Hexaaquanickel(II) disulfato(1,4,8,11-tetraazacyclotetradecane)nickelate(II) dihydrate

Abstract

The title compound, [Ni(H(2)O)(6)][Ni(SO(4))(2)(C(10)H(24)N(4))].2H(2)O, is an unusual compound in that it is composed of a hexaaqua complex, formally a dication, and a mixed-donor complex (four N and two O atoms), formally a dianion, with substantial charge separation between the two nickel centres (6.536 A). The homoleptic dication complex consists of the weaker-field ligands, whilst the dianion retains the coordination of all the higher-field donors. Both nickel ions are located at centres of symmetry. This rare compound is placed in the context of previously reported structures which emphasizes its peculiarity.

[Ag(OH2)2][Ag(SO4)2]: A Hydrate of a Silver(II) Salt

“…Thus, the title compound may be described better as [Ag(OH 2 ) 2 ][Ag(SO 4 ) 2 ], some sulfate anionsb eing in fact shared between different Ag 2 + cations. [17] This feature renders AgSO 4 ·H 2 Os imilar to its Cu 2 + analogue. [18] The [Ag(SO 4 ) 2 ]s ublattice forms infinite 1D chains [Ag(SO 4 ) 4/2 ] 1 reminiscent of those seen in the crystal structure of relatedAg(SO 3 CF 3 ) 2 (see the Supporting Information).…”

“…Inspection of the crystal structure of AgSO 4 ⋅H 2 O (Figure ) shows that water molecules are distributed unequally at various silver sites: one (Ag1) is coordinated by two water molecules and another (Ag2) site by none. Thus, the title compound may be described better as [Ag(OH 2 ) 2 ][Ag(SO 4 ) 2 ], some sulfate anions being in fact shared between different Ag 2+ cations . This feature renders AgSO 4 ⋅H 2 O similar to its Cu 2+ analogue .…”

Kinetic measurements and quantum chemical calculations on low spin Ni(II)/(III) macrocyclic complexes in aqueous and sulphato medium

“…It is interesting to note that [Ni(II)L 1 ] also forms axial coordination with sulphate through bridging oxygen. 69 In addition to the formation of axial coordinate bond, the sulphato oxygen atoms O 3 Analysis of bonding involving the axial water molecule reveals a striking difference in the mode of bonding in 3 and 6. The water molecule is coordinately bound in the axial position in 3 with Ni(III)-O 1 bond length 2.269 Å and the corresponding bond order is 0.24.…”