Tuesday, May 23, 2017

Carbon–Fluorine Reductive Elimination from Nickel(III) Complexes #chempaperaday 297

This is "the first direct evidence of a C-F reductive elimination from a 1st row transition metal fluoride complex". They were able to structurally characterize one of these complexes and provide more evidence for the proposed Ni(III) intermediates. 

A fantastic paper and study. The barrier for reductive elimination of Ni-F was also found to be less than the Pd-F complexes. I am glad nickel is getting more and more attention. I like octahedral nickel complexes and I think we will see more of those in the future.

Monday, May 22, 2017

Terminal Parent Phosphanide and Phosphinidene Complexes of Zirconium(IV) #chempaperaday 296

I don't post papers about early metals (not 1st row ones; 2nd and 3rd row), and I think this may even be the first one I am sharing here. If you follow Prof. Liddle's group, you are probably aware of their U=P, Th=P complexes. I think I posted the one about thorium recently if not both. Here, they expand the same chemistry to early transition metals to investigate the M-P bond. They were able to structurally characterize both a phosphanide and a phosphinidene. They found out that the Zr-P bond is also polarized just like actinide-P bonds, and even less covalent than those (DFT). I am actually not completely surprised that it is not much covalent. 
If you look at Scheme 1, you will see that Zr-PH bond is drawn as a double bond. The distance is actually ~0.2 A larger than the sum of their covalent radii and there is an agostic interaction Zr-H (check the crystal structure). But they calculated the Mayer Bond order as 1.48 and assigned it as a double bond. Sometimes schemes are not enough to visualize what really is going on. Anyway, I like this gorup's work and try to read their work as much as possible.

Friday, May 19, 2017

N2-to-NH3 Conversion by a triphos–Iron Catalyst and Enhanced Turnover under Photolysis #chempaperaday 295

Another fantastic paper from one of my favorite groups. They were able to produce ammonia (again!) now with some hydride complexes. They also found out that photolysis improves the yield.  I bet they tried or they are still working on it but I am wondering if you can reduce 2 and then make a hydride or dihydride complex. As always, very nice synthetic work and characterization.