[(dcpe)Pt(ECp*)₂] (E = Al, Ga):  Synthesis, Structure, and Bonding Situation of the First Aluminum(I) and Gallium(I) Complexes of Phosphine-Substituted Transition Metal Centers

Abstract

Herein we describe the first phosphine-substituted transition metal complexes with terminal coordinated Cp*E ligands (E ) Al, Ga; Cp* ) pentamethylcyclopentadienyl). The reaction of [(dcpe)Pt(H)(CH 2 t-Bu)] (dcpe ) bis(dicyclohexylphosphino)ethane) with Cp*E yields the tetrahedrally coordinated complexes [(dcpe)Pt(AlCp*) 2 ] (1) and [(dcpe)Pt(GaCp*) 2 ] (2), respectively. Quantum-chemical DFT calculations on the model complexes [(dhpe)Pt-(AlCp) 2 ] (1M) and [(dhpe)Pt(GaCp) 2 ] (2M; dhpe ) diphosphinoethane) verify rather weak Pt-E bonds for both complexes. A comparison with the complexes [M(ER) 4 ] and [(CO) n M-ER] shows that Cp*E represents a moderate σ-donor/π-acceptor and that the bond strength is strongly influenced by the ancillary ligands at the transition metal center; in particular, (CO) n M fragments give more polar bonds than phosphine-substituted metal centers such as L 2 Pt.

The Clusters [Ma(ECp*)b] (M=Pd, Pt; E=Al, Ga, In): Structures, Fluxionality, and Ligand Exchange Reactions

“…However, compounds of that kind do exist, for example, [Pt(ECp*) 2 (dcpe)] (dcpe = bis(dicyclohexylphosphino)ethane), and were synthesized by trapping the in situ formed [L 2 Pt] with stoichiometric amounts of ECp*. [24,25] In the presence of stronger p-acceptor ligands the dinuclear molecular structure M 2 Ga 3 is retained and disubstituted species similar to 5 are formed. Thus, the reaction of Pt 2 Ga 5 with an excess of CO or CNtBu yields the complexes [Pt 2 (CO) 2 (m 2 -GaCp*) 3 ] (6) and [Pt 2 (CNtBu) 2 (m 2 -GaCp*) 3 ] (7), respectively (Scheme 2).…”

Wechselwirkung zwischen d‐ und p‐Block‐Metallen: Synthese und Struktur von Platin‐Alan‐Addukten

“…Diese Verbindung weist jedoch eine zusätzliche Pt-Al-p-Rückbindung auf, die den geringen Pt-Al-Abstand bewirkt. [18] Abbildung 1. Molekülstruktur von 2 (ohne Wasserstoffatome, thermische Ellipsoide bei 50 % Wahrscheinlichkeit).…”

Transition Metal Chemistry of Low Valent Group 13 Organyls

“…[28] It was shown that compound 4a can act as a building block for the synthesis of dinuclear complexes affording [Mo 2 (CO) 6 [29,30] The unsaturated 14 VE fragment [(dcpe) 2 Pt] is thermally formed from [(dcpe) 2 PtH(neopentyl)] and trapped in the presence of E I R ligands (Scheme 2). An unsaturated carbonyl system which has been studied in more detail is the reaction of GaCp* with the multiple bonded dimeric complexes [CpM(CO) 2 ] 2 (M ϭ Mo, W).…”