Tetra­kis(1,3,4,6,7,8-hexa­hydro-2H-pyrimido[1,2-a]pyrimidin-9-ido-κ2N1,N9)niobium(V) hexa­fluorido­phosphate

Cotton, F.A.; Murillo, C.A.; Poplaukhin, P.V.; Bhuvanesh, N.; Tiekink, E.R.T.

doi:10.1107/S1600536808026627

metal-organic compounds

CRYSTALLOGRAPHIC
COMMUNICATIONS

ISSN: 2056-9890

Volume 64| Part 9| September 2008| Page m1197

doi:10.1107/S1600536808026627

Open

access

Tetrakis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-9-ido-κ²N¹,N⁹)niobium(V) hexafluoridophosphate

F. Albert Cotton,^a Carlos A. Murillo,^a ^* Pavel V. Poplaukhin,^a Nattamai Bhuvanesh ^b and Edward R. T. Tiekink ^c

^aLaboratory for Molecular Structure and Bonding, Department of Chemistry, Texas A&M University, PO Box 30012 College Station, Texas 77842-3012, USA, ^bX-ray Diffraction Laboratory, Department of Chemistry, Texas A & M University, PO Box 30012 College Station, Texas 77842-3012, USA, and ^cDepartment of Chemistry, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249-0698, USA
^*Correspondence e-mail: murillo@tamu.edu

(Received 11 August 2008; accepted 18 August 2008; online 23 August 2008)

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 $[\overline{4}]$ , and the PF₆⁻ anion has crystallographic fourfold symmetry.

Related literature

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

Experimental

Crystal data

[Nb(C₇H₁₂N₃)₄]PF₆
M_r = 790.66
Tetragonal, P 4/n
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 ) T_min = 0.910, T_max = 0.953
10356 measured reflections
1655 independent reflections
1381 reflections with I > 2σ(I)

Refinement

R[F² > 2σ(F²)] = 0.050
wR(F²) = 0.144
S = 1.05
1655 reflections
111 parameters
H-atom parameters constrained
Δρ_max = 0.69 e Å⁻³
Δρ_min = −0.39 e Å⁻³

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

Supporting information

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

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

checkCIF report

Comment top

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).

Related literature top

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

Experimental top

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.

Computing details top

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

Figures top

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.

Tetrakis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-9-ido- κ²N¹,N⁹)niobium(V) hexafluoridophosphate top

Crystal data top

[Nb(C₇H₁₂N₃)₄]PF₆	D_x = 1.566 Mg m⁻³
M_r = 790.66	Mo Kα radiation, λ = 0.71069 Å
Tetragonal, P4/n	Cell parameters from 10356 reflections
Hall symbol: -P 4a	θ = 2.1–27.5°
a = 13.531 (6) Å	µ = 0.48 mm⁻¹
c = 9.159 (4) Å	T = 213 K
V = 1676.9 (13) Å³	Block, yellow
Z = 2	0.20 × 0.15 × 0.10 mm
F(000) = 820

Data collection top

Bruker SMART 1K CCD area-detector diffractometer	1655 independent reflections
Radiation source: fine-focus sealed tube	1381 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.025
Detector resolution: 10 pixels mm^-1	θ_max = 26.0°, θ_min = 2.1°
ω and ϕ scans	h = −17→12
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	k = −17→16
T_min = 0.910, T_max = 0.953	l = −10→11
10356 measured reflections

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.050	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.144	H-atom parameters constrained
S = 1.05	w = 1/[σ²(F_o²) + (0.067P)² + 3.4248P] where P = (F_o² + 2F_c²)/3
1655 reflections	(Δ/σ)_max < 0.001
111 parameters	Δρ_max = 0.69 e Å⁻³
0 restraints	Δρ_min = −0.39 e Å⁻³

Crystal data top

[Nb(C₇H₁₂N₃)₄]PF₆	Z = 2
M_r = 790.66	Mo Kα radiation
Tetragonal, P4/n	µ = 0.48 mm⁻¹
a = 13.531 (6) Å	T = 213 K
c = 9.159 (4) Å	0.20 × 0.15 × 0.10 mm
V = 1676.9 (13) Å³

Data collection top

Bruker SMART 1K CCD area-detector diffractometer	1655 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	1381 reflections with I > 2σ(I)
T_min = 0.910, T_max = 0.953	R_int = 0.025
10356 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.050	0 restraints
wR(F²) = 0.144	H-atom parameters constrained
S = 1.05	Δρ_max = 0.69 e Å⁻³
1655 reflections	Δρ_min = −0.39 e Å⁻³
111 parameters

Special details top

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) top

	x	y	z	U_iso*/U_eq
Nb	0.7500	0.2500	0.5000	0.0388 (2)
N1	0.6548 (3)	0.1964 (3)	0.3195 (4)	0.0670 (11)
N2	0.6131 (3)	0.1782 (3)	0.5468 (4)	0.0677 (11)
N3	0.4885 (3)	0.1508 (3)	0.3731 (4)	0.0598 (9)
C1	0.6352 (4)	0.1994 (4)	0.1664 (5)	0.0730 (14)
H1A	0.6931	0.1747	0.1137	0.088*
H1B	0.6245	0.2682	0.1370	0.088*
C2	0.5483 (5)	0.1405 (7)	0.1244 (6)	0.116 (3)
H2A	0.5295	0.1587	0.0247	0.139*
H2B	0.5675	0.0706	0.1231	0.139*
C3	0.4618 (4)	0.1511 (4)	0.2179 (6)	0.0783 (15)
H3A	0.4158	0.0967	0.1985	0.094*
H3B	0.4281	0.2132	0.1945	0.094*
C4	0.4136 (3)	0.1333 (4)	0.4827 (6)	0.0694 (14)
H4A	0.3720	0.0777	0.4523	0.083*
H4B	0.3713	0.1919	0.4909	0.083*
C5	0.4580 (4)	0.1111 (4)	0.6279 (6)	0.0839 (18)
H5A	0.4830	0.0431	0.6279	0.101*
H5B	0.4067	0.1159	0.7032	0.101*
C6	0.5406 (4)	0.1802 (4)	0.6648 (5)	0.0745 (14)
H6A	0.5149	0.2474	0.6772	0.089*
H6B	0.5718	0.1599	0.7566	0.089*
C7	0.5805 (3)	0.1735 (3)	0.4103 (5)	0.0549 (10)
P1	0.2500	0.2500	0.9214 (2)	0.0475 (5)
F1	0.13862 (19)	0.2132 (2)	0.9219 (3)	0.0772 (9)
F2	0.2500	0.2500	0.7468 (5)	0.0695 (14)
F3	0.2500	0.2500	1.0963 (5)	0.0562 (11)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Nb	0.0438 (3)	0.0438 (3)	0.0288 (4)	0.000	0.000	0.000
N1	0.056 (2)	0.107 (3)	0.0386 (18)	−0.013 (2)	−0.0009 (16)	−0.0025 (19)
N2	0.061 (2)	0.095 (3)	0.0472 (19)	−0.019 (2)	0.0110 (18)	−0.003 (2)
N3	0.051 (2)	0.067 (2)	0.062 (2)	0.0073 (17)	−0.0030 (17)	0.0021 (19)
C1	0.077 (3)	0.099 (4)	0.043 (2)	−0.014 (3)	−0.009 (2)	0.005 (2)
C2	0.084 (4)	0.217 (8)	0.047 (3)	−0.053 (5)	−0.014 (3)	0.001 (4)
C3	0.061 (3)	0.096 (4)	0.078 (3)	−0.001 (3)	−0.023 (3)	0.010 (3)
C4	0.048 (2)	0.055 (3)	0.105 (4)	−0.0021 (19)	0.012 (3)	−0.006 (3)
C5	0.090 (4)	0.072 (3)	0.089 (4)	−0.004 (3)	0.054 (3)	0.000 (3)
C6	0.076 (3)	0.101 (4)	0.047 (2)	−0.013 (3)	0.018 (2)	0.000 (3)
C7	0.055 (2)	0.065 (3)	0.045 (2)	−0.005 (2)	0.0064 (18)	0.0035 (19)
P1	0.0530 (7)	0.0530 (7)	0.0365 (10)	0.000	0.000	0.000
F1	0.0582 (15)	0.112 (2)	0.0619 (17)	−0.0192 (15)	0.0028 (13)	−0.0233 (16)
F2	0.087 (2)	0.087 (2)	0.035 (2)	0.000	0.000	0.000
F3	0.0660 (18)	0.0660 (18)	0.036 (2)	0.000	0.000	0.000

Geometric parameters (Å, º) top

Nb—N2	2.135 (4)	C2—H2B	0.9800
Nb—N2ⁱ	2.135 (4)	C3—H3A	0.9800
Nb—N1	2.218 (4)	C3—H3B	0.9800
Nb—N1ⁱ	2.218 (4)	C4—C5	1.490 (8)
Nb—C7	2.648 (4)	C4—H4A	0.9800
Nb—C7ⁱ	2.648 (4)	C4—H4B	0.9800
N1—C7	1.341 (5)	C5—C6	1.496 (8)
N1—C1	1.428 (5)	C5—H5A	0.9800
N2—C7	1.328 (6)	C5—H5B	0.9800
N2—C6	1.460 (6)	C6—H6A	0.9800
N3—C7	1.326 (5)	C6—H6B	0.9800
N3—C4	1.447 (6)	P1—F1	1.587 (3)
N3—C3	1.466 (6)	P1—F1ⁱⁱ	1.587 (3)
C1—C2	1.472 (7)	P1—F1ⁱⁱⁱ	1.587 (3)
C1—H1A	0.9800	P1—F1^iv	1.587 (3)
C1—H1B	0.9800	P1—F2	1.600 (5)
C2—C3	1.457 (8)	P1—F3	1.602 (5)
C2—H2A	0.9800

N2—Nb—N2ⁱ	156.8 (2)	C7—N1—C1	118.4 (4)
N2—Nb—N2^v	92.31 (4)	C7—N1—Nb	92.8 (3)
N2ⁱ—Nb—N2^v	92.31 (4)	C1—N1—Nb	146.2 (3)
N2—Nb—N2^vi	92.31 (4)	C7—N2—C6	118.3 (4)
N2ⁱ—Nb—N2^vi	92.31 (4)	C7—N2—Nb	97.0 (3)
N2^v—Nb—N2^vi	156.8 (2)	C6—N2—Nb	136.4 (3)
N2—Nb—N1	59.80 (14)	C7—N3—C4	121.1 (4)
N2ⁱ—Nb—N1	143.38 (14)	C7—N3—C3	118.7 (4)
N2^v—Nb—N1	80.23 (16)	C4—N3—C3	120.0 (4)
N2^vi—Nb—N1	82.54 (17)	N1—C1—C2	112.9 (4)
N2—Nb—N1^v	82.54 (17)	N1—C1—H1A	109.0
N2ⁱ—Nb—N1^v	80.23 (16)	C2—C1—H1A	109.0
N2^v—Nb—N1^v	59.80 (14)	N1—C1—H1B	109.0
N2^vi—Nb—N1^v	143.38 (14)	C2—C1—H1B	109.0
N1—Nb—N1^v	123.75 (12)	H1A—C1—H1B	107.8
N2—Nb—N1^vi	80.23 (16)	C3—C2—C1	115.7 (6)
N2ⁱ—Nb—N1^vi	82.54 (17)	C3—C2—H2A	108.3
N2^v—Nb—N1^vi	143.38 (14)	C1—C2—H2A	108.3
N2^vi—Nb—N1^vi	59.80 (14)	C3—C2—H2B	108.3
N1—Nb—N1^vi	123.75 (12)	C1—C2—H2B	108.3
N1^v—Nb—N1^vi	83.6 (2)	H2A—C2—H2B	107.4
N2—Nb—N1ⁱ	143.38 (14)	C2—C3—N3	111.8 (4)
N2ⁱ—Nb—N1ⁱ	59.80 (14)	C2—C3—H3A	109.3
N2^v—Nb—N1ⁱ	82.54 (17)	N3—C3—H3A	109.3
N2^vi—Nb—N1ⁱ	80.23 (16)	C2—C3—H3B	109.3
N1—Nb—N1ⁱ	83.6 (2)	N3—C3—H3B	109.3
N1^v—Nb—N1ⁱ	123.75 (12)	H3A—C3—H3B	107.9
N1^vi—Nb—N1ⁱ	123.75 (12)	N3—C4—C5	111.7 (4)
N2—Nb—C7	29.86 (14)	N3—C4—H4A	109.3
N2ⁱ—Nb—C7	172.73 (14)	C5—C4—H4A	109.3
N2^v—Nb—C7	89.57 (16)	N3—C4—H4B	109.3
N2^vi—Nb—C7	83.26 (16)	C5—C4—H4B	109.3
N1—Nb—C7	30.39 (13)	H4A—C4—H4B	107.9
N1^v—Nb—C7	106.74 (15)	C4—C5—C6	112.1 (4)
N1^vi—Nb—C7	100.07 (15)	C4—C5—H5A	109.2
N1ⁱ—Nb—C7	113.57 (13)	C6—C5—H5A	109.2
N2—Nb—C7^vi	89.57 (15)	C4—C5—H5B	109.2
N2ⁱ—Nb—C7^vi	83.26 (16)	C6—C5—H5B	109.2
N2^v—Nb—C7^vi	172.73 (14)	H5A—C5—H5B	107.9
N2^vi—Nb—C7^vi	29.86 (14)	N2—C6—C5	108.9 (4)
N1—Nb—C7^vi	106.74 (15)	N2—C6—H6A	109.9
N1^v—Nb—C7^vi	113.57 (13)	C5—C6—H6A	109.9
N1^vi—Nb—C7^vi	30.39 (13)	N2—C6—H6B	109.9
N1ⁱ—Nb—C7^vi	100.07 (15)	C5—C6—H6B	109.9
C7—Nb—C7^vi	95.53 (5)	H6A—C6—H6B	108.3
N2—Nb—C7^v	83.26 (16)	N3—C7—N2	124.4 (4)
N2ⁱ—Nb—C7^v	89.57 (15)	N3—C7—N1	126.7 (4)
N2^v—Nb—C7^v	29.86 (14)	N2—C7—N1	108.8 (4)
N2^vi—Nb—C7^v	172.73 (14)	N3—C7—Nb	169.6 (3)
N1—Nb—C7^v	100.07 (15)	N2—C7—Nb	53.2 (2)
N1^v—Nb—C7^v	30.39 (13)	N1—C7—Nb	56.8 (2)
N1^vi—Nb—C7^v	113.57 (13)	F1—P1—F1ⁱⁱ	90.000 (2)
N1ⁱ—Nb—C7^v	106.74 (15)	F1—P1—F1ⁱⁱⁱ	179.7 (2)
C7—Nb—C7^v	95.53 (5)	F1ⁱⁱ—P1—F1ⁱⁱⁱ	90.000 (2)
C7^vi—Nb—C7^v	143.83 (18)	F1—P1—F1^iv	90.000 (1)
N2—Nb—C7ⁱ	172.73 (14)	F1ⁱⁱ—P1—F1^iv	179.7 (2)
N2ⁱ—Nb—C7ⁱ	29.86 (14)	F1ⁱⁱⁱ—P1—F1^iv	90.000 (2)
N2^v—Nb—C7ⁱ	83.26 (16)	F1—P1—F2	90.16 (12)
N2^vi—Nb—C7ⁱ	89.57 (16)	F1ⁱⁱ—P1—F2	90.16 (12)
N1—Nb—C7ⁱ	113.57 (13)	F1ⁱⁱⁱ—P1—F2	90.16 (12)
N1^v—Nb—C7ⁱ	100.07 (15)	F1^iv—P1—F2	90.16 (12)
N1^vi—Nb—C7ⁱ	106.74 (15)	F1—P1—F3	89.84 (12)
N1ⁱ—Nb—C7ⁱ	30.39 (13)	F1ⁱⁱ—P1—F3	89.84 (12)
C7—Nb—C7ⁱ	143.83 (18)	F1ⁱⁱⁱ—P1—F3	89.84 (12)
C7^vi—Nb—C7ⁱ	95.53 (5)	F1^iv—P1—F3	89.84 (12)
C7^v—Nb—C7ⁱ	95.53 (5)	F2—P1—F3	180.000 (2)

N2—Nb—N1—C7	7.7 (3)	N3—C4—C5—C6	45.0 (6)
N2ⁱ—Nb—N1—C7	−173.2 (3)	C7—N2—C6—C5	39.2 (7)
N2^v—Nb—N1—C7	106.2 (3)	Nb—N2—C6—C5	179.1 (4)
N2^vi—Nb—N1—C7	−89.4 (3)	C4—C5—C6—N2	−54.6 (6)
N1^v—Nb—N1—C7	63.0 (4)	C4—N3—C7—N2	3.0 (7)
N1^vi—Nb—N1—C7	−43.6 (4)	C3—N3—C7—N2	178.2 (5)
N1ⁱ—Nb—N1—C7	−170.3 (4)	C4—N3—C7—N1	−176.2 (5)
C7^vi—Nb—N1—C7	−71.7 (3)	C3—N3—C7—N1	−1.0 (7)
C7^v—Nb—N1—C7	83.7 (2)	C4—N3—C7—Nb	−70.1 (19)
C7ⁱ—Nb—N1—C7	−175.65 (18)	C3—N3—C7—Nb	105.1 (17)
N2—Nb—N1—C1	165.9 (7)	C6—N2—C7—N3	−14.1 (7)
N2ⁱ—Nb—N1—C1	−15.0 (8)	Nb—N2—C7—N3	−167.5 (4)
N2^v—Nb—N1—C1	−95.6 (7)	C6—N2—C7—N1	165.2 (5)
N2^vi—Nb—N1—C1	68.8 (7)	Nb—N2—C7—N1	11.8 (4)
N1^v—Nb—N1—C1	−138.8 (6)	C6—N2—C7—Nb	153.4 (5)
N1^vi—Nb—N1—C1	114.6 (6)	C1—N1—C7—N3	1.6 (8)
N1ⁱ—Nb—N1—C1	−12.1 (6)	Nb—N1—C7—N3	168.0 (4)
C7—Nb—N1—C1	158.2 (9)	C1—N1—C7—N2	−177.7 (5)
C7^vi—Nb—N1—C1	86.5 (7)	Nb—N1—C7—N2	−11.3 (4)
C7^v—Nb—N1—C1	−118.0 (7)	C1—N1—C7—Nb	−166.4 (5)
C7ⁱ—Nb—N1—C1	−17.4 (7)	N2—Nb—C7—N3	80.4 (17)
N2ⁱ—Nb—N2—C7	173.5 (3)	N2^v—Nb—C7—N3	175.8 (17)
N2^v—Nb—N2—C7	−85.1 (3)	N2^vi—Nb—C7—N3	−26.3 (17)
N2^vi—Nb—N2—C7	72.2 (3)	N1—Nb—C7—N3	−113.0 (18)
N1—Nb—N2—C7	−7.8 (3)	N1^v—Nb—C7—N3	117.6 (17)
N1^v—Nb—N2—C7	−144.2 (3)	N1^vi—Nb—C7—N3	31.3 (18)
N1^vi—Nb—N2—C7	131.0 (3)	N1ⁱ—Nb—C7—N3	−102.5 (17)
N1ⁱ—Nb—N2—C7	−4.5 (5)	C7^vi—Nb—C7—N3	1.0 (17)
C7^vi—Nb—N2—C7	101.9 (3)	C7^v—Nb—C7—N3	146.5 (18)
C7^v—Nb—N2—C7	−113.6 (3)	C7ⁱ—Nb—C7—N3	−106.3 (18)
N2ⁱ—Nb—N2—C6	28.4 (5)	N2^v—Nb—C7—N2	95.4 (3)
N2^v—Nb—N2—C6	129.7 (6)	N2^vi—Nb—C7—N2	−106.7 (3)
N2^vi—Nb—N2—C6	−73.0 (5)	N1—Nb—C7—N2	166.6 (5)
N1—Nb—N2—C6	−153.0 (6)	N1^v—Nb—C7—N2	37.2 (3)
N1^v—Nb—N2—C6	70.6 (5)	N1^vi—Nb—C7—N2	−49.1 (3)
N1^vi—Nb—N2—C6	−14.2 (5)	N1ⁱ—Nb—C7—N2	177.1 (3)
N1ⁱ—Nb—N2—C6	−149.7 (5)	C7^v—Nb—C7—N2	66.1 (3)
C7—Nb—N2—C6	−145.2 (7)	C7ⁱ—Nb—C7—N2	173.3 (3)
C7^vi—Nb—N2—C6	−43.3 (5)	N2—Nb—C7—N1	−166.6 (5)
C7^v—Nb—N2—C6	101.2 (5)	N2^v—Nb—C7—N1	−71.2 (3)
C7—N1—C1—C2	−22.7 (8)	N2^vi—Nb—C7—N1	86.7 (3)
Nb—N1—C1—C2	−177.8 (5)	N1^v—Nb—C7—N1	−129.3 (3)
N1—C1—C2—C3	44.3 (9)	N1^vi—Nb—C7—N1	144.4 (3)
C1—C2—C3—N3	−43.2 (8)	N1ⁱ—Nb—C7—N1	10.5 (4)
C7—N3—C3—C2	21.6 (8)	C7^vi—Nb—C7—N1	114.0 (3)
C4—N3—C3—C2	−163.1 (5)	C7^v—Nb—C7—N1	−100.5 (3)
C7—N3—C4—C5	−19.0 (6)	C7ⁱ—Nb—C7—N1	6.8 (3)
C3—N3—C4—C5	165.8 (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.

Experimental details

Crystal data
Chemical formula	[Nb(C₇H₁₂N₃)₄]PF₆
M_r	790.66
Crystal system, space group	Tetragonal, P4/n
Temperature (K)	213
a, c (Å)	13.531 (6), 9.159 (4)
V (Å³)	1676.9 (13)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	0.48
Crystal size (mm)	0.20 × 0.15 × 0.10

Data collection
Diffractometer	Bruker SMART 1K CCD area-detector diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 2004)
T_min, T_max	0.910, 0.953
No. of measured, independent and observed [I > 2σ(I)] reflections	10356, 1655, 1381
R_int	0.025
(sin θ/λ)_max (Å⁻¹)	0.617

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.050, 0.144, 1.05
No. of reflections	1655
No. of parameters	111
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.69, −0.39

Computer programs: SMART (Bruker, 2001), SAINT (Bruker, 2001), SHELXTL (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEPII (Johnson, 1976).

Acknowledgements

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

References

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

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.