Eaters... #chempaperaday 231

This is new to me. So, apparently, it was long known (or believed) to be that there were/are people who eat white arsenic to become immune to certain diseases or to get healthier! Stories of these people were told in several parts of the world including Europe and several novels, poems etc. are based on these people.

In this interesting article, you can read whether this phenomenon is real or not. The author mentions as many of these literature examples as possible and like a detective, he tries to find the truth. I think it is a really good read if you enjoy history of chemistry.

Heterometallic Effects in Trinuclear Complexes Supported by p-Terphenyl Diphosphine Ligands #chempaperaday 230

Not the most conclusive study, but a good work on the synthesis and characterization of three trinuclear complexes.

One of the most interesting parts for me is that compound 3[BF4]  (-1.31V) was reduced by cobaltocene (-1.32 V).

 

http://pubs.acs.org/doi/abs/10.1021/acs.organomet.5b00579

Heterogeneous catalysis with metal nitrides #chempaperaday 229

Although I am working on making catalysts for homogeneous catalysis, one of my biggest passions is heterogeneous catalysis.

Metal nitrides are one of the most interesting class of these catalysts. There are several examples of them used and being explored in ammonia synthesis, hydrotreating, hydrogenation and so on. There are examples of these in this paper. You can also read several different methods to make these catalysts and some distinctive features of each.

There is a nice paragraph summarizing the limitations of the experiments and analysis of these catalysts too such as surface structure-activity reaction.

For those who know nothing about metal nitrides in heterogeneous catalysis, I think the key is that they are believed to show "noble-metal like behaviour."

 

Diiron Azadithiolates as Models for the [FeFe]-Hydrogenase Active Site... #chempaperaday 228

More on diiron complexes in this post. This is a nice and beautifully written summary of Prof. Rauchfuss' work on the topic.

"To the eyes of an organometallic chemist, the active site of the [FeFe]-H₂ases combines the familiar and unfamiliar."

A few things to note :

- Diiron, nickel-iron and iron based hydrogenases have no evolutionary relationship.

- low spin iron centers in general stabilizes hydrides better than high spin ones

Synthetic Advances Inspired by the Bioactive Dinitrosyl Iron Unit #chempaperaday 227

Ok, first of all, I am not dead and I didn't stop reading. In fact, I've probably read more than ever. I mostly read papers related to my research and a specific research problem though. That's why I keep them to myself. Hopefully, I will get on track again starting with this post.

This is a really good article on dinitrosyl iron units which are believed to be very important in cell biology. As the authors say "DNICs have been documented to be the largest NO-derived adduct in cells".

You can find some really cool synthetic routes to make these complexes and their electrochemistry in this paper. Hope you enjoy.

Cobalt(III) Werner Complexes with 1,2-Diphenylethylenediamine Ligands #chempaper 226

I think this is a really nice study. They checked 80 crystal structures of [Co(en)3]3+ and then came up with this useful approach to catalyze the addition of malonate esters to nitroalkenes. Classical Werner complexes once again proved that they are very promising in catalysis.

http://pubs.acs.org/doi/full/10.1021/acscentsci.5b00035

Amide-Functionalized Naphthyridines on a Rh(II)–Rh(II) Platform #chempaper 225

This is an interesting paper on dirhodium complexes where the authors try to synthesize some catalytically active compounds, but instead they found out and reported the steric effects of the ligands. Some of the complexes do show some catalytic activity but the known and simple dirhodium acetate complex is still much more active.

Anyway, it's worth reading and seeing some interesting ligands and synthetic work.


http://onlinelibrary.wiley.com/doi/10.1002/chem.201402936/full

Multiple Metal-Metal Bonds #chempaper 224

This is another paper by F.A. Cotton on (of course) multiple metal-metal bonds. It was basically a lecture he gave in ACS Seattle (1983). Not surprisingly he summarizes multiple M-M bonding starting as early as mid 18th century. So, I got to learn a lot from this paper that I had not known. There is also a really interesting quote and talk by Linus Pauling on metal-metal bonding where he tries to describe a few Mo-Mo, W-W and Ta-Ta bonds. Cotton also confesses that he had heard about Pauling's paper by pure coincidence.

On the famous Re-Re multiple bonding, Cotton says :

As always, it was a pleasure to read the paper. I hope you enjoy it too.

Learning Python - My First Program

I have tried to learn some coding before but didn't have enough time/ambition to do so. This year, I started learning Python again and I am taking it more seriously. I am determined to learn it and do something "useful" with it. One of the courses I am taking is An Introduction to Interactive Programming in Python on Coursera and the code below is for our first Miniproject (Rock-paper-scissors-lizard-Spock). Any feedback is appreciated.

# My first program
# Rock-paper-scissors-lizard-Spock

import random
import math

def name_to_number(name): # converts name to number
    if name == "rock":
        return "0"  
    elif name == "Spock":
        return "1"
    elif name == "paper":
        return "2"
    elif name == "lizard":
        return "3"
    elif name == "scissors":
        return "4"
    else:
        print "Please choose one of these : rock, Spock, paper, lizard, scissors."

def number_to_name(number): # converts number to a name
    if number == 0:
        return "rock"
   
    elif number == 1:
        return "Spock"
       
    elif number == 2:
        return "paper"
       
    elif number == 3:
        return "lizard"
       
    elif number == 4:
        return "scissors"
   
def rpsls(player_choice):
   
    print "New game!"
   
    print ""
   
    print "Player chooses " + player_choice
   
    comp_number = int(random.randrange(0 , 5)) # computes random guess for comp_number
   
    comp_choice = number_to_name(comp_number)
   
    player_number = int(name_to_number(player_choice))
       
    print "Computer chooses", comp_choice

    num = int((comp_number - player_number) % 5) # computes difference of comp_number and player_number modulo five
   
    if (num == 1) or (num == 2) or (num == - 1) or (num == - 2):
       
        print "Computer wins!"
       
    elif (num == 3) or (num == 4)or (num == - 3) or (num == - 4):
       
        print "Player wins!"
       
    elif (num == 0):
       
        print "Player and computer tie!"

rpsls("rock")
rpsls("Spock")
rpsls("paper")
rpsls("lizard")
rpsls("scissors")

Inorganic Chemistry Notes 1 - On Oxides

I have recently decided to write down some notes on inorganic chemistry for a few purposes:

    - so that I don't forget a few basic things

    - to memorize some of the tricky details

    - to be able to use the blog as my notebook

      and several other reasons.

These mostly will be from the papers or references I read from time to time.

Here comes the first one on oxides from Cotton and Wilkinson's Basic Inorganic Chemistry textbook.

Ionic oxides react with water to make metal hydroxides. But, they dissolve in acids to produce the metal cation and water.

Covalent oxides, on the other side are acidic in water. The water insoluble ones dissolve in bases. 

Amphoteric oxides are bases towards strong acids and they act as acids in bases.

Evaluating Molecular Cobalt Complexes for the Conversion of N2 to NH3 #chempaper 223

Another great (IMO) example and very well studied complex for nitrogen fixation. As an inorganic chemist, I love this type of work with synthetic routes and nice tables that give good information.

A fast metal–metal bonded water oxidation catalyst #chempaper 222

If you are one of those people who are interested in metal-metal bonding, you might have already read this article. It's in one of those less known journals (Journal of Catalysis). But, I try to look for some articles every once in a while. I think it's a really useful journal. 

To me, the most important part of the article is the proof that compounds having metal-metal bonds can be useful in catalysis. There are tons of examples of them, but this is one of the most recent ones. You don't have to develop an industrial catalyst, but you can still prove people that you can achieve catalysis using these complexes. 

A Career in Catalysis: John E. Bercaw #chempaper 221

This is a great "Account" highlighting John Bercaw's career and success. If you are in inorganic chemistry, it is very often that you will see his papers cited or his work is mentioned in many papers. If you are doing organometallic work, you will always find some help in his work. 

http://pubs.acs.org/doi/abs/10.1021/acscatal.5b00076

Thermal Activation of N-H Bonds by Transition-metal Oxide Cations: Does a Hierarchy Exist in the First Row? #chempaper 220

A computational and experimental study of N-H bond activation using first row transition metals except Cu. Because, they couldn't generate [CuO] cation. Three general reactions among the series as follows:

As expected, the three type of reactions are not observed among all the 1st row TMs. The oxophilic early metals for example tend to give the first type of reaction.

I think it is a good study and worth reading.

Strong homonuclear metal-metal bonds #chempaper 219

For some, this might be an "old" article. For people like me, it is another learning opportunity with incredibly valuable information that you can't even read in textbooks. Of course, some of them are outdated now.