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Coordination of N 2 and Other Small Molecules to the Phosphorus Centre of RPW(CO) 5 : A Theoretical Study on the Janus Facets of the Stabilization/Activation Problem
Author(s) -
Espinosa Ferao Arturo,
Streubel Rainer
Publication year - 2017
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.201700524
Subject(s) - ligand (biochemistry) , chemistry , covalent bond , crystallography , molecule , bond length , single bond , dissociation (chemistry) , bridging ligand , stereochemistry , crystal structure , receptor , biochemistry , alkyl , organic chemistry
Bonding of neutral terminal phosphinidene tungsten(0) complexes stabilized by ligands bound to phosphorus (ligand‐to‐P) have been studied using a large testbed of predominantly N‐ligands. Most complexes ( 1 a – r , v – z and 2 l ) exhibit a pyramidal P centre with a formal single ligand‐to‐P bond order. Three ligand‐to‐P complexes ( 1 s – u ) exhibit planar sp 2 ‐hybridization of P and P,N bonds featuring double bond character. All derivatives with C‐ligands ( 1 v , x – z ) exhibit a ligand‐to‐P bond strength intermediate between the P−N single and double bonded species. Remarkably, dinuclear complexes containing CN − ( 1 p , w ), N 3 − ( 1 r ) and N 2 ( 1 – 3 t ) as bridging ligands between two phosphorus centres show intertwined terminal W(CO) 5 fragments. In particular, the case of N 2 bridging ligand ( 1 – 3 t ) represents a noteworthy example of activation, displaying a weakened N,N bond and two sets of very strong P,N double bonds, the latter resembling the activation‐picture of dinitrogen by transition metal complexes. Bond dissociation energies (BDEs) of ligand‐to‐P bonds do not show any correlation with a range of bond strength descriptors, but display some meaningful, roughly linear variation with the ligand softness. Based on Haaland's definition of dative bonding, a reasonable linear correlation of BDE with dativity ( d 1 ) and the dative covalence energy (DCE 1 ) was found. A moderate correlation was also obtained with the vertical ionization potential of the ligand ( I (L)) as well as with the ligands HOMO energy.