Complexes of cobalt(II) halides with 4-substituted pyridines

Abstract

Complexes have been obtained from cobalt(11) chloride, bromide, iodide, and thiocyanate with eight 4-substituted pyridines, NC5H4R, where R = CH2C6H5, p-CH2C,6H,4Cl, CH2OH, Cl, Br, C02C4H9, COC6H5, and CN, in order of decreasing basicity. Twenty-nine of the compounds prepared are of the type CoX2B2, thirteen of the type CoX2B4, three CoX2B33 two CoX2B5, two CoX2B2(H2O)2, and one CoX2B(CH3OH). The stereochemistry of the cobalt atom has been assigned in each case on the basis of magnetic properties and reflectance spectra. In all cases but one the cobalt appears to exhibit octahedral or tetrahedral stereochemistry and to have the high-spin configuration; diiodotris(p-chloropyridine)cobalt(11) is probably an example of a low-spin 5-coordinate compound. The stereochemistry is largely determined by the halogen, the preference for octahedral stereochemistry increasing in the order I � Br < C1 � NCS. There is also a small effect due to the base, octahedral stereochemistry being favoured by the weaker bases. The behaviour of the compounds in nitrobenzene solution has also been studied.

Nature of the Coordination Bond in Metal Complexes of Substituted Pyridine Derivatives. VI. Electronic Spectra of Some Complexes of Copper(II)

“…We suspect that the structure of the complex may also play an important role. Recently, Graddon et al proposed a polymeric octahedral structure for the cobalt(I1) complex of 4-carbinylpyridine with the oxygen atom in the carbinyl group taking part in the coordination (13). Whether the same situation occurs in the copper Ccarbinylpyridine bromide complex needs further investigation.…”

The infrared spectra (3500-140 cm?1) of the 2,2'-bipyridine, 2-aminomethylpyridine and ethylenediamine adducts and the sodium tris-compounds of cobalt(II), nickel(II) and zinc(II) acetylacetonates

“…spectra of bipy, amp and en and certain metal(ll) complexes containing these ligands has been relatively well estab-lished0 [2][3][4][5][6][7][8][9][10][11][12][13][14]. spectra of bipy, amp and en and certain metal(ll) complexes containing these ligands has been relatively well estab-lished0 [2][3][4][5][6][7][8][9][10][11][12][13][14].…”

Modified Metal Dibenzoylmethanates for Soft Supramolecular Materials: Extension to Oligomeric and Polymeric Host Receptors with Nanosized Void Spaces

“…Inclusion of the same molecule both as a part of the host complex and as a guest in the same compound has been observed and discussed before, ,,,,− and the inclusion of bipy in such instance was recently demonstrated. − It is quite surprising though that inclusion of bipy occurs even upon application of 2 orders molar concentration excess of tert -butylbenzene. Both guest bipy and tert -butylbenzene interact with the host lattice by van Waals forces only, and the resulting structure must reflect the spatial complementarity.…”