[2,6-Bis(di-tert-butyl­phosphinometh­yl)­phen­yl-κ³P,C¹,P′](nitrato-κO)nickel(II)

The Ni^II atom in the title compound, [Ni(C₂₄H₄₃P₂)(NO₃)], adopts a distorted square-planar geometry with the P atoms in a trans arrangement. The compound contains a twofold rotational axis with the nitrate group offset from this axis, except for an O atom of the nitrate group, generating two positions of 50% occupancy for the other atoms of the nitrate group.

Key indicators

• Single-crystal X-ray study
• T = 225 K
• Mean [sigma](C-C) = 0.003 Å
• Disorder in main residue
• R factor = 0.030
• wR factor = 0.099
• Data-to-parameter ratio = 26.1

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT220_ALERT_2_B Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       4.01 Ratio
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        C10

Alert level C
            Value of measurement temperature given =   225.000
            Value of melting point given =     0.000
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.70 Ratio
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N1
PLAT301_ALERT_3_C Main Residue  Disorder .........................       9.00 Perc.
PLAT412_ALERT_2_C Short Intra XH3 .. XHn     H7A    ..  H13B    ..       1.88 Ang.

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           30.50
           From the CIF: _reflns_number_total               4078
           Count of symmetry unique reflns         2102
           Completeness (_total/calc)            194.01%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1976
           Fraction of Friedel pairs measured     0.940
           Are heavy atom types Z>Si present        yes

   0 ALERT level A = In general: serious problem
   2 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

The title compound, (I) (Fig. 1), was prepared from {2,6-bis[(di-tert-butylphosphino)methyl]phenyl}chloridonickel(II) (Boro et al., 2008) via a synthesis adopted from the preparation of the Pd analogue (Cámpora et al., 2004). Our research has been directed towards the activation of molecular oxygen using pincer complexes of the late transition metals (Denney et al., 2006; Keith et al., 2006). Compound (I) was prepared as a precursor along the path of the attempted synthesis of a Ni^II-hydroperoxide.

The compound is bisected by a twofold rotational axis running through C4, C1, Ni1, and O3. The nitrate group is offset from this axis with a C1—Ni1—O1 angle of 164.64 (11)°. As a result of this symmetry induced disorder the nitrate group occupies two positions each with 50% occupancy. The Ni1—O1 bond length 1.976 (3) Å is significantly shorter than the corresponding Pd—O bond length 2.164 (2) Å in the Pd analogue (Johansson et al. 2007). This not surprising, given the smaller size of the Ni atom. The M—C and M—P bonds were also shorter in the Ni compound compared to the Pd. The P—M—P angle, however was closer to the ideal linear geometry with Ni (168.87 (3)°) than Pd (163.41 (3)°).

In their report on the Pd analogue of (I), Johansson et al. (2007) observed non-traditional hydrogen bonding between one of the nitrato O atoms and a hydrogen from the methylene arm of the pincer ligand to form a zigzag chain. The C—H···O interaction measured 3.263 (4) Å (C···O) with an angle of 137°. The same pattern is observed in I (Fig. 2) between C5—H5b···O2, with corresponding measurements of 3.5616 (54) Å and 171.81 (18)°.

Related literature

The synthetic preparation was adopted from that employed to prepare the Pd analogue (Cámpora et al., 2004). For the crystallographic characterization of the Pd analogue, see: Olsson et al. (2007). For the crystallographic characterization of the starting {2,6-bis[(di-tert-butylphosphino)methyl]phenyl}chloridonickel complex, see: Boro et al. (2008). For related literature, see: Denney et al. (2006); Johansson et al. (2007); Keith et al. (2006).

S2. Experimental

{2,6-Bis[(di-tert-butylphosphino)methyl]phenyl}chloronickel(II) (0.135 g, 0.28 mmol) and AgNO₃ (0.05 g, 0.29 mmol) were combined with THF (20 ml) and the solution was stirred at room temperature for 48 h. The THF was then removed under vacuum and the product was extracted into diethyl ether (15 ml). After filtering, the solution was layered with hexanes and placed in a 238 K freezer. The product crystallized as orange-brown prisms.

Yield 0.118 g, 82%. ¹H NMR (250 MHz, C₆D₆): 6.93 (d, J_HH = 7.5 Hz, 1H, Ar-H_para), 6.68 (t, J_HH = 7.5 Hz, 2H, Ar-H_meta), 2.80 (virtual t, 4H, J_HP = 7.15 Hz,CH₂), 1.25 (virtual t, 36H, J = 13.1 Hz C(CH₃)₃) p.p.m.. ¹³C{¹H} (63 MHz, C₆D₆): 152.8 (t, ²J_PC = 11.6 Hz, Ar-C_ipso), 147.1 (virtual t, J_CP= 32.3 Hz, Ar-C_ortho), 125.8 (s, Ar-C_para), 122.1 (virtual t, J_CP = 15.8 Hz, Ar-C_para), 34.5 (virtual t, J_CP = 13.2 Hz, PCH₂), 32.7 (virtual t, J_CP = 24.6 Hz, PC(CH₃)₃), 29.6 (s, CH₃) p.p.m.. ³¹P{¹H} (101 MHz, C₆D₆): 69.5 (s) p.p.m..

S3. Refinement

Hydrogen atoms were included at geometrically idealized positions with C—H distances at the range of 0.93 - 0.98 Å and were treated as riding on their respective heavy atoms. The isotropic thermal parameters of the hydrogen atoms were fixed at 1.2 or 1.5 U_eq of the parent atom.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: APEX2 (Bruker, 2007); data reduction: APEX2 (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: publCIF (Westrip, 2008).

Figures

	Fig. 1. View of the title compound showing full numbering scheme. Ellipsoids are shown at 50% probability and hydrogen atoms have been removed for clarity. Only one of the two symmetry equivalent positions for the nitrate group is shown.
	Fig. 2. Hydrogen bonding in (I). For clarity the tert-butyl substituents on P have been removed.

[2,6-Bis(di-tert-butylphosphinomethyl)phenyl- κ³P,C¹,P'](nitrato-κO)nickel(II)

Crystal data

[Ni(C24H43P2)(NO3)]	F(000) = 2208
Mr = 514.24	Dx = 1.276 Mg m^−3
Orthorhombic, Fdd2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: F 2 -2d	Cell parameters from 9535 reflections
a = 24.0023 (14) Å	θ = 2.2–30.3°
b = 12.6350 (6) Å	µ = 0.87 mm^−1
c = 17.6528 (6) Å	T = 225 K
V = 5353.5 (4) Å^3	Cut-prism, orange–brown
Z = 8	0.50 × 0.40 × 0.20 mm

Data collection

Bruker SMART CCD area-detector diffractometer	4078 independent reflections
Radiation source: fine-focus sealed tube	3703 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.037
ϕ and ω scans	θmax = 30.5°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −34→34
Tmin = 0.671, Tmax = 0.846	k = −18→18
33484 measured reflections	l = −25→25

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.030	H-atom parameters constrained
wR(F^2) = 0.099	w = 1/[σ^2(Fo^2) + (0.1P)^2 + 0.25P] where P = (Fo^2 + 2Fc^2)/3
S = 0.81	(Δ/σ)max = 0.001
4078 reflections	Δρmax = 0.38 e Å^−3
156 parameters	Δρmin = −0.38 e Å^−3
1 restraint	Absolute structure: Flack (1983), 1976 Freidel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.012 (10)

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 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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Ni1	0.2500	0.2500	0.594610 (14)	0.02536 (9)
P1	0.232841 (19)	0.07823 (3)	0.58242 (3)	0.02639 (10)
C1	0.2500	0.2500	0.48634 (16)	0.0263 (5)
C2	0.22870 (9)	0.16438 (14)	0.44415 (10)	0.0293 (3)
C3	0.22918 (11)	0.16401 (17)	0.36544 (11)	0.0381 (4)
H3	0.2153	0.1051	0.3390	0.046*
C4	0.2500	0.2500	0.32575 (19)	0.0443 (8)
H4	0.2500	0.2500	0.2725	0.053*
C5	0.20438 (10)	0.07210 (16)	0.48626 (12)	0.0357 (4)
H5A	0.2149	0.0054	0.4618	0.043*
H5B	0.1636	0.0770	0.4875	0.043*
C6	0.17578 (10)	0.02125 (17)	0.64252 (13)	0.0356 (4)
C7	0.15103 (12)	−0.08133 (18)	0.60934 (17)	0.0492 (6)
H7A	0.1803	−0.1337	0.6038	0.074*
H7B	0.1348	−0.0665	0.5602	0.074*
H7C	0.1225	−0.1082	0.6431	0.074*
C8	0.13040 (11)	0.1061 (2)	0.64349 (17)	0.0490 (5)
H8A	0.1001	0.0833	0.6759	0.073*
H8B	0.1166	0.1170	0.5925	0.073*
H8C	0.1458	0.1718	0.6627	0.073*
C9	0.19464 (14)	0.00157 (19)	0.72359 (15)	0.0484 (6)
H9A	0.1623	−0.0057	0.7561	0.073*
H9B	0.2171	0.0607	0.7408	0.073*
H9C	0.2166	−0.0628	0.7256	0.073*
C10	0.29710 (10)	−0.00713 (16)	0.58017 (16)	0.0434 (5)
C11	0.33545 (12)	0.0368 (3)	0.5189 (2)	0.0635 (9)
H11A	0.3615	−0.0176	0.5032	0.095*
H11B	0.3558	0.0970	0.5388	0.095*
H11C	0.3134	0.0590	0.4757	0.095*
C12	0.32896 (19)	0.0019 (4)	0.6540 (3)	0.100 (2)
H12A	0.3293	−0.0663	0.6793	0.150*
H12B	0.3110	0.0538	0.6864	0.150*
H12C	0.3669	0.0240	0.6437	0.150*
C13	0.28517 (17)	−0.1214 (3)	0.5629 (4)	0.106 (2)
H13A	0.2705	−0.1274	0.5118	0.159*
H13B	0.2580	−0.1484	0.5986	0.159*
H13C	0.3193	−0.1621	0.5670	0.159*
N1	0.2619 (2)	0.2312 (5)	0.7546 (2)	0.0478 (13)	0.50
O1	0.22947 (16)	0.2640 (3)	0.70255 (19)	0.0394 (7)	0.50
O2	0.3061 (2)	0.1884 (5)	0.7355 (3)	0.0732 (13)	0.50
O3	0.2500	0.2500	0.8206 (2)	0.0869 (14)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.03377 (16)	0.01934 (13)	0.02296 (14)	−0.00129 (11)	0.000	0.000
P1	0.0305 (2)	0.01967 (19)	0.0290 (2)	0.00015 (15)	0.00072 (17)	0.00082 (15)
C1	0.0312 (13)	0.0241 (12)	0.0238 (11)	0.0033 (8)	0.000	0.000
C2	0.0344 (8)	0.0280 (8)	0.0256 (8)	0.0006 (7)	−0.0019 (7)	−0.0025 (6)
C3	0.0478 (11)	0.0397 (11)	0.0267 (9)	−0.0013 (8)	−0.0025 (8)	−0.0070 (7)
C4	0.059 (2)	0.0497 (19)	0.0237 (12)	0.0046 (13)	0.000	0.000
C5	0.0468 (11)	0.0289 (9)	0.0314 (9)	−0.0077 (8)	−0.0027 (8)	−0.0030 (7)
C6	0.0378 (10)	0.0323 (8)	0.0368 (10)	−0.0059 (8)	0.0047 (8)	0.0017 (7)
C7	0.0514 (13)	0.0399 (11)	0.0564 (14)	−0.0172 (10)	0.0099 (11)	−0.0066 (9)
C8	0.0387 (11)	0.0530 (13)	0.0552 (14)	0.0026 (10)	0.0096 (10)	−0.0039 (11)
C9	0.0621 (16)	0.0468 (14)	0.0364 (11)	−0.0120 (11)	0.0025 (10)	0.0099 (9)
C10	0.0380 (10)	0.0317 (10)	0.0606 (15)	0.0095 (7)	0.0119 (10)	0.0072 (9)
C11	0.0397 (12)	0.0590 (16)	0.092 (2)	0.0147 (12)	0.0217 (15)	0.0184 (17)
C12	0.061 (2)	0.168 (6)	0.070 (3)	0.056 (3)	−0.0012 (18)	0.028 (2)
C13	0.069 (2)	0.0339 (14)	0.215 (7)	0.0129 (13)	0.034 (3)	−0.011 (2)
N1	0.057 (4)	0.052 (4)	0.0350 (19)	−0.016 (2)	−0.0114 (18)	0.0079 (18)
O1	0.0488 (17)	0.0462 (17)	0.0233 (14)	−0.0022 (15)	0.0012 (13)	−0.0048 (12)
O2	0.054 (2)	0.104 (4)	0.062 (3)	0.012 (3)	−0.011 (2)	0.019 (3)
O3	0.098 (3)	0.137 (4)	0.0265 (13)	−0.012 (2)	0.000	0.000

Geometric parameters (Å, º)

Ni1—C1	1.911 (3)	C7—H7C	0.9700
Ni1—O1^i	1.976 (3)	C8—H8A	0.9700
Ni1—O1	1.976 (3)	C8—H8B	0.9700
Ni1—P1^i	2.2195 (4)	C8—H8C	0.9700
Ni1—P1	2.2195 (4)	C9—H9A	0.9700
P1—C5	1.831 (2)	C9—H9B	0.9700
P1—C6	1.876 (2)	C9—H9C	0.9700
P1—C10	1.882 (2)	C10—C13	1.503 (4)
C1—C2^i	1.409 (2)	C10—C12	1.516 (6)
C1—C2	1.409 (2)	C10—C11	1.525 (4)
C2—C3	1.389 (3)	C11—H11A	0.9700
C2—C5	1.501 (3)	C11—H11B	0.9700
C3—C4	1.386 (3)	C11—H11C	0.9700
C3—H3	0.9400	C12—H12A	0.9700
C4—C3^i	1.386 (3)	C12—H12B	0.9700
C4—H4	0.9400	C12—H12C	0.9700
C5—H5A	0.9800	C13—H13A	0.9700
C5—H5B	0.9800	C13—H13B	0.9700
C6—C9	1.521 (3)	C13—H13C	0.9700
C6—C8	1.528 (4)	N1—O3	1.223 (5)
C6—C7	1.541 (3)	N1—O2	1.239 (7)
C7—H7A	0.9700	N1—O1	1.273 (5)
C7—H7B	0.9700	O3—N1^i	1.223 (5)
C1—Ni1—O1^i	164.64 (11)	C6—C8—H8B	109.5
C1—Ni1—O1	164.64 (11)	H8A—C8—H8B	109.5
C1—Ni1—P1^i	84.437 (14)	C6—C8—H8C	109.5
O1^i—Ni1—P1^i	97.74 (10)	H8A—C8—H8C	109.5
O1—Ni1—P1^i	93.00 (10)	H8B—C8—H8C	109.5
C1—Ni1—P1	84.435 (14)	C6—C9—H9A	109.5
O1^i—Ni1—P1	93.00 (10)	C6—C9—H9B	109.5
O1—Ni1—P1	97.74 (10)	H9A—C9—H9B	109.5
P1^i—Ni1—P1	168.87 (3)	C6—C9—H9C	109.5
C5—P1—C6	103.63 (10)	H9A—C9—H9C	109.5
C5—P1—C10	105.18 (12)	H9B—C9—H9C	109.5
C6—P1—C10	112.97 (10)	C13—C10—C12	110.1 (3)
C5—P1—Ni1	101.56 (7)	C13—C10—C11	108.7 (3)
C6—P1—Ni1	117.12 (7)	C12—C10—C11	106.1 (3)
C10—P1—Ni1	114.22 (8)	C13—C10—P1	113.5 (2)
C2^i—C1—C2	116.2 (3)	C12—C10—P1	110.6 (2)
C2^i—C1—Ni1	121.90 (13)	C11—C10—P1	107.52 (16)
C2—C1—Ni1	121.90 (13)	C10—C11—H11A	109.5
C3—C2—C1	121.9 (2)	C10—C11—H11B	109.5
C3—C2—C5	119.73 (18)	H11A—C11—H11B	109.5
C1—C2—C5	118.39 (19)	C10—C11—H11C	109.5
C4—C3—C2	120.4 (2)	H11A—C11—H11C	109.5
C4—C3—H3	119.8	H11B—C11—H11C	109.5
C2—C3—H3	119.8	C10—C12—H12A	109.5
C3^i—C4—C3	119.3 (3)	C10—C12—H12B	109.5
C3^i—C4—H4	120.4	H12A—C12—H12B	109.5
C3—C4—H4	120.4	C10—C12—H12C	109.5
C2—C5—P1	106.33 (13)	H12A—C12—H12C	109.5
C2—C5—H5A	110.5	H12B—C12—H12C	109.5
P1—C5—H5A	110.5	C10—C13—H13A	109.5
C2—C5—H5B	110.5	C10—C13—H13B	109.5
P1—C5—H5B	110.5	H13A—C13—H13B	109.5
H5A—C5—H5B	108.7	C10—C13—H13C	109.5
C9—C6—C8	108.4 (2)	H13A—C13—H13C	109.5
C9—C6—C7	109.6 (2)	H13B—C13—H13C	109.5
C8—C6—C7	108.6 (2)	O1^i—N1—O3	165.1 (6)
C9—C6—P1	112.18 (18)	O1^i—N1—O2	64.8 (4)
C8—C6—P1	104.93 (15)	O3—N1—O2	123.0 (4)
C7—C6—P1	112.90 (16)	O3—N1—O1	118.8 (4)
C6—C7—H7A	109.5	O2—N1—O1	117.9 (5)
C6—C7—H7B	109.5	N1^i—O1—O2^i	69.6 (4)
H7A—C7—H7B	109.5	O2^i—O1—N1	104.4 (4)
C6—C7—H7C	109.5	N1^i—O1—Ni1	152.8 (5)
H7A—C7—H7C	109.5	O2^i—O1—Ni1	133.8 (4)
H7B—C7—H7C	109.5	N1—O1—Ni1	121.0 (3)
C6—C8—H8A	109.5

Symmetry code: (i) −x+1/2, −y+1/2, z.