Structural Chemistry Of Complexes With N,N-Dimethyl-1,3-Propanediamine And Its Schiff Base Ligands

In recent years, complexes with diamine and its derivatives ofSchiff base ligands have gained special attention as chelate reagent,stabilizer, bioactive reagent and catalyst which have been widely used inthe study of many science fields such as chemistry, biology, and medicine.In this paper, the author has carried out the study on the complexes withN,N-dimethyl-1,3-propanediamine and its Schiff base ligands.1. Twelve complexes with N,N-dimethyl-1,3-propanediamine (dropda) and its Schiff base ligands have been synthesized. The complexes areshown following: [Ni(dmpda)(tta)₂] (1), [Cu(dmpda)(bzac)Cl] (2),[Zn(dmpda)(dbm)₂] (3), [Cd(dmpda)(dbm)₂] (4), [Zn(dmpda)Cl₂] (5),[NIL₂¹] (6), [Zn(HL¹)Cl₂]·CHCl₃ (7), [ZnL₂¹]·2H₂O (8), [CdL²Cl₂] (9),[Cd₂L₂¹Cl₂] (10), [Cd₂L₂¹E(NCS)₂] (11), [Zn₃L₂¹(N₃)₄]·CH₂Cl₂ (12).2. The crystal structures of these complexes have been determinedby single-crystal X-ray diffraction. The results are summarized below. (1)Five complexes with dmpda ligand are all mononuclear complexes. Inthese complexes, dmpda binds to metal ion via two nitrogen atoms,forming a six-membered chelate ring with a chair-configuration.Intermolecular hydrogen bonding interactions lead to a dinuclear structure in complex 1, an one-dimensional chain in complex 2 and atetranuclear structure in complex 5, respectively. (2) HL¹ ligand can bindto metal ion via four donor atoms or part of them to form mononuclear,dinuclear or trinuclear complexes. In complexes 6, 7 and 8, the ligandbinds to metal ions via two donor atoms of the phenolic oxygen and theimino nitrogen or three donor atoms of the phenolic oxygen, the iminonitrogen and the tertiary amino nitrogen to form mononuclear structures.Intermolecular hydrogen bonding interactions lead to one-dimensionalchains in complexes 7 and 8, respectively. In complexes 10 and 11, all offour donor atoms take part in coordination, and the phenolic oxygen atombridges two metal ions to form dinuclear structures. In complex 12, fourdonor atoms take part in coordination, the phenolic oxygen atom andazide bridge three zinc ions to form a trinuclear structure. (3) L² ligandbinds to divalent cadmium ion via three nitrogen atoms to form amononuclear complex 9.3. All complexes have been characterized by IR and EA, and a fewof them have been characterized by thermal analyses. They show that themajority of complexes undergo two consecutive steps of weight loss, andresidues are the oxides.