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Acta Crystallogr Sect E Struct Rep Online. 2008 September 1; 64(Pt 9): m1197.
Published online 2008 August 23. doi:  10.1107/S1600536808026627
PMCID: PMC2960609

Tetra­kis(1,3,4,6,7,8-hexa­hydro-2H-pyrimido[1,2-a]pyrimidin-9-ido-κ2 N 1,N 9)niobium(V) hexa­fluorido­phosphate

Abstract

The title complex, [Nb(C7H12N3)4]PF6, features chelating hpp anions (hpp is 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrim­idine) that define a distorted dodeca­hedral coordination geometry based on an N8 donor set. The Nb atom is situated on a site of symmetry An external file that holds a picture, illustration, etc.
Object name is e-64-m1197-efi1.jpg, and the PF6 anion has crystallographic fourfold symmetry.

Related literature

For background literature, see: Cotton et al. (1998 [triangle], 2005 [triangle]). For related structures, see: Cotton et al. (2000 [triangle]); Coles & Hitchcock (2001 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-64-m1197-scheme1.jpg

Experimental

Crystal data

  • [Nb(C7H12N3)4]PF6
  • M r = 790.66
  • Tetragonal, An external file that holds a picture, illustration, etc.
Object name is e-64-m1197-efi3.jpg
  • a = 13.531 (6) Å
  • c = 9.159 (4) Å
  • V = 1676.9 (13) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.48 mm−1
  • T = 213 (2) K
  • 0.20 × 0.15 × 0.10 mm

Data collection

  • Bruker SMART 1K CCD area-detector diffractometer
  • Absorption correction: multi-scan (SADABS; Sheldrick, 2004 [triangle]) T min = 0.910, T max = 0.953
  • 10356 measured reflections
  • 1655 independent reflections
  • 1381 reflections with I > 2σ(I)

Refinement

  • R[F 2 > 2σ(F 2)] = 0.050
  • wR(F 2) = 0.144
  • S = 1.05
  • 1655 reflections
  • 111 parameters
  • H-atom parameters constrained
  • Δρmax = 0.69 e Å−3
  • Δρmin = −0.39 e Å−3

Data collection: SMART (Bruker, 2001 [triangle]); cell refinement: SAINT (Bruker, 2001 [triangle]); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: ORTEPII (Johnson, 1976 [triangle]); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808026627/lx2067sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808026627/lx2067Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Acknowledgments

The authors thank the Robert A. Welch Foundation and Texas A&M University for financial support.

supplementary crystallographic information

Comment

The title complex, [Nb(hpp)4][PF6] (I), feaures a [Nb(hpp)4]+ cation, with the Nb atom located on a site of symmetry 4, and a [PF6]- anion, with fourfold symmetry; where hpp is 1,3,4,6,7,8-hexahydro-2H-pyrimido(1,2 - a)pyrimidine. The Nb atom is chelated four hpp ligands and the N8 donor set defines an approximate dodecahedral coordination environment (Fig. 1).

The conformations of the N1- and N-2 containing six-membered rings is twisted chair. Such a binding mode as observed in (I) is uncommon for the hpp ligand, which normally acts as a bridging group in various paddlewheel complexes (Cotton et al., 2005). A related example of hpp acting as a chelating ligand is [Ta(hpp)4][Ta(CO)6] (Cotton et al., 2000). Both complexes were obtained by oxidizing the precursors Nb2(hpp)4 and [Et4N][Ta(CO)6], respectively. The chelating mode of hpp is also found in some Ti complexes (Coles & Hitchcok, 2001).

Experimental

The title complex (I) was obtained unintentionally in an attempt to oxidize the paddlewheel complex Nb2(hpp)4 with [Cp2Fe][PF6] in CH2Cl2. X-ray quality crystals were obtained by slow diffusion of hexanes into a CH2Cl2 solution of (I) at room temperature.

Refinement

The H atoms were geometrically placed (C—H = 0.98 Å) and refined as riding with Uiso(H) = 1.2Ueq(C).

Figures

Fig. 1.
Molecular structure of the cation in (I) showing the crystallographic numbering scheme. Displacement ellipsoids are shown at the 35% probability level. The Nb atom is located on a site of symmetry 4.

Crystal data

[Nb(C7H12N3)4]PF6Z = 2
Mr = 790.66F000 = 820
Tetragonal, P4/nDx = 1.566 Mg m3
Hall symbol: -P 4aMo Kα radiation λ = 0.71069 Å
a = 13.531 (6) ÅCell parameters from 10356 reflections
b = 13.531 (6) Åθ = 2.1–27.5º
c = 9.159 (4) ŵ = 0.48 mm1
α = 90ºT = 213 (2) K
β = 90ºBlock, yellow
γ = 90º0.20 × 0.15 × 0.10 mm
V = 1676.9 (13) Å3

Data collection

Bruker SMART 1K CCD area-detector diffractometer1655 independent reflections
Radiation source: fine-focus sealed tube1381 reflections with I > 2σ(I)
Monochromator: graphiteRint = 0.025
Detector resolution: 10 pixels mm-1θmax = 26.0º
T = 213(2) Kθmin = 2.1º
ω and [var phi] scansh = −17→12
Absorption correction: multi-scan(SADABS; Sheldrick, 2004)k = −17→16
Tmin = 0.910, Tmax = 0.953l = −10→11
10356 measured reflections

Refinement

Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.050H-atom parameters constrained
wR(F2) = 0.144  w = 1/[σ2(Fo2) + (0.067P)2 + 3.4248P] where P = (Fo2 + 2Fc2)/3
S = 1.05(Δ/σ)max < 0.001
1655 reflectionsΔρmax = 0.69 e Å3
111 parametersΔρmin = −0.39 e Å3
Primary atom site location: structure-invariant direct methodsExtinction correction: none

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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)

xyzUiso*/Ueq
Nb0.75000.25000.50000.0388 (2)
N10.6548 (3)0.1964 (3)0.3195 (4)0.0670 (11)
N20.6131 (3)0.1782 (3)0.5468 (4)0.0677 (11)
N30.4885 (3)0.1508 (3)0.3731 (4)0.0598 (9)
C10.6352 (4)0.1994 (4)0.1664 (5)0.0730 (14)
H1A0.69310.17470.11370.088*
H1B0.62450.26820.13700.088*
C20.5483 (5)0.1405 (7)0.1244 (6)0.116 (3)
H2A0.52950.15870.02470.139*
H2B0.56750.07060.12310.139*
C30.4618 (4)0.1511 (4)0.2179 (6)0.0783 (15)
H3A0.41580.09670.19850.094*
H3B0.42810.21320.19450.094*
C40.4136 (3)0.1333 (4)0.4827 (6)0.0694 (14)
H4A0.37200.07770.45230.083*
H4B0.37130.19190.49090.083*
C50.4580 (4)0.1111 (4)0.6279 (6)0.0839 (18)
H5A0.48300.04310.62790.101*
H5B0.40670.11590.70320.101*
C60.5406 (4)0.1802 (4)0.6648 (5)0.0745 (14)
H6A0.51490.24740.67720.089*
H6B0.57180.15990.75660.089*
C70.5805 (3)0.1735 (3)0.4103 (5)0.0549 (10)
P10.25000.25000.9214 (2)0.0475 (5)
F10.13862 (19)0.2132 (2)0.9219 (3)0.0772 (9)
F20.25000.25000.7468 (5)0.0695 (14)
F30.25000.25001.0963 (5)0.0562 (11)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
Nb0.0438 (3)0.0438 (3)0.0288 (4)0.0000.0000.000
N10.056 (2)0.107 (3)0.0386 (18)−0.013 (2)−0.0009 (16)−0.0025 (19)
N20.061 (2)0.095 (3)0.0472 (19)−0.019 (2)0.0110 (18)−0.003 (2)
N30.051 (2)0.067 (2)0.062 (2)0.0073 (17)−0.0030 (17)0.0021 (19)
C10.077 (3)0.099 (4)0.043 (2)−0.014 (3)−0.009 (2)0.005 (2)
C20.084 (4)0.217 (8)0.047 (3)−0.053 (5)−0.014 (3)0.001 (4)
C30.061 (3)0.096 (4)0.078 (3)−0.001 (3)−0.023 (3)0.010 (3)
C40.048 (2)0.055 (3)0.105 (4)−0.0021 (19)0.012 (3)−0.006 (3)
C50.090 (4)0.072 (3)0.089 (4)−0.004 (3)0.054 (3)0.000 (3)
C60.076 (3)0.101 (4)0.047 (2)−0.013 (3)0.018 (2)0.000 (3)
C70.055 (2)0.065 (3)0.045 (2)−0.005 (2)0.0064 (18)0.0035 (19)
P10.0530 (7)0.0530 (7)0.0365 (10)0.0000.0000.000
F10.0582 (15)0.112 (2)0.0619 (17)−0.0192 (15)0.0028 (13)−0.0233 (16)
F20.087 (2)0.087 (2)0.035 (2)0.0000.0000.000
F30.0660 (18)0.0660 (18)0.036 (2)0.0000.0000.000

Geometric parameters (Å, °)

Nb—N22.135 (4)C2—H2B0.9800
Nb—N2i2.135 (4)C3—H3A0.9800
Nb—N12.218 (4)C3—H3B0.9800
Nb—N1i2.218 (4)C4—C51.490 (8)
Nb—C72.648 (4)C4—H4A0.9800
Nb—C7i2.648 (4)C4—H4B0.9800
N1—C71.341 (5)C5—C61.496 (8)
N1—C11.428 (5)C5—H5A0.9800
N2—C71.328 (6)C5—H5B0.9800
N2—C61.460 (6)C6—H6A0.9800
N3—C71.326 (5)C6—H6B0.9800
N3—C41.447 (6)P1—F11.587 (3)
N3—C31.466 (6)P1—F1ii1.587 (3)
C1—C21.472 (7)P1—F1iii1.587 (3)
C1—H1A0.9800P1—F1iv1.587 (3)
C1—H1B0.9800P1—F21.600 (5)
C2—C31.457 (8)P1—F31.602 (5)
C2—H2A0.9800
N2—Nb—N2i156.8 (2)C7—N1—C1118.4 (4)
N2—Nb—N2v92.31 (4)C7—N1—Nb92.8 (3)
N2i—Nb—N2v92.31 (4)C1—N1—Nb146.2 (3)
N2—Nb—N2vi92.31 (4)C7—N2—C6118.3 (4)
N2i—Nb—N2vi92.31 (4)C7—N2—Nb97.0 (3)
N2v—Nb—N2vi156.8 (2)C6—N2—Nb136.4 (3)
N2—Nb—N159.80 (14)C7—N3—C4121.1 (4)
N2i—Nb—N1143.38 (14)C7—N3—C3118.7 (4)
N2v—Nb—N180.23 (16)C4—N3—C3120.0 (4)
N2vi—Nb—N182.54 (17)N1—C1—C2112.9 (4)
N2—Nb—N1v82.54 (17)N1—C1—H1A109.0
N2i—Nb—N1v80.23 (16)C2—C1—H1A109.0
N2v—Nb—N1v59.80 (14)N1—C1—H1B109.0
N2vi—Nb—N1v143.38 (14)C2—C1—H1B109.0
N1—Nb—N1v123.75 (12)H1A—C1—H1B107.8
N2—Nb—N1vi80.23 (16)C3—C2—C1115.7 (6)
N2i—Nb—N1vi82.54 (17)C3—C2—H2A108.3
N2v—Nb—N1vi143.38 (14)C1—C2—H2A108.3
N2vi—Nb—N1vi59.80 (14)C3—C2—H2B108.3
N1—Nb—N1vi123.75 (12)C1—C2—H2B108.3
N1v—Nb—N1vi83.6 (2)H2A—C2—H2B107.4
N2—Nb—N1i143.38 (14)C2—C3—N3111.8 (4)
N2i—Nb—N1i59.80 (14)C2—C3—H3A109.3
N2v—Nb—N1i82.54 (17)N3—C3—H3A109.3
N2vi—Nb—N1i80.23 (16)C2—C3—H3B109.3
N1—Nb—N1i83.6 (2)N3—C3—H3B109.3
N1v—Nb—N1i123.75 (12)H3A—C3—H3B107.9
N1vi—Nb—N1i123.75 (12)N3—C4—C5111.7 (4)
N2—Nb—C729.86 (14)N3—C4—H4A109.3
N2i—Nb—C7172.73 (14)C5—C4—H4A109.3
N2v—Nb—C789.57 (16)N3—C4—H4B109.3
N2vi—Nb—C783.26 (16)C5—C4—H4B109.3
N1—Nb—C730.39 (13)H4A—C4—H4B107.9
N1v—Nb—C7106.74 (15)C4—C5—C6112.1 (4)
N1vi—Nb—C7100.07 (15)C4—C5—H5A109.2
N1i—Nb—C7113.57 (13)C6—C5—H5A109.2
N2—Nb—C7vi89.57 (15)C4—C5—H5B109.2
N2i—Nb—C7vi83.26 (16)C6—C5—H5B109.2
N2v—Nb—C7vi172.73 (14)H5A—C5—H5B107.9
N2vi—Nb—C7vi29.86 (14)N2—C6—C5108.9 (4)
N1—Nb—C7vi106.74 (15)N2—C6—H6A109.9
N1v—Nb—C7vi113.57 (13)C5—C6—H6A109.9
N1vi—Nb—C7vi30.39 (13)N2—C6—H6B109.9
N1i—Nb—C7vi100.07 (15)C5—C6—H6B109.9
C7—Nb—C7vi95.53 (5)H6A—C6—H6B108.3
N2—Nb—C7v83.26 (16)N3—C7—N2124.4 (4)
N2i—Nb—C7v89.57 (15)N3—C7—N1126.7 (4)
N2v—Nb—C7v29.86 (14)N2—C7—N1108.8 (4)
N2vi—Nb—C7v172.73 (14)N3—C7—Nb169.6 (3)
N1—Nb—C7v100.07 (15)N2—C7—Nb53.2 (2)
N1v—Nb—C7v30.39 (13)N1—C7—Nb56.8 (2)
N1vi—Nb—C7v113.57 (13)F1—P1—F1ii90.000 (2)
N1i—Nb—C7v106.74 (15)F1—P1—F1iii179.7 (2)
C7—Nb—C7v95.53 (5)F1ii—P1—F1iii90.000 (2)
C7vi—Nb—C7v143.83 (18)F1—P1—F1iv90.000 (1)
N2—Nb—C7i172.73 (14)F1ii—P1—F1iv179.7 (2)
N2i—Nb—C7i29.86 (14)F1iii—P1—F1iv90.000 (2)
N2v—Nb—C7i83.26 (16)F1—P1—F290.16 (12)
N2vi—Nb—C7i89.57 (16)F1ii—P1—F290.16 (12)
N1—Nb—C7i113.57 (13)F1iii—P1—F290.16 (12)
N1v—Nb—C7i100.07 (15)F1iv—P1—F290.16 (12)
N1vi—Nb—C7i106.74 (15)F1—P1—F389.84 (12)
N1i—Nb—C7i30.39 (13)F1ii—P1—F389.84 (12)
C7—Nb—C7i143.83 (18)F1iii—P1—F389.84 (12)
C7vi—Nb—C7i95.53 (5)F1iv—P1—F389.84 (12)
C7v—Nb—C7i95.53 (5)F2—P1—F3180.000 (2)
N2—Nb—N1—C77.7 (3)N3—C4—C5—C645.0 (6)
N2i—Nb—N1—C7−173.2 (3)C7—N2—C6—C539.2 (7)
N2v—Nb—N1—C7106.2 (3)Nb—N2—C6—C5179.1 (4)
N2vi—Nb—N1—C7−89.4 (3)C4—C5—C6—N2−54.6 (6)
N1v—Nb—N1—C763.0 (4)C4—N3—C7—N23.0 (7)
N1vi—Nb—N1—C7−43.6 (4)C3—N3—C7—N2178.2 (5)
N1i—Nb—N1—C7−170.3 (4)C4—N3—C7—N1−176.2 (5)
C7vi—Nb—N1—C7−71.7 (3)C3—N3—C7—N1−1.0 (7)
C7v—Nb—N1—C783.7 (2)C4—N3—C7—Nb−70.1 (19)
C7i—Nb—N1—C7−175.65 (18)C3—N3—C7—Nb105.1 (17)
N2—Nb—N1—C1165.9 (7)C6—N2—C7—N3−14.1 (7)
N2i—Nb—N1—C1−15.0 (8)Nb—N2—C7—N3−167.5 (4)
N2v—Nb—N1—C1−95.6 (7)C6—N2—C7—N1165.2 (5)
N2vi—Nb—N1—C168.8 (7)Nb—N2—C7—N111.8 (4)
N1v—Nb—N1—C1−138.8 (6)C6—N2—C7—Nb153.4 (5)
N1vi—Nb—N1—C1114.6 (6)C1—N1—C7—N31.6 (8)
N1i—Nb—N1—C1−12.1 (6)Nb—N1—C7—N3168.0 (4)
C7—Nb—N1—C1158.2 (9)C1—N1—C7—N2−177.7 (5)
C7vi—Nb—N1—C186.5 (7)Nb—N1—C7—N2−11.3 (4)
C7v—Nb—N1—C1−118.0 (7)C1—N1—C7—Nb−166.4 (5)
C7i—Nb—N1—C1−17.4 (7)N2—Nb—C7—N380.4 (17)
N2i—Nb—N2—C7173.5 (3)N2v—Nb—C7—N3175.8 (17)
N2v—Nb—N2—C7−85.1 (3)N2vi—Nb—C7—N3−26.3 (17)
N2vi—Nb—N2—C772.2 (3)N1—Nb—C7—N3−113.0 (18)
N1—Nb—N2—C7−7.8 (3)N1v—Nb—C7—N3117.6 (17)
N1v—Nb—N2—C7−144.2 (3)N1vi—Nb—C7—N331.3 (18)
N1vi—Nb—N2—C7131.0 (3)N1i—Nb—C7—N3−102.5 (17)
N1i—Nb—N2—C7−4.5 (5)C7vi—Nb—C7—N31.0 (17)
C7vi—Nb—N2—C7101.9 (3)C7v—Nb—C7—N3146.5 (18)
C7v—Nb—N2—C7−113.6 (3)C7i—Nb—C7—N3−106.3 (18)
N2i—Nb—N2—C628.4 (5)N2v—Nb—C7—N295.4 (3)
N2v—Nb—N2—C6129.7 (6)N2vi—Nb—C7—N2−106.7 (3)
N2vi—Nb—N2—C6−73.0 (5)N1—Nb—C7—N2166.6 (5)
N1—Nb—N2—C6−153.0 (6)N1v—Nb—C7—N237.2 (3)
N1v—Nb—N2—C670.6 (5)N1vi—Nb—C7—N2−49.1 (3)
N1vi—Nb—N2—C6−14.2 (5)N1i—Nb—C7—N2177.1 (3)
N1i—Nb—N2—C6−149.7 (5)C7v—Nb—C7—N266.1 (3)
C7—Nb—N2—C6−145.2 (7)C7i—Nb—C7—N2173.3 (3)
C7vi—Nb—N2—C6−43.3 (5)N2—Nb—C7—N1−166.6 (5)
C7v—Nb—N2—C6101.2 (5)N2v—Nb—C7—N1−71.2 (3)
C7—N1—C1—C2−22.7 (8)N2vi—Nb—C7—N186.7 (3)
Nb—N1—C1—C2−177.8 (5)N1v—Nb—C7—N1−129.3 (3)
N1—C1—C2—C344.3 (9)N1vi—Nb—C7—N1144.4 (3)
C1—C2—C3—N3−43.2 (8)N1i—Nb—C7—N110.5 (4)
C7—N3—C3—C221.6 (8)C7vi—Nb—C7—N1114.0 (3)
C4—N3—C3—C2−163.1 (5)C7v—Nb—C7—N1−100.5 (3)
C7—N3—C4—C5−19.0 (6)C7i—Nb—C7—N16.8 (3)
C3—N3—C4—C5165.8 (5)

Symmetry codes: (i) −x+3/2, −y+1/2, z; (ii) −y+1/2, x, z; (iii) −x+1/2, −y+1/2, z; (iv) y, −x+1/2, z; (v) −y+1, x−1/2, −z+1; (vi) y+1/2, −x+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LX2067).

References

  • Bruker (2001). SMART and SAINT Bruker AXS Inc., Madison, Wisconsin, USA.
  • Coles, M. P. & Hitchcock, P. B. (2001). J. Chem. Soc. Dalton Trans. pp. 1169–1171.
  • Cotton, F. A., Matonic, J. H. & Murillo, C. A. (1998). J. Am. Chem. Soc.120, 6047–6052.
  • Cotton, F. A., Murillo, C. A. & Walton, R. A. (2005). Multiple Bonds between Metal Atoms, 3rd ed. New York: Springer Science and Business Media.
  • Cotton, F. A., Murillo, C. A. & Wang, X. (2000). Inorg. Chim. Acta, 300, 1–6.
  • Johnson, C. K. (1976). ORTEPII Report ORNL-5138. Oak Ridge National Laboratory, Tennessee, USA.
  • Sheldrick, G. M. (2004). SADABS University of Göttingen, Germany.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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