Bis[μ-N′-(adamantan-1-ylcarbonyl)-2-oxidobenzohydrazidato(3−)]tetrapyridinetrinickel(II) dimethylformamide monosolvate monohydrate

In the title trinuclear NiII compound, [Ni3(C18H19N2O3)2(C5H5N)4]·C3H7NO·H2O, three NiII cations are bridged by two N′-(adamantan-1-ylcarbonyl)-2-oxidobenzohydrazidate trianions. The central NiII cation has a distorted octahedral N4O2 coordination environment where a reverse torsion occurs between the two bridging ligands, whereas the two NiII cations on the sides each adopt an N2O2 square-planar coordination. Weak intramolecular C—H⋯O and C—H⋯N interactions help to stabilize the molecular structure. In the crystal, the lattice water molecule links with the NiII complex and dimethylformamide solvent molecule via O—H⋯O hydrogen bonding.

In the title trinuclear Ni II compound, [Ni 3 (C 18 H 19 N 2 O 3 ) 2 -(C 5 H 5 N) 4 ]ÁC 3 H 7 NOÁH 2 O, three Ni II cations are bridged by two N 0 -(adamantan-1-ylcarbonyl)-2-oxidobenzohydrazidate trianions. The central Ni II cation has a distorted octahedral N 4 O 2 coordination environment where a reverse torsion occurs between the two bridging ligands, whereas the two Ni II cations on the sides each adopt an N 2 O 2 square-planar coordination. Weak intramolecular C-HÁ Á ÁO and C-HÁ Á ÁN interactions help to stabilize the molecular structure. In the crystal, the lattice water molecule links with the Ni II complex and dimethylformamide solvent molecule via O-HÁ Á ÁO hydrogen bonding.
coordination polymers with interesting structural motifs, such as the one-dimensional, the two-dimensional, the threedimensional and the metallacrown (Liu et al., 2008;Moon et al., 2006;Qin et al., 2011;Wang et al., 2005). For nickel (II) complexes with N-acylsalicylhydrazide ligands, we can see that trinuclear complexes is more common from the former reports (Lin et al., 2007);Meng et al., 2007);Xiao & Jin, 2008);Yang & Lin, 2005) and most of them are unstable in air.
In the molecular structure, the arrangement of three Ni 2+ ions and the ligands which were coordinated to the central Ni 2+ ion in axial positions are different from the reported trinuclear nickel(II) complexes containing N-acylsalicylhydrazide ligands (Yang & Lin, 2005;Xiao & Jin, 2008). In this complex, three Ni 2+ ions are arranged in an arcuate shape. The central Ni2 atom adopts a distorted octahedral geometry and is coordinated by two hydrazide nitrogen atoms (N1, N4) and two salicyl carbonyl oxygen atoms (O2, O5) from two bridge deprotonated N-adamantanecarbonylsalicylichydrazide ligands (abbreviated as (ashz) 3-) in the equatorial plane and by two nitrogen atoms (N7, N10) from twopyridine molecules in the axial positions. There is a reverse torsion to be occurred between the two planes of the bridge (ashz) 3ligands because of the steric hindrance effect caused by adamantly. This torsion led the bond angles of O5-Ni2-N10 and O2-Ni2-N10 to be pressed to 85.958 (3)° and 84.284 (3)° respectively from the ideal 90°. Two other Ni 2+ ions on two side adopt square-planar coordination environments and are coordinated respectively by a phenolic oxygen atom, a adamantanecarbonyl oxygen atom, a hydrazide nitrogen atom and a pyridine nitrogen atom. By O(8)-H(8 A)···O(7) and O(8)-H(8B)···O(6) hydrogen bonds, two hydrogen atoms of water molecule are respectively connected to the phenolic oxygen atom(O6) and the oxygen atom(O7) of DMF to forming dimethylformamide solvate monohydrate.

Synthesis of ligand H 3 ashz
Adamantanecarbonyl chloride (6.0 g, 0.03 mol) which was dissolved in tetrahydrofuran(30.0 ml)was dropped slowly into a solution of salicylhydrazide (5.5 g, 0.036 mol) and triethylamine(2.0 ml) dissolved in 60.0 ml of tetrahydrofuran at 0°C. After dropped off, the mixture was slowly warmed up to the room temperature, stirred continually for 24 h and then filtered. The filtrate was recrystallizated by distilled water, and the yellow product was obtained(yield 8.31 g, 87.5%).

Bis[µ-N′-(adamantan-1-ylcarbonyl)-2-oxidobenzohydrazidato(3-)]tetrapyridinetrinickel(II) dimethylformamide monosolvate monohydrate
Crystal data [Ni 3 (C 18 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
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