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Synthesis and Characterization of Bis(sigma)borate and Bis–zwitterionic Complexes of Rhodium and Iridium
Author(s) -
Roy Dipak Kumar,
Borthakur Rosmita,
De Anangsha,
Varghese Babu,
Phukan Ashwini K.,
Ghosh Sundargopal
Publication year - 2016
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201600980
Subject(s) - rhodium , iridium , chemistry , adduct , carbene , benzothiazole , medicinal chemistry , boron , ligand (biochemistry) , stereochemistry , catalysis , organic chemistry , biochemistry , receptor
Building upon the chemistry of Rh–N,S‐heterocyclic carbene complex, [(Cp*Rh)(L 2 )(1‐benzothiazol‐2‐ylidene)], 2 (Cp*=η 5 ‐C 5 Me 5 ; L=C 7 H 4 NS 2 ) with various monoboranes‐Lewis adducts, we explored the chemistry of 2 with BH 3 ⋅thf at elevated temperature. As a result, mild thermolysis of 2 with BH 3 ⋅thf led to the formation of bis(sigma)borate [(η 4 ‐C 5 Me 5 H)Rh(η 2 ‐H 3 BL)], 3 and a bis‐zwitterionic species [Cp*RhS(BH 2 L 2 )], 4 with the concomitant release of BH 3 ⋅bt (bt=benzothiazole). The RhS 3 C 2 N 2 B 2 atoms in 4 generates two six membered rings fused by a common Rh−S bond, which may be considered as a bicycle [4.4.0] cage at the rhodium center. In an effort to generate the iridium analogue of 3 , reaction of [Cp*IrCl 2 ] 2 with Na[H 3 B(mbt)] (mbt=2‐mercaptobenzothiazole) was carried out that produced bis(sigma)borate complex [(η 4 ‐C 5 Me 5 H)Ir(η 2 ‐H 3 BL)], 1 . The solid state X‐ray structures of 1 and 3 showed that the Cp*H ligand coordinated to the metal center in a η 4 ‐fashion. In compound 3 , the methyl group is oriented towards rhodium center, whereas it is away from Ir center in 1 . In addition, the DFT computations were performed to shed light on the bonding and electronic structures of these compounds.