“…Under the sole perspective that second-row metals form stronger metal–nitrogen bonds than the first-row ones, isomer 12b (with a “PdN 3 ” core) would be expected more stable than 12a , which features three nickel–nitrogen bonds. However, the “M(Cl)(PPh 3 )” fragment in the trigonal-planar site is more likely to be occupied by the metal that is more easily reduced and/or that produces stronger π-imine bonds.…”