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Crystallography 2018
Structural Chemistry & Crystallography Communication
ISSN: 2470-9905
Page 52
June 04-05, 2018
London, UK
3
rd
Edition of International Conference on
Advanced Spectroscopy,
Crystallography and Applications
in Modern Chemistry
M
onodithiolen complexes of molybdenum and tungsten have
always attracted significant scientific interest as firstly they
canpotentiallybeadaptedasartificialmolybdopterin/tungstopterin
cofactors and secondly their crystal structures can provide
powerful information about the coordination sphere in the natural
Mo/W cofactor. With this information a better comprehension
of the reaction mechanisms as well as the physicochemical
properties of the natural enzyme can be achieved. So far the
most accurate structural analogue of native molybdoenzymes´
first coordination sphere was designed by Holm et al in 2001 [1].
Today´smany challenges remain regarding the synthetic efficiency,
structural accuracy and catalytic
activity.Inour lab, we developed a
novel synthetic strategy for establishing Mo and Wmonodithiolene
complexes. The synthetic success was supported by some notable
crystal structures of those complexes and their metalprecursors
[2]. Pre activated compounds 1 and 2 are isomorphous and
crystalize in the P21/c space groups with clearly octahedral
geometry and trans angles of 172.22(12)° to 176.38(14)° in 1
and 171.9(4)° to 176.8(4)° in 2. The Bailar twist angle in 1 ranges
between 54.95° and 60.43° and in 2 between 55.34° and 59.88°.
The focal molecules 3 and 4, which were synthesized from 1 and
2, respectively, by replacing the labile thf and one of the basal CO
ligands, crystallize in the orthorhombic space group P212121. The
geometry of the final compounds changes from clearly octahedral
to decidedly trigonal prismatic, which is strongly associated with
dithiolene complexes as evidenced by several related crystal
structures [3-8], even though such complexes are extremely rare. It
has to be pointed out that in the case of 3 and 4 the nearly perfect
trigonal prismatic geometry is confirmed by the Bailar twist angle.
Most surprisingly in 3 and 4 the torsion angles of the P-C-C-P
moiety of dppe is close to 0 with only 7.3°. This indicates an almost
planar arrangement which is extraordinary for dppe complexes.
Figure 1:
[Mo(CO)3(dppe)(THF)] (1), [Wo(CO)3(dppe)(THF)] (2) top and
[Mo(CO)2(cydt)(dppe)] (3), [Mo(CO)2(cydt)(dppe)] (4) bottom. Thermal
ellipsoids are shown at the 50% probability level. H atoms are not shown for
clarity reasons.[2]
Recent Publications
1. Lim B., Willer M., Miao M., Holm R. J. Am. Chem. Soc.,
2001, 123, 8343-8349
2. Elvers B., Nowack R., Schulzke C., Fischer C. in
preparation.
3. Yan Y., Keating C., Chandrasekaran P., Jayarathne U.,
Mague J., DeBeer S., Lancaster K., Sproules S., Rubtsov
I., Donahue J. Inorg. Chem. 2013, 52, 6743-6751.
4. Tsukada S., Abe N., Gunji T., Polyhedron 2016, 117, 73-
79
5. Chandrasekaran P., Arumugam K., Jayarathne U., Pérez
CRYSTALLOGRAPHY OF NOVEL MONODITHIOLENE MOLYBDENUM AND
TUNGSTEN COMPLEXES AND THEIR PRECUSORS
Chrysochos Nicolas
1
, Benedict Elvers, Christian Fischer
and
Carola Schulzke
University of Greifswald, Germany
Chrysochos Nicolas et al., Struct Chem Crystallogr Commun 2018, Volume 4
DOI: 10.21767/2470-9905-C1-006