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The one-dimensional chain catena-poly­[[aqua(2,2′:6′,2′′-terpyridyl-κ3N)­nickel(II)]-μ-cyano-κ2N:C-[bis­(cyano-κC)nickelate(II)]-μ-cyano-κ2C:N], [Ni(terpy)(H2O)]-trans-[Ni-μ-(CN)2-(CN)2]n or [Ni2­(CN)4­(C15H11N3)(H2O)], consists of infinite linear chains along the crystallographic [10\overline 1] direction. The chains are composed of two distinct types of nickel ions, paramagnetic octahedral [Ni(terpy)(H2O)]2+ cations (with twofold crystallographic symmetry) and diamagnetic planar [Ni(CN)4]2− anions (with the Ni atom on an inversion center). The [Ni(CN)4]2− units act as bidentate ligands bridging through two trans cyano groups thus giving rise to a new example of a transtrans chain among planar tetra­cyano­nickelate complexes. The coordination geometry of the planar nickel unit is typical of slightly distorted octahedral nickel(II) complexes, but for the [Ni(CN)4]2− units, the geometry deviates from a planar configuration due to steric interactions with the ter­pyridine ligands.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101009234/da1188sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270101009234/da1188Isup2.hkl
Contains datablock I

CCDC reference: 173344

Comment top

Low-dimensional materials, including one-dimensional chains, are of interest to chemists and physicists alike due to characteristic structural and physical properties that are often different from their two and three-dimensional analogs. Alternating linear chains, those composed of two distinct structural units, are a special case of one-dimensional compounds. These materials can be engineered using a "brick and mortar" synthetic strategy (Willet et al., 1993). The bricks, complexes of metal ions and blocking ligands are linked to one-another by the mortar, or bridging units. In the title compound, the bricks are the paramagnetic [Ni(terpy)(H2O)]2+ groups where the 2,2':6',2"-terpyridine ligand not only influences the coordination geometry of the nickel ion within the chain but "blocks" the extension of the structure along the second and third dimensions. The mortar, the [Ni(CN)4]2- groups, is the cement that holds the bricks together within the chain due to the ability of such ligands to coordinate to other metal complexes through cyano groups. There are now several examples of linear chains containing bridging [Ni(CN)4]2- units (Yuge et al., 1994, 1995; Iwamoto, 1996). A trans-trans (TT) linear chain structure was observed in Ni(en)2Ni(CN)4, (en is ethylenediamine; Černák, Chromič et al., 1988) and [M(en)2Ni(CN)4].2PhNH2 (M = Cd, Zn, Cu, and Ni) (Yuge and Iwamoto, 1994), where the bridging cyano groups occupy trans positions in both the cation and the anion. Conversely, a cis-cis (CC) zigzag chain structure was found in Cd(en)2Ni(CN)4 (two polymorphs; Yuge et al., 1995). Furthermore, a cis-trans or trans-cis (CT or TC) zigzag chain was reported for [Ni(bipy)2Ni(CN)4] where the bridging cyano groups are trans within the anion, but occupy alternating cis and trans positions on the cation along the chain (Černák and Abboud, 2000). A more complicated CCTC chain-like structure was observed in [Ni(en)2Ni(CN)4].2.16 H2O (periodicity doubled; Černák et al., 1990). The coordination geometry of the blocking ligand can influence the stereochemistry of the [Ni(CN)4]2- ligands along the chains by directing the bridging ligands to specific coordination sites on the metal center. This paper describes the crystal structure analysis of a new compound, [Ni(terpy)(H2O)]-trans-[Ni(CN)4], (I), a TT linear chain containing tetracyanonickelate bridging units. \sch

The structure of the title compound consists of linear chains along the [101] direction composed of alternating paramagnetic octahedral [Ni(terpy)(H2O]2+ cations and diamagnetic [Ni(CN)4]2- anions. The bridging cyano nitrogen atoms from the anion are coordinated trans to one another on the cation completing the chromophore NiN3ON2. The blocking ligands coordinated to the cation are 2,2':6',2"-terpyridine, a tris-mer- chelating ligand, and a water molecule. The terpy ligands are staggered along the chain in an alternating fashion while the terminal cyano groups coordinated to the anion are arranged perpendicular to those of adjacent tetracyanonickelate ligands. Within a chain, the distance between paramagnetic and diamagnetic nickel ions is approximately 5.075 Å while the distance between two paramagnetic or diamagnetic metal centers is about 10.149 Å. It is known that bridging cyano groups effectively transmit magnetic superexchange interactions and that the five atom trans-N—C—Ni—C—N bridge may permit coupling between the two paramagnetic nickel ions (Orendáč et al., 2000). However, the diamagnetic tetracyanonickelate units turn out to be poor mediators of magnetic exchange since no significant coupling was observed along the chains (Woodward et al., 1999).

The chains are held together by a combination of interdigitating terpy ligands between chains (with a terpy-terpy separation distance of alternating 3.416 and 3.509 Å distances) and hydrogen-bonding interactions between the hydrogen atoms of the coordinated water molecules with the nitrogen atoms of the terminal cyano groups on adjacent chains. No interstitial molecules are present between the chains.

Interactions between the [Ni(CN)4]2- chromophore and nearby terpyridine ligands force the bridging ligand to twist, thereby relieving the repulsion between the terpy and the terminal cyano ligand. This twist forces angles Ni2—N2—C2 172.2 (2)° and Ni1—C2—N2 176.2 (2)°, to deviate significantly from the ideal geometry (180°). This repulsion can also be seen in the opening of angle C1—Ni1—C2 to 91.1 (1)°. The bond distances for the [Ni(CN)4]2- complex are typical of those found in smilar tetracyaonickelate chains (Černák, Dunaj-Jurčo et al., 1988). In the octahedral NiN3ON2 chromophore, the equatorial coordination sites are comprised of three nitrogen atoms from the terpyridine ligand, one oxygen atom from the coordinated water, and two axial positions are filled by N atoms from the trans bridging cyano groups. A deviation from true octahedral geometry is observed due to the geometrical requirements of the sterically bulky terpy ligand. The Ni—O (water) and Ni—N (terpy) bond angles and distances agree well with those of similar monomeric complexes [Ni(terpy)(NO2)(ONO)(H2O)] (Cortés et al., 1986), [Ni(terpy)(Cl)(H2O)2](Cl).H2O (Cortés et al., 1985), and [Ni(terpy)2](ClO4)2.H2O (Baker et al., 1995). The Ni—N bond distances on the cation from the bridging cyano groups are also comparable to those found in [Ni(en)2Ni(CN)4].2 PhNH2 (Yuge & Iwamoto, 1994) and [Ni(bipy)2Ni(CN)4] (Černák & Abboud, 2000).

Experimental top

The starting materials nickel(II) perchlorate hexahydrate (98%) and 2,2':6',2"-terpyridine (98%) were purchased from Aldrich Chemical Co. (Milwaukee, WI) and potassium cyanide (99.9%) was purchased from Fisher Scientific (Pittsburgh, PA). All reagents were used without further purification. The combination of Ni(ClO4)2.6 H2O (366 mg, 1 mmol) with terpy (234 mg, 1 mmol) and KCN (97.5 mg, 1.5 mmol) in 50 ml of water produced a tan precipitate. Addition of NH3 (20 ml, 15 M) solution and 50 ml of ethanol with stirring dissolved the precipitate resulting in a yellow-colored solution. The reaction mixture was filtered into a 500 ml Erlenmeyer flask, capped with paraffin (punctured with small holes), and set aside for crystallization. Within about four months, small brown blocks appeared in solution. These blocks were determined to be [Ni(terpy)2](ClO4)2.H2O, a known material (Baker et al., 1995). After five months, collection of the product revealed the presence of gray needles, the title compound.

Refinement top

A C—H distance of 0.95 Å was used for the Csp2 atoms with displacement parameters of 1.2Ueq of the parent C atoms. A hemisphere of frames, 0.3° in ω, was collected. The lone unique proton of the water molecule was obtained from a difference Fourier map and refined freely. All other H atoms were refined riding on their parent atoms.

Computing details top

Cell refinement: SMART & SAINT (Bruker 1998); data reduction: SHELXTL (Bruker 1998); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. Molecular structure of (I), with 50% probability ellipsoids, showing the atom numbering scheme [symmetry codes: (i) 3/2 - x, 1/2 - y, -z; (ii) 1 - x, y, 1/2 - z].
[Figure 2] Fig. 2. Packing diagram showing chains and the hydrogen bonds linking them.
(I) top
Crystal data top
[Ni2(CN)4(C15H11N3)(H2O)]F(000) = 960
Mr = 236.39Dx = 1.564 Mg m3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
a = 15.5712 (8) ÅCell parameters from 2835 reflections
b = 11.5546 (6) Åθ = 2.5–27.5°
c = 11.2428 (6) ŵ = 1.90 mm1
β = 97.076 (1)°T = 173 K
V = 2007.4 (2) Å3Needles, gray
Z = 80.17 × 0.09 × 0.09 mm
Data collection top
SMART CCD area detector
diffractometer
2307 independent reflections
Radiation source: normal-focus sealed tube1602 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.029
ω scansθmax = 27.5°, θmin = 2.2°
Absorption correction: integration
based on measured indexed crystal faces, SHELXTL
h = 2020
Tmin = 0.726, Tmax = 0.871k = 1512
6721 measured reflectionsl = 1214
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.031Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.072H atoms treated by a mixture of independent and constrained refinement
S = 1.07 w = 1/[σ2(Fo2) + (0.0211P)2 + 2.9223P]
where P = (Fo2 + 2Fc2)/3
2307 reflections(Δ/σ)max < 0.001
140 parametersΔρmax = 0.29 e Å3
0 restraintsΔρmin = 0.32 e Å3
Crystal data top
[Ni2(CN)4(C15H11N3)(H2O)]V = 2007.4 (2) Å3
Mr = 236.39Z = 8
Monoclinic, C2/cMo Kα radiation
a = 15.5712 (8) ŵ = 1.90 mm1
b = 11.5546 (6) ÅT = 173 K
c = 11.2428 (6) Å0.17 × 0.09 × 0.09 mm
β = 97.076 (1)°
Data collection top
SMART CCD area detector
diffractometer
2307 independent reflections
Absorption correction: integration
based on measured indexed crystal faces, SHELXTL
1602 reflections with I > 2σ(I)
Tmin = 0.726, Tmax = 0.871Rint = 0.029
6721 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0310 restraints
wR(F2) = 0.072H atoms treated by a mixture of independent and constrained refinement
S = 1.07Δρmax = 0.29 e Å3
2307 reflectionsΔρmin = 0.32 e Å3
140 parameters
Special details top

Experimental. The first 50 frames were remeasured at the end of data collection to monitor instrument and crystal stability. Full data collection details are in the relevant -special-details section of the archived CIF and also reported elsewhere (Abboud et al., 1997).

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 F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 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 (Å2) top
xyzUiso*/Ueq
Ni10.75000.25000.00000.02335 (12)
C10.81308 (16)0.1397 (2)0.0950 (2)0.0315 (6)
N10.85152 (17)0.0713 (2)0.1529 (2)0.0531 (7)
C20.66616 (14)0.2547 (2)0.1047 (2)0.0268 (5)
N20.61120 (12)0.25587 (19)0.16389 (19)0.0310 (5)
Ni20.50000.25378 (4)0.25000.02138 (12)
O10.50000.4305 (3)0.25000.0764 (12)
H10.451 (2)0.483 (3)0.224 (3)0.086 (12)*
N30.50000.0800 (2)0.25000.0240 (6)
N40.42238 (12)0.21546 (18)0.08575 (17)0.0260 (4)
C30.38415 (16)0.2909 (3)0.0051 (2)0.0343 (6)
H30.39510.37120.01710.041*
C40.32910 (16)0.2558 (3)0.0951 (2)0.0408 (7)
H40.30310.31110.15090.049*
C50.31294 (17)0.1395 (3)0.1120 (2)0.0421 (7)
H50.27480.11350.17910.051*
C60.35260 (16)0.0610 (3)0.0307 (2)0.0373 (6)
H60.34250.01960.04170.045*
C70.40754 (15)0.1010 (2)0.0675 (2)0.0274 (5)
C80.45393 (14)0.0233 (2)0.1599 (2)0.0260 (5)
C90.45264 (16)0.0971 (2)0.1575 (2)0.0330 (6)
H90.41990.13750.09370.040*
C100.50000.1566 (3)0.25000.0374 (9)
H100.50000.23880.25000.045*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ni10.01807 (19)0.0288 (2)0.0244 (2)0.00027 (18)0.00744 (15)0.00074 (19)
C10.0272 (12)0.0348 (15)0.0331 (13)0.0014 (11)0.0056 (10)0.0003 (12)
N10.0521 (15)0.0480 (17)0.0575 (16)0.0115 (13)0.0005 (13)0.0088 (13)
C20.0221 (10)0.0326 (13)0.0258 (11)0.0024 (11)0.0035 (9)0.0030 (11)
N20.0231 (9)0.0430 (13)0.0279 (10)0.0015 (10)0.0075 (8)0.0015 (10)
Ni20.01729 (19)0.0258 (2)0.0220 (2)0.0000.00623 (14)0.000
O10.0416 (19)0.0340 (19)0.146 (4)0.0000.019 (2)0.000
N30.0180 (13)0.0281 (16)0.0268 (14)0.0000.0058 (11)0.000
N40.0226 (9)0.0338 (12)0.0228 (10)0.0008 (8)0.0069 (8)0.0002 (8)
C30.0319 (13)0.0419 (16)0.0297 (13)0.0045 (12)0.0067 (11)0.0039 (12)
C40.0348 (13)0.059 (2)0.0281 (13)0.0120 (14)0.0011 (10)0.0066 (13)
C50.0322 (14)0.065 (2)0.0274 (14)0.0027 (14)0.0027 (11)0.0057 (14)
C60.0320 (13)0.0462 (17)0.0335 (14)0.0039 (12)0.0029 (11)0.0089 (12)
C70.0225 (11)0.0355 (14)0.0252 (12)0.0005 (10)0.0074 (9)0.0032 (10)
C80.0211 (11)0.0309 (14)0.0272 (12)0.0009 (10)0.0077 (9)0.0030 (10)
C90.0305 (12)0.0335 (14)0.0356 (14)0.0048 (11)0.0073 (11)0.0059 (11)
C100.038 (2)0.026 (2)0.051 (2)0.0000.0155 (18)0.000
Geometric parameters (Å, º) top
Ni1—C21.863 (2)N3—C81.339 (3)
Ni1—C2i1.863 (2)N3—C8ii1.339 (3)
Ni1—C1i1.863 (3)N4—C31.342 (3)
Ni1—C11.863 (3)N4—C71.354 (3)
C1—N11.145 (3)C3—C41.389 (4)
C2—N21.147 (3)C4—C51.377 (4)
N2—Ni22.085 (2)C5—C61.378 (4)
Ni2—N32.008 (3)C6—C71.390 (3)
Ni2—O12.041 (3)C7—C81.490 (3)
Ni2—N2ii2.085 (2)C8—C91.392 (4)
Ni2—N42.125 (2)C9—C101.382 (3)
Ni2—N4ii2.125 (2)C10—C9ii1.382 (3)
O1—H11.00 (3)
C2—Ni1—C2i180.00 (8)N2ii—Ni2—N4ii90.85 (7)
C2—Ni1—C1i88.9 (1)N4—Ni2—N4ii155.95 (12)
C2i—Ni1—C1i91.1 (1)Ni2—O1—H1128 (2)
C2—Ni1—C191.1 (1)H1—O1—H1ii104 (4)
C2i—Ni1—C188.9 (1)C8—N3—C8ii121.4 (3)
C1i—Ni1—C1180.0 (1)C8—N3—Ni2119.30 (15)
N1—C1—Ni1179.5 (3)C8ii—N3—Ni2119.30 (15)
N2—C2—Ni1176.2 (2)C3—N4—C7118.6 (2)
C2—N2—Ni2172.2 (2)C3—N4—Ni2127.50 (19)
N3—Ni2—O1180.0C7—N4—Ni2113.80 (16)
N3—Ni2—N290.66 (6)N4—C3—C4122.4 (3)
O1—Ni2—N289.34 (6)C5—C4—C3118.7 (3)
N3—Ni2—N2ii90.66 (6)C4—C5—C6119.5 (3)
O1—Ni2—N2ii89.34 (6)C5—C6—C7119.3 (3)
N2—Ni2—N2ii178.67 (13)N4—C7—C6121.5 (2)
N3—Ni2—N477.97 (6)N4—C7—C8115.0 (2)
O1—Ni2—N4102.03 (6)C6—C7—C8123.5 (2)
N2—Ni2—N490.85 (7)N3—C8—C9120.6 (2)
N2ii—Ni2—N489.43 (7)N3—C8—C7113.7 (2)
N3—Ni2—N4ii77.97 (6)C9—C8—C7125.7 (2)
O1—Ni2—N4ii102.03 (6)C10—C9—C8118.5 (3)
N2—Ni2—N4ii89.43 (7)C9ii—C10—C9120.3 (4)
Symmetry codes: (i) x+3/2, y+1/2, z; (ii) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N1iii1.00 (3)1.94 (3)2.926 (3)171 (3)
Symmetry code: (iii) x1/2, y+1/2, z.

Experimental details

Crystal data
Chemical formula[Ni2(CN)4(C15H11N3)(H2O)]
Mr236.39
Crystal system, space groupMonoclinic, C2/c
Temperature (K)173
a, b, c (Å)15.5712 (8), 11.5546 (6), 11.2428 (6)
β (°) 97.076 (1)
V3)2007.4 (2)
Z8
Radiation typeMo Kα
µ (mm1)1.90
Crystal size (mm)0.17 × 0.09 × 0.09
Data collection
DiffractometerSMART CCD area detector
diffractometer
Absorption correctionIntegration
based on measured indexed crystal faces, SHELXTL
Tmin, Tmax0.726, 0.871
No. of measured, independent and
observed [I > 2σ(I)] reflections
6721, 2307, 1602
Rint0.029
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.072, 1.07
No. of reflections2307
No. of parameters140
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.29, 0.32

Computer programs: SMART & SAINT (Bruker 1998), SHELXTL (Bruker 1998), SHELXTL.

Selected geometric parameters (Å, º) top
Ni1—C21.863 (2)N2—Ni22.085 (2)
Ni1—C11.863 (3)Ni2—N32.008 (3)
C1—N11.145 (3)Ni2—O12.041 (3)
C2—N21.147 (3)Ni2—N42.125 (2)
C2—Ni1—C1i88.9 (1)O1—Ni2—N289.34 (6)
C2—Ni1—C191.1 (1)N3—Ni2—N477.97 (6)
N1—C1—Ni1179.5 (3)O1—Ni2—N4102.03 (6)
N2—C2—Ni1176.2 (2)N2—Ni2—N490.85 (7)
C2—N2—Ni2172.2 (2)N2ii—Ni2—N489.43 (7)
N3—Ni2—O1180.0Ni2—O1—H1128 (2)
N3—Ni2—N290.66 (6)H1—O1—H1ii104 (4)
Symmetry codes: (i) x+3/2, y+1/2, z; (ii) x+1, y, z+1/2.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O1—H1···N1iii1.00 (3)1.94 (3)2.926 (3)171 (3)
Symmetry code: (iii) x1/2, y+1/2, z.
 

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