cis-Bis[(1-adamantylmeth­yl)amine-κN]­dichloridoplatinum(II) N,N-dimethyl­formamide solvate

Fernande D Rochon; Christian Tessier

doi:10.1107/S1600536809037982

. 2009 Oct 3;65(Pt 11):m1297–m1298. doi: 10.1107/S1600536809037982

cis-Bis[(1-adamantylmethyl)amine-κN]dichloridoplatinum(II) N,N-dimethylformamide solvate

Fernande D Rochon ^a,^*, Christian Tessier ^a

PMCID: PMC2970952 PMID: 21578064

Abstract

The asymmetric unit of the title compound {systematic name: cis-dichloridobis[(3,7-dimethylbicyclo[3.3.1]non-1-ylmethyl)amine-κN]platinum(II) N,N-dimethylformamide solvate}, [PtCl₂(C₁₁H₁₉N)₂]·C₃H₇NO, consists of two metrically similar Pt complexes and two dimethylformamide solvent molecules. Each Pt^II center is coordinated by the amine groups of two (1-adamantylmethyl)amine ligands and two Cl atoms in a cis-square-planar arrangement. The Pt^II centers lie slightly outside [0.031 (4) and 0.038 (4) Å] the coordination planes. The N—Pt—N and Cl—Pt—Cl angles [92.1 (4)–92.30 (11)°] are slightly more open than the N—Pt—Cl angles [87.3 (3)–88.3 (3)°]. N—H⋯O and N—H⋯Cl intermolecular hydrogen bonds are observed, forming two discrete pairs of complexes and solvent molecules.

Related literature

For the antiviral and antitumor activity of Pt complexes with polycyclic cages such as adamantamine, see: Hay et al. (1985 ▶); Ho et al. (1972 ▶); Widell et al. (1986 ▶). The synthesis and spectroscopic characterization of the title compound is described by Rochon et al. (1993 ▶).

Experimental

Crystal data

[PtCl₂(C₁₁H₁₉N)₂]·C₃H₇NO
M _r = 669.63
Triclinic,
a = 12.299 (3) Å
b = 14.035 (4) Å
c = 15.644 (4) Å
α = 81.137 (3)°
β = 82.323 (3)°
γ = 89.292 (3)°
V = 2644.3 (12) Å³
Z = 4
Mo Kα radiation
μ = 5.53 mm⁻¹
T = 200 K
0.35 × 0.29 × 0.23 mm

Data collection

Bruker SMART APEXII CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2001 ▶) T _min = 0.151, T _max = 0.281
26513 measured reflections
9285 independent reflections
5724 reflections with I > 2σ(I)
R _int = 0.099

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.152
S = 0.97
9285 reflections
581 parameters
H-atom parameters constrained
Δρ_max = 7.80 e Å⁻³
Δρ_min = −2.82 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXTL and publCIF (Westrip, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536809037982/hy2221sup1.cif

e-65-m1297-sup1.cif^{(42.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809037982/hy2221Isup2.hkl

e-65-m1297-Isup2.hkl^{(454.1KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Pt1—N11	2.040 (9)
Pt1—N12	2.026 (9)
Pt1—Cl11	2.304 (3)
Pt1—Cl12	2.312 (3)
Pt2—N21	2.048 (8)
Pt2—N22	2.056 (9)
Pt2—Cl21	2.307 (3)
Pt2—Cl22	2.306 (3)

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Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N11—H11A⋯O2	0.92	1.95	2.863 (13)	170
N11—H11B⋯Cl12ⁱ	0.92	2.64	3.409 (10)	141
N12—H12A⋯Cl11ⁱ	0.92	2.63	3.299 (9)	131
N12—H12B⋯O2	0.92	1.93	2.843 (11)	175
N21—H21A⋯Cl22ⁱⁱ	0.92	2.55	3.238 (10)	132
N21—H21B⋯O1	0.92	1.91	2.821 (12)	173
N22—H22A⋯O1	0.92	1.94	2.843 (11)	165
N22—H22B⋯Cl21ⁱⁱ	0.92	2.64	3.354 (10)	136

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

The authors are grateful to the Natural Sciences and Engineering Research Council of Canada for financial support.

supplementary crystallographic information

Comment

Cisplatin [cis-Pt(NH₃)₂Cl₂] is now a well known antitumor drug, but it has numerous side effects and resistance to the drug is an important problem. Replacement of the NH₃ ligand by an amine more compatible to the human system might possibly surmount some of these problems. One such amine is the polycyclic cage molecule adamantanamine, which has been demonstrated to exhibit both antiviral (Hay et al., 1985; Widell et al., 1986) and antitumor activity (Ho et al., 1972). The synthesis and the spectroscopic study of Pt^II compounds with adamantanamine derivatives have been reported (Rochon et al., 1993).

In the title compound (one of the Pt complex is shown in Fig. 1), the Pt metal center exhibits a cis square-planar geometry formed by two amine groups from (1-adamantylmethyl)amine and two Cl atoms. The Pt centers are slightly outside [0.031 (4) and 0.038 (4) Å] the N₂Cl₂ planes. The bulky adamantane cycles slightly open the N—Pt—N angles [92.1 (4)°] compared to the N—Pt—Cl angles [87.3 (3)–88.3 (3)°]. However, the Cl—Pt—Cl angles are also opened to the same extent [92.17 (11)–92.30 (11)°]. The Pt—N [2.026 (9)–2.056 (9) Å] and Pt—Cl [2.304 (3)–2.312 (3) Å] are normal as well as all other bond distances and angles.

The asymmetric unit of the title compound is described as two crystallographically independent Pt complexes and two dimethylformamide (DMF) solvent molecules linked by N—H···O hydrogen bonds (Fig. 2) between the amine groups and the O atoms from the DMF molecules. N—H···Cl hydrogen bonds between the amine groups and Cl atoms from symmetry equivalent complexes are also observed, forming discrete pairs of complexes and solvent molecules (Fig. 3).

Experimental

One mmol of K₂[PtCl₄] and 2 mmol of (1-adamantylmethyl)amine were heated in a DMF solution at 80°C for 3 h. The solution was concentrated, cooled to 0°C and the KCl was filtered off. The mixture was evaporated to dryness and the residue washed with ether, acetone and then with water. After drying, the residue was washed with ether and dried. Yield 68%, dec. 195–225°C, ν(Pt—Cl) IR 341, 325, Raman 334, 325 cm^-1, ¹⁹⁵Pt NMR -2213 p.p.m. The crystals were recrystalized in DMF for crystallographic studies.