Neutral Lewis Base Adducts of Silicon Tetraazide

Abstract

Highly energetic and still stable: The first base adducts of silicon tetraazide, Si(N3)4(L2) (L2=bipyridine, 1,10‐phenanthroline), were prepared and fully characterized (picture: the ball and stick model of the adduct with L2=2,2'‐bipyridine in front of its FTIR spectrum; dark gray C, white H, light gray Si, blue N). The highly energetic compounds combine a remarkable thermal stability, with a high reactive nitrogen content (up to 48 %) and convenient accessibility.

NHC‐stabilized Silicon(II) Halides: Reactivity Studies with Diazoalkanes and Azides

“…The Si–N α (azide) bond length of 7 [1.785(1) Å], the Si–N α –N β bond angle [126.9(1)°] as well as the difference Δ(NN) between the N α –N β and N β –N γ bond lengths of 7.5 pm are typical for four‐coordinate azidosilanes , . Also the distinctive ν(N 3 ) asym IR absorption band of 7 at 2141 cm –1 appears at a similar position to those of other azidosilanes …”

Taming Tin(IV) Polyazides

“…In the crystal,a ll complexesh ave distorted octahedral Sn[N] 6 coordination with N 3 ligands that often adopt disordered orientations. The neutral Lewis base adducts of Sn(N 3 ) 4 show slightly highert hermals tability than the related adducts of Si(N 3 ) 4 and Ge(N 3 ) 4 ,b ut lower sensitivity toward atmospheric moisture than the stabilized hexa(azido)silicate(IV) salt (PPN) 2 [Si(N 3 ) 6 ]i ns olution. An ew methodh as been developed to access and isolate charge-neutral polyazido tin complexes that extends the concept of Lewis base stabilizationt om onodentatel igands.…”

“…As aconsequence, C(N 3 ) 4 in particular,a nd also its heavier homologuesc annotb e isolated by conventionalm ethods. In contrast, our previous work demonstrated that the relatedc omplex ions [E(N 3 ) 6 ] 2À [4,7-9a] and neutral[ E(N 3 ) 4 (L 2 )],E = Si, [4] Ge, [9a] L 2 = bpy, phen, possess significantly increased stability( T dec up tõ 250 8C) and reduced sensitivity,w hich allowed their isolation and full characterization.T he increased stabilityi nt hese coordination compounds arises from the combined effects of lower specific endothermicities due to reduced nitrogen content, and changes in the nature of the EÀNb onds caused by hypercoordination which raisest he activation barriers for N 2 elimination. It has been proven previously [1] that these stable,n egatively charged complex hexa(azido) ions as well as the chargeneutrala dducts of binary azidesw ith nitrogen heterocycles [9] can be synthesized by reactions of NaN 3 with suitable chlorides, followed by eithers alt metathesis or ligand exchange.…”

Picosecond time-resolved infrared spectroscopy of rhodium and iridium azides

“…An IR Harrick cell spectroscopic cell equipped with CaF 2 windows and optical path lengths ranging from 0.1 to 0.5 mm was used for all TRIR measurements. The solvents THF (spectrometric grade, >99.5 %), CH 3 CN (anhydrous, >99.5%), CH 2 Cl 2 (spectrophotometric grade, >99.5%), toluene (anhydrous, 99.8%) were used as received from Aldrich or obtained from Grubbs columns 35 Crystallographic data for complex 1: Bruker APEX-II CCD, graphite monochromated Mo(k 1,2 ) radiation,  = 0.71073 Å, C 28 DFT calculations were performed using Gaussian 09, 36 the B3LYP 44 functional and the 6-311G** basis set 45 for H, C, N, and P. The SDD pseudopotential 46 was used for Rh and Ir. The effects of solvent were included using the polarisable continuum model 47 using the parameters for acetonitrile.…”