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The title compound, [Co(C5H9N)4(H2O)2](ClO4)2, crystallizes in the monoclinic space group C2/m. The cation has space-group-imposed 2/m symmetry, while the perchlorate ion is disordered about a mirror plane. The two slightly non-equivalent Co—C bonds [1.900 (3) and 1.911 (3) Å] form a rectangular plane, with a C—Co—C bond angle of 86.83 (11)°, and the linear O—Co—O C2 axis is perpendicular to this plane. The C[triple bond]N bond lengths are 1.141 (4) Å and the Co—C[triple bond]N and C[triple bond]N—C angles average 175.5 (4)°. The per­chlorate counter-ions are hydrogen bonded to the water mol­ecules. The title compound is the first example of four alkyl isocyanide ligands coordinating CoII upon initial reaction of Co(ClO4)2·6H2O/EtOH with alkyl isocyanide. In all other known examples, five alkyl isocyanide mol­ecules are coordinated, as in [(RNC)5Co—Co(CNR)5](ClO4)4 (R = Me, Et, CHMe2, CH2Ph, C4H9-n or C6H11) or [Co(CNC8H17-t)5](ClO4)2. This complex, therefore, is unique and somewhat unexpected.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270109024500/fg3104sup1.cif
Contains datablocks global, I

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270109024500/fg3104Isup2.hkl
Contains datablock I

CCDC reference: 746044

Comment top

Reactions of CoII perchlorate with alkyl isocyanide ligands have been shown to produce metal–metal bonded diamagnetic dimeric complexes in the solid state, of general formula [Co2(CNR)10](ClO4)4 and maroon–red in colour, dissociating into dark-blue one-electron paramagnetic monomeric complexes in solution. The crystallographic structure of [(MeNC)5Co—Co(CNMe)5](ClO4)4 has been determined (Cotton et al., 1964), and structures with CNR = CNEt (Boorman et al., 1970), CNCHMe2 (Becker, 1993) and CNCH2Ph (Becker & Malete, 2003) were assumed to be analogous. Complexes with CNR = CNC4H9-n and CNC6H11 (Becker, 1993, 1994) have not been satisfactorily isolated, but appear to exhibit analogous behaviour. The t-butyl isocyanide ligand (CNCMe3), however, has been unique in forming low-spin monomeric CoII complexes with only four alkyl isocyanide ligands (Becker et al., 1986; Becker, 1993). Even recent work with the t-octyl isocyanide ligand (CNC8H17-t, i.e. 1,1,3,3-tetramethylbutyl isocyanide) has also produced low-spin monomeric CoII complexes but with the usual 5:1 alkyl isocyanide:CoII mole ratio, i.e. [Co(CNC8H17-t)5](ClO4)2 and [Co(CNC8H17-t)5](BF4)2.2H2O (Becker et al., 2008). The unique composition of the title complex, (I), especially when initially reported as [Co(CNCMe3)4H2O](ClO4)2, prompted a crystallographic investigation to determine if possible aspects such as steric crowding of the relatively bulky t-butyl isocyanide ligands or unusually strong coordination of the water molecule(s) may be favouring this particular stereochemistry.

Compound (I) is observed to crystallize in the monoclinic space group C2/m. The molecular structure is shown in Figs. 1 and 2. The CoII atom is at a site with point-group symmetry of 2/m (C2h) and is at the centre of a rectangular bipyramid. The CoC4 moiety is strictly planar, with the linear O—Co—O C2 axis perpendicular to this plane, but the two non-equivalent Co—C bonds [1.900 (3) and 1.911 (3) Å] form a rectangular, but not square, plane, with the unique C—Co—C bond angle being 86.83 (11)°. The Co—C bond lengths are sufficiently short to justify the dπ π* back-bonding expected from organoisocyanide ligands, and the CN bonds [both 1.141 (4) Å] are just slightly shorter than that in the free CNCH3 molecule (1.166 Å; Costain, 1958). The Co—CN and CN—C bond angles average 175.5 (4)°, approximately equal to, but slightly less than, the theoretically expected 180.0°.

The unique coordinated water molecule is so orientated that the H atoms are only 15° staggered from being directly over the Co—C1 bonds, i.e. the shorter Co—C bonds. The H-atom placements of the coordinated water were constrained according to interatomic attraction. These assigned locations are probably the result of attraction to the perchlorate anions, rather than any interaction with the Co—CN bonds. The unique water H atom takes part in an O—H···O hydrogen bond with an adjacent perchlorate atom O2, with dimensions H1W···O2 = 2.04 Å, O1···O2 = 2.993 (5) Å and O1—H1W···O2 180°, leading to an infinite hydrogen-bond chain in the b direction, as shown in Fig. 2. The perchlorate ion is disordered, as is not atypical for these anions.

Many known structures for CNCMe3 complexes with cobalt are for multiple mixed-ligand complexes, usually of CoI or CoIII. Compounds most relevant for comparison with (I) would appear to be the other CoII complexes of the form [Co(CNPh)5](ClO4)2.0.5ClCH2CH2Cl, especially when viewed as [Co(CNPh)5ClO4]ClO4.0.5ClCH2CH2Cl, (II) (Jurnak et al., 1975), [Co(CNC6H4Me-p)4I2], (III) (Gilmore et al., 1969), [Co(CNC6H3Et2-2,6)4(ClO4)2], (IV) (Becker & Cooper, 1991), [Co(CNC6H4CO2Me-4)4I2], (V) (Squires & Mayr, 1997), trans-[Co(CNC6H4OSiMe3-2)4I2], (VI) (Hahn & Lügger, 1994), and trans-[Co(CNC6H2iPr2-2,6-4-C CH)4I2], (VII) (Lu et al., 1999). Structural comparisons based on these compounds are shown in Table 1.

The Co—O bond length of 2.245 (2) Å is definitely rather long, since a Co—O single-bond length of about 1.97 Å should be expected (Slade et al., 1971), although this bond is known over the rather wide range of about 1.75–2.40 Å, with 1.85–2.20 Å being most common (Cambridge Structural Database, 2009 [Specific release?]; Allen, 2002). However, the Co—I bonds in (III), (V), (VI) and (VII) are also consistently elongated, while the Co—O bond in (IV), i.e. 2.266 (7) Å, would be considered long, albeit short for a coordinated perchlorate bond. In none of the CoII complexes considered does it appear that the CoC4 moiety is actually square-planar. The CoC4 unit may be planar, having equal [(VII)] or unequal [(IV), (V) or (VI)] Co—C bond lengths, but is also has unequal C—Co—C bond angles, i.e. forming a rectangular plane. Alternatively, as in (III), there is a C2/S4 axis because alternating Co—C bonds are bent above and below the Co centre (~5°). Complex (IV) would appear to approximate most closely the coordination structure for [Co(CNCMe3)4(H2O)2]2+.

Once tetragonal coordination is recognized for (I), analogy with addition complexes of selected nitrogen bases, [Co(CNCMe3)4L2](ClO4)2 (Becker, 1992), becomes apparent. The N-base complexes are blue in colour, due to a crystal field band at 630–670 nm, while (I) is beige to flesh-coloured [Please be more specific - an objective colour is required], with a comparable band at 814 nm. This underscores the higher position in the spectrochemical series of N-ligands over O-ligands (Wulfsberg, 2000). However, the diffuse reflectance electronic spectrum for (IV) (λmax = 875 nm; Becker & Cooper, 1991) is similar to that for (I).

The coordination structure in (I), [Co(CNCMe3)4(H2O)2](ClO4), has thus been shown to be analogous to known [Co(CNR)4X2] complexes with aryl isocyanide ligands. The t-butyl substituents are not seen to be sterically crowded to the extent of precluding coordination of a fifth alkyl isocyanide ligand, and the relatively long Co—O bond lengths contradict the possibility of particularly strong water-molecule coordination, so except for a rather unconvincing argument of strong hydrogen bonding between the coordinated water molecules and the anionic perchlorates, there appears to be no crystallographic explanation as to why a dimeric structure, or at least pentakis-alkyl isocyanide coordination, has not been observed for the title complex.

Experimental top

Complex (I), [Co(C5H9N)4(H2O)2](ClO4)2, initially reported as [Co(C5H9N)4H2O](ClO4)2, was synthesized and routinely characterized by Becker and co-workers (Becker et al., 1986; Becker, 1993), by reaction of excess and/or stoichiometric amounts of CNCMe3 with Co(ClO4)2.6H2O in ethanol solution (94% yield). The complex can be recrystallized from CH3CN and diethyl ether (85% recovery) [m.p. 383–385 K (decomposition)]. X-ray quality crystals of (I) were obtained by slow diffusion of Et2O into a CH3CN solution at room temperature. Elemental analysis, calculated for C20H40Cl2CoN4O10: C 38.35, H 6.44, N 8.94, Cl 11.32%; found: C 37.89, H 6.47, N 8.94, Cl 11.64%. IR spectrum (Nujol mull, ν, cm-1): –NC 2214 (vs), ~2185 (vw, sh), 2031 (w); O—H 3448 (s), ~3500 (m, sh); diffuse reflectance electronic spectrum (nm): ~814 (br, A = 0.289), ~ 525 (s, h), 462 (0.338), ~276 (s, h), 263 (1.54), 216 (1.32); magnetic susceptibility: χg = 3.74 (7) × 10-6 cgs, µeff = 2.52 (5) BM.

Refinement top

All H atoms were refined using a riding model, with C—H = 0.98Å and O—H = 0.95 Å, and with Uiso(H) = 1.5Ueq(C) or 1.5Ueq(O). Perchlorate disorder was apparent in the structure, hence atoms O3A and O3B, and atoms O4A and O4B, were refined with complementary occupancies, respectively.

Structure description top

Reactions of CoII perchlorate with alkyl isocyanide ligands have been shown to produce metal–metal bonded diamagnetic dimeric complexes in the solid state, of general formula [Co2(CNR)10](ClO4)4 and maroon–red in colour, dissociating into dark-blue one-electron paramagnetic monomeric complexes in solution. The crystallographic structure of [(MeNC)5Co—Co(CNMe)5](ClO4)4 has been determined (Cotton et al., 1964), and structures with CNR = CNEt (Boorman et al., 1970), CNCHMe2 (Becker, 1993) and CNCH2Ph (Becker & Malete, 2003) were assumed to be analogous. Complexes with CNR = CNC4H9-n and CNC6H11 (Becker, 1993, 1994) have not been satisfactorily isolated, but appear to exhibit analogous behaviour. The t-butyl isocyanide ligand (CNCMe3), however, has been unique in forming low-spin monomeric CoII complexes with only four alkyl isocyanide ligands (Becker et al., 1986; Becker, 1993). Even recent work with the t-octyl isocyanide ligand (CNC8H17-t, i.e. 1,1,3,3-tetramethylbutyl isocyanide) has also produced low-spin monomeric CoII complexes but with the usual 5:1 alkyl isocyanide:CoII mole ratio, i.e. [Co(CNC8H17-t)5](ClO4)2 and [Co(CNC8H17-t)5](BF4)2.2H2O (Becker et al., 2008). The unique composition of the title complex, (I), especially when initially reported as [Co(CNCMe3)4H2O](ClO4)2, prompted a crystallographic investigation to determine if possible aspects such as steric crowding of the relatively bulky t-butyl isocyanide ligands or unusually strong coordination of the water molecule(s) may be favouring this particular stereochemistry.

Compound (I) is observed to crystallize in the monoclinic space group C2/m. The molecular structure is shown in Figs. 1 and 2. The CoII atom is at a site with point-group symmetry of 2/m (C2h) and is at the centre of a rectangular bipyramid. The CoC4 moiety is strictly planar, with the linear O—Co—O C2 axis perpendicular to this plane, but the two non-equivalent Co—C bonds [1.900 (3) and 1.911 (3) Å] form a rectangular, but not square, plane, with the unique C—Co—C bond angle being 86.83 (11)°. The Co—C bond lengths are sufficiently short to justify the dπ π* back-bonding expected from organoisocyanide ligands, and the CN bonds [both 1.141 (4) Å] are just slightly shorter than that in the free CNCH3 molecule (1.166 Å; Costain, 1958). The Co—CN and CN—C bond angles average 175.5 (4)°, approximately equal to, but slightly less than, the theoretically expected 180.0°.

The unique coordinated water molecule is so orientated that the H atoms are only 15° staggered from being directly over the Co—C1 bonds, i.e. the shorter Co—C bonds. The H-atom placements of the coordinated water were constrained according to interatomic attraction. These assigned locations are probably the result of attraction to the perchlorate anions, rather than any interaction with the Co—CN bonds. The unique water H atom takes part in an O—H···O hydrogen bond with an adjacent perchlorate atom O2, with dimensions H1W···O2 = 2.04 Å, O1···O2 = 2.993 (5) Å and O1—H1W···O2 180°, leading to an infinite hydrogen-bond chain in the b direction, as shown in Fig. 2. The perchlorate ion is disordered, as is not atypical for these anions.

Many known structures for CNCMe3 complexes with cobalt are for multiple mixed-ligand complexes, usually of CoI or CoIII. Compounds most relevant for comparison with (I) would appear to be the other CoII complexes of the form [Co(CNPh)5](ClO4)2.0.5ClCH2CH2Cl, especially when viewed as [Co(CNPh)5ClO4]ClO4.0.5ClCH2CH2Cl, (II) (Jurnak et al., 1975), [Co(CNC6H4Me-p)4I2], (III) (Gilmore et al., 1969), [Co(CNC6H3Et2-2,6)4(ClO4)2], (IV) (Becker & Cooper, 1991), [Co(CNC6H4CO2Me-4)4I2], (V) (Squires & Mayr, 1997), trans-[Co(CNC6H4OSiMe3-2)4I2], (VI) (Hahn & Lügger, 1994), and trans-[Co(CNC6H2iPr2-2,6-4-C CH)4I2], (VII) (Lu et al., 1999). Structural comparisons based on these compounds are shown in Table 1.

The Co—O bond length of 2.245 (2) Å is definitely rather long, since a Co—O single-bond length of about 1.97 Å should be expected (Slade et al., 1971), although this bond is known over the rather wide range of about 1.75–2.40 Å, with 1.85–2.20 Å being most common (Cambridge Structural Database, 2009 [Specific release?]; Allen, 2002). However, the Co—I bonds in (III), (V), (VI) and (VII) are also consistently elongated, while the Co—O bond in (IV), i.e. 2.266 (7) Å, would be considered long, albeit short for a coordinated perchlorate bond. In none of the CoII complexes considered does it appear that the CoC4 moiety is actually square-planar. The CoC4 unit may be planar, having equal [(VII)] or unequal [(IV), (V) or (VI)] Co—C bond lengths, but is also has unequal C—Co—C bond angles, i.e. forming a rectangular plane. Alternatively, as in (III), there is a C2/S4 axis because alternating Co—C bonds are bent above and below the Co centre (~5°). Complex (IV) would appear to approximate most closely the coordination structure for [Co(CNCMe3)4(H2O)2]2+.

Once tetragonal coordination is recognized for (I), analogy with addition complexes of selected nitrogen bases, [Co(CNCMe3)4L2](ClO4)2 (Becker, 1992), becomes apparent. The N-base complexes are blue in colour, due to a crystal field band at 630–670 nm, while (I) is beige to flesh-coloured [Please be more specific - an objective colour is required], with a comparable band at 814 nm. This underscores the higher position in the spectrochemical series of N-ligands over O-ligands (Wulfsberg, 2000). However, the diffuse reflectance electronic spectrum for (IV) (λmax = 875 nm; Becker & Cooper, 1991) is similar to that for (I).

The coordination structure in (I), [Co(CNCMe3)4(H2O)2](ClO4), has thus been shown to be analogous to known [Co(CNR)4X2] complexes with aryl isocyanide ligands. The t-butyl substituents are not seen to be sterically crowded to the extent of precluding coordination of a fifth alkyl isocyanide ligand, and the relatively long Co—O bond lengths contradict the possibility of particularly strong water-molecule coordination, so except for a rather unconvincing argument of strong hydrogen bonding between the coordinated water molecules and the anionic perchlorates, there appears to be no crystallographic explanation as to why a dimeric structure, or at least pentakis-alkyl isocyanide coordination, has not been observed for the title complex.

Computing details top

Data collection: APEX2 (Bruker, 2005); cell refinement: SAINT-NT (Bruker, 2005); data reduction: SAINT-NT (Bruker, 2005); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Figures top
[Figure 1] Fig. 1. A view of (I), with the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level. H atoms have been omitted for clarity. [Symmetry codes: (i) x, -y, z; (ii) 1 - x, y, 1 - z; (iii) 1 - x, 1 - y, 1 - z; (iv) x, 1 - y, z.]
[Figure 2] Fig. 2. A packing diagram for (I), displaying the infinite hydrogen-bonded chain along the b axis. Hydrogen bonds are shown as dashed lines.
Diaquatetrakis(tert-butyl isocyanide)cobalt(II) bis(perchlorate) top
Crystal data top
[Co(C5H9N)4(H2O)2](ClO4)2F(000) = 658
Mr = 626.39Dx = 1.38 Mg m3
Monoclinic, C2/mMo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yCell parameters from 5327 reflections
a = 15.830 (1) Åθ = 2.6–28.3°
b = 8.1176 (5) ŵ = 0.80 mm1
c = 13.8319 (9) ÅT = 173 K
β = 122.013 (1)°Block, brown
V = 1507.12 (17) Å30.73 × 0.33 × 0.08 mm
Z = 2
Data collection top
Bruker APEXII CCD area-detector
diffractometer
1867 reflections with I > 2σ(I)
φ and ω scansRint = 0.018
Absorption correction: integration
(XPREP; Bruker, 1999)
θmax = 28°, θmin = 1.7°
Tmin = 0.595, Tmax = 0.939h = 2020
6901 measured reflectionsk = 1010
1949 independent reflectionsl = 1618
Refinement top
Refinement on F230 restraints
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.039 w = 1/[σ2(Fo2) + (0.0579P)2 + 3.0958P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.106(Δ/σ)max < 0.001
S = 1.04Δρmax = 0.72 e Å3
1949 reflectionsΔρmin = 0.88 e Å3
112 parameters
Crystal data top
[Co(C5H9N)4(H2O)2](ClO4)2V = 1507.12 (17) Å3
Mr = 626.39Z = 2
Monoclinic, C2/mMo Kα radiation
a = 15.830 (1) ŵ = 0.80 mm1
b = 8.1176 (5) ÅT = 173 K
c = 13.8319 (9) Å0.73 × 0.33 × 0.08 mm
β = 122.013 (1)°
Data collection top
Bruker APEXII CCD area-detector
diffractometer
1949 independent reflections
Absorption correction: integration
(XPREP; Bruker, 1999)
1867 reflections with I > 2σ(I)
Tmin = 0.595, Tmax = 0.939Rint = 0.018
6901 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.03930 restraints
wR(F2) = 0.106H-atom parameters constrained
S = 1.04Δρmax = 0.72 e Å3
1949 reflectionsΔρmin = 0.88 e Å3
112 parameters
Special details top

Experimental. Numerical integration absorption corrections based on indexed crystal faces were applied using the XPREP routine (Bruker, 1999)

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
C10.6396 (2)0.50.5621 (2)0.0200 (5)
C20.83352 (19)0.50.6665 (2)0.0219 (5)
C30.8722 (2)0.50.7937 (3)0.0296 (6)
H3A0.8480.59840.81260.044*0.5
H3B0.94520.50030.83750.044*
H3C0.84820.40130.81270.044*0.5
C40.86394 (15)0.6558 (3)0.63079 (19)0.0310 (5)
H4A0.83250.65660.54780.047*
H4B0.93650.6580.66740.047*
H4C0.84240.75280.65430.047*
C50.53119 (19)0.50.6537 (2)0.0203 (5)
C60.6022 (2)0.50.8727 (2)0.0225 (5)
C70.56749 (19)0.3448 (3)0.90333 (19)0.0358 (5)
H7A0.49480.3470.86590.054*
H7B0.59810.33960.98620.054*
H7C0.58720.24780.87770.054*
C80.7144 (2)0.50.9255 (3)0.0365 (8)
H8A0.73370.40110.90120.055*0.5
H8B0.7480.50061.00880.055*
H8C0.73370.59830.90060.055*0.5
O10.50.7765 (3)0.50.0300 (5)
H1W0.5560.84750.53920.045*
Co10.50.50.50.01634 (16)
N10.72436 (17)0.50.6058 (2)0.0221 (5)
N20.55687 (18)0.50.7479 (2)0.0226 (5)
Cl10.70949 (5)10.73994 (6)0.0280 (2)
O20.6765 (2)1.0001 (8)0.62335 (9)0.0992 (18)
O3A0.6758 (6)0.8631 (6)0.7661 (5)0.138 (3)0.737 (11)
O4A0.81225 (5)1.0001 (12)0.8031 (2)0.101 (3)0.737 (11)
O4B0.62531 (17)0.9998 (11)0.7481 (3)0.123 (8)0.263 (11)
O3B0.7616 (6)0.8692 (6)0.7970 (5)0.110 (6)0.263 (11)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
C10.0194 (12)0.0244 (13)0.0167 (11)00.0099 (10)0
C20.0120 (11)0.0317 (14)0.0205 (12)00.0077 (10)0
C30.0238 (13)0.0422 (17)0.0209 (13)00.0106 (11)0
C40.0239 (10)0.0379 (12)0.0303 (11)0.0062 (8)0.0137 (9)0.0013 (9)
C50.0165 (11)0.0248 (13)0.0189 (12)00.0090 (10)0
C60.0230 (13)0.0311 (14)0.0118 (11)00.0082 (10)0
C70.0445 (13)0.0390 (12)0.0233 (10)0.0079 (10)0.0176 (10)0.0030 (9)
C80.0239 (14)0.061 (2)0.0208 (14)00.0089 (12)0
O10.0261 (10)0.0256 (11)0.0326 (11)00.0117 (9)0
Co10.0118 (2)0.0250 (3)0.0113 (2)00.00546 (19)0
N10.0160 (11)0.0271 (12)0.0228 (11)00.0100 (9)0
N20.0231 (11)0.0281 (12)0.0158 (11)00.0097 (9)0
Cl10.0298 (4)0.0300 (4)0.0181 (3)00.0085 (3)0
O20.075 (3)0.196 (6)0.0235 (15)00.0235 (16)0
O3A0.204 (7)0.096 (4)0.155 (5)0.080 (4)0.123 (5)0.006 (3)
O4A0.036 (2)0.188 (8)0.051 (3)00.005 (2)0
O4B0.076 (9)0.167 (14)0.146 (13)00.073 (9)0
O3B0.155 (10)0.068 (7)0.056 (6)0.071 (7)0.021 (6)0.024 (5)
Geometric parameters (Å, º) top
C1—N11.142 (4)C7—H7A0.98
C1—Co11.900 (3)C7—H7B0.98
C2—N11.467 (3)C7—H7C0.98
C2—C41.525 (3)C8—H8A0.98
C2—C4i1.525 (3)C8—H8B0.98
C2—C31.527 (4)C8—H8C0.98
C3—H3A0.98O1—Co12.245 (2)
C3—H3B0.98O1—H1W0.95
C3—H3C0.98Co1—C1ii1.900 (3)
C4—H4A0.98Co1—C5ii1.911 (3)
C4—H4B0.98Co1—O1ii2.245 (2)
C4—H4C0.98Cl1—O3Biii1.320 (8)
C5—N21.141 (4)Cl1—O3B1.3196
C5—Co11.911 (3)Cl1—O3Aiii1.363 (7)
C6—N21.476 (3)Cl1—O3A1.3628
C6—C81.521 (4)Cl1—O4A1.3794
C6—C7i1.522 (3)Cl1—O4B1.3959
C6—C71.522 (3)Cl1—O21.4074
N1—C1—Co1175.8 (2)C1ii—Co1—C1180.00 (16)
N1—C2—C4107.04 (15)C1ii—Co1—C5ii86.83 (11)
N1—C2—C4i107.04 (15)C1—Co1—C5ii93.17 (11)
C4—C2—C4i112.0 (2)C1ii—Co1—C593.17 (11)
N1—C2—C3106.9 (2)C1—Co1—C586.83 (11)
C4—C2—C3111.75 (15)C5ii—Co1—C5180.0000 (10)
C4i—C2—C3111.75 (15)C1ii—Co1—O190
C2—C3—H3A109.5C1—Co1—O190
C2—C3—H3B109.5C5ii—Co1—O190
H3A—C3—H3B109.5C5—Co1—O190
C2—C3—H3C109.5C1ii—Co1—O1ii90
H3A—C3—H3C109.5C1—Co1—O1ii90
H3B—C3—H3C109.5C5ii—Co1—O1ii90
C2—C4—H4A109.5C5—Co1—O1ii90
C2—C4—H4B109.5O1—Co1—O1ii180
H4A—C4—H4B109.5C1—N1—C2177.7 (3)
C2—C4—H4C109.5C5—N2—C6173.3 (3)
H4A—C4—H4C109.5O3Biii—Cl1—O3B107.2 (3)
H4B—C4—H4C109.5O3Biii—Cl1—O3Aiii52.66 (16)
N2—C5—Co1175.1 (2)O3B—Cl1—O3Aiii134.92 (12)
N2—C6—C8106.4 (2)O3Biii—Cl1—O3A134.92 (15)
N2—C6—C7i107.60 (15)O3B—Cl1—O3A52.7
C8—C6—C7i111.59 (16)O3Aiii—Cl1—O3A109.3 (2)
N2—C6—C7107.60 (15)O3Biii—Cl1—O4A57.8 (2)
C8—C6—C7111.59 (16)O3B—Cl1—O4A57.9
C7i—C6—C7111.8 (3)O3Aiii—Cl1—O4A109.14 (11)
C6—C7—H7A109.5O3A—Cl1—O4A109.2
C6—C7—H7B109.5O3Biii—Cl1—O4B105.88 (10)
H7A—C7—H7B109.5O3B—Cl1—O4B105.7
C6—C7—H7C109.5O3Aiii—Cl1—O4B56.9 (2)
H7A—C7—H7C109.5O3A—Cl1—O4B56.8
H7B—C7—H7C109.5O4A—Cl1—O4B143.6
C6—C8—H8A109.5O3Biii—Cl1—O2114.80 (17)
C6—C8—H8B109.5O3B—Cl1—O2114.9
H8A—C8—H8B109.5O3Aiii—Cl1—O2110.14 (11)
C6—C8—H8C109.5O3A—Cl1—O2110.2
H8A—C8—H8C109.5O4A—Cl1—O2108.8
H8B—C8—H8C109.5O4B—Cl1—O2107.6
Co1—O1—H1W127.3
Symmetry codes: (i) x, y+1, z; (ii) x+1, y+1, z+1; (iii) x, y+2, z.

Experimental details

Crystal data
Chemical formula[Co(C5H9N)4(H2O)2](ClO4)2
Mr626.39
Crystal system, space groupMonoclinic, C2/m
Temperature (K)173
a, b, c (Å)15.830 (1), 8.1176 (5), 13.8319 (9)
β (°) 122.013 (1)
V3)1507.12 (17)
Z2
Radiation typeMo Kα
µ (mm1)0.80
Crystal size (mm)0.73 × 0.33 × 0.08
Data collection
DiffractometerBruker APEXII CCD area-detector
Absorption correctionIntegration
(XPREP; Bruker, 1999)
Tmin, Tmax0.595, 0.939
No. of measured, independent and
observed [I > 2σ(I)] reflections
6901, 1949, 1867
Rint0.018
(sin θ/λ)max1)0.661
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.106, 1.04
No. of reflections1949
No. of parameters112
No. of restraints30
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.72, 0.88

Computer programs: APEX2 (Bruker, 2005), SAINT-NT (Bruker, 2005), SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 1997), WinGX (Farrugia, 1999) and PLATON (Spek, 2009).

Selected geometric parameters (Å, °) for [Co(CNCMe3)4(H2O)2](ClO4)2 with six analogous CoII–aryl isocyanide complexes top
CompoundCo—CCNCo—CNCN-C
(I)1.900 (3)1.911 (3)1.141 (4)–1.142 (4)175.8 (2)–175.1 (2)177.7 (3)–173.3 (3)
(II)1.84 (2)1.16 (1)174.6 (6)173.5 (10)–179.0 (13)
(III)1.81 (4)1.14 (4)178.8 (42)174.4 (40)
(IV)1.896 (9)1.887 (9)1.152 (12)175.3 (7)174.0 (7)–177.2 (9)
(V)1.865 (10)1.835 (15)1.15 (3)173 (1)–178 (1)166 (1)–178 (1)
(VI)1.858 (2)1.866 (2)1.148 (3)–1.137 (3)175.9 (2)–174.6 (2)174.7 (2)–173.6 (2)
(VII)1.850 (7)1.139 (7)175.6 (6)
References: (I), [Co(CNCMe3)4(H2O)2](ClO4)2 (this work); (II), [Co(CNPh)5ClO4]ClO4.0.5ClCH2CH2Cl (Jurnak et al., 1975); (III), Co(CNC6H4Me-p)4I2] (Gilmore et al., 1969); (IV), [Co(C6H3Et2-2,6)4(ClO4)2] (Becker & Cooper, 1991); (V), [Co(CNC6H4CO2Me-4)2I2] (Squires & Mayr, 1997); (VI), [Co(CNC6H4OSiMe3-2)4I2] (Hahn & Lügger, 1994); (VII), [Co(CNC6H2iPr2-2,6-4-CCH)4I2] (Lu et al., 1999).
 

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