Bis(7-amino-2,4-dimethyl-1,8-naphthyridine)dichloridonickel(II) methanol solvate

In the title compound, [NiCl₂(C₁₀H₁₁N₃)₂]·CH₄O, the Ni^II ion lies on a crystallographic twofold axis and is coordinated in a distorted octa­hedral geometry by four N atoms from two bidentate naphthyridine ligands and two chlorine atoms. The unique methanol solvent mol­ecule has half occupancy. In the crystal structure, inter­molecular N—H...Cl and O—H...Cl hydrogen bonds connect mol­ecules into one-dimensional chains which propagate along the c-axis direction.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.008 Å
• Disorder in solvent or counterion
• R factor = 0.052
• wR factor = 0.167
• Data-to-parameter ratio = 15.5

checkCIF/PLATON results

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Alert level C
PLAT094_ALERT_2_C Ratio of Maximum / Minimum Residual Density ....       2.03
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.57 Ratio
PLAT302_ALERT_4_C Anion/Solvent Disorder .........................      50.00 Perc.
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          8

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......         19

   0 ALERT level A = In general: serious problem
   0 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
   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
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The molecular structures and chemical properties (Kukrek et al., 2006; Che et al., 2001) of transition metal complexes of 1,8-naphthyridine (napy) and its derivatives have received much attention, as the ligands can link to metals with several coordination modes such as monodentate, chelating bidentate, and dinuclear bridging binding fashion (Gavrilova & Bosnich, 2004). 5,7-dimethyl-1,8-naphthyridin-2-amine is a potentially tridentate ligand and is capable of linking two to four metal atoms together to form metal aggregates (Oskui et al., 1999; Mintert & Sheldrick, 1995a; Oskui & Sheldrick, 1999; Mintert & Sheldrick, 1995b). The coordination chemistry of 5,7-dimethyl-1,8-naphthyridine-2-amine (L) has not been well studied although an Ni(II) complex (Ni(L)₂(Cl)₂)(Bayer, 1979) has been decribed in a US patent. As an extension of our study (Jin et al., 2007) on naphthyridine coordination chemistry, we have determined the crystal structure of the the title complex (Ni(L)₂(Cl)₂)·(CH₃OH).

The title compound was obtained as blue crystals by reacting of nickel chloride hexahydrate and L in methanol. The compound is a neutral compound which is air stable and light insensitive. The complex does not dissolve in water and common organic solvent. X-ray structural analysis shows that the complex is mononuclear. The molecular structure of the compound is shown in Fig. 1.

The Ni atom lies on a crystallographic twofold axis and is coordinated to two L ligands, and two chloride ions. The Cl atoms are in a cis orientation with respect to each other (Cl1—Ni1—Cl1ⁱ = 96.55 (10)°; symmetry code: (i) -x + 2, y, -z + 3/2). Both L ligands coordinate through N atoms in a bidentate chelate fashion to form two four-membered Ni/N/C/N rings. Two chloride anions coordinate to the Ni^II ion to complete the distorted octahedral geometry. The amine group of the 5,7-dimethyl-1,8-naphthyridin-2-amine ligand does not form any bonding interactions with Ni atoms. All the bond lengths and bond angles in the ligand are in the normal ranges (Allen et al., 1987). The N2—C2 bond distance is 1.340 (5) Å, typical for a C—N double bond. The two naphthyridine rings are almost perpendicular to each other with the N1ⁱ—Ni1—N1—C8, N2ⁱ—Ni1—N1—C8 torsion angles of 75.41 (16), and 14.39 (14)°. N2—Ni1—N1ⁱ, and N1ⁱ—Ni1—N1 are 100.08 (14), and 85.1 (2) ° respectively. The solvent methanol molecules are bonded to the corresponding (Ni_(L)2(Cl₎2) moiety through hydrogen bonds and a (Ni(L)₂(Cl)₂) moiety is bonded to two neighbouring (Ni(L)₂(Cl)₂) moieties via hydrogen bonds. Hence, in the crystal structure, the compound forms 1-D chains along the c axis via intermolecular hydrogen bonds, (Fig. 2).

Related literature

For related literature, see: Bayer (1979); Che et al. (2001); Gavrilova & Bosnich (2004); Jin et al. (2007); Kukrek et al. (2006); Mintert & Sheldrick (1995a,b); Oskui & Sheldrick (1999); Oskui, Mintert & Sheldrick (1999); Allen et al. (1987).

S2. Experimental

All reagents and solvents were used as obtained without further purification. The CH,N elemental analyses were performed on a Perkin-Elmer model 2400 elemental analyzer.

To an methanol solution of nickel chloride hexahydrate (24 mg, 0.1 mmol), was added L (17.4 mg, 0.1 mmol) in 10 ml of methanol. The solution was stirred for a few minutes, then the solution was filtered. The solution was left standing at room temperature for several days. Light blue crystals were isolated after slow evaporation of its solution in air. Yield: 33 mg, 65%. Anal. Calcd for C₂₁H₂₆Cl₂N₆Ni_O: C, 49.60; H, 5.12; N, 16.53; Found: C, 49.52; H, 5.05; N, 16.47.

S3. Refinement

All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with N—H = 0.86, C—H = 0.93–0.96 and O—H = 0.82 Å. They were included in the refinement in the riding-model approximation with U_iso(H) = 1.2U_eq(C,N) or 1.5U_eq(O and methyl C atoms)

Computing details

Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The molecular structure, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level [symmetry code: (A): -x + 2, y, -z + 3/2].
	Fig. 2. Part of the crystal structure showing hydrogen bonds as dashed lines.

Bis(7-amino-2,4-dimethyl-1,8-naphthyridine)dichloridonickel(II) methanol solvate

Crystal data

[NiCl2(C10H11N3)2]·CH4O	F(000) = 1056
Mr = 508.09	Dx = 1.278 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 1560 reflections
a = 13.609 (10) Å	θ = 2.5–21.3°
b = 15.399 (11) Å	µ = 0.96 mm^−1
c = 12.632 (9) Å	T = 298 K
β = 94.337 (11)°	Block, blue
V = 2640 (3) Å^3	0.18 × 0.14 × 0.12 mm
Z = 4

Data collection

Bruker SMART-APEX diffractometer	2323 independent reflections
Radiation source: fine-focus sealed tube	1552 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.053
ϕ and ω scans	θmax = 25.0°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −16→16
Tmin = 0.846, Tmax = 0.894	k = −18→14
6731 measured reflections	l = −15→14

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)] = 0.052	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.167	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.097P)^2 + 0.4954P] where P = (Fo^2 + 2Fc^2)/3
2323 reflections	(Δ/σ)max < 0.001
150 parameters	Δρmax = 0.57 e Å^−3
19 restraints	Δρmin = −0.28 e Å^−3

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	1.0000	0.12244 (5)	0.7500	0.0366 (3)
Cl1	1.13154 (9)	0.01906 (8)	0.76050 (9)	0.0498 (4)
N1	0.9035 (3)	0.2275 (3)	0.7978 (3)	0.0450 (10)
N2	0.9990 (3)	0.1486 (2)	0.9113 (3)	0.0362 (9)
N3	1.1018 (3)	0.0618 (3)	1.0176 (3)	0.0492 (11)
H3A	1.1205	0.0366	0.9618	0.059*
H3B	1.1261	0.0460	1.0794	0.059*
O1	0.8427 (10)	0.3836 (8)	0.3032 (12)	0.142 (5)	0.50
H1	0.7837	0.3941	0.3035	0.213*	0.50
C1	0.9341 (3)	0.2147 (3)	0.9013 (3)	0.0392 (11)
C2	1.0359 (3)	0.1249 (3)	1.0084 (3)	0.0373 (11)
C3	1.0054 (4)	0.1694 (4)	1.0990 (4)	0.0533 (14)
H3	1.0298	0.1519	1.1664	0.064*
C4	0.9421 (4)	0.2359 (4)	1.0888 (4)	0.0597 (15)
H4	0.9239	0.2645	1.1492	0.072*
C5	0.9021 (4)	0.2635 (3)	0.9862 (4)	0.0498 (13)
C6	0.8347 (4)	0.3297 (4)	0.9603 (5)	0.0669 (16)
C7	0.8050 (5)	0.3422 (4)	0.8555 (5)	0.0712 (17)
H7	0.7608	0.3867	0.8370	0.085*
C8	0.8387 (4)	0.2902 (4)	0.7755 (4)	0.0604 (15)
C9	0.7974 (5)	0.3884 (4)	1.0462 (6)	0.096 (2)
H9A	0.8501	0.4251	1.0745	0.143*
H9B	0.7744	0.3533	1.1021	0.143*
H9C	0.7443	0.4237	1.0161	0.143*
C10	0.8065 (5)	0.3040 (5)	0.6585 (5)	0.096 (2)
H10A	0.8608	0.2923	0.6165	0.144*
H10B	0.7853	0.3630	0.6476	0.144*
H10C	0.7530	0.2654	0.6379	0.144*
C11	0.8902 (16)	0.4248 (14)	0.3805 (17)	0.155 (7)	0.50
H11A	0.9272	0.4714	0.3524	0.233*	0.50
H11B	0.9343	0.3855	0.4192	0.233*	0.50
H11C	0.8442	0.4480	0.4271	0.233*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni1	0.0416 (5)	0.0413 (6)	0.0266 (4)	0.000	0.0006 (3)	0.000
Cl1	0.0544 (8)	0.0553 (9)	0.0388 (7)	0.0143 (6)	−0.0016 (5)	−0.0065 (5)
N1	0.045 (2)	0.049 (3)	0.041 (2)	0.010 (2)	0.0026 (17)	0.0066 (19)
N2	0.041 (2)	0.037 (2)	0.0300 (18)	0.0033 (18)	0.0014 (16)	−0.0001 (16)
N3	0.059 (3)	0.058 (3)	0.029 (2)	0.010 (2)	−0.0054 (18)	0.0034 (19)
O1	0.130 (8)	0.148 (8)	0.146 (8)	0.055 (6)	−0.005 (7)	−0.023 (7)
C1	0.041 (3)	0.039 (3)	0.037 (2)	0.000 (2)	0.005 (2)	0.002 (2)
C2	0.038 (3)	0.044 (3)	0.030 (2)	−0.002 (2)	0.0023 (19)	0.002 (2)
C3	0.060 (3)	0.069 (4)	0.031 (2)	0.000 (3)	0.006 (2)	−0.002 (2)
C4	0.071 (4)	0.067 (4)	0.043 (3)	0.001 (3)	0.021 (3)	−0.012 (3)
C5	0.053 (3)	0.043 (3)	0.056 (3)	0.001 (3)	0.016 (2)	−0.006 (2)
C6	0.059 (4)	0.059 (4)	0.085 (4)	0.014 (3)	0.022 (3)	−0.007 (3)
C7	0.066 (4)	0.056 (4)	0.093 (5)	0.027 (3)	0.010 (4)	0.015 (4)
C8	0.055 (3)	0.063 (4)	0.064 (3)	0.017 (3)	0.007 (3)	0.019 (3)
C9	0.093 (5)	0.074 (5)	0.123 (6)	0.026 (4)	0.032 (5)	−0.027 (4)
C10	0.099 (5)	0.106 (6)	0.080 (4)	0.035 (4)	−0.020 (4)	0.025 (4)
C11	0.153 (11)	0.141 (10)	0.167 (11)	0.034 (8)	−0.018 (8)	−0.025 (9)

Geometric parameters (Å, º)

Ni1—N2^i	2.078 (4)	C3—H3	0.9300
Ni1—N2	2.078 (4)	C4—C5	1.432 (7)
Ni1—N1^i	2.197 (4)	C4—H4	0.9300
Ni1—N1	2.197 (4)	C5—C6	1.394 (8)
Ni1—Cl1^i	2.3918 (18)	C6—C7	1.368 (9)
Ni1—Cl1	2.3918 (18)	C6—C9	1.529 (8)
N1—C8	1.323 (6)	C7—C8	1.393 (8)
N1—C1	1.356 (6)	C7—H7	0.9300
N2—C2	1.340 (5)	C8—C10	1.524 (8)
N2—C1	1.348 (6)	C9—H9A	0.9600
N3—C2	1.322 (6)	C9—H9B	0.9600
N3—H3A	0.8600	C9—H9C	0.9600
N3—H3B	0.8600	C10—H10A	0.9600
O1—C11	1.295 (15)	C10—H10B	0.9600
O1—H1	0.8200	C10—H10C	0.9600
C1—C5	1.405 (6)	C11—H11A	0.9600
C2—C3	1.422 (6)	C11—H11B	0.9600
C3—C4	1.338 (7)	C11—H11C	0.9600
N2^i—Ni1—N2	157.6 (2)	C3—C4—C5	120.8 (5)
N2^i—Ni1—N1^i	62.57 (14)	C3—C4—H4	119.6
N2—Ni1—N1^i	100.08 (14)	C5—C4—H4	119.6
N2^i—Ni1—N1	100.08 (14)	C6—C5—C1	116.6 (5)
N2—Ni1—N1	62.57 (14)	C6—C5—C4	128.9 (5)
N1^i—Ni1—N1	85.1 (2)	C1—C5—C4	114.4 (5)
N2^i—Ni1—Cl1^i	97.75 (10)	C7—C6—C5	118.1 (5)
N2—Ni1—Cl1^i	97.07 (11)	C7—C6—C9	121.0 (6)
N1^i—Ni1—Cl1^i	159.27 (10)	C5—C6—C9	120.9 (6)
N1—Ni1—Cl1^i	92.59 (12)	C6—C7—C8	122.1 (5)
N2^i—Ni1—Cl1	97.07 (11)	C6—C7—H7	119.0
N2—Ni1—Cl1	97.75 (10)	C8—C7—H7	119.0
N1^i—Ni1—Cl1	92.59 (12)	N1—C8—C7	121.0 (5)
N1—Ni1—Cl1	159.27 (10)	N1—C8—C10	116.5 (5)
Cl1^i—Ni1—Cl1	96.55 (9)	C7—C8—C10	122.4 (5)
C8—N1—C1	117.5 (4)	C6—C9—H9A	109.5
C8—N1—Ni1	151.8 (4)	C6—C9—H9B	109.5
C1—N1—Ni1	90.7 (3)	H9A—C9—H9B	109.5
C2—N2—C1	119.3 (4)	C6—C9—H9C	109.5
C2—N2—Ni1	144.6 (3)	H9A—C9—H9C	109.5
C1—N2—Ni1	96.2 (3)	H9B—C9—H9C	109.5
C2—N3—H3A	120.0	C8—C10—H10A	109.5
C2—N3—H3B	120.0	C8—C10—H10B	109.5
H3A—N3—H3B	120.0	H10A—C10—H10B	109.5
C11—O1—H1	109.5	C8—C10—H10C	109.5
N2—C1—N1	110.6 (4)	H10A—C10—H10C	109.5
N2—C1—C5	124.8 (4)	H10B—C10—H10C	109.5
N1—C1—C5	124.6 (4)	O1—C11—H11A	109.5
N3—C2—N2	119.1 (4)	O1—C11—H11B	109.5
N3—C2—C3	121.4 (4)	H11A—C11—H11B	109.5
N2—C2—C3	119.6 (4)	O1—C11—H11C	109.5
C4—C3—C2	121.1 (5)	H11A—C11—H11C	109.5
C4—C3—H3	119.4	H11B—C11—H11C	109.5
C2—C3—H3	119.4

Symmetry code: (i) −x+2, y, −z+3/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···Cl1^ii	0.82	2.49	3.250 (12)	155
N3—H3B···Cl1^iii	0.86	2.49	3.308 (4)	159
N3—H3A···Cl1	0.86	2.57	3.368 (4)	154

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