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S 2 N 2 – A 6π‐Electron Ligand with Tunable σ‐ and π‐ Donor‐Acceptor Property
Author(s) -
Sadik Mohammed N. K.,
De Susmita
Publication year - 2020
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.202003299
Subject(s) - lone pair , chalcogen , chemistry , crystallography , metal , ligand (biochemistry) , valence electron , covalent bond , valence (chemistry) , acceptor , transition metal , electron donor , atom (system on chip) , electron , stereochemistry , molecule , physics , organic chemistry , biochemistry , receptor , quantum mechanics , computer science , embedded system , catalysis , condensed matter physics
The usage of inorganic cyclic N‐donor based ligands, whose electronic properties can be easily and extensively tuned, are still underdeveloped. One such system is sulfur‐nitrogen compounds known to form η 1 and η 2 ‐complexes with mono‐ and bi‐metallic transition metal fragments. We have undertaken an extensive theoretical investigation of the bonding nature between S 2 N 2 and 14 valence electron (VE) metal fragments in the mono and bi‐metallic S 2 N 2 [Mo(NO)Cl 4 ] − and S 2 N 2 [Mo 2 (NO) 2 (Cl) 8 ] 2 − . Our results indicate that S 2 N 2 is a σ‐donor and π‐acceptor ligand. The EDA‐NOCV analysis demonstrates that the interaction between S 2 N 2 and metal fragments has a higher electrostatic character than a covalent character. On the contrary, the σ‐lone pair on N‐atom in S 2 N 2 is donated to the electron‐deficient 12 valence electron [Mo(NO)Cl 4 ] + fragment in S 2 N 2 [Mo(NO)Cl 4 ] + and S 2 N 2 [Mo 2 (NO) 2 (Cl) 8 ] 2 + , while the electrons from the S 2 N 2 π‐MO are donated to the vacant d‐orbitals of the metal fragment. Besides, all these complexes show donation of lone pair on Cl attached to transition metal fragment to the S−N σ*‐MO, which can be considered as a σ‐hole that is involved in the chalcogen bond formation. Hence, our theoretical calculations suggest that the S 2 N 2 is a versatile ligand which can be tuned as σ‐donor, σ‐acceptor, π‐donor and π‐acceptor.