η <sup>3</sup> ‐Coordination and Functionalization of the 2‐Phosphaethynthiolate Anion at Lanthanum(III)**
Fabian A. Watt, Lukas Burkhardt, Roland Schoch, Stefan Mitzinger, Matthias Bauer, Florian Weigend, José M. Goicoechea, Frank Tambornino, Stephan Hohloch
Abstract
Abstract We present the η 3 ‐coordination of the 2‐phosphaethynthiolate anion in the complex (PN) 2 La(SCP) ( 2 ) [PN=N‐(2‐(diisopropylphosphanyl)‐4‐methylphenyl)‐2,4,6‐trimethylanilide)]. Structural comparison with dinuclear thiocyanate‐bridged (PN) 2 La(μ‐1,3‐SCN) 2 La(PN) 2 ( 3 ) and azide‐bridged (PN) 2 La(μ‐1,3‐N 3 ) 2 La(PN) 2 ( 4 ) complexes indicates that the [SCP] − coordination mode is mainly governed by electronic, rather than steric factors. Quantum mechanical investigations reveal large contributions of the antibonding π*‐orbital of the [SCP] − ligand to the LUMO of complex 2 , rendering it the ideal precursor for the first functionalization of the [SCP] − anion. Complex 2 was therefore reacted with CAACs which induced a selective rearrangement of the [SCP] − ligand to form the first CAAC stabilized group 15–group 16 fulminate‐type complexes (PN) 2 La{SPC( R CAAC)} ( 5 a,b , R=Ad, Me). A detailed reaction mechanism for the SCP‐to‐SPC isomerization is proposed based on DFT calculations.