catena-Poly[[[diaqua­(nitrato-κ2 O,O′)(2,2′:6′,2′′-terpyridine-κ3 N,N′,N′′)neodymium(III)]-μ-cyanido-κ2 N:C-[dicyanidoplatinum(II)]-μ-cyanido-κ2 C:N] acetonitrile solvate 2,2′:6′,2′′-terpyridine hemisolvate]

Branson A Maynard; Philip A Smith; Richard E Sykora

doi:10.1107/S160053680903325X

. 2009 Aug 26;65(Pt 9):m1132–m1133. doi: 10.1107/S160053680903325X

catena-Poly[[[diaqua(nitrato-κ² O,O′)(2,2′:6′,2′′-terpyridine-κ³ N,N′,N′′)neodymium(III)]-μ-cyanido-κ² N:C-[dicyanidoplatinum(II)]-μ-cyanido-κ² C:N] acetonitrile solvate 2,2′:6′,2′′-terpyridine hemisolvate]

Branson A Maynard ^a, Philip A Smith ^a, Richard E Sykora ^a,^*

PMCID: PMC2969978 PMID: 21577470

Abstract

The title compound, {[NdPt(CN)₄(NO₃)(C₁₅H₁₁N₃)(H₂O)₂]·CH₃CN·0.5C₁₅H₁₁N₃}_n, was isolated from solution as a one-dimensional coordination polymer. The Nd³⁺ site in the structure has a ninefold coordination with a distorted tricapped trigonal-prismatic geometry, while the Pt^II ion is coordinated by four cyanide groups in an almost regular square-planar geometry. Cis-bridging by the tetracyanidoplatinate anions links the Nd³⁺ cations, forming the one-dimensional chains. Additionally, each Nd³⁺ contains coordination by two water molecules, one tridentate 2,2′:6′,2′′-terpyridine molecule, and one bidentate nitrate anion. 2,2′:6′,2′′-Terpyridine and acetonitrile solvent molecules are incorporated between the chains, the former form π-stacking interactions (average interplanar distance 3.33 Å) with terpyridine molecules located in the chains. Relatively long Pt⋯Pt interactions [3.847 (1) Å] are observed in the structure. O—H⋯N and O—H⋯O hydrogen bonding interactions between the consituents consolidates the crystal packing.

Related literature

For related lanthanide tetracyanidoplatinate structures containing 2,2′:6′,2′′-terpyridine, see: Maynard et al. (2008 ▶); Maynard, Smith, Ladner et al. (2009 ▶); Maynard, Smith, Jaleel et al. (2009 ▶). For structural and spectroscopic information on simpler lanthanide tetracyanidoplatinates, see: Gliemann & Yersin (1985 ▶); Holzapfel et al. (1981 ▶). For luminescence data on lanthanide terpyridine systems, see: Mukkala et al. (1995 ▶).

Experimental

Crystal data

[NdPt(CN)₄(NO₃)(C₁₅H₁₁N₃)(H₂O)₂]·C₂H₃N·0.5C₁₅H₁₁N₃
M _r = 932.4
Monoclinic,
a = 33.231 (6) Å
b = 14.3642 (17) Å
c = 13.823 (3) Å
β = 108.931 (16)°
V = 6241.5 (19) Å³
Z = 8
Mo Kα radiation
μ = 6.18 mm⁻¹
T = 290 K
0.45 × 0.17 × 0.08 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: analytical (XPREP; Bruker, 1998 ▶) T _min = 0.308, T _max = 0.632
5824 measured reflections
5722 independent reflections
4089 reflections with I > 2σ(I)
R _int = 0.031
3 standard reflections frequency: 120 min intensity decay: none

Refinement

R[F ² > 2σ(F ²)] = 0.036
wR(F ²) = 0.087
S = 1.00
5722 reflections
420 parameters
H-atom parameters constrained
Δρ_max = 0.86 e Å⁻³
Δρ_min = −0.84 e Å⁻³

Data collection: CAD-4-PC Software (Enraf–Nonius, 1993 ▶); cell refinement: CAD-4-PC Software; data reduction: XCAD4 (Harms & Wocadlo, 1996 ▶); 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: publCIF (Westrip, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S160053680903325X/nc2153sup1.cif

e-65-m1132-sup1.cif^{(24.9KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S160053680903325X/nc2153Isup2.hkl

e-65-m1132-Isup2.hkl^{(280.2KB, hkl)}

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
O4—H4A⋯N4ⁱ	0.85	2.00	2.760 (9)	149.1
O4—H4B⋯N3ⁱⁱ	0.85	2.00	2.814 (10)	160.5
O5—H5B⋯N9ⁱⁱⁱ	0.85	2.16	2.993 (9)	167.4
O5—H5C⋯O1^iv	0.85	1.99	2.770 (8)	152.2

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

Acknowledgments

The authors gratefully acknowledge the National Science Foundation for their generous support (NSF-CAREER grant to RES, CHE-0846680).

supplementary crystallographic information

Comment

One of our research goals is to prepare systems where the generally weak Ln³⁺ emissions are enhanced through the use of sensitizing ligands coordinated directly to Ln³⁺ cations. Recent efforts in our lab have focused on the novel lanthanide compounds that incorporate two ligand groups simultaneously to achieve this goal. The effort has focused on preparing lanthanide compounds that contain both tetracyanoplatinate(II) anions (TCP) and 2,2':6',2''-terpyridine (tpy) ligands, since each of these ligands have been shown to act as sensitizers for various Ln³⁺ cations (Gliemann & Yersin, 1985; Mukkala et al., 1995). We recently communicated some of our findings in this area (Maynard et al., 2008; Maynard, Smith, Ladner et al., 2009). Through our efforts we have prepared a number of novel compounds incorporating various Ln³⁺ cations, terpyridine, and TCP anions and have also recently reported on these structures (Maynard et al., 2008; Maynard, Smith, Ladner et al., 2009; Maynard, Smith, Jaleel, et al., 2009).

The title compound, (I), is similar to several previously reported compounds in that it contains one-dimensional [Nd(C₁₅H₁₁N₃)(H₂O)₂(NO₃)(Pt(CN)₄)] chains reminiscent of those found in Ln(C₁₅H₁₁N₃)(H₂O)₂(NO₃)[Pt(CN)₄].CH₃CN (Ln = Eu (Maynard et al., 2008; Maynard, Smith, Ladner et al., 2009) or Ln = Ho (Maynard, Smith, Jaleel, et al., 2009)) and Yb(C₁₅H₁₁N₃)(H₂O)₂(NO₃)[Pt(CN)₄].0.5CH₃CN.1.5H₂O (Maynard, Smith, Jaleel, et al., 2009). The major structural differences between these related structure types can be attributed in part to the crystallization of various solvent or guest molecules between the one-dimensional chains.

The neutral, one-dimensional [Nd(C₁₅H₁₁N₃)(H₂O)₂(NO₃)(Pt(CN)₄)] chains in the structure of (I) are illustrated in Figure 1 and a thermal ellipsoid plot of the asymmetric unit is illustrated in Figure 2. The chains are formed by the linkage of the Nd³⁺ cations by cis-bridging tetracyanoplatinate anions. The coordination of the Nd site is ninefold and can be described as a distorted [NdO₄N₅] tri-capped trigonal prism. The five nitrogen atoms in the inner sphere of the Nd³⁺ cations result from the coordination of one tridentate terpyridine ligand and two N-bound TCP anions while the four oxygen atoms are a result of one bidentate nitrate anion and two coordinated water molecules. The two longest Nd—O bond distances for each compound are those to the nitrate anion. The Nd—N bonds to the cyano groups are shorter by an average of ~0.08 Å than the Nd—N bonds to the tpy molecule. The Pt—C distances have an average of 1.984 (8) Å.

The packing diagram of (I) viewed along the c axis is shown in Figure 3. The predominant inter-chain feature is the existence of Pt—Pt interactions. These interactions in (I) are quite long (3.847 (1) Å), but are otherwise reminiscent of those observed in earlier reported lanthanide TCP compounds in that they form dimeric groups (Maynard, Smith, Ladner et al., 2009; Maynard, Smith, Jaleel, et al., 2009). This is in contrast to many reported lanthanide TCP compounds where there exist pseudo-1-D columnar stacks (Gliemann & Yersin, 1985; Holzapfel et al., 1981) containing planar TCP anions parallel to one another. Additional features found in the packing diagram for (I) include porous channels along the c axis that contain acetonitrile solvate molecules, numerous inter-chain hydrogen bonding interactions, and also the presence of π-stacking interactions. These latter interactions (3.33 Å average distance between planes) are between the coordinated tpy and the guest tpy molecule that is co-crystallized between the one-dimensional chains. Also worth noting is the orientation of the coordinated tpy molecules in the one-dimensional chains; viewing along the c axis reveals that these molecules are located on either side of the chains. A similar situation also occurs in Eu(C₁₅H₁₁N₃)(H₂O)₂(NO₃)[Pt(CN)₄].CH₃CN (Maynard et al., 2008; Maynard, Smith, Ladner et al., 2009) while Yb(C₁₅H₁₁N₃)(H₂O)₂(NO₃)[Pt(CN)₄].0.5CH₃CN.1.5H₂O (Maynard, Smith, Jaleel, et al., 2009) contains one-dimensional chains where all of the terpyridine molecules reside on a single side of the chain.

Experimental

The title compound was synthesized by reacting Nd(NO₃).6H₂O (Strem, 99.9%), K₂Pt(CN)₄.3H₂O (Alfa Aesar, 99.9%), and 2,2':6',2''-terpyridine (Aldrich, 98%) in a 1:1:1 molar ratio. The reaction proceeded by adding 1 ml of a 0.10 M solution of potassium tetracyanoplatinate in 20%:80% water:acetonitrile mixture to 1 ml of a 0.10 M solution of neodymium nitrate in acetonitrile. Next, 1 ml of a 0.10 M solution of 2,2':6',2''-terpyridine in acetonitrile was layered on the former mixture. Purple crystals were harvested from the reaction tube after several days.