Crystal structure of aquatris{μ-N-[bis(diethylamino)phosphoryl]-2,2,2-trichloroacetamidato-κ3 O,O′:O}calciumsodium

In the title compound, three ligands are coordinated to the Ca2+ ion in a bidentate-chelated manner via the O atoms of the CO and PO groups. The sodium ion is encapsulated between three chelated metallacycles {CaL}(where L − = Cl3CC(O)NP(O)[N(C2H5)2]2) due to the bridging function of the carbonyl O atoms and it is capped by the water molecule.


Chemical context
In recent years, the interest of many researchers has been focused on metal-phosphorus containing chelates and their usefulness as reagents (principally the alkali metal derivatives) and as potential precursors (the alkaline earth derivatives) for chemical vapor deposition (CVD) (Hanusa, 2003), thin films (Hitzbleck et al., 2004;Demadis et al., 2009Demadis et al., , 2010, antitumor activity (Liu et al., 2012) and as models for calcium-binding proteins (bearing biologically relevant ligands) (Hoang et al., 2003).
Polyfunctional phosphorus compounds [O P-C(R)-P O](L), having oxygen-donor groups capable of binding a number of metal ions into structurally versatile metal phosphonate hybrids M 2+ /L (Sr 2+ , Ba 2+ , Ca 2+ ) or A + /M 2+ /L (A = Na, K) have received considerable attention (Colodrero et al., 2011;Niekiel & Stock, 2014). Complexes based on carbacylamido-phosphates (CAPhos) containing the phosphorylated structural core [O C-NH-P O] have been used as luminescence markers (Litsis et al., 2015), for their cytotoxic activity (Grynuyk et al., 2016) and as buildingblocks in aimed synthesis of coordination compounds with specified structure (Shatrava et al., 2016). The especially interesting feature of carbacylamidophosphate ligands is the bidentate or bidentate-chelate character of their coordination to the central atom (Amirkhanov et al., 2014;Gubina et al., 2000). On this subject, two papers related to complexes of an alkali element in the coordination chemistry of carbacylamidophosphates have been published (Trush et al., 2005;Litsis et al., 2010).
The present paper is devoted to the synthesis and structural analysis of a Ca 2+ -containing complex [CaNa(L) 3 (H 2 O)], (I), ISSN 2056-9890 in which the Na + ion is four-coordinate and has additional contacts with two Cl atoms and where L À is the CAPhos ligand with a bidentate-chelate and bridging function of the carbonyl group.
The P O, C-N and C O bond lengths in (I) are in good agreement with those observed for complexes based on CAPhos ligands (Amirkhanov et al., 2014). The coordination polyhedron around Na + has a distorted tetrahedron-like geometry, formed by three carbonyl oxygen atoms from three ligands and one from the coordinating water molecule with O(C)-Na-O(C) and O(C)-Na-O(W) angle ranges of 76.19 (8)-77.48 (7) and 126.09 (10)-141.26 (9) , respectively. The Na ion also has additional contacts with two Cl atoms of CCl 3 groups [2.976 (1) and 3.086 (1)

Supramolecular features
In the crystal, the complex molecules are linked into chains along the c axis via O-HÁ Á ÁO hydrogen-bonding interactions (Fig. 2

Synthesis and crystallization
The synthesis of HL was carried out according to a previously reported method (Amirkhanov et al., 1996b). Anhydrous CaCl 2 (0.027 g, 0.24 mmol) was dissolved in hot methanol and added to a solution of NaL (0.257 g, 0.73 mmol) in acetone. Colorless crystals of the complex suitable for X-ray diffraction The molecular structure of (I), showing 30% probability displacement ellipsoids and the atom-numbering scheme. Labels and H atoms of ethyl groups have been omitted for clarity. Table 1 Hydrogen-bond geometry (Å , ).        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.