1,3,5‐Triazapentadiene Nickel(II) Complexes Derived from a Ketoxime‐Mediated Single‐Pot Transformation of Nitriles

A series of cationic (2+) [Ni{HN=C(R)NHC(R)=NH} 2 ](X) 2 {R = 4‐(Cl)C 6 H 4 ( 1 ), 3‐(NC)C 6 H 4 ( 3 ), 4‐(NC)C 6 H 4 ( 4 ) and Me ( 7 ); X = Cl – ( 1 , 3 , 4 ) or MeCOO – · H 2 O ( 7 )} and neutral [Ni{HN=C(R)NC(R)=NH} 2 ](solvate) {R = 3‐(Cl)‐4‐py ( 2 ), 3‐py ( 5 ) and 4‐py ( 6 ); solvate = MeOH and/or H 2 O; py = pyridyl} N , N ‐chelating bis(1,3,5‐triazapentadiene/ato)nickel(II) [Ni(tap) 2 ] 2+/0 complexes has been easily generated by a ketoxime‐mediated single‐pot reaction of a nickel(II) salt [NiCl 2 · 2H 2 O or Ni(MeCOO) 2 · 4H 2 O] with 4‐chlorobenzonitrile, isophthalonitrile, terephthalonitrile, acetonitrile, 2‐chloro‐4‐cyanopyridine, 3‐cyanopyridine or 4‐cyanopyridine, respectively. The obtained compounds have been characterized by IR, 1 H and 13 C{ 1 H} NMR spectroscopy, FAB‐MS(+) or ESI‐MS(+), elemental analyses and single‐crystal X‐ray diffraction [for 7 and solvated mono‐ { 1a· (Me 2 CO) 0.33 · (MeOH) 0.67 } and bis‐deprotonated ( 2b· 2Me 2 CO, 4b· CHCl 3 , 5b· Me 2 CO and 6b· MeOH) products, formed upon recrystallization of 1 , 2 , 4 , 5 and 6 , respectively]. The crystal structures of all compounds bear similar monomeric Ni(tap) 2 units with a nearly square‐planar geometry. In addition, the structure of 7 features the formation of infinite 1D zig‐zag water–acetate chains {[(H 2 O) 2 (MeCOO) 2 ] 2– } n , which multiply interact with the [Ni(tap) 2 ] 2+ cations to generate a 2D hydrogen‐bonded supramolecular assembly.