Synthesis and crystal structure of bis[trans-diaqua(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)nickel(II)] trans-(1,4,8,11-tetraazacyclotetradecane-κ4 N 1,N 4,N 8,N 11)bis[4,4′,4′′-(1,3,5-trimethylbenzene-2,4,6-triyl)tris(hydrogen phenylphosphonato-κO)]nickel(II) decahydrate

The centrosymmetric trans-NiN4O2 coordination polyhedra of the Ni2+ ions in the complex cations and anions of the title compound are tetragonally distorted octahedra. In the crystal, O—H⋯O hydrogen bonds between the phosphonate groups of the anions result in the formation of layers oriented parallel to the bc plane, which are further arranged into a three-dimensional network due to hydrogen-bonding involving the macrocyclic di-aqua cations and water molecules.

Synthesis and crystal structure of bis [transdiaqua(1,4,8,11-tetraazacyclotetradecanej 4 N 1 ,N 4 ,N 8 ,N 11 )nickel(II)] trans- (1,4,8,11-tetraazacyclotetradecane-j 4 N 1 ,N 4 ,N 8 ,N 11  The components of the title compound, [Ni(C 10 4À tetra-anion and five crystallographically unique water molecules of crystallization. All of the nickel ions are coordinated by the four secondary N atoms of the macrocyclic cyclam ligands, which adopt the most energetically stable trans-III conformation, and the mutually trans O atoms of either water molecules in the cations or the phosphonate groups in the anion in a tetragonally distorted NiN 4 O 2 octahedral coordination geometry. Strong O-HÁ Á ÁO hydrogen bonds between the protonated and the non-protonated phosphonate O atoms of neighboring anions result in the formation of layers oriented parallel to the bc plane, which are linked into a three-dimensional network by virtue of numerous N-HÁ Á ÁO and O-HÁ Á ÁO hydrogen bonds arising from the sec-NH groups of the macrocycles, phosphonate O atoms and coordinated and non-coordinated water molecules.
The rigid trigonal aromatic linker 1,3,5-benzenetricarboxylate, C 9 H 3 O 6 3-, is widely used for the assembly of MOFs based on azamacrocyclic cations (Lampeka & Tsymbal, 2004). Its tris-monodentate coordination in the trans-axial coordination positions of the metal ions leads predominantly to the formation of two-dimensional coordination polymers with hexagonal nets of 6 3 topology (Alexandrov et al., 2017).
Usually, the modification of this bridge through the substitution of the carboxylic groups by para-carboxybenzyl fragments (the ligand H 3 BTB, 4,4 0 ,4 00 -benzene-1,3,5-triyltribenzoic acid) does not affect the coordination properties of the carboxylate groups or the topological characteristics of polymeric nets but results in the enlargement of the hexagonal structural unit of the coordination polymers allowing interpenetration of the subnets (Lampeka et al., 2012;Gong et al., 2016). Compared to carboxylates, linkers with other coordinating functions, in particular oligophosphonates, have been studied to a much lesser extent (Gagnon et al., 2012;Firmino et al., 2018;Yü cesan et al., 2018), though one can expect that the substitution of a mono-anionic carboxylic group by a di-anionic phosphonate group with distinct acidity, number of donor atoms and spatial directivity of coordination bonds will strongly influence the composition and topology of the coordination nets. However, except for a very recent publication (Tsymbal et al., 2022), no papers dealing with structural characterization of the complexes formed by metal azamacrocyclic cations and phosphonate ligands have been published to date.

Structural commentary
The molecular structure of I is shown in Fig. 1. It represents a non-polymeric compound in which atom Ni1 is coordinated by two monodentate H 3 Me 3 BTP 3ligands via their phosphonate O atoms, resulting in the formation of an [Ni(L)(H 3-3Me 3 BTP) 2 ] 4complex anion, which is charge-balanced by two structurally non-equivalent [Ni(L)(H 2 O) 2 ] 2+ divalent cations formed by atoms Ni2 and Ni3. The coordination geometries of all the nickel ions in I have much in common: the Ni 2+ ions (all with site symmetry 1) are coordinated by the four secondary N atoms of the macrocyclic ligands L, which adopt the most energetically stable trans-III (R,R,S,S) conformation (Bosnich et al., 1965a;Barefield et al., 1986) with the five-membered (N-Ni-N bite angles ' 85 ) and six- The extended asymmetric unit in I showing the coordination environment of the Ni atoms and the atom-labeling scheme (displacement ellipsoids are drawn at the 30% probability level). C-bound H atoms and uncoordinated water molecules are omitted for clarity. Symmetry codes: (i) Àx + 2, Ày + 1, Àz + 2; (ii) Àx + 2, Ày + 2, Àz + 1; (iii) Àx + 1, Ày + 3, Àz + 1.

Supramolecular features
In the crystal of I, the [Ni1(L)(H 3 Me 3 BTP) 2 ] 4anions, [Ni2/ Ni3(L)(H 2 O) 2 ] 2+ cations and water molecules of crystallization are linked by numerous hydrogen bonds with participation of the phosphonate groups, the secondary amino groups of the macrocycles and both the coordinated and crystalline water molecules (Table 2). A distinct lamellar structure is inherent for this compound. In particular, strong hydrogen-bonding interactions between the protonated fragments of the P1 and P3 phosphonate groups of one molecule as the donors with the non-protonated O4 and O5 atoms of the P2 group of another molecule as the acceptors [P1-O3-H3CÁ Á ÁO5(x, y À 1, z), P3-O9-H9CÁ Á ÁO49(x, y À 1, z + 1)], together with a weak N1-H1Á Á ÁO6 (x, y À 1, z) hydrogen bond between the secondary amino group of the macrocyclic cation [Ni1(L)] and protonated P2-O6 phosphonate fragment result in the formation of anionic layers oriented parallel to the bc plane. The distance between the parallel mean planes of the staggered by 60 trimethylbenzene rings of neighboring H 3 Me 3 BTP 3anions is 5.248 (3) Å , thus allowing us to exclude the possibility of aromaticstacking interactions between them. Additionally, the negative charge of the layers are partially compensated by the incorporation within the layers of the [Ni2(L)(H 2 O) 2 ] 2+ cations via hydrogen bonding between the coordinated water molecules and the phosphonate O7 atom [O1W-H1WBÁ Á ÁO7(x, y, z À 1)] (Fig. 2).

Figure 2
The hydrogen-bonded (dashed lines) layers in I viewed down the a axis. C-bound H atoms and macrocyclic cations formed by Ni3 have been omitted; C and N atoms of the macrocyclic cations formed by Ni2 are shown in green.

Figure 3
The structure of I viewed down the b axis. C-bound H atoms have been omitted; C and N atoms of the macrocyclic cation formed by Ni2 and Ni3 are shown in green and violet, respectively. Water molecules of crystallization are not shown; hydrogen bonds are depicted as dashed lines.
numerous O-HÁ Á ÁO hydrogen bonds involving the water molecules of crystallization, O3W-O7W (Table 2). On the other hand, because of the absence of methyl substituents, the molecules of the anions H n BTP (6-n)as a whole are flatter than H 3 Me 3 BTP 3in I with a maximal tilting angle of pendant versus central benzene rings of ca 49 observed in ISELAV02. In addition, in the majority of complexes formed by H n BTP (6-n)ligands (except AKEPOY and ISELAV02), aromaticstacking interactions of different strengths are observed with centroid-to-centroid distances between the central aromatic rings ranging from 3.4 to 3.9 Å . The Cambridge Structural Database contains also 18 hits describing the structure of the [Ni(L)(H 2 O) 2 ] 2+ complex cation in salts of different inorganic and organic anions as well as the charge-compensating part in anionic coordination polymers. In general, the structure of this cation in I is similar to other compounds, both from the point of view of the conformation of the macrocycle and the bond distances and angles characterizing the coordination polyhedron of the metal.
[Ni(L)](ClO 4 ) 2 (46 mg, 0.1 mmol) in 5 ml of water was added to 5 ml of an aqueous solution of H 6 Me 3 BTP (18 mg, 0.03 mmol) containing 2 ml of pyridine. The pink precipitate, which formed in a week, was filtered off, washed with small amounts of water, methanol and diethyl ether, and dried in air. Yield: 7 mg (10% based on acid). Analysis calculated for C 84 H 148 N 12 Ni 3 O 32 P 6 : C 45.85, H 6.78, N 7.64%. Found: C 45.73, H 6.87, N 7.51%. Single crystals of I suitable for X-ray diffraction analysis were selected from the sample resulting from the synthesis.
Caution! Perchlorate salts of metal complexes are potentially explosive and should be handled with care.

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 3 -(1,4,8,11-tetraazacyclotetradecaneκ 4 N 1 ,N 4 ,N 8 ,N 11   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max < 0.001 Δρ max = 0.67 e Å −3 Δρ min = −0.46 e Å −3 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.