Organocobaloximes with Mixed Dioxime Equatorial Ligands:  A Convenient One-Pot Synthesis. X-ray Structures and Cis−Trans Influence Studies

Abstract

A simple and general route to the synthesis of organocobaloxime with mixed dioxime ligands, RCo(L)(dpgH)Py [L ) dmgH and chgH] (R ) Me-Dec), has been described. The crystal structure of four complexes, ClCo(L)(dpgH)Py and MeCo(L)(dpgH)Py [L ) dmgH and chgH], is reported. The structural study reveals that both the nonclassical C-H‚‚‚O as well as the classical O-H‚‚‚O intermolecular hydrogen bonding is present and leads to the formation of one-dimensional dimeric or polymeric structures. 1 H and 13 C NMR coordination shifts in the axial pyridine ligand show clear correlations with the chemical shift of the equatorial ligand. These correlations can be rationalized with the aid of the ring current model.

μ-Polymethylene bridged dicobaloximes: Structural, photolysis and thermal decomposition properties

“…Recently, inter and intra-molecular weak interactions of monocobaloximes have been discussed by Gupta et al [29,30]. In our cases, it is of interest to note that prismatic crystal 2 can be stored in air for months, however, claviform crystals 1 and 3 would effloresce within a few minutes once exposure to air.…”

In Search of High‐Performance Platinum(II) Phosphorescent Materials for the Fabrication of Red Electroluminescent Devices

“…The proposed intramolecular H-bonding interactions are reminiscent of those reported for pyridyl pyrazolate Os complexes as well as cobaloxime complexes. [10] It is believed that this unusual H-bonding pattern, to a certain extent, provides a strong driving force to stabilize the observed trans-geometry. In contrast to our discovery, the X-ray structural analyses of related Pt II complexes such as Pt(thppy) 2 , where thppy is 2-(2¢-thienyl) pyridine, revealed that ligated thiophene and pyridine fragments are oriented exclusively in a cis-configuration, despite the large distortion and deformation of square planar geometry that occurred at the junction of the ligands.…”

Pyridyl Azolate Based Luminescent Complexes: Strategic Design, Photophysics, and Applications

“…Of particular interest are the relatively weak nonbonding contacts (N3A -H1 ∼ 2.50 Å ) observed between the ortho -hydrogen atom of the pyridyl moiety and the N atom of the nearby pyrazolate fragment. It is speculated that this hydrogen bonding, to a certain extent, is akin to that observed in the cobaloxime complexes [40] . As indicated in Table 5.3 , the UV/Vis spectra of these osmium complexes showed similar patterns, with three notable absorption maxima.…”