Jiwen Cai

The phenomenon of conglomerate crystallization. XXXII: The crystallization behaviour of [cis-Co(en)2(NO2)2]I. (I). Counter-ion effects on crystallization pathway of racemate solutions. III

Abstract [Cis-Co(en)2(NO2)2]I (I), ICoO4N6C4H16, cystallizes from water at 18°C as both a racemate and a conglomerate. The structure of the latter was determined in this study. Unlike its chloride and bromide brethren, which crystallize exclusively as conglomerates, in the space group P21, the iodide crystallizes in the tetragonal space group P41 (No. 76). The absolute configuration was determined by comparison with that of the parent compound, (−)589-[Λ(δλ)-cis-Co(en)2(NO2)2]Br (III), from which it was made by metathesis. Unlike the chloride and parent bromide, whose chiroptical symbols are [cis-(−)589-Λ(δλ)-Co(en)2(NO2)2]Cl (II) and [cis-(−)589-Λ(δλ)-Co(en)2(NO2)2]Br (III), in the solid state that of [cis-(−)589-Co(en)2(NO2)2]I (I) is Λ(λλ). The cations of I form infinitely hydrogen-bonded, homochiral, helical strings about the four-fold screw axis of the crystals. In turn, adjacent helical strings are held together by hydrogen bonds between the iodides and—NH2 hydrogens of the amine ligands. Such an arrangement is also present in the isomorphous chloride and bromide derivatives; however, in those compounds the infinite spirals are wound about the two-fold screw axis of the space group P21.

THE PHENOMENON OF KRYPTORACEMIC CRYSTALLIZATION. PART 1. COUNTERION CONTROL OF CRYSTALLIZATION PATHWAY SELECTION. PART 4. THE CRYSTALLIZATION BEHAVIOR OF (+/−)-[Co(tren)(NO2)2]Br(I), (+/−)-[Co(tren)(NO2)2]2Br(ClO4) · H2O(II), (+/(−)-[Co(tren)(NO2)2]ClO4(III) AND ATTEMPTS TO SOLVE THE STRUCTURE OF (+/−)-[Co(tren)(NO2)2]NO3(IV)

Abstract Racemic aqueous solutions of (+/−)-[Co(tren)(NO2)2]Br (I), (+/−)-[Co(tren)(NO2)2]ClO4 (III) and [Co(tren)(NO2)2]NO3(IV) crystallize as racemates. By contrast, the double salt, (+/−)-[Co(tren)(NO2)2]2Br(ClO4) · H2O(II), produces kryptoracemic crystals belonging to the enantiomorphic space group P212121 (No. 19). The former three species crystallize with one molecule in the asymmetric unit; in the latter, a racemic pair is the asymmetric unit, a fact which is hidden by the enantiomorphic nature of its space group – thus the name of the crystallization phenomenon reported. In (II) pairs of cations are related by an approximate, non-crystallographic, inversion center. The crystal structure and polarity of (I) and the absolute configuration of (II) were determined by refinement. The crystalline contents of (I) to (III) consist of infinite strings of hydrogen bonded cations, the counter ions and (where relevant) waters of crystallization acting as a hydrogen-bonding glue linking the spiral strings In (...

The phenomenon of conglomerate crystallization—XXXIII. Counter-ion effects on crystallization pathway of racemate solutions—IV. The crystal and molecular structure of racemic (H3O+)[Co(en)2ox]Cl2 · H2O (I)

Abstract (H 3 O + )[Co(en) 2 ox]Cl 2 · H 2 O( I ), CoCl 2 O 6 N 4 C 6 H 21 , crystallizes as a racemate in the monoclinic space group P 2 1 /c (No. 14). Infinitely hydrogen-bond spiral strings of homochiral [Co(en) 2 ox] + cations are formed which are wrapped about the two-fold screw axis of the crystals. Adjacent spirals are held together by hydrogen bonds between the waters and chlorides and the—NH 2 hydrogens of the cations. Such an arrangement is also present in the conglomerate crystals of the [Co(en) 2 ox]Cl · 4H 2 O ( II ) and [Co(en) 2 ox] Br · H 2 O ( III ) derivatives; however, unlike II and III , which crystallize as conglomerates and all spiral strings are of the same helicity, in I adjacent spirals are of opposite helical chirality and related to one another by the inversion operation of the space group.

The phenomenon of conglomerate crystallization. Part 40: The crystallization behavior oftrans- Co(III) amines (+)546-trans-[Co(3,2,3-tet)(NO2)2]Cl·3H2O (I), (−)589-trans-[Co(3,2,3-tet)Cl2]NO3 (II), and of (+)546-trans-[Co(3,2,3-tet)(NO2)2]NO3 (III)

A racemic solution of (I) crystallizes as a conglomerate from which a crystal we selected was found to be (+)546-trans-[Co(3,2,3-tet)(NO2)2]Cl·3H2O (I), CoClO7N6C8H28. It crystallizes in the enantiomorphic space groupP2l2l2l, with lattice constantsa=18.501(15) å,b=14.433(2) å, andc=6.441(3) å;V=1720.07 å3 andd(calc. M.W.=414.73,Z=4)=1.601 g cm−3. A total of 2305 data were collected over the range of 4‡≤2θ ≤55‡; of these, 1724 (independent and withI > 3σ(I)) were used in the structural analysis. Data were corrected for absorption (Μ=11.920 cm−1), and the relative transmission coefficients ranged from 0.8258 to 0.9565. Refinement was carried out for both lattice enantiomorphs, and at this stage theR(F) andRw(F) residuals were, respectively, 0.0381 and 0.0479 for (+ + +) and 0.0448 and 0.0532 for (− − −). Thus, the former was selected as correct for our specimen, and the final cycle of refinement with the (+ + +) model converged toR(F) andRw(F) of 0.0315 and 0.0365. A racemic solution of (II) crystallizes as a conglomerate from which a crystal we selected was found to be (−)589-trans-[Co(3,2,3-tet)Cl2]NO3 (II), CoCl2O3N5C8H22. It crystallizes in the enantiomorphic space groujp,P2l with lattice constantsa=6.395(2) å,b=8.886(2) å,c=13.185(2) å, andΒ=99.24(2)‡;V=739.59 å3 andd(calc. M.W.=366.14,Z=2)=1.646 g cm−3. A total of 2912 data were collected over the range of 4‡<2θ<64‡; of these, 2147 (independent and withI≥3σ(I)) were used in the structural analysis. Data were corrected for absorption (Μ =15.424 cm−1), and the relative transmission coefficients ranged from 0.9632 to 0.9985. Refinement was carried out for both lattice enantiomorphs, and the finalR(F) andRw(F) residuals were, respectively, 0.0326 and 0.0328 for (+ + +) and 0.0347 and 0.0348 for (− − −). Thus, the (+ + +) was selected as correct for our specimen. A racemic solution of (III) crystallizes as a conglomerate from which a crystal we selected was found to be (+)589-trans-[Co(3,2,3-tet)(NO2)2]NO3 (III), CoO7N7C8H22. It crystallizes in the enantiomorphic space group,P2l with lattice constantsa=6.295(1) å, b=15.108(3) å,c=8.029(1) å, andΒ=100.28(2)‡;V=751.35 å3 andd(calc. M.W.=387.24,Z=2)=1.712 g cm−3. A total of 2393 data were collected over the range of 4‡≤2θ≤60‡; of these, 1869 (independent and withI≥3σ(I)) were used in the structural analysis. Data were corrected for absorption (Μ=11.859 cm−1), and the relative transmission coefficients ranged from 0.8814 to 0.9976. Refinement was carried out for both lattice enantiomorphs and the finalR(F) andRw(F) residuals were, respectively, 0.0463 and 0.0482 for (+ + +) and 0.0441 and 0.0442 for (− − −). Thus, the latter was selected as correct for our specimen, and the final cycle of refinement with the (− − −) model converged toR(F) andRw(F) of 0.0436 and 0.0421. For all three compounds, the six-membered rings are chairs; the secondary nitrogens are chiral centers, and the five-membered rings are ordered and conformationally dissymmetric, as expected. Coincidentally, in (I), (II), and (III) the central rings are right-handed helices withδ(+50.0‡),δ(+53.3‡), andδ(+48.3‡), respectively. Thus, the secondary nitrogens of all three cations are (R), rendering the cations chiral. The incidence of conglomerate crystallization intrans coordination compounds is rare, and those known are asymmetrically substituted (see Ref. 4 for the four known cases). Thus, the incidence of such crystallization mode in a new series of [trans- Co(amine ligands)X2]+ cations bearing symmetrical pairs oftrans ligands was an unexpected and welcomed event. In all three cases, the counteranions are bonded to the hydrogens of the terminal -NH2 moieties, thus forming an overall entity which resembles a macrocycle. In fact, parallels between the crystallization behavior of our compounds and that of macrocycles bearing related fragments is discussed. Finally, in the three compounds, homochiral cations are linked into infinite strings by hydrogen bonds between the axial ligands and amino hydrogens on adjacent cations of the string. In turn, strings are stitched together by the counteranions which form bonds with amino hydrogens on cations of adjacent strings.

THE PHENOMENON OF CONGLOMERATE CRYSTALLIZATION, PART 41. THE CRYSTALLIZATION BEHAVIOR OF (H5O2)[cis-α-Co(edda)ox](I), K[cis-β-Co(edda)ox]·H2O (II) AND K[cis-α-Co(edda)malonate]·3H2O (III)

Abstract (H5O2)[cis-α-Co(edda)ox]·H2O (I), CoO10N2C8H15, crystallizes, at 22°C, from a dilute HCl solution of K[cis-α-Co(edda)ox] in space group P21/n (a variant of No. 14), with lattice constants: a = 9.370(2), b = 9.872(3), c = 14.433(2) A, β = 106.43(1)° V = 1280.50 A3 and d(calc; MW = 358.15, Z = 4) = 1.858 g-cm−3. A total of 3687 data were collected over the range of 4° 3σ(I)) were used in the structural analysis. Data were corrected for absorption (μ = 13.902 cm−1) and the transmission coefficients ranged from 0.7678 to 0.9993. The final R(F) and Rw (F) residuals were, respectively 0.0378 and 0.0348. The anions exist in the lattice as enantiomeric pairs with chiropital descriptors Λ(δλλ)[cis-α-Co(edda)ox] and δ(λδλ)[cis-α-Co(edda)ox]. K[cis-β-Co(edda)ox]·H2O (II), CoKO9N2C8H12, crystallizes from water at 22°C in space group P21/c(No. 14), with lattice constants: a = 8.993(2), b = 10.302(3), c = 14.900(2) A, β = 106.24(2)°; V = 1297.66 A3 and d(cal...

The phenomenon of conglomerate crystallization. XXXV. The crystallization behaviour of {cis-α-Co(trien)ox]Cl}2·9H2O (1), cis-β-Co(3,2,3-tet)ox]Cl·4H2O(2), {cis-α-Co(trien)ox]NO3}2· H2O (3), and [mer-Co(dien)ox (NO2)] (4)

SummaryAs expected from previous studies, the four title compounds crystallize as racemates from H2O solutions allowed to evaporate at room temperature (ca. 18° C). All four complexes have been characterized by X-ray crystallography. The outer, six-membered rings in (2) are in the chair conformation; and, in the first three species, the secondary nitrogens are chiral centres. In (1) the five-membered rings of the two cations in the asymmetric unit are characterized: Co(1), δ, δ and λ, with the chiralities of the secondary nitrogens (S) and (S); Co(2), λ, λ and δ, with secondary nitrogens (R) and (R). In (3), the five-membered rings of the two cations in the asymmetric unit are: Co(1), δ, δ and λ, with secondary nitrogens (S) and (S); Co(2), δ, λ and δ, with secondary nitrogens (S) and (S). In (2), the five-membered ring is δ and the chiralities of the secondary nitrogens are (R) and (R). In (4), the unique five-membered ring is λ and the central —NH— fragment lies at a mirror plane.Comparison of the crystallization pathways of these complexes with those of related substances are made, and suggestions as to why (1)–(4) select the racemic crystallization pathway are offered.

THE PHENOMENON OF CONGLOMERATE CRYSTALLIZATION. PART 49. THE CRYSTALLIZATION BEHAVIOR OF K[cis-β-(EDDA)(ox)l · H2O(I), AND OF [mer-Co(dien)(NH3(ox)]BR (II)

Abstract Racemic solutions of K[cis-β-(edda)(ox)]H2O (I) CoKO9N2C8H12, crystallize as racemic crystals, space group P21/c (No. 14) with cell constants of a = 8.993(4), 10.302(4), c = 14.590(9), (3=106.24(4)°, V= 1297.44 A3, d= 1.936 gm-cm3. (MW = 378.22 gm-mole−1; z = 4). A total of 3081 data were collected over the range of 4° ≤ 2θ ≤ 50° of these, 1695 (independent and with 1 ≥ 2.5[sgrave](I)) were used in the structural analysis. Data were corrected for absorption (μ = 16.861 cm−1) and the transmission coefficients ranged from 0.9163 to 0.9965. The final R(F) and Rw(F) residuals were, respectively 0.0299 and 0.0322. The anions exist in the lattice as enantiomeric pairs and the conformation of the central, five-membered ring for the molecule described here is δ(N1-C1-C2-N2 =+47.3°); that of the five-membered acetato ligands are, respectively, δ(+162.0°) and λ(-156.8°). The secondary nitrogens are both R. The potassium cation is bonded to the six oxygens. Racemic solutions of [mer-Co(dien)(NH3)(ox)]Br (II...

THE PHENOMENON OF CONGLOMERATE CRYSTALLIZATION. PART 43. THE CRYSTALLIZATION BEHAVIOR OF K[cis-α-Co(N-N′-Et2-Edda)(NO2)2] · 2H2O (I), {CS[cis-α-Co(Edda)(NO2)2]}2 · 3H2O (II), Rb[cis-α-Co(Edda)(NO2)2 · H2O (III) and NH4[cis-α-Co(Edda)(NO2)2] · 2H2O (IV)

Abstract K[cis-α-Co(Et2-edda)(NO2)2] · 2H2O (I), CoKO10N4C10H22, crystallizes in the space group P21/n(No. 14), with lattice constants: a = 7.339(2), b = 15.750(3), c = 15.492(4) A and β 101.65(2)°; V = 1753.86A3 and d(calc; MW = 456.34, Z = 4) = 1.728 g-cm−3. A total of 3335 data were collected over the range of 4° ≤ 2θ ≤ 50°; of these, 2553 (independent and with I > 3σ(I)) were used in the structural analysis. Data were corrected for absorption (μ = 12.688 cm−1) and the transmission coefficients ranged from 0.8860 to 0.9997. Final values of the residuals were R(F) = 0.0275 and Rw (F) = 0.0301. The anions of the racemic pairs in the unit cell have the chiroptical symbols A(δΛδ) and Δ(ΛδΛ). {Cs[cis-α-Co(edda)(NO2)2]}2 · 3H2O (II), Cs2Co2O19N8C8H18, crystallizes in the space group C2/c(No. 15), with lattice constants: a = 19.304(6), b = 10.992(4), c = 13.809 (5) A and β = 106.42(3)°; V = 2827.11 A3 and d(calc; MW = 913.95 Z = 4) = 2.147 g-cm−1. A total of 4192 data were collected over the range of 4° ≤ 2θ ...

Why are Hexol Cluster Cations [Tris(cis-tetraaminedihydroxo)Co]+6 So Easily Resolved into Their Antipodes? Part 2. Preparation, Crystal Structural Studies and the Nine Sources of Chirality of Hexol Clusters

AbstractHeretofore, it had been impossible to determine the structure of the original Werners hexol cation inasmuch as the synthetic procedure given by Werner produces crystals unsuitable for single crystal X-ray (XRD) diffraction studies. Thus, it was greatly satisfying that crystals obtained here, using a different method of preparation, produced useful crystals of three different derivatives. X-ray quality crystals of composition [Co(NH3)4CO3][Co{(HO)2Co(NH3)4}3](NO3)6(OH) · 2 H2O(III) were obtained while attempting to grow crystals of [Co(NH3)5CO3]NO3 from water solutions allowed to evaporate at room temperature (ca. 22°C). (III) crystallizes in space group P