Preparation, characterization and solid state thermal studies of nickel(II) squarate complexes of 1,2-ethanediamine and its derivatives

Das, Debasis ; Ghosh, Ashutosh ; Chaudhuri, Nirmalendu Ray (1997) Preparation, characterization and solid state thermal studies of nickel(II) squarate complexes of 1,2-ethanediamine and its derivatives Bulletin of the Chemical Society of Japan, 70 (4). pp. 789-797. ISSN 0009-2673

Full text not available from this repository.

Official URL: http://www.journal.csj.jp/doi/abs/10.1246/bcsj.70....

Related URL: http://dx.doi.org/10.1246/bcsj.70.789

Abstract

[NiL3]C4O4 [L = 1,2-ethanediamine (en) and 1,2-N,N′-dimethylethanediamine (N,N′-dmen)], [NiL3]C4O4•nH2O [for L = 1,2-N-methylethanediamine (meen) and 2-methyl-1,2-propanediamine (ibn); n = 1, and for L = 1,2-propanediamine (pn); n = 2] and [NiL2C4O4]•2H2O [L = 1,2-N-ethylethanediamine (eten), 1,2-N-propylethanediamine (pren), 1,2-N,N-dimethylethanediamine (N,N-dmen) and 1,2-N,N′-diethylethanediamine (N,N′-deten)] have been synthesized by the addition of the respective diamines to finely powdered nickel (II) squarate dihydrate, NiC4O4•2H2O. All of the tris-species, except for [Ni(N,N′-dmen)3]C4O4 were also prepared by adding diamines to NiC4O4•2H2O dissolved in aqueous ammonia (25%). When the latter method was followed, the bis-species [NiL2C4O4] [L = eten, pren, 1,2-N-isopropylethanediamine (ipren), N,N-dmen, N,N′-dmen, and N,N′-deten] were also obtained. [NiL2C4O4] (L = en, meen, N,N′-dmen, pn, and ibn) were also prepared from their corresponding tris (diamine) species upon heating in the solid state. [Ni(ibn)3]C4O4•nH2O after dehydration underwent an irreversible endothermic (145-160 °C; ΔH = 6.5 kJ mol−1) phase transition without showing any visual color change. [Ni(ipren)2C4O4] exhibited a reversible phase transition (78-107 °C; ΔH = 1.4 kJ mol−1 for heating and 105-72°C; ΔH = −1.3 kJ mol−1 for cooling). The phase transitions are considered to have been due to conformational changes of the diamine chelate rings. All of the tris as well as bis (diamine) complexes possess an octahedral geometry, except for [Ni(ibn)2]C4O4, which is square-planar. The bis-species [NiL2C4O4] (L = eten, pren, N,N-dmen and N,N′-deten) exists in two isomeric forms.

Item Type:Article
Source:Copyright of this article belongs to Chemical Society of Japan.
ID Code:108433
Deposited On:13 Oct 2017 12:58
Last Modified:13 Oct 2017 12:58

Repository Staff Only: item control page