THE PHENOMENON OF CONGLOMERATE CRYSTALLIZATION. PART 50. THE CRYSTALLIZATION BEHAVIOR OF [trans-Co(en)2(NO2)2]ClO4 (I), MESO-[Co-trans-Me-(N-Me-ETHYLENEDIAMINE)2-trans-(NO2)2]ClO4 (II), K[trans-Co(β-ALANINATO)2(NO2)2] (III) AND THE ISOLATION AND PARTIAL STRUCTURAL DESCRIPTION OF (H5O2)[trans-Co(β-ALANINATO)2(NO2)2] (IV)

Abstract

[trans-Co(en)2(NO2)2]ClO4 (I) crystallizes, at 22°C, from a deionized water solution, as a racemate, in space group P$1 (No. 2), with lattice constants: a = 6.581(2)Å, b = 8.274(1) Å, c = 12.660(3)Å, α = 77.28(2)Å, β = 76.58(2)°, γ = 75.20(2)° V = 638.71;Å3 and d(calc; MW = 370.59,z = 2) = 1.927gcm−3. A total of 2233 data were collected over the range of 4° ≤ 2θ ≤ 50° of these, 1961 (independent and with I ≤ 3σ(I)) were used in the structural analysis. Data were corrected for absorption (μ = 15.989 cm−1) and the relative transmission coefficients ranged from 0.6792 to 0.9874. The final R(F) and R≤(F) residuals were, respectively, 0.0738 and 0.0763. Two half cations are located at inversion centers; the anions are in general positions. meso-[Co-trans-Me-(N-Me-ethylenediamine)2-trans(NO2)2]ClO4 (II) [(N-Meen) = N-methyl-ethylenediamine] crystallizes at 22°C, from a deionized water solution in space group Pbca (No. 61) with lattice constants: a = 16.882(5) Å, b = 11.990(3) Å, c = 15.017(5) Å; V = 3039.72 Å3 and d (calc;MW = 398.64, z = 8) = 1.742g cm−3. A total of 5281 data were collected over the range of 4° ≤ 2θ ≤ 50° of these, 1779 (independent and with I ≤ 2.5σ(I) were used in the structural analysis. Data were corrected for absorption (μ = 13.501 cm−1 and the transmission coefficients ranged from 0.7956 to 0.9947. The final refinement of the structure (anisotropic thermal parameters for the heavy atoms; idealized hydrogens for the cation) are R(F) = 0.045 and Rw (F) = 0.052). The -NO2 ligands are trans to one another in the axial direction while the N-methyl groups are trans to one another across the basal plane. The cations are located in general positions and the torsional angles of the en rings are δ(N1-C1-C2-N2 = 52.0°) and δ(N3-C3-C4-C4 = 51.0°), in contrast with those of (I) which are of opposite helical chirality. This compound is one of two trans-Co(III)X2 cations of which we are aware that, while sitting at a general position of the space group, has two ethytenediamine rings of the same helical chirality. K[trans-Co(β-alaninato)2(NO2)2] (III) obtained after several batches of crystals of (TV) had separated from the mother liquor (see Syntheses). (III) crystallizes at 22°C, in space group Cc (No. 9) with lattice constants: a = 12.385(6)Å, b=13.109(5)Å, c = 8.290(5)Å, β=115.19° V = 1217.97 Å3 and d(calc; MW = 366.22, z = 4) = 1.997 g cm−3. A total of 1238 data were collected over the range of 4° ≤ 2θ 50° of these, 1016 (independent and with I ≤ 2.5σ(I) were used in the structural analysis. Data were corrected for absorption (μ 17.90cm−1) and the transmission coefficients ranged from 0.5322 to 0.6627. The final R(F) and Rw (F) residuals were, respectively 0.020 and 0.022. Solution of the structure, using the first batch of crystals, proved that the compound isolated was the (H5O2)+ derivative (see below and Discussion). A later batch of crystals contained (III). We have previously observed the precipitation of hydronium salts, trapped by amine carboxylato salts of cobalt (see Discussion). The anions consist of two six-membered rings formed by the metal and two (O,N)-bound β-alaninato ligands; and, both have chair conformations. (H5O2) [trans-Co(β-alaninato)2(NO2)2] (IV) is the substance that first crystalized from an aqueous solution of (III) (see Experimental). It crystallizes, at 22°C, in space group Cc (No. 9) or C2/c (No. 15) with lattice constants: a=12.389(39)Å, b=13.120(11)Å, c=8.299(9) Å, β=115.09(19)° V=1221.72 Å3 and d(calc; MW=364.15, z=4) = 1.980 g cm−3. An incomplete data set of 1592 reflections was collected over the range 4° ≤ 2θ ≤ 50° because the crystal decomposes in air due to rapid loss of water of crystallization, as shown by differential scanning calorimetry. 956 data were independent with I ≤ 2.5°(I) and were used in the structural analysis. Data were not corrected for absorption because of decomposition of the crystal. The final R(F) and Rw (F) residuals were, respectively, 0.14 and 0.16. To the precision of such a data set, the anions are identical with those found in (III); however the cation, which sits at an inversion center, consists of a proton sandwiched between the oxygens of two waters thus forming (H5O2)+ cations similar to those we have described in the past (see Refs. [15–18]).