Crystalline Half-Parent Vinyl-tetrylenes: Synthesis and Coordination Chemistry

High Resolution Image Download MS PowerPoint Slide A family of stable, crystalline half-parent vinyl-tetrylenes R L(C 2 H 3 )E: ( 4 - 6; R L = {[R 2 PCH 2 Si( i Pr) 2 ](Dipp)N} −; Dipp = 2,6- i Pr 2 C 6 H 3; R = Ph, Cy) is reported, accessed via a straightforward salt-metathesis pathway, and their electronic properties and initial reactivity explored. All compounds display downfield-shifted signals in both the 1 H and 13 C NMR spectra for their [C 2 H 3 ] ligand, being most extreme for Pb due to relativistic effects. UV–vis spectra of compounds 4 – 6 reveal bathochromic shifts relative to the halo-tetrylene derivatives (i.e., R LEX; X = Cl, Br), due to stabilization of the LUMO through overlap of the E-centered p -orbital and the π*-orbital of the [C 2 H 3 ] unit. Vinyl group elimination is demonstrated in the plumbylene system, whereby reaction with the strong electrophile [Ph 3 C][BAr F 4 ] (Ar F = 3,5–(CF 3 ) 2 C 6 H 3 ) afforded low-coordinate Pb II cation 7, stabilized by the chelating ligand and secondary interactions with the weakly coordinating BAr F 4 anion. Finally, addition of vinyl-germylenes ( 4 ) to Ni 0 synthons enabled the synthesis of mono- and bis(vinylgermylene)-nickel(0) complexes 8 and 9, whereby binding occurs through the tetryl centers and not the vinyl fragment, representing the first examples of vinyl-tetrylene coordination complexes reported to date.