Syntheses and structures of highly hindered N-functionalised alkyl and amido group 12 complexes MR2 (M=Zn, Cd, and Hg), [MRCl]2 (M=Zn and Hg)

A Selective Redox and Chromogenic Probe for Hg(II) in Aqueous Environment Based on a Ferrocene−Azaquinoxaline Dyad

“…By contrast, the H-6 proton is further downshifted (Δδ H-6 = +0.19−0.12 ppm) and the H-8 proton is shifted less (Δδ H-8 = +0.33−0.28 ppm) upon complexation with Zn 2+ or Hg 2+ than with Pb 2+ cations, which means that the N-5 of the pyridine ring could be involved in the complexation process. Taking into account the 1:1 stoichiometry of the complex with Hg 2+ , deduced from spectroscopic and spectrometric data, as well as the broad signals in the 1 H NMR spectrum, participation of N-4 and N-5 (exobidentate ligand) in the complex formation is not discarded . Titration isotherms, generated from the change in chemical shift of the H 7 signal upon addition of Hg 2+ , Zn 2+ , and Pb 2+ cations, confirmed the stoichiometries of the complexes formed, using the computer program EQNMR .…”

Alkaline Earth Complexes of Silylated Aminopyridinato Ligands: Homoleptic Compounds and Heterobimetallic Coordination Polymers

“…The ease of variation of the substituents in the 6-position of the pyridyl ring and on the amino group offers many possibilities in terms of the steric demands of these aminopyridinato ligands. This amenability to steric tuning has led to reports of a range of main group, transition metal, and f-block compounds of these ligands. Of note is the use of the sterically demanding 2-aminomesityl-6-(tripp)pyridinato ligand (tripp = 2,4,6-triisopropylphenyl) by Kempe and co-workers to stabilize a complex featuring an ultrashort Cr–Cr quintuple bond .…”

Heavier alkali metal complexes of the bulky alkyl ligand 2-(bis(trimethylsilyl)methyl)-6-methylpyridine: Crystal structures of [{6-Me(2 Pyr)}(Me3Si)2CNa(pmdta)] and [{6-Me(2-Pyr)}(Me3Si)2CK]∞

“…Due to their ability to deliver stable organometallic complexes displaying unusual metal oxidation states and bonding modes, amongst significant structural diversity, bulky ligands derived from trimethylsilyl substituted methylpyridines have been widely used in exploring the chemistry of both main group and transition metals [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. The basic template of these ligands provides several attractive features for the synthetic and structural chemist; in conjunction with either 2-or 2,6-substitution of the pyridyl ring the number of Me 3 Si groups can be varied altering the steric bulk and degree of kinetic protection afforded metal centres, the pyridyl nitrogen can provide stabilisation through internal coordination, and the ligand can electronically re-arrange to accommodate both r and p metal-ligand bonding modes.…”

“…The basic template of these ligands provides several attractive features for the synthetic and structural chemist; in conjunction with either 2-or 2,6-substitution of the pyridyl ring the number of Me 3 Si groups can be varied altering the steric bulk and degree of kinetic protection afforded metal centres, the pyridyl nitrogen can provide stabilisation through internal coordination, and the ligand can electronically re-arrange to accommodate both r and p metal-ligand bonding modes. Our earlier studies with [(2-Pyr)(Me 3 Si) 2 C À ] [1,7,[12][13][14][15][16][17][18] and [(2-Pyr)(Me 3 Si)HC À ] [19] have shown how the p-block and transition metals invariably have the metal r-bonded to the substituted methyl C, with coordination of the pyridyl N, while the s-block metals display a greater variety in bonding modes revealing carbanionic, aza-allylic and amido complexes. A similar pattern has also been observed with [6-Me(2-Pyr)-(Me 3 Si) 2 C À ] (=R) [15] though to-date there have been no alkali metal complexes of this ligand structurally characterised.…”