Schiff base chemistry of the {ReO}3+ core: structural characterization of the unusual ‘3+2’ complex [ReO(η3-OC6H4–CHNC6H4-2-S)(η2-OC6H4)]

Abstract

The reaction of [ReOCl(3)(PPh(3))(2)] with salicylaldehyde-2-mercaptoanil (1) in methanol yields [ReO(OCH(3))(PPh(3))(eta(3)-OC(6)H(4)CH=NC(6)H(4)S)] (3). Reaction of 3 with 2-(2-hydroxyphenyl)benzothiazole (2) produces [ReO(eta(3)-OC(6)H(4)CH=NC(6)H(4)S)( eta(2)-OC(6)H(4))] (4) in good yield. Compound 4 may also be prepared directly from the reaction of [ReOCl(3)(PPh(3))(2)] with excess 1, after prolonged reaction times in the presence of atmospheric oxygen. The structure of 3 exhibits a distorted octahedral Re(V) center coordinated to a terminal oxo-group, a methoxy ligand, a triphenylphosphine ligand, and the N, O and S donors of the tridentate Schiff base ligand. The octahedral geometry of 4 is defined by the terminal oxo-group, the N, O and S donors of the tridentate Schiff base ligand, and the N and O donors of the bidentate 2-(2-hydroxophenyl)benzothiazole ligand. Oxidation and cyclization of the Schiff base salicylaldehyde-2-mercaptoanil to produce 2-(2-hydroxyphenyl)benzothiazole is precedented and in this instance may be driven by the formation of the robust '3+2' complex 4.

Rhenium(V) Complexes with Selenolato‐ and Tellurolato‐Substituted Schiff Bases – Released PPh3as a Facile Reductant

“…This means that the imine double bonds remain mainly localized and no significant delocalization of π‐electron density is observed in this chelate ring. A similar bonding situation is observed in analogous oxidorhenium(V) complexes with the salicylidene Schiff bases derived from 2‐aminophenol ({L O } 2– ) or 2‐aminothiophenol ({L S } 2– ),, despite the fact that the tridentate O , N , O and O , N,S ligands are both coordinated in a meridional arrangement.…”

“…Since all hitherto structurally studied Re(V) complexes with the {L O } 2– and {L S } 2– show a mer ‐arrangement of these ligands, and the complexes with their selenium and tellurium analogues of the present study contain the tridentate ligand exclusively in a facial coordination mode, we undertook a series of DFT calculations on the B3LYP level for both isomers of the [ReO(L Y )Cl(PPh 3 )] (Y = O, S, Se, Te) complexes. Frequency calculations after the optimizations showed convergence of at least two out of four criteria in all cases and full convergence on the experimentally expected isomers.…”

Reactivity of 2-(2-hydroxyphenyl)benzoxazole and 2-(2-hydroxyphenyl)benzothiazole towards group 10 transition metals. Evaluation in palladium catalyzed Suzuki–Miyaura C–C couplings

“…Being known now a days complexes of almost any transition metal [4][5][6][7][8][9][10][11][12][13] and rare earth [14][15][16][17]. Thus, metal derivatives of HPBO and HPBT have attracted much attention due to their optical and luminescent properties.…”

Synthesis and structural characterization of rhenium(I) tricarbonyl complexes with the bidentate ligands o-(diphenylphosphino)benzaldehyde (P∩O) and o-[(diphenylphosphino)benzylidene]analine (P∩N)

“…These '3+1' integrated complexes eliminated the possibility of syn and anti stereoisomers that are often produced in the tetradentate complexes, but they were found to be relatively unstable in vitro and in vivo due to metabolism and replacement of the monothiol ligand through transchelation by physiological thiols such as cysteine and glutathione [15]. By replacing the monothiolate ligand with a bidentate [NO] or [PO] donor set, '3+2' sixcoordiante oxometal complexes of the general formulation [ReO(η 3 -L A )(η 2 -L B )], possessing a maximum electron count (MEC) of 18 rather than 16 which were always encountered in the case of '3+1' complexes, improved the kinetic stability substantially [16][17][18].…”