INTRODUCTION: Improving the quality of healthcare is a common goal of consumers, providers, payer groups, and governments. There is evidence that patient satisfaction influences the perceptions of the quality of care received.
METHODS: This exploratory, qualitative study described and analyzed, the similarities and differences in satisfaction and dissatisfaction experiences of patients attending physicians (social justice) and chiropractors (market justice) for healthcare services in Niagara Region, Ontario. Using inductive content analysis the satisfaction and dissatisfaction experiences were themed to develop groups, categories, and sub-categories of quality judgments of care experiences.
RESULTS: Study participants experienced both satisfying and dissatisfying critical incidents in the areas of standards of practice, professional and practice attributes, time management, and treatment outcomes. Cost was not a marked source of satisfaction or dissatisfaction.
CONCLUSION: Patients may be more capable of generating quality judgments on the technical aspects of medical and chiropractic care, particularly treatment outcomes and standards of practice, than previously thought.
KEYWORDS: chiropractic care; quality; satisfaction
In this Viewpoint, the impact of the paper published by Gautam R. Desiraju and Angelo Gavezzotti (J. Chem. Soc., Chem. Commun., 1989, 621) upon the development of Crystal Engineering, now recognised a key discipline in contemporary chemical/pharmaceutical/materials science, is discussed.
Despite being disparaged for their malodorous and toxic demeanour, compounds of selenium, a bio-essential element, and tellurium, offer possibilities as therapeutic agents. Herein, their potential use as drugs, for example, as anti-viral, anti-microbial, anti-inflammatory agents, etc., will be surveyed along with a summary of the established biological functions of selenium. The natural biological functions of tellurium remain to be discovered.
The title supra-molecular polymer, [Cu(S(3)O(6))(H(2)O)(4)](n), features a tetra-gonally distorted octa-hedral Cu(II) centre within an O(6) donor set with the longer Cu-O bonds linking the dication and the trithio-nate dianion. Extensive O-H⋯O hydrogen-bonding inter-actions connect the supra-molecular chains into a three-dimensional network.
The Cambridge Structural Database was evaluated for crystals containing Se…O chalcogen bonding interactions. These secondary bonding interactions are found to operate independently of complementary intermolecular interactions in about 13% of the structures they can potentially form. This number rises significantly when more specific interactions are considered, e.g. Se…O(carbonyl) interactions occur in 50% of cases where they can potentially form. In about 55% of cases, the supramolecular assemblies sustained by Se…O(oxygen) interactions are one-dimensional architectures, with the next most prominent being zero-dimensional assemblies, at 30%.
In the title compound, C14H8N4O6, the benzoxazin-4-one fused-ring system (r.m.s. deviation = 0.018 Å) is coplanar with the attached benzene ring [dihedral angle = 0.81 (4)°], there being an intra-molecular N-H⋯N hydrogen bond between them. Each nitro group is twisted out of the plane of the attached benzene ring [O-N-C-C torsion angles = 167.94 (11) and 170.38 (11)°]. In the crystal, amine-nitro N-H⋯O hydrogen bonds lead to centrosymmetric dimeric aggregates that are connected into a three-dimensional architecture by oxazin-yl-nitro C-H⋯O and π-π inter-actions [inter-centroid distance between the oxazinyl and terminal benzene rings = 3.5069 (7) Å].
The asymmetric unit of title co-crystal, C10H8N2·2C7H7NO2, comprises a centrosymmetric 4,4'-bi-pyridine mol-ecule, and a 2-amino-benzoic acid mol-ecule in a general position. The latter is effectively planar [C-C-C-O torsion angle = 5.0 (3)°] owing to an intra-molecular N-H⋯O(carbon-yl) hydrogen bond. Three-mol-ecule aggregates are formed via O-H⋯N(pyrid-yl) hydrogen bonds and these are connected into supra-molecular layers in the bc plane by N-H⋯O(carbon-yl) hydrogen bonds and π-π inter-actions between pyridyl and benzene rings [inter-centroid distance = 3.634 (2) Å]. Layers are connected along the a axis by weak π-π inter-actions between benzene rings [3.964 (2) Å].
The asymmetric unit of the title co-crystal, C10H6O8·2C8H10N4O2, comprises a centrosymmetric benzene-1,2,4,5-tetra-carb-oxy-lic acid (LH4) mol-ecule and a mol-ecule of caffeine in a general position. LH4 is nonplanar, with the dihedral angles between the ring and pendent carb-oxy-lic acid groups being 44.22 (7) and 49.74 (7)°. By contrast, the caffeine mol-ecule is planar (r.m.s. deviation = 0.040 Å). Supra-molecular layers parallel to (-1-10) are sustained by carb-oxy-lic acid O-H⋯O(carbon-yl) and O-H⋯N(imidazole) hydrogen bonds, as well as by meth-yl-carbonyl C-H⋯O inter-actions. These stack via π-π inter-actions between the benzene and imidazole rings [inter-centroid distance = 3.4503 (10) Å].
The asymmetric unit of the title co-crystal, C12H12N2·2C7H7NO2, comprises a centrosymmetric 4-[2-(pyridin-4-yl)eth-yl]pyridine mol-ecule and a 2-amino-benzoic acid mol-ecule in a general position. The acid has a small twist between the carb-oxy-lic acid residue and the ring [dihedral angle = 7.13 (6)°] despite the presence of an intra-molecular N-H⋯O(carbon-yl) hydrogen bond. Three-mol-ecule aggregates are formed via O-H⋯N(pyrid-yl) hydrogen bonds, and these are connected into supra-molecular layers in the bc plane by N-H⋯O(carbon-yl) hydrogen bonds and π-π inter-actions between pyridine and benzene rings [inter-centroid distance = 3.6332 (9) Å]. Layers are connected along the a axis by weak π-π inter-actions between benzene rings [3.9577 (10) Å].
The title compound, C(13)H(10)Cl(2)N(2)S, represents a monoclinic polymorph of the previously reported ortho-rhom-bic form [Ramnathan et al. (1996 ▶). Acta Cryst. C52, 134-136]. The mol-ecule is twisted with the dihedral angle between the benzene rings being 55.37 (7)°. The N-H atoms are syn to each other, which contrasts their anti disposition in the ortho-rhom-bic form. In the crystal, mol-ecules assemble into zigzag chains along the c axis via N-H⋯S hydrogen bonds. Chains are connected into layers via C-H⋯Cl inter-actions, and these stack along the a axis.
The asymmetric unit of the title compound, {(C34H28FeP2)[Au(C5H8NS2)]2}, comprises half a mol-ecule, with the full mol-ecule being generated by the application of a centre of inversion. The independent Au(I) atom is coordinated by thiol-ate S and phosphane P atoms that define an approximate linear geometry [S-Au-P = 169.35 (3)°]. The deviation from the ideal linear is traced to the close approach of the (intra-molecular) non-coordinating thione S atom [Au⋯S = 3.1538 (8) Å]. Supra-molecular layers parallel to (100) feature in the crystal packing, being sustained by phen-yl-thione C-H⋯S inter-actions, with the non-coordinating thione S atom in the role of a dual acceptor. Layers stack with no specific inter-actions between them.
The asymmetric unit of the title 1:2 co-crystal, C14H10O4S2·2C7H6O2, comprises half a mol-ecule of di-thiodi-benzoic acid [systematic name: 2-[(2-carb-oxy-phen-yl)disulfan-yl]benzoic acid, DTBA], as the mol-ecule is located about a twofold axis of symmetry, and a mol-ecule of benzoic acid (BA). The DTBA mol-ecule is twisted about the di-sulfide bond [the C-S-S-C torsion angle is -83.19 (8)°] resulting in a near perpendicular relationship between the benzene rings [dihedral angle = 71.19 (4)°]. The carb-oxy-lic acid group is almost co-planar with the benzene ring to which it is bonded [dihedral angle = 4.82 (12)°]. A similar near co-planar relationship pertains for the BA mol-ecule [dihedral angle = 3.65 (15)°]. Three-mol-ecule aggregates are formed in the crystal whereby two BA mol-ecules are connected to a DTBA mol-ecule via hy-droxy-O-H⋯O(hydroxy) hydrogen bonds and eight-membered {⋯HOC=O}2 synthons. These are connected into a supra-molecular layer in the ab plane through C-H⋯O inter-actions. The inter-actions between layers to consolidate the three-dimensional architecture are π-π stacking inter-actions between DTBA and BA rings [inter-centroid separation = 3.8093 (10) Å] and parallel DTBA-hy-droxy-O⋯π(BA) contacts [O⋯ring centroid separation = 3.9049 (14) Å]. The importance of the specified inter-actions as well as other weaker contacts, e.g. π-π and C-H⋯S, are indicated in the analysis of the calculated Hirshfeld surface and inter-action energies.
Dibenzo[1,5]diazocine scaffolds are present in a wide range of organic building blocks, for example in pharmaceuticals, materials and structural chemistry. However, the development of these structural frameworks has not received significant attention owing to limited synthetic protocols and strategies. Herein, a summary of the attractive synthetic approaches for the construction of dibenzo[1,5]diazocines, epiminodibenzo[1,5]diazocines and epoxydibenzo[1,5]diazocines developed over the past two decades is presented. The spectroscopic, synthetic mechanisms for the formation of the heterocyclic rings and remarkable structural features, including in the solid-state, are discussed.
The crystal and mol-ecular structures of the title mol-ecular salts, C4H12NO+·C7H5N2O4 -, (I), C6H16NO+·C7H5N2O4 -, (II), and C4H12NO3 +·C7H5N2O4 -, (III), are described. The common feature of these salts is the presence of the 2-amino-4-nitro-benzoate anion, which exhibit non-chemically significant variations in the conformational relationships between the carboxyl-ate and nitro groups, and between these and the benzene rings they are connected to. The number of ammonium-N-H H atoms in the cations increases from one to three in (I) to (III), respectively, and this variation significantly influences the supra-molecular aggregation patterns in the respective crystals. Thus, a linear supra-molecular chain along [100] sustained by charge-assisted tertiary-ammonium-N-H⋯O(carboxyl-ate), hy-droxy-O-H⋯O(carboxyl-ate) and amino-N-H⋯O(carboxyl-ate) hydrogen-bonds is apparent in the crystal of (I). Chains are connected into a three-dimensional architecture by methyl-C-H⋯O(hy-droxy) and π-π inter-actions, the latter between benzene rings [inter-centroid separation = 3.5796 (10) Å]. In the crystal of (II), a supra-molecular tube propagating along [901] arises as a result of charge-assisted secondary-ammonium-N-H⋯O(carboxyl-ate) and hy-droxy-O-H⋯O(carboxyl-ate) hydrogen-bonding. These are connected by methyl-ene- and methyl-C-H⋯O(nitro) and π-π stacking between benzene rings [inter-centroid separation = 3.5226 (10) Å]. Finally, double-layers parallel to (100) sustained by charge-assisted ammonium-N-H⋯O(carboxyl-ate), ammonium-N-H⋯O(hy-droxy) and hy-droxy-O-H⋯O(carboxyl-ate) hydrogen-bonds are apparent in the crystal of (III). These are connected in a three-dimensional architecture by amine-N-H⋯O(nitro) hydrogen-bonds.
The asymmetric unit of the title co-crystal, 2,2'-thiodi-benzoic acid-tri-phenyl-phosphane oxide (1/2), C14H10O4S·2C18H15OP, comprises two mol-ecules of 2,2'-thiodi-benzoic acid [TDBA; systematic name: 2-[(2-carb-oxy-phen-yl)sulfan-yl]benzoic acid] and four mol-ecules of tri-phenyl-phosphane oxide [TPPO; systematic name: (di-phenyl-phosphor-yl)benzene]. The two TDBA mol-ecules are twisted about their di-sulfide bonds and exhibit dihedral angles of 74.40 (5) and 72.58 (5)° between the planes through the two SC6H4 residues. The carb-oxy-lic acid groups are tilted out of the planes of the rings to which they are attached forming a range of CO2/C6 dihedral angles of 19.87 (6)-60.43 (8)°. Minor conformational changes are exhibited in the TPPO mol-ecules with the range of dihedral angles between phenyl rings being -2.1 (1) to -62.8 (1)°. In the mol-ecular packing, each TDBA acid mol-ecule bridges two TPPO mol-ecules via hy-droxy-O-H⋯O(oxide) hydrogen bonds to form two three-mol-ecule aggregates. These are connected into a three-dimensional architecture by TPPO-C-H⋯O(oxide, carbon-yl) and TDBA-C-H⋯(oxide, carbon-yl) inter-actions. The importance of H⋯H, O⋯H/H⋯O and C⋯H/H⋯C contacts to the calculated Hirshfeld surfaces has been demonstrated. In terms of individual mol-ecules, O⋯H/H⋯O contacts are more important for the TDBA (ca 28%) than for the TPPO mol-ecules (ca 13%), as expected from the chemical composition of these species. Computational chemistry indicates the four independent hy-droxy-O-H⋯O(oxide) hydrogen bonds in the crystal impart about the same energy (ca 52 kJ mol-1), with DTBA-phenyl-C-H⋯O(oxide) inter-actions being next most stabilizing (ca 40 kJ mol-1).
The asymmetric unit of the three-component title compound, 2,2'-di-thiodi-benzoic acid-2-chloro-benzoic acid-N,N-di-methyl-formamide (1/1/1), C14H10O4S2·C7H5ClO2·C3H7NO, contains a mol-ecule each of 2,2'-di-thiodi-benzoic acid (DTBA), 2-chloro-benzoic acid (2CBA) and di-methyl-formamide (DMF). The DTBA mol-ecule is twisted [the C-S-S-C torsion angle is 88.37 (17)°] and each carb-oxy-lic group is slightly twisted from the benzene ring to which it is connected [CO2/C6 dihedral angles = 7.6 (3) and 12.5 (3)°]. A small twist is evident in the mol-ecule of 2CBA [CO2/C6 dihedral angle = 4.4 (4)°]. In the crystal, the three mol-ecules are connected by hydrogen bonds with the two carb-oxy-lic acid residues derived from DTBA and 2CBA forming a non-symmetric eight-membered {⋯HOCO}2 synthon, and the second carb-oxy-lic acid of DTBA linked to the DMF mol-ecule via a seven-membered {⋯HOCO⋯HCO} heterosynthon. The three-mol-ecule aggregates are connected into a supra-molecular chain along the a axis via DTBA-C-H⋯O(hydroxyl-2CBA), 2CBA-C-H⋯O(hydroxyl-DTBA) and DTBA-C-H⋯S(DTBA) inter-actions. Supra-molecular layers in the ab plane are formed as the chains are linked via DMF-C-H⋯S(DTBA) contacts, and these inter-digitate along the c-axis direction without specific points of contact between them. A Hirshfeld surface analysis points to additional but, weak contacts to stabilize the three-dimensional architecture: DTBA-C=O⋯H(phenyl-DTBA), 2CBA-Cl⋯H(phenyl-DTBA), as well as a π-π contact between the delocalized eight-membered {⋯HOC=O}2 carb-oxy-lic dimer and the phenyl ring of 2CBA. The latter was confirmed by electrostatic potential (ESP) mapping.
The title 1:1 solvate, C14H10O4S2·C3H7NO, features a twisted mol-ecule of 2,2'-di-thiodi-benzoic acid (DTBA), with the central C-S-S-C torsion angle being -88.57 (6)°, and a mol-ecule of di-methyl-formamide (DMF). The carb-oxy-lic acid groups are, respectively, close to co-planar and twisted with respect to the benzene rings to which they are connected as seen in the CO2/C6 torsion angles of 1.03 (19) and 7.4 (2)°. Intra-molecular, hypervalent S←O inter-actions are noted [S⋯O = 2.6140 (9) and 2.6827 (9) Å]. In the crystal, four-mol-ecule aggregates are formed via DTBA-O-H⋯O(DMF) and DTBA-O-H⋯O(DTBA) hydrogen bonding, the latter via an eight-membered {⋯OHCO}2 homosynthon. These are linked into supra-molecular layers parallel to (011) via benzene-C-H⋯O(DTBA) and DTBA-C=O⋯π(benzene) inter-actions, with the connections between these, giving rise to a three-dimensional architecture, being of the type benzene-C-H⋯π(benzene). An analysis of the calculated Hirshfeld surfaces indicates, in addition to the aforementioned inter-molecular contacts, the presence of stabilizing inter-actions between a benzene ring and a quasi-π-system defined by O-H⋯O hydrogen bonds between a DTBA dimer, i.e. the eight-membered {⋯OCOH}2 ring system, and between a benzene ring and a quasi-π(OCOH⋯OCH) system arising from the DTBA-O-H⋯O(DMF) hydrogen bond. The inter-centroid separations are 3.65 and 3.49 Å, respectively.
The common structural feature of the title compounds, [Zn(C4H8NOS2)2(C5H5N)]·C5H5N (I) and [Zn(C5H10NOS2)2(C5H5N)]·C5H5N (II), which differ by having di-thio-carbamate N-bound methyl (I) and ethyl (II) groups, is the coordination of each ZnII atom by two non-symmetrically chelating di-thio-carbamate ligands and by a pyridine ligand; in each case, the non-coordinating pyridine mol-ecule is connected to the Zn-containing mol-ecule via a (hy-droxy)O-H⋯N(pyridine) hydrogen bond. The resulting NS4 coordination geometry is closer to a square-pyramid than a trigonal bipyramid in the case of (I), but almost inter-mediate between the two extremes in (II). The mol-ecular packing features (hy-droxy)O-H⋯O(hy-droxy) hydrogen bonds, leading to supra-molecular chains with a zigzag arrangement along [10-1] (I) or a helical arrangement along [010] (II). In (I), π-π [inter-centroid distances = 3.4738 (10) and 3.4848 (10) Å] between coordinating and non-coordinating pyridine mol-ecules lead to stacks comprising alternating rings along the a axis. In (II), weaker π-π contacts occur between centrosymmetrically related pairs of coordinating pyridine mol-ecules [inter-centroid separation = 3.9815 (14) Å]. Further inter-actions, including C-H⋯π(chelate) inter-actions in (I), lead to a three-dimensional architecture in each case.
The title structures, [M(C6H12NOS2)2(C10H8N2)]·0.5C10H8N2, for M = Zn, (I), and Cd, (II), feature terminally bound 4,4'-bipyridyl ligands and non-coordinating 4,4'-bi-pyridyl mol-ecules, with the latter disposed about a centre of inversion. The coordination geometry about the metal atom is defined by two non-symmetrically chelating di-thio-carbamate ligands and a pyridyl N atom. The NS4 donor sets are distorted but, approximate to trigonal bipyramidal in each case. In the crystal, hy-droxy-O-H⋯O(hy-droxy) and hy-droxy-O-H⋯N(pyrid-yl) hydrogen bonds between the zinc-containing mol-ecules lead to a supra-molecular layer parallel to (100). The three-dimensional architecture arises as the layers are linked via methine-C-H⋯S, pyridyl-C-H⋯O(hy-droxy) and π-π [inter-centroid distance between coordinated pyridyl rings = 3.6246 (18) Å] inter-actions. Channels along the c-axis direction are occupied by the non-coordinating 4,4'-bipyridine mol-ecules, which are held in place by C-H⋯π(chelate ring) contacts.
The asymmetric unit of the title 1:2 co-crystal, C14H14N4O2·2C7H5ClO2, comprises two half mol-ecules of oxalamide (4 LH2), as each is disposed about a centre of inversion, and two mol-ecules of 4-chloro-benzoic acid (CBA), each in general positions. Each 4 LH2 mol-ecule has a (+)anti-periplanar conformation with the pyridin-4-yl residues lying to either side of the central, planar C2N2O2 chromophore with the dihedral angles between the respective central core and the pyridyl rings being 68.65 (3) and 86.25 (3)°, respectively, representing the major difference between the independent 4 LH2 mol-ecules. The anti conformation of the carbonyl groups enables the formation of intra-molecular amide-N-H⋯O(amide) hydrogen bonds, each completing an S(5) loop. The two independent CBA mol-ecules are similar and exhibit C6/CO2 dihedral angles of 8.06 (10) and 17.24 (8)°, indicating twisted conformations. In the crystal, two independent, three-mol-ecule aggregates are formed via carb-oxy-lic acid-O-H⋯N(pyrid-yl) hydrogen bonding. These are connected into a supra-molecular tape propagating parallel to [100] through amide-N-H⋯O(amide) hydrogen bonding between the independent aggregates and ten-membered {⋯HNC2O}2 synthons. The tapes assemble into a three-dimensional architecture through pyridyl- and methyl-ene-C-H⋯O(carbon-yl) and CBA-C-H⋯O(amide) inter-actions. As revealed by a more detailed analysis of the mol-ecular packing by calculating the Hirshfeld surfaces and computational chemistry, are the presence of attractive and dispersive Cl⋯C=O inter-actions which provide inter-action energies approximately one-quarter of those provided by the amide-N-H⋯O(amide) hydrogen bonding sustaining the supra-molecular tape.