Anion‐Directed Template Synthesis and Hydrolysis of Mono‐Condensed Schiff Base of 1,3‐Pentanediamine and o ‐Hydroxyacetophenone in Ni II and Cu II Complexes

Bis( o ‐hydroxyacetophenone)nickel(II) dihydrate, on reaction with 1,3‐pentanediamine, yields a bis‐chelate complex [NiL 2 ] · 2H 2 O ( 1 ) of mono‐condensed tridentate Schiff baseligand HL {2‐[1‐(3‐aminopentylimino)ethyl]phenol}. The Schiff base has been freed from the complex by precipitating the Ni II as a dimethylglyoximato complex. HL reacts smoothly with Ni(SCN) 2 · 4H 2 O furnishing the complex [NiL(NCS)] ( 2 ) and with CuCl 2 · 2H 2 O in the presence of NaN 3 or NH 4 SCN producing [CuL(N 3 )] 2 ( 3 ) or [CuL(NCS)] ( 4 ). On the other hand, upon reaction with Cu(ClO 4 ) 2 · 6H 2 O and Cu(NO 3 ) 2 · 3H 2 O, the Schiff base undergoes hydrolysis to yield ternary complexes [Cu(hap)(pn)(H 2 O)]ClO 4 ( 5 ) and [Cu(hap)(pn)(H 2 O)]NO 3 ( 6 ), respectively (Hhap = o ‐hydroxyacetophenone and pn = 1,3‐pentanediamine). The ligand HL undergoes hydrolysis also on reaction with Ni(ClO 4 ) 2 · 6H 2 O or Ni(NO 3 ) 2 · 6H 2 O to yield [Ni(hap) 2 ] ( 7 ). The structures of the complexes 2 , 3 , 5 , 6 , and 7 have been confirmed by single‐crystal X‐ray analysis. In complex 2 , Ni II possesses square‐planar geometry, being coordinated by the tridentate mono‐negative Schiff base, L and the isothiocyanate group. The coordination environment around Cu II in complex 3 is very similar to that in complex 2 but here two units are joined together by end‐on, axial‐equatorial azide bridges to result in a dimer in which the geometry around Cu II is square pyramidal. In both 5 and 6 , the Cu II atoms display the square‐pyramidal environment; the equatorial sites being coordinated by the two amine groups of 1,3‐pentanediamine and two oxygen atoms of o ‐hydroxyacetophenone. The axial site is coordinated by a water molecule. Complex 7 is a square‐planar complex with the Ni atom bonded to four oxygen atoms from two hap moieties. The mononuclear units of 2 and dinuclear units of 3 are linked by strong hydrogen bonds to form a one‐dimensional network. The mononuclear units of 5 and 6 are joined together to form a dimer by very strong hydrogen bonds through the coordinated water molecule. These dimers are further involved in hydrogen bonding with the respective counteranions to form 2‐D net‐like open frameworks. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)