Dimethylaminophosphoniumsalze

Gloede, J.; Waschke, R.

doi:10.1002/zaac.19875450221

Cited by 5 publications

(1 citation statement)

References 13 publications

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“…1‐PCl 2 and 1‐PBr 2 both show a broad 11 B NMR resonance around 41 ppm and a 31 P NMR singlet at 163.0 and 166.8 ppm, respectively. The latter are slightly upfield‐shifted compared to the 31 P NMR shifts of PCl 2 (NMe 2 ) and PBr 2 (NMe 2 ) at 165 and 174 ppm, respectively [34] …”

Section: Resultsmentioning

confidence: 85%

Aromatic 1,2‐Azaborinin‐1‐yls as Electron‐Withdrawing Anionic Nitrogen Ligands for Main Group Elements

Lindl

Lamprecht

Arrowsmith

et al. 2023

Chemistry A European J

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The 2‐aryl‐3,4,5,6‐tetraphenyl‐1,2‐azaborinines 1‐EMe3 and 2‐EMe3 (E=Si, Sn; aryl=Ph (1), Mes (=2,4,6‐trimethylphenyl, 2)) were synthesized by ring‐expansion of borole precursors with N3EMe3‐derived nitrenes. Desilylative hydrolysis of 1‐ and 2‐SiMe3 yielded the corresponding N‐protonated azaborinines, which were deprotonated with nBuLi or MN(SiMe3)2 (M=Na, K) to the corresponding group 1 salts, 1‐M and 2‐M. While the lithium salts crystallized as monomeric Lewis base adducts, the potassium salts formed coordination polymers or oligomers via intramolecular K⋅⋅⋅aryl π interactions. The reaction of 1‐M or 2‐M with CO2 yielded N‐carboxylate salts, which were derivatized by salt metathesis to methyl and silyl esters. Salt metathesis of 1‐M or 2‐M with methyl triflate, [Cp*BeCl] (Cp*=C5Me5), BBr2Ar (Ar=Ph, Mes, 2‐thienyl), ECl3 (E=B, Al, Ga) and PX3 (X=Cl, Br) afforded the respective group 2, 13 and 15 1,2‐azaborinin‐2‐yl complexes. Salt metathesis of 1‐K with BBr3 resulted not only in N‐borylation but also Ph‐Br exchange between the endocyclic and exocyclic boron atoms. Solution 11B NMR data suggest that the 1,2‐azaborinin‐2‐yl ligand is similarly electron‐withdrawing to a bromide. In the solid state the endocyclic bond length alternation and the twisting of the C4BN ring increase with the sterics of the substituents at the boron and nitrogen atoms, respectively. Regression analyses revealed that the downfield shift of the endocyclic 11B NMR resonances is linearly correlated to both the degree of twisting of the C4BN ring and the tilt angle of the N‐substituent. Calculations indicate that the 1,2‐azaborinin‐1‐yl ligand has no sizeable π‐donor ability and that the aromaticity of the ring can be subtly tuned by the electronics of the N‐substituent.

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Section: Resultsmentioning

confidence: 85%