Three-dimensional hydrogen-bonded supra­molecular assembly in tetrakis­(1,3,5-triaza-7-phosphaadamantane)copper(I) chloride hexa­hydrate

Abstract

The structure of the title compound, [Cu(PTA)₄]Cl·6H₂O (PTA is 1,3,5-triaza-7-phosphaadamantane, C₆H₁₂N₃P), is composed of discrete monomeric [Cu(PTA)₄]⁺ cations, chloride anions and uncoordinated water mol­ecules. The Cu^I atom exhibits tetra­hedral coordination geometry, involving four symmetry-equivalent P–bound PTA ligands. The structure is extended to a regular three-dimensional supra­molecular framework via numerous equivalent O—H⋯N hydrogen bonds between all solvent water mol­ecules (six per cation) and all PTA N atoms, thus simultaneously bridging each [Cu(PTA)₄]⁺ cation with 12 neighbouring units in multiple directions. The study also shows that PTA can be a convenient ligand in crystal engineering for the construction of supra­molecular architectures.

Related literature

For general background, see: Kirillov et al. (2007 ▶, 2008 ▶); Karabach et al. (2006 ▶); Di Nicola et al. (2007 ▶). For a comprehensive review of PTA chemistry, see: Phillips et al. (2004 ▶). For PTA-derived polymeric networks, see: Lidrissi et al. (2005 ▶); Frost et al. (2006 ▶); Mohr et al. (2006 ▶). For related compounds, see: Forward et al. (1996 ▶); Darensbourg et al. (1997 ▶, 1999 ▶).

Experimental

Crystal data

• [Cu(C₆H₁₂N₃P)₄]Cl·6H₂O

• M _r = 835.71

• Cubic,

• a = 19.795 (4) Å

• V = 7757 (3) ų

• Z = 8

• Mo Kα radiation

• μ = 0.85 mm⁻¹

• T = 150 (2) K

• 0.20 × 0.17 × 0.12 mm

Data collection

• Bruker APEXII CCD area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Sheldrick, 2003 ▶) T _min = 0.848, T _max = 0.905

• 3022 measured reflections

• 447 independent reflections

• 361 reflections with I > 2σ(I)

• R _int = 0.049

Refinement

• R[F ² > 2σ(F ²)] = 0.034

• wR(F ²) = 0.092

• S = 1.08

• 447 reflections

• 28 parameters

• H-atom parameters constrained

• Δρ_max = 0.75 e Å⁻³

• Δρ_min = −0.32 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶), PLATON (Spek, 2003 ▶) and Mercury (Macrae et al., 2006 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

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

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O10—H10⋯N1	0.81	2.04	2.843 (3)	174

supplementary crystallographic information

Comment

1,3,5-triaza-7-phosphaadamantane (PTA) is a water soluble aminophosphine that has sparked recent interest in coordination chemistry in view of the significance of transition metal PTA complexes in aqueous phase catalysis, photochemistry and medicinal chemistry (Phillips et al., 2004). Besides, PTA and its derivatives can also be convenient building blocks for the construction of polymeric networks (Lidrissi et al., 2005; Frost et al., 2006; Mohr et al., 2006) due to several potentially available coordination sites, protonation ability of N atoms, and strong affinity towards hydrogen bonds. Nevertheless, the use of PTA ligands in crystal design and engineering has remained little explored. Hence, in pursuit of our recent studies directed towards the synthesis of new copper compounds including PTA complexes (Kirillov et al., 2007) and various coordination polymers, supramolecular frameworks and host–guest systems with other ligands (Karabach et al., 2006; Di Nicola et al., 2007; Kirillov et al., 2008), we have prepared compound (I) whose crystal structure and supramolecular features are reported herein.

The moiety formula of (I) consists of the [Cu(PTA)₄]⁺ cation (Fig. 1), one chloride anion and six symmetry equivalent crystallization water molecules. The [Cu(PTA)₄]⁺ unit possesses a very high symmetry, being generated from only five symmetry nonequivalent atoms (Cu1, P1, N1, C1 and C2). The Cu^I atom lies on -43m site symmetry and its coordination environment is filled by four equivalent P–bound PTA ligands, arranged in a perfect tetrahedral coordination geometry with the corresponding P—Cu—P angles of 109.47 (2)°. The Cu—P bond distances of 2.2598 (6) Å as well as other bonding parameters within the cage-like PTA cores are comparable to those reported for tetrahedral PTA complexes of Cu (Kirillov et al., 2007), Au (Forward et al., 1996), Pt (Darensbourg et al., 1999) and Ni (Darensbourg et al., 1997).

An interesting feature of (I) consists in the extensive intermolecular hydrogen bonding that arises from only one type of O-H···N H-bond (Table 1). Hence, each crystallization water molecule (O10) repeatedly acts as a double H-bond donor bridging to two N1 atoms of two different [Cu(PTA)₄]⁺ units. This results in the extensive interlinkage in multiple directions of every monomeric copper unit with twelve neighbouring ones (Fig. 2), thus leading to the formation of a regular three-dimensional supramolecular framework (Fig. 3). That framework has the shortest Cu···Cu separation of 13.977 (1) Å and possesses the repeating channels (ca 4.8 Å diameter) filled by water molecules.

Experimental

To the ethanolic solution (5 ml) of CuCl₂ (27 mg, 0.20 mmol) was added solid PTA (126 mg, 0.80 mmol). The obtained mixture was refluxed for 3 h resulting in a white suspension. This was filtered off and the colourless filtrate was left to evaporate in a beaker in air and at ambient temperature. A small crop of the colourless X-ray quality crystals of (I) was formed in several days. ¹H NMR data are similar to those reported for [Cu(PTA)₄]NO₃ (Kirillov et al., 2007). FT–IR (KBr pellet), cm^-1: 3430 m, br and 3195 w [ν(H₂O)], 2940 m and 2901 m [ν_as(C—H)], 2863 m and 2808 w [ν_s(C—H)], 1645 w br [δ(H₂O)], 1437 m, 1413 m, 1365 m, 1296 s, 1242 s, 1180 m, 1105 m, 1037 w, 1015 s, 971 s, 906 w, 890 m, 808 s, 797 s, 744 m, 694 m, 670 w, 582 s, 551 w, 451 s, 406 m [PTA bands]. FAB-MS⁺ (m-nitrobenzylalcohol), m/z: 691 [Cu(PTA)₄]⁺.

Refinement

All H atoms attached to C atoms were fixed geometrically and treated as riding with C—H = 0.97 Å and U_iso(H) = 1.2U_eq(C). H atom of the water molecule were located in difference Fourier maps and included in the subsequent refinement using restraint (O-H= 0.82 (1)Å) with U_iso(H) = 1.5U_eq(O). In the last stage of refinement,it was treated as riding on the O atom.

Figures

Fig. 1.

Molecular view of the cation with the atom-labelling scheme. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms are omitted for clarity. [Symmetry codes: (i) z, x, y; (ii) y, z, x; (iii) -x+1/4, y, -z+1/4; (iv) -x+1/4, -y+1/4, z; (v) x, -y+1/4, -z+1/4]

Fig. 2.

Fragment of the crystal packing diagram of (I) showing the simultaneous multidimensional interlinkage of the central monomeric [Cu(PTA)4]+ unit (black coloured) with twelve neighbouring ones (each represented by different colour) via repeating O10—H10···N1 hydrogen bonding interactions (black dashed lines) between crystallization water molecules O10 (coloured balls) and PTA N1 atoms. H and Cl atoms are omitted for clarity.

Fig. 3.

Fragment of the crystal packing diagram of (I) (view along the a axis) showing the extensive hydrogen bonding interactions (pale blue dashed lines) resulting in the formation of a regular three-dimensional H-bonded supramolecular assembly. H atoms are omitted for clarity. Cu, green; P, orange; N, blue; C, grey; O, red (balls); Cl, yellow (balls).

Crystal data

[Cu(C6H12N3P)4]Cl·6H2O	Z = 8
Mr = 835.71	F000 = 3536
Cubic, Fd3m	Dx = 1.431 Mg m−3
Hall symbol: -F 4vw 2vw 3	Mo Kα radiation λ = 0.71069 Å
a = 19.795 (4) Å	Cell parameters from 743 reflections
b = 19.795 (4) Å	θ = 2.9–27.0º
c = 19.795 (4) Å	µ = 0.85 mm−1
α = 90º	T = 150 (2) K
β = 90º	Prism, colourless
γ = 90º	0.20 × 0.17 × 0.12 mm
V = 7757 (3) Å3

Data collection

Bruker APEXII CCD area-detector diffractometer	447 independent reflections
Radiation source: fine-focus sealed tube	361 reflections with I > 2σ(I)
Monochromator: graphite	Rint = 0.049
T = 150(2) K	θmax = 27.0º
φ and ω scans	θmin = 2.9º
Absorption correction: multi-scan(SADABS; Sheldrick, 2003)	h = −24→23
Tmin = 0.848, Tmax = 0.905	k = −16→11
3022 measured reflections	l = −6→25

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.034	H-atom parameters constrained
wR(F2) = 0.092	w = 1/[σ2(Fo2) + (0.0463P)2 + 19.2954P] where P = (Fo2 + 2Fc2)/3
S = 1.08	(Δ/σ)max < 0.001
447 reflections	Δρmax = 0.75 e Å−3
28 parameters	Δρmin = −0.32 e Å−3
Primary atom site location: structure-invariant direct methods	Extinction 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 > 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)
C1	0.25075 (10)	0.15137 (15)	0.25075 (10)	0.0199 (6)
H1A	0.2258	0.1228	0.2818	0.024*	0.50
H1B	0.2818	0.1228	0.2258	0.024*	0.50
C2	0.33080 (15)	0.24509 (11)	0.24509 (11)	0.0239 (7)
H2A	0.3607	0.2726	0.2726	0.029*
H2B	0.3587	0.2166	0.2166	0.029*
N1	0.29002 (8)	0.20160 (12)	0.29002 (8)	0.0212 (6)
Cu1	0.1250	0.1250	0.1250	0.0134 (3)
P1	0.19090 (4)	0.19090 (4)	0.19090 (4)	0.0156 (3)
Cl1	0.3750	0.3750	0.3750	0.0165 (5)
O10	0.3750	0.12300 (14)	0.3750	0.0240 (7)
H10	0.3521	0.1480	0.3521	0.036*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
C1	0.0193 (8)	0.0212 (14)	0.0193 (8)	−0.0005 (7)	−0.0053 (11)	−0.0005 (7)
C2	0.0193 (15)	0.0262 (10)	0.0262 (10)	−0.0036 (8)	−0.0036 (8)	−0.0027 (12)
N1	0.0218 (8)	0.0202 (13)	0.0218 (8)	−0.0019 (7)	−0.0056 (10)	−0.0019 (7)
Cu1	0.0134 (3)	0.0134 (3)	0.0134 (3)	0.000	0.000	0.000
P1	0.0156 (3)	0.0156 (3)	0.0156 (3)	−0.0009 (3)	−0.0009 (3)	−0.0009 (3)
Cl1	0.0165 (5)	0.0165 (5)	0.0165 (5)	0.000	0.000	0.000
O10	0.0255 (10)	0.0210 (16)	0.0255 (10)	0.000	−0.0083 (12)	0.000

Geometric parameters (Å, °)

C1—N1	1.482 (3)	C2—H2A	0.9700
C1—P1	1.849 (3)	C2—H2B	0.9700
C1—H1A	0.9700	Cu1—P1	2.2596 (13)
C1—H1B	0.9700	P1—C1i	1.849 (3)
C2—N1i	1.478 (2)	O10—H10	0.8104
C2—N1	1.478 (2)
N1—C1—P1	112.8 (2)	P1—Cu1—P1iv	109.5
N1—C1—H1A	109.0	P1iii—Cu1—P1iv	109.5
P1—C1—H1B	109.0	P1—Cu1—P1v	109.5
H1A—C1—H1B	107.8	P1iii—Cu1—P1v	109.5
N1i—C2—N1	113.7 (3)	P1iv—Cu1—P1v	109.5
N1—C2—H2A	108.8	C1ii—P1—C1i	97.57 (12)
N1—C2—H2B	108.8	C1ii—P1—C1	97.57 (12)
H2A—C2—H2B	107.7	C1i—P1—C1	97.57 (12)
C2ii—N1—C2	108.5 (3)	C1ii—P1—Cu1	119.70 (9)
C2ii—N1—C1	111.21 (16)	C1i—P1—Cu1	119.70 (9)
C2—N1—C1	111.21 (16)	C1—P1—Cu1	119.70 (9)
P1—Cu1—P1iii	109.5

Symmetry codes: (i) z, x, y; (ii) y, z, x; (iii) −x+1/4, y, −z+1/4; (iv) −x+1/4, −y+1/4, z; (v) x, −y+1/4, −z+1/4.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
O10—H10···N1	0.81	2.04	2.843 (3)	174