NHC‐stabilized Parent Arsanylalanes and ‐gallanes

Abstract

The synthesis and characterization of the unprecedented compounds IDipp⋅E′H2AsH2 (E′=Al, Ga; IDipp=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) are reported, the first monomeric, parent representatives of an arsanylalane and arsanylgallane, respectively, stabilized only by a LB (LB=Lewis Base). They are prepared by a salt metathesis reaction of KAsH2 with IDipp⋅E′H2Cl (E′=Al, Ga). The H2‐elimination pathway through the reaction of AsH3 with IDipp⋅E′H3 (E′=Al, Ga) was found to be a possible synthetic route with some disadvantages compared to the salt metathesis reaction. The corresponding organo‐substituted compounds IDipp⋅GaH2AsPh2 (1) and IDipp⋅AlH2AsPh2 (2) were obtained by the reaction of KAsPh2 with IDipp⋅E′H2Cl (E′=Al, Ga). The novel branched parent compounds IDipp⋅E′H(EH2)2 (E′=Al, Ga; E=P, As) were synthesized by salt metathesis reactions starting from IDipp⋅E′HCl2 (E′=Al, Ga). Supporting DFT computations give insight into the different synthetic pathways and the stability of the products.

Cyclo‐Dipnictadialanes

“…1a-c crystallise in the triclinic space group P1 ¯with two molecules in the unit cell (Figure 1). [28] 1a is situated on acrystallographically imposed centre of inversion, resulting in acentral Al 2 P 2 rectangle with alternating Pa nd Al atoms and P À Al distances of 2.3176(7) and 2.3317 (7) ,respectively,which agrees well with the sixmembered species (Mes*AlPPh) 3 [cf. d avg.…”

“… [4] Dehydrogenative trimerisation in CH 2 Cl 2 solution afforded the six‐membered species [(CO 5 W)P(H)−Al(H)NMe 3 )] 3 , which transforms into a bicyclic species upon further loss of H 2 . [5] By judicious choice of a sterically demanding (kinetically stabilising) LB, e.g., IDip 2 (IDip 2 =(HCNDip) 2 C, Dip=2,6‐ i Pr 2 C 6 H 3 ), the first only LB‐stabilised parent compounds IDip 2 ⋅H 2 EPnH 2 (E=Al, Ga; Pn=P, [6] As [7] ) have recently been realised. In general, dimeric species of the type [R 2 Al−PR′ 2 ] 2 ( A , Scheme 1 ) are obtained by condensation reactions.…”

Taming PH3: State of the Art and Future Directions in Synthesis

“…91 Scheer has undertaken salt metathesis reactions of NaPH 2 with IPrGaHCl 2 (8) and the Al analogue (8′) to generate the corresponding bis-(dihydrophosphide) complexes (9/9′, Scheme 14c). 92 Hassler undertook a study into hypersilyl substituted phosphanes and, as part of this investigation, employed PH 3 or NaPH 2 to prepare tris(trimethylsilyl)silyldihydrophosphide (10). This species can undergo deprotonation with KOtBu, forming (Me 3 Si) 3 SiPHK (11), which is remarkably stable at room temperature, and can undergo reductive coupling to generate a mixture of the meso-and rac-isomers (12, Scheme 14d).…”

Cyclische Dipnictadialane

“…[4] Die sechsgliedrige Spezies [(CO 5 W)P(H)ÀAl(H)NMe 3 )] 3 entsteht durch die dehydrierende Tr imerisierung in CH 2 Cl 2 ,d ie sich bei weiterem H 2 -Verlust in eine bicyclische Spezies umwandelt. [5] Durch geschickte Wahl einer sterisch anspruchsvollen (kinetisch stabilisierenden) LB,z .B.I Dip 2 (IDip 2 = (HCNDip) 2 C, Dip = 2,6-iPr 2 C 6 H 3 ), wurden kürzlich die ersten, nur durch eine LB stabilisierten Stammverbindungen IDip 2 •H 2 EPnH 2 (E = Al, Ga;P n = P, [6] As [7] )r ealisiert. Im Allgemeinen werden dimere Spezies des Ty ps [R 2 AlÀPR' 2 ] 2 (A,Schema 1) durch Kondensationsreaktionen erhalten.…”

“…Durch geschickte Wahl einer sterisch anspruchsvollen (kinetisch stabilisierenden) LB, z. B. IDip 2 (IDip 2 =(HCNDip) 2 C, Dip=2,6‐ i Pr 2 C 6 H 3 ), wurden kürzlich die ersten, nur durch eine LB stabilisierten Stammverbindungen IDip 2 ⋅H 2 EPnH 2 (E=Al, Ga; Pn=P, [6] As [7] ) realisiert. Im Allgemeinen werden dimere Spezies des Typs [R 2 Al−PR′ 2 ] 2 ( A , Schema 1) durch Kondensationsreaktionen erhalten.…”