Mono- and di-nuclear complexes of molybdenum carbonyl derivatives with pyridine-2-carbaldehyde azine and phosphines: syntheses, structure, spectroscopic and electrochemical characterisation and solvatochromic effects

Abstract

Complexes containing phosphorus-donor ligands, [Mo(CO),(PPh,)(pa)] (pa = pyridine-2-carbaldehyde azine), bis(diphenylphosphino)ethane], have been characterised by infrared and electronic spectroscopy, cyclic voltammetry and for the [M02(Co),(p-dppe)(p-p)] complex a single crystal X-ray structure. All of the complexes show strong solvatochromism which has been analysed both by using the empirical parameter E*MLCT and by using McRae's equation. The results are compared with those of their parent complexes [Mo(CO),(pa)] and [Mo,(CO),(p-pa)], and with the results of extended-Hiickel calculations with charge iteration. [Mo2(Co),(PPh3>2(pL-pa)l 9 [Mo2(Co)7(PPh3>(p-pa)l and [Mo2(Co>6(pL-dppe)(C-Pa)l Cdppe = ,2-

A combined experimental and DFT study of a novel unsymmetrical azine 2-(4-methoxybenzylidene)-1-(1-(4-isobutylphenyl) ethylidene) hydrazine

“…The carbon chemical shifts are presented in Table 3. The low field signal observed around 15 ppm in 13 at C20 and hence the C17 carbon is shielded by the electrons from methoxy group is exposed at down field 127.0 ppm and the ipso carbon C20 is deshielded and the peak is observed at 157.9 ppm.…”

“…In this study, an unsymmetrical azine 2-(4-methoxybenzylidene)-1-(1-(4-isobutylphenyl) ethylidene) hydrazine (UA) is prepared and characterized by IR, 1 H and 13 C NMR spectral studies. The B3LYP level of calculations available in Gaussian 03 software package is used for computational investigation of the synthesized unsymmetrical azines (UA).…”

“…The GIAO 1 H NMR and13 C NMR chemical shift calculations of the stable conformer is made in CDCl 3 [scrf= (solvent=chloroform)] by using B3LYP / 6 -31G (d, p) basis set and the scaling factor used at this level are 31.7099 and 192.6365 for 1 H NMR and 13 C NMR chemical shift calculations respectively. The chemical shifts obtained at B3LYP / 6 -31G(d,p) level of computation are compared with the experimental results.…”

Spectral and conformational studies on 3-pyridinealdazine by DFT approach

“…The ability of azines derived from 2-pyridinecarboxaldehyde as polydentate ligand to form very stable complexes with different cations is well known [13]. Azines have been used extensively as ligands for the synthesis of novel organometallic compounds [14][15][16]. Inspite of these synthetic utility, azines have good electronic, linear and non-linear optical properties [17][18][19][20].…”

A novel triply bridged dinuclear four-coordinate copper(I) complex with sterically bulky bis(dicyclohexylphosphino)methane ligand

“…Pyridine-2-carbaldehyde azine (paa) has formally a single N-N bond and can adopt nearly planar, Z or E, and twisted conformations depending upon the co-ligands bonded to the metal ions and their preference for different coordination geometries. Thus the dinuclear complexes with paa ligands attracted extensive attention, not only with respect to their structures but also for the influence of the structure on the interaction between the two metal ions or neighboring ligands [4][5][6][7][8][9]. However, most of the work about these ligands is mainly on the complexes of the metal ions such as Mo(0), Fe(II), Ni(II), Co(II), Cu(II), Ir(II), Zn(II), Ag(I), Rh(III), and Hg(0).…”