Structural, Non-Covalent Interaction, and Natural Bond Orbital Studies on Bromido-Tricarbonyl Rhenium(I) Complexes Bearing Alkyl-Substituted 1,4-Diazabutadiene (DAB) Ligands

Abstract

The synthesis, characterization, structural and computational studies of Re(I) tricarbonyl bromo complexes bearing alkyl-substituted 1,4-diazabutadiene ligands, [Re(CO)3(1,4-DAB)Br], where 1,4-DAB = N,N-bis(2,4-dimethylbenzene)-1,4-diazabutadiene, 2,4-Me2DAB (1); N,N-bis(2,4-dimethylbenzene)-2,3-dimethyl-1,4-diazabutadiene, 2,4-Me2DABMe (2); N,N-bis(2,4,6-trimethylbenzene)-1,4-diazabutadiene, 2,4,6-Me3DAB (3); and N,N-bis(2,6-diisopropylbenzene)-1,4-diazabutadiene, 2,6-ipr2DAB (4) are reported. The complexes were characterized by different spectroscopic methods such as FT-IR, 1H-NMR, 13C-NMR, and elemental analyses and their solid-state structures were confirmed by X-ray diffraction. In each complex, the Re(I) centre shows a distorted octahedral shape with a facial geometry of carbonyl groups. The gas phase geometry of the complexes was identified by density functional theory. Interesting intermolecular n…π* interactions of complexes 1 and 3 were investigated by non-covalent interaction index (NCI), and natural bond orbital (NBO) analyses. The intramolecular n…σ*, σ…π*, π…σ* interactions were also studied in complexes 3 and 4.

Synthesis and Characterization of Novel [2 + 1] Tricarbonyl Rhenium Complexes with the Hydrophilic Phosphine Ligands PTA and CAP

“…In addition to the exploration of the [2 + 1] strategy for the design of new Re(I) complexes by using the appropriate ligands, there is an increased interest on the study of intermolecular interactions of Re(I) complexes in the solid state [ 33 – 35 ] based on diverse types of interactions of rhenium complexes with DNA [ 36 , 37 ]. Similar systematic crystal structure studies [ 38 – 40 ] have revealed the importance of lone pair π and more specifically the role of carbonyl-carbonyl interactions on the supramolecular assembly of Re complexes.…”

Supramolecular assembly through intermolecular n → π* interactions through a coordinated perrhenate formed via superoxidation of Re(i) to Re(vii) in the formation of substituted Re(CO)3 complexes bearing Diimine ligands

“…To this effect, the study of metal carbonyls complexes on the basis of participation in a n→π* interaction similar to their organic counterparts and related to their role in catalysis are of considerable interest. Therefore, in a continuation of our interest in intra-and intermolecular n→π* interactions in metal-carbonyl complexes, [27][28][29][30] herein, we report the synthesis, full structural and computational studies of two new Re(CO)3 complexes bearing diimine ligands with a coordinated perrhenate, formed via superoxidation of Re(I), and its potential as supramolecular synthon for assembly through n→π* interactions. Please do not adjust margins Please do not adjust margins the [Re(CO)3(Ph4TAP)] + and [Re(CO)3(Dafone)] + cations to form the neutral di-rhenium mixed oxidation state complexes in good yields (69% for 1 and 70% for 2).…”