catena-Poly[lead(II)-[μ-2,4-diamino-6-(piperidin-1-yl)pyrimidine N-oxide-κ²O:O]di-μ-iodido]

The N-oxide O atom of the minoxidil unit in the 1/1 adduct with lead(II) iodide, [PbI₂(C₉H₁₅N₅O)]_n, bridges two Pb^II atoms, as do each of the I atoms. The bridging inter­actions give rise to a linear chain motif that propagates along the a axis of the ortho­rhom­bic unit cell. The coordination sphere around the six-coordinate Pb^II atom is a distorted ψ-monocapped octa­hedron in which the stereochemically active lone pair caps one of the faces defined by the O and I atoms forming the longer Pb—O or Pb—I bonds. The Pb^II atom lies on a mirror plane; the mirror plane is perpendicular to the pyrimidine ring and it bis­ects the piperidine ring. The aromatic ring is disordered about the mirror plane with respect to the 1-nitro­gen and 5-carbon atoms.

Key indicators

• Single-crystal X-ray study
• T = 140 K
• Mean [sigma](C-C) = 0.005 Å
• Disorder in main residue
• R factor = 0.018
• wR factor = 0.043
• Data-to-parameter ratio = 20.2

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT414_ALERT_2_A Short Intra D-H..H-X       H2     ..  H4A     ..       1.74 Ang.

Author Response: This is an artifact of the disorder in the pyrimidyl ring. Details are given in _publ_section_exptl_refinement.

Alert level C
PLAT420_ALERT_2_C D-H Without Acceptor       N3     -   H31    ...          ?

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.906
            Tmax scaled      0.472 Tmin scaled      0.139
PLAT301_ALERT_3_G Note Main Residue  Disorder ....................       6.00 Perc.
PLAT062_ALERT_4_G Rescale T(min) & T(max) by .....................       0.91
PLAT779_ALERT_4_G Suspect or Irrelevant (Bond) Angle in CIF ......       0.00 Deg.
              C2   -C3   -N2      7.575   1.555   7.575

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   2 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
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Related literature

For the crystal structure of minoxidil, see: Akama et al. (2004); Martín-Islán et al. (2008).

S1. Experimental

Minoxidil [6-(1-piperidinyl)-2,4-pyrimidinediamide 3-oxide) (0.10 g, 0.5 mmol), lead(II) acetate (0.17 g, 0.5 mmol) and potassium iodide (0.16 g, 1 mmol) were placed one arm of a two-arm glass tube. Methanol was added to fill both arms. The tube was sealed and the arm containing the reactants immersed in an oil bath at 333 K while the other arm was kept at ambient temperature. After 10 days, light-brown crystals deposited in the cooler arm. These were collected, washed with acetone and ether, and finally air dried.

S2. Refinement

Carbon-bound H-atoms were placed in calculated positions (C–H 0.95 to 0.99 Å) and were included in the refinement in the riding model approximation, with U(H) set to 1.2U(C). The amino H-atoms were similarly treated (N–H 0.88 Å).

The minoxidil molecule is disordered about a mirror plane that is perpendicular to the pyrimidinyl ring; the mirror plane also bisects piperidinyl ring. In the aromatic ring, the nitrogen atom at the 1-position shares the same site as the carbon atom at the 5-position; this site was refined as half a nitrogen atom and half a C-H group. The short H2···H4a distance of 1.74 Å is an artifact of the disorder about a mirror plane.

Computing details

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: publCIF (Westrip, 2009).

Figures

Fig. 1. Thermal ellisoid plot (Barbour, 2001) of the lead diiodide–minoxidil adduct extended to show the coordination geometries of two lead atoms of the linear chain formed in the crystal structure. Atoms comprising the asymmetric unit are labelled, probability levels are set at 70% and H-atoms are drawn as spheres of arbitrary radius. Only one component of the disorder is shown.

catena-Poly[lead(II)-[µ-2,4-diamino-6-(piperidin-1-yl)pyrimidine N-oxide-κ²O:O]di-µ-iodido]

Crystal data

[PbI2(C9H15N5O)]	F(000) = 1200
Mr = 670.25	Dx = 2.902 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 5726 reflections
a = 8.1010 (1) Å	θ = 2.9–28.3°
b = 13.5126 (2) Å	µ = 15.02 mm^−1
c = 14.0140 (2) Å	T = 140 K
V = 1534.05 (4) Å^3	Prism, yellow
Z = 4	0.20 × 0.10 × 0.05 mm

Data collection

Bruker SMART APEX diffractometer	1837 independent reflections
Radiation source: fine-focus sealed tube	1752 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
ω scans	θmax = 27.5°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→10
Tmin = 0.153, Tmax = 0.521	k = −17→17
10101 measured reflections	l = −18→18

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.018	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.043	H-atom parameters constrained
S = 1.05	w = 1/[σ^2(Fo^2) + (0.0233P)^2 + 1.8105P] where P = (Fo^2 + 2Fc^2)/3
1837 reflections	(Δ/σ)max = 0.001
91 parameters	Δρmax = 0.72 e Å^−3
0 restraints	Δρmin = −0.90 e Å^−3

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Pb1	0.55277 (2)	0.7500	0.769395 (12)	0.01565 (6)
I1	0.26714 (3)	0.588041 (17)	0.831700 (16)	0.02101 (7)
O1	0.3482 (4)	0.7500	0.6436 (2)	0.0171 (7)
N1	0.3822 (5)	0.7500	0.5481 (3)	0.0137 (8)
N2	0.4236 (4)	0.6615 (2)	0.4053 (2)	0.0184 (6)	0.50
N3	0.3560 (4)	0.5806 (2)	0.5498 (2)	0.0237 (7)
H31	0.3565	0.5226	0.5213	0.028*
H32	0.3340	0.5847	0.6112	0.028*
N4	0.4716 (6)	0.7500	0.2638 (3)	0.0187 (9)
C1	0.3887 (4)	0.6625 (3)	0.5000 (2)	0.0183 (7)
C2	0.4236 (4)	0.6615 (2)	0.4053 (2)	0.0184 (6)	0.50
H2	0.4352	0.6007	0.3718	0.022*	0.50
C3	0.4417 (6)	0.7500	0.3590 (3)	0.0173 (9)
C4	0.5041 (5)	0.6591 (3)	0.2101 (3)	0.0224 (7)
H4A	0.4732	0.6010	0.2493	0.027*
H4B	0.6234	0.6544	0.1956	0.027*
C5	0.4058 (5)	0.6583 (3)	0.1176 (3)	0.0280 (9)
H5A	0.4367	0.5992	0.0798	0.034*
H5B	0.2867	0.6535	0.1326	0.034*
C6	0.4363 (8)	0.7500	0.0587 (4)	0.0350 (14)
H6A	0.5517	0.7500	0.0354	0.042*
H6B	0.3621	0.7500	0.0026	0.042*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Pb1	0.01521 (10)	0.01598 (10)	0.01577 (10)	0.000	−0.00072 (6)	0.000
I1	0.02066 (14)	0.01606 (12)	0.02631 (12)	−0.00058 (9)	0.00187 (9)	0.00768 (8)
O1	0.0150 (17)	0.0263 (18)	0.0099 (13)	0.000	0.0015 (12)	0.000
N1	0.0143 (19)	0.0163 (19)	0.0105 (16)	0.000	−0.0019 (14)	0.000
N2	0.0168 (16)	0.0230 (17)	0.0155 (14)	−0.0007 (13)	0.0001 (12)	−0.0035 (12)
N3	0.0270 (17)	0.0148 (15)	0.0294 (15)	−0.0038 (13)	−0.0040 (13)	−0.0053 (12)
N4	0.026 (2)	0.018 (2)	0.0118 (18)	0.000	0.0012 (16)	0.000
C1	0.0145 (16)	0.0208 (18)	0.0197 (16)	−0.0011 (14)	−0.0007 (13)	−0.0043 (13)
C2	0.0168 (16)	0.0230 (17)	0.0155 (14)	−0.0007 (13)	0.0001 (12)	−0.0035 (12)
C3	0.014 (2)	0.022 (2)	0.016 (2)	0.000	−0.0009 (18)	0.000
C4	0.0249 (19)	0.0211 (18)	0.0211 (16)	0.0032 (16)	0.0036 (15)	−0.0038 (14)
C5	0.025 (2)	0.036 (2)	0.0226 (18)	−0.0012 (17)	−0.0035 (15)	−0.0130 (16)
C6	0.039 (4)	0.051 (4)	0.014 (2)	0.000	−0.006 (2)	0.000

Geometric parameters (Å, º)

Pb1—O1	2.419 (3)	N4—C3	1.356 (6)
Pb1—O1^i	2.686 (3)	N4—C4	1.464 (4)
Pb1—I1	3.3024 (3)	N4—C4^iii	1.464 (4)
Pb1—I1^ii	3.1325 (3)	C3—C2^iii	1.368 (4)
Pb1—I1^i	3.1325 (3)	C3—N2^iii	1.368 (4)
Pb1—I1^iii	3.3024 (3)	C4—C5	1.522 (5)
O1—N1	1.366 (5)	C4—H4A	0.9900
N1—C1	1.363 (4)	C4—H4B	0.9900
N1—C1^iii	1.363 (4)	C5—C6	1.509 (5)
N2—C1	1.358 (4)	C5—H5A	0.9900
N2—C3	1.368 (4)	C5—H5B	0.9900
N3—C1	1.335 (4)	C6—C5^iii	1.509 (5)
N3—H31	0.8800	C6—H6A	0.9900
N3—H32	0.8800	C6—H6B	0.9900
O1—Pb1—O1^i	160.22 (9)	C4—N4—C4^iii	114.1 (4)
O1—Pb1—I1^i	92.88 (5)	N3—C1—N2	123.0 (3)
O1^i—Pb1—I1^i	73.21 (5)	N3—C1—N1	116.9 (3)
O1—Pb1—I1^ii	92.88 (5)	N2—C1—N1	120.1 (3)
O1^i—Pb1—I1^ii	73.21 (5)	N4—C3—N2	119.0 (2)
I1^i—Pb1—I1^ii	88.636 (10)	N4—C3—C2^iii	119.0 (2)
O1—Pb1—I1	73.30 (5)	N2—C3—C2^iii	121.9 (4)
O1^i—Pb1—I1	120.29 (4)	N4—C3—N2^iii	119.0 (2)
I1^i—Pb1—I1	92.581 (7)	N2—C3—N2^iii	121.9 (4)
I1^ii—Pb1—I1	166.169 (8)	C2^iii—C3—N2^iii	0.0 (3)
O1—Pb1—I1^iii	73.30 (5)	N4—C4—C5	110.5 (3)
O1^i—Pb1—I1^iii	120.29 (4)	N4—C4—H4A	109.6
I1^i—Pb1—I1^iii	166.169 (8)	C5—C4—H4A	109.6
I1^ii—Pb1—I1^iii	92.581 (7)	N4—C4—H4B	109.6
I1—Pb1—I1^iii	83.011 (9)	C5—C4—H4B	109.6
Pb1^iv—I1—Pb1	78.806 (5)	H4A—C4—H4B	108.1
N1—O1—Pb1	125.2 (3)	C6—C5—C4	112.0 (4)
N1—O1—Pb1^iv	128.6 (3)	C6—C5—H5A	109.2
Pb1—O1—Pb1^iv	106.25 (11)	C4—C5—H5A	109.2
O1—N1—C1	119.5 (2)	C6—C5—H5B	109.2
O1—N1—C1^iii	119.5 (2)	C4—C5—H5B	109.2
C1—N1—C1^iii	120.5 (4)	H5A—C5—H5B	107.9
C1—N2—C3	118.5 (3)	C5^iii—C6—C5	110.4 (4)
C1—N3—H31	120.0	C5^iii—C6—H6A	109.6
C1—N3—H32	120.0	C5—C6—H6A	109.6
H31—N3—H32	120.0	C5^iii—C6—H6B	109.6
C3—N4—C4	122.51 (19)	C5—C6—H6B	109.6
C3—N4—C4^iii	122.51 (19)	H6A—C6—H6B	108.1
O1—Pb1—I1—Pb1^iv	−35.49 (5)	C3—N2—C1—N3	174.6 (4)
O1^i—Pb1—I1—Pb1^iv	160.24 (6)	C3—N2—C1—N1	−3.9 (5)
I1^i—Pb1—I1—Pb1^iv	−127.726 (10)	O1—N1—C1—N3	1.9 (5)
I1^ii—Pb1—I1—Pb1^iv	−32.94 (2)	C1^iii—N1—C1—N3	−169.9 (3)
I1^iii—Pb1—I1—Pb1^iv	39.115 (7)	O1—N1—C1—N2	−179.5 (3)
O1^i—Pb1—O1—N1	0.000 (2)	C1^iii—N1—C1—N2	8.7 (7)
I1^i—Pb1—O1—N1	−44.389 (6)	C4—N4—C3—N2	−7.1 (7)
I1^ii—Pb1—O1—N1	44.389 (6)	C4^iii—N4—C3—N2	−175.6 (4)
I1—Pb1—O1—N1	−136.222 (16)	C4—N4—C3—C2^iii	175.6 (4)
I1^iii—Pb1—O1—N1	136.222 (17)	C4^iii—N4—C3—C2^iii	7.1 (7)
O1^i—Pb1—O1—Pb1^iv	180.0	C4—N4—C3—N2^iii	175.6 (4)
I1^i—Pb1—O1—Pb1^iv	135.611 (6)	C4^iii—N4—C3—N2^iii	7.1 (7)
I1^ii—Pb1—O1—Pb1^iv	−135.611 (6)	C1—N2—C3—N4	−178.0 (4)
I1—Pb1—O1—Pb1^iv	43.778 (16)	C1—N2—C3—C2^iii	−0.8 (7)
I1^iii—Pb1—O1—Pb1^iv	−43.778 (16)	C1—N2—C3—N2^iii	−0.8 (7)
Pb1—O1—N1—C1	94.1 (3)	C3—N4—C4—C5	134.8 (5)
Pb1^iv—O1—N1—C1	−85.9 (3)	C4^iii—N4—C4—C5	−55.8 (6)
Pb1—O1—N1—C1^iii	−94.1 (3)	N4—C4—C5—C6	54.1 (5)
Pb1^iv—O1—N1—C1^iii	85.9 (3)	C4—C5—C6—C5^iii	−53.5 (6)

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