The η 1 -H-CHg agostic interactions in the mercury complexes of N-confused porphyrin.

Six four-coordinated complexes of the chemical formulae [Hg(2-N CH2COOCH2CH3-21-H-NCIPP)X1 with X = Cl (5), Br (6), I (7), [Hg(2-NCH3-21-H-NCIPP)C1] (4) and Hg(2-NCH2COOCH2C6H5-21-H-NCIPP)X1 with X- CI (8), I (9) are synthesized and structurally determined. The bond path for the weak eta(1)-H(17) C(17)center dot center dot center dot Hg agostic interactions between the Hg center and H(17) in complexes 4-9 was a through-space interaction from Hg to agostic carbon [C(17)] followed by a through-bond interaction from C(17) to an agostic proton H(17)]. The magnitude of J[Hg----H(17)) for the agostic upheld shift A6,,, of the C(17)] for these complexes increases as the halide ligand varies from iodide to chloride, ranging from 33.2 Hz (or 14.3 ppm) for I- to 36 Hz (or 15.8 ppm) for Br- and 36.9 Hz (or 16.0 ppm) for Cl-. The plot of J[Hg----H(17)] for the agostic proton H(17) versus vertical bar Delta delta(ago)vertical bar for the agostic carbon atom C(17) in compounds 3-9 was linearly expressed as J[Hg-H(17)] = 2.29 1 vertical bar Delta delta(ago)vertical bar + 0.13.