Synthesis, molecular and crystal structure, and features of the electronic structure of bis(O’i)-chelated bis(2,2-dimethylbenzo-[2H]-4-oxo-1,3-oxazino-3-methyl)difluorosilane

Abstract

Keywords: compounds of hexacoordinated silicon, hypervalency, quantum-chemical calculations, electron density distribution, X-ray structural investigation, synthesis.Neutral bis-chelated (LCH 2 ) 2 MHal 2 which contain a bidentate, monoionic, C,X-coordinated LCH 2 ligands (X = N, O) are quite well investigated compounds of hexacoordinated germanium and tin [1]. According to X-ray analysis the majority of them in the solid phase have a close to octahedral configuration with carbon atoms in trans and with the coordinated X and halogen atoms in cis positions relative to one another. At the same time their silicon analogs are virtually unstudied [2] and only a few examples of this type of compound with N→Si coordinated bis(8-dimethylamino-1-naphthyl)dichloro-and -difluorosilanes [3] and also (8-dimethylamino-1-naphthyl)(2-dimethylaminomethylphenyl)difluorosilanes [4] have been reported. In the case of the latter an X-ray investigation of the coordination about the Si atom has reported a doubly capped tetrahedron.We set out to attempt the preparation of neutral hexacoordinated dichlorosilanes (LCH 2 ) 2 SiCl 2 by treating trimethylsilyl (TMS) derivatives of five-, six-, and seven-membered lactams with bis(chloromethyl)dichlorosilane (ClCH 2 ) 2 SiCl 2 in the ratio 2 : 1 and obtained unstable, readily hydrolyzed materials. Treatment of the latter with Me 3 SiOTf or HgCl 2 under conditions which did not exclude access of the _______ * Dedicated to Prof. Edmunds Lukevics on the occasion of his 70th birthday __________________________________________________________________________________________ 1 A. N.

Hypercoordinate Silicon Complexes of (O,N,N′ vs. O,N,O′) Schiff Base Type N‐(2‐Carbamidophenyl)imines: Examples of Exclusively O‐Silylated Carbamides

“…Although representing an unexpected side product, 6a complements a wide range of silicon coordination compounds bearing carbamide carbonyl oxygen donor atoms in their coordination sphere. [10] In contrast to the pentacoordination of the silicon atoms in 4a, 4b, and 5b, the products obtained from the reactions of ligands 2a and 2b with diphenyldichlorosilane did not give any indication of the presence of hypercoordinate silicon compounds, neither in solution nor in the solid state. Ligand 2a, upon reaction with Ph 2 SiCl 2 in the presence of triethylamine, afforded a product mixture, which as solution in CDCl 3 , produced one predominant signal in the 29 Si NMR spectrum at δ = -43.2 ppm (7a).…”

Understanding the structure of salicyl hydrazone metallocomplexes: crystal structure, AIM and Hirshfeld surface analysis of trichloro-(N-salicylidenebenzoylhydrazinato-N,O,O′)-tin(IV)

“…The value of V e (r) can be calculated from values of ρ(r) and ∇ 2 ρ(r) in CP(3, −1) using Kirzhnitz formula for kinetic energy density and local virial theorem expression [28,29]. Previously, we used the results of topological analysis for calculations of bond energies formed by the Si(Ge) atoms [30][31][32]. Such estimation is based on the usage of above-mentioned correlation (I).…”

“…Similar to hexacoordinated Si atoms in [N-(dimethylamino)Fig. 3 Experimental static deformation electron density in 1 drawn with ±0.3 eÅ −3 isosurface (positive shown in fuchsia, negative in red) (Color figure online)phenylacetimide[66] and benzo-2H-1,3-oxazine-4-one[30] complexes, the Sn(1) atom in 1 bears strong positive charge. Overall PW-DFT/MP2/6-311G(d,p) charge (Z) of SnCl 3 moiety is 0.80/0.56 e. Thus, the amount of charge density donated from L to SnCl 3 is equal to 0.2/0.4 e that looks quite reasonable and is in good accord with the amount of charger transfer obtained for silatranes (ca.…”