ic7b02621_si_001.pdf (3.22 MB)
Labile Low-Valent Tin Azides: Syntheses, Structural Characterization, and Thermal Properties
journal contribution
posted on 2017-12-15, 20:35 authored by Rory Campbell, Sumit Konar, Steven Hunter, Colin Pulham, Peter PortiusThe first two examples of the class
of tetracoordinate low-valent,
mixed-ligand tin azido complexes, Sn(N3)2(L)2, are shown to form upon reaction of SnCl2 with
NaN3 and SnF2 with Me3SiN3 in either pyridine or 4-picoline (2, L = py; 3, L = pic). These adducts of Sn(N3)2 are shock- and friction-insensitive and stable at r.t. under an
atmosphere of pyridine or picoline, respectively. A new, fast, and
efficient method for the preparation of Sn(N3)2 (1) directly from SnF2, and by the stepwise
de-coordination of py from 2 at r.t., is reported that
yields 1 in microcrystalline form, permitting powder
X-ray diffraction studies. Reaction of 1 with a nonbulky
cationic H-bond donor forms the salt-like compound {C(NH2)3}Sn(N3)3 (4) which
is comparably stable despite its high nitrogen content (55%) and the
absence of bulky weakly coordinating cations that are conventionally
deemed essential in related systems of homoleptic azido metallates.
The spectroscopic and crystallographic characterization of the polyazides 1–4 provides insight into azide-based
H-bonded networks and unravels the previously unknown structure of 1 as an important lighter binary azide homologue of Pb(N3)2. The atomic coordinates for 1 and 2–4 were derived from powder and single
crystal XRD data, respectively; those for 1 are consistent
with predictions made by DFT-D calculations under periodic boundary
conditions.