Premium
Ligands Based on Phosphine‐Stabilized Aluminum(I), Boron(I), and Carbon(0)
Author(s) -
Vondung Lisa,
Jerabek Paul,
Langer Robert
Publication year - 2019
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201805123
Subject(s) - chemistry , protonation , ligand (biochemistry) , phosphine , isomerization , reactivity (psychology) , metal , dissociation (chemistry) , transition metal , cationic polymerization , electrophile , photochemistry , oxidative addition , crystallography , stereochemistry , polymer chemistry , organic chemistry , ion , catalysis , medicine , biochemistry , receptor , alternative medicine , pathology
A systematic quantum chemical study of the bonding in d 6 ‐transition‐metal complexes, containing phosphine‐stabilized, main‐group‐element fragments, (R 3 P) 2 E, as ligands (E=AlH, BH, CH + , C), is reported. By using energy decomposition analysis, it is demonstrated that a strong M−E bond is accompanied by weak P−E bonds, and vice versa. Although the Al−M bond is, for example, found to be very strong, the weak Al−P bond suggests that the corresponding metal complexes will not be stable towards phosphine dissociation. The interaction energies for the boron(I)‐based ligand are lower, but still higher than those for two‐carbon‐based ligands. For neutral ligands, electrostatic interactions are the dominating contributions to metal–ligand bonding, whereas for the cationic ligand a significant destabilization, with weak orbital and even weaker electrostatic metal–ligand interactions, is observed. Finally, for iron(II) complexes, it is demonstrated that different reactivity patterns are expected for the four donor groups: the experimentally observed reversible E−H reductive elimination of the borylene‐based ligand (E=BH) exhibits significantly higher barriers for the protonated carbodiphosphorane (CDP) ligand (E=CH) and would proceed through different intermediates and transition states. For aluminum, such reaction pathways are not feasible (E=AlH). Moreover, it is demonstrated that the metal hydrido complexes with CDP ligands might not be stable towards reduction and isomerization to a protonated CDP ligand and a reduced metal center.