Τίτλος:
2,2 ‘-Bipyridine,1,10-phenanthroline and 2,2 ‘: 6,2 ‘’-terpyridine in
gallium(III) chemistry: Complexes containing the
Ga-2(III)(mu-OH)(2)(4+) core
Περίληψη:
The reactions of Ga(NO3)(3) center dot 9H(2)O with 2,2’-bipyridine
(bpy), 1, 10-phenanthroline (phen) and 2,2’:6’,2”-terpyridine (terpy)
in alcohols afford the complexes [Ga-2(OH)(2)(bpy)(4)](NO3)(4) (1),
[Ga-2(OH)(2)(phen)(4)](NO3)(4) (2) and
[Ga-2(OH)(2)(H2O)(2)(terpy)(2)](NO3)(4) (3), respectively, in good
yields. The crystal structures of 1 center dot 1.3MeOH center dot
1.4H(2)O, 2 center dot 4.5MeOH and 3 have been solved by single-crystal
X-ray crystallography. The three complexes contain the
Ga-2(III)(mu-OH)(2)(4), core. Four nitrogen atoms from two chelating
bpy (1) or phen (2) complete distorted octahedral coordination at each
metal centre. In 3 one tridentate chelating terpy and one aquo ligand
complete six coordination at each Ga-III atom. The crystal structure of
2 - 4.5MeOH is stabilized by hydrogen bonds and intermolecular pi-pi
stacking interactions, while in 3 hydrogen bonds create a double-chain,
ladder-like architecture. Characteristic IR data are discussed in terms
of the nature of bonding and the structures of the three complexes. The
H-1 NMR spectra of complexes 2 and 3 suggest the presence of the free
ligand and one solution species containing the coordinated ligand. The
structure of the cation [Ca-2(OH)(2)(bpy)(4)](4+) is retained in D2O
as deduced by the 2D homonuclear COSY map. (c) 2006 Elsevier B.V. All
rights reserved.
