Mol­ecules of the title compound, C21H16BrNO, are linked through pairs of N—H⋯O inter­molecular hydrogen bonds into centrosymmetric R22(10) dimers. One of the C atoms of the cyclohex-2-enone ring is disordered with refined occupancies of 0.61 (2) and 0.39 (2).

6-Bromo-2-(3-phenyl-allyl-idene)-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

J. Appl. Cryst.の発刊に際して

About the Catharanthus Alkaloids

The Catharanthus Alkaloids : Edited by W. I. Taylor and N. R. Farnsworth; Marcel Dekker Inc., New York, 1975. 323 pages. $29.50.

https://journals.iucr.org/e/issues/2011/12/00/bt5677/bt5677.pdf

An account is given of the development of the SHELX system of computer programs from SHELX-76 to the present day. In addition to identifying useful innovations that have come into general use through their implementation in SHELX, a critical analysis is presented of the less-successful features, missed opportunities and desirable improvements for future releases of the software. An attempt is made to understand how a program originally designed for photographic intensity data, punched cards and computers over 10000 times slower than an average modern personal computer has managed to survive for so long. SHELXL is the most widely used program for small-molecule refinement and SHELXS and SHELXD are often employed for structure solution despite the availability of objectively superior programs. SHELXL also finds a niche for the refinement of macromolecules against high-resolution or twinned data; SHELXPRO acts as an interface for macromolecular applications. SHELXC, SHELXD and SHELXE are proving useful for the experimental phasing of macromolecules, especially because they are fast and robust and so are often employed in pipelines for high-throughput phasing. This paper could serve as a general literature citation when one or more of the open-source SHELX programs (and the Bruker AXS version SHELXTL) are employed in the course of a crystal-structure determination.

/pdf/a-short-history-of-shelx-2p8xg3qghr.pdf

methods

A short history of SHELX

Computer Program Abstracts The category Computer Program Abstracts provides a rapid means of communicating up-to-date information concerning both new programs or systems and significant updates to existing ones. Following normal submission, a Computer Program Abstract will be reviewed by one or two members of the IUCr Commission on Crystallographic Computing. It should not exceed 500 words in length and should follow the standard format given on page 189 of the June 1985 issue of the Journal [J. Appl. CrysL (1985). 18, 189190] and on the World Wide Web at http://www.iucr. ac. uk/journals/jac/software/. Lists of software presented and~or reviewed in the Journal of Applied Crystallography are available on the World Wide Web at the above address, together with information about the availability of the software where this is known. J. App/. CrysL (1997). 30, 565 ORTEP-3 for Windows a version of ORTEP-III with a Graphical User Interface (GUI)

ORTEP-3 for Windows - a version of ORTEP-III with a Graphical User Interface (GUI)

Automated structure validation was introduced in chemical crystallography about 12 years ago as a tool to assist practitioners with the exponential growth in crystal structure analyses. Validation has since evolved into an easy-to-use checkCIF/PLATON web-based IUCr service. The result of a crystal structure determination has to be supplied as a CIF-formatted computer-readable file. The checking software tests the data in the CIF for completeness, quality and consistency. In addition, the reported structure is checked for incomplete analysis, errors in the analysis and relevant issues to be verified. A validation report is generated in the form of a list of ALERTS on the issues to be corrected, checked or commented on. Structure validation has largely eliminated obvious problems with structure reports published in IUCr journals, such as refinement in a space group of too low symmetry. This paper reports on the current status of structure validation and possible future extensions.

/pdf/structure-validation-in-chemical-crystallography-487m3el0s4.pdf

Structure validation in chemical crystallography

Whereas much of organic chemistry has classically dealt with the preparation and study of the properties of individual molecules, an increasingly significant portion of the activity in chemical research involves understanding and utilizing the nature of the interactions between molecules. Two representative areas of this evolution are supramolecular chemistry and molecular recognition. The interactions between molecules are governed by intermolecular forces whose energetic and geometric properties are much less well understood than those of classical chemical bonds between atoms. Among the strongest of these interactions, however, are hydrogen bonds, whose directional properties are better understood on the local level (that is, for a single hydrogen bond) than many other types of non-bonded interactions. Nevertheless, the means by which to characterize, understand, and predict the consequences of many hydrogen bonds among molecules, and the resulting formation of molecular aggregates (on the microscopic scale) or crystals (on the macroscopic scale) has remained largely enigmatic. One of the most promising systematic approaches to resolving this enigma was initially developed by the late M. C. Etter, who applied graph theory to recognize, and then utilize, patterns of hydrogen bonding for the understanding and design of molecular crystals. In working with Etter's original ideas the power and potential utility of this approach on one hand, and on the other, the need to develop and extend the initial Etter formalism was generally recognized. It with that latter purpose that we originally undertook the present review.

6-Bromo-2-(3-phenyl-allyl-idene)-2,3,4,9-tetra-hydro-1H-carbazol-1-one.

Citations

J. Appl. Cryst.の発刊に際して

About the Catharanthus Alkaloids

The Catharanthus Alkaloids : Edited by W. I. Taylor and N. R. Farnsworth; Marcel Dekker Inc., New York, 1975. 323 pages. $29.50.

References

A short history of SHELX

ORTEP-3 for Windows - a version of ORTEP-III with a Graphical User Interface (GUI)

Structure validation in chemical crystallography

J. Appl. Cryst.の発刊に際して

Patterns in Hydrogen Bonding: Functionality and Graph Set Analysis in Crystals