Weak η 2 –C–H⋯Hg interactions. Crystal structures of Hg(II) 2-N substituted N-confused porphyrin: Hg(2-NCH 2 - p -C 6 H 4 -CH 3 -21-H-NCTPP)I and Hg(2-NCH 2 - p -C 6 H 4 -isoC 3 H 7 -21-H-NCTPP)I·C 6 H 5 CH 3

The crystal structures of 2-aza-2-[p-(isopropyl)benzyl]-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N′,N″)palladium(II) [Pd (2-NCH2-p-C6H4-isoC3H7NCTPP); 3], (2-azo-2-[p-(isopropyl)]-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N′,N″)platinum(II) [Pt(2-NCH2-p-C6H4-isoC3H7NCTPP); 4], iodo(2-azo-2-[p-(isopropyl)benzyl]-5,10,15,20-tetraphenyl-21-hydrogen-21-carbaporphyrinato-N,N′,N″)mercury(II) toluene solvate [Hg(2-NCH2-p-C6H4-isoC3H7-21-H-NCTPP)I⋅C6H5CH3; 5⋅C6H5CH3], (2-azo-2-[p-methylbenzyl]-5,10,15,20-tetraphenyl-21-carbaporphyrinato-N,N′,N″)nickel(II) [Ni(2-NCH2-p-C6H4-CH3NCTPP); 6] and iodo(2-azo-2-[p-methylbenzyl]-5,10,15,20-tetraphenyl-21-hydrogen-21-carbaporphyrinato-N,N′,N″)mercury(II) [Hg(2-NCH2-p-C6H4-CH3-21-H-NCTPP)I; 7] were determined. The coordination sphere around the Pd2+ (or Pt2+, Ni2+) ion in 3 (or 4, 6) is distorted square planar (DSP) whereas for Hg2+ in 5 (or 7), it is a distorted tetrahedral complex with the T-based pyramid of the C2v symmetry. The coupling of H(17) in 5 (7) to 199Hg with J [199Hg–H(17)] = 34.8 Hz (5) and J [199Hg–H(17)] = 34.2 Hz (7), supported the assignment of agostic η2–C–H(17)⋯Hg interactions in these two mercury complexes.