SIR2011: a new package for crystal structure determination and refinement

Abstract

SIR2011, the successor of SIR2004, is the latest program of the SIR suite. It can solve ab initio crystal structures of small-and medium-size molecules, as well as protein structures, using X-ray or electron diffraction data. With respect to the predecessor the program has several new abilities: e.g. a new phasing method (VLD) has been implemented, it is able to exploit prior knowledge of the molecular geometry via simulated annealing techniques, it can use molecular replacement methods for solving proteins, it includes new tools like free lunch and new approaches for electron diffraction data, and it visualizes threedimensional electron density maps. The graphical interface has been further improved and allows the straightforward use of the program even in difficult cases.

The charge-flipping algorithm in crystallography

“…If is smaller, the phases of the most important reflections will be fixed and the iteration will stagnate. Interestingly, a similar observation has also been made in the framework of direct methods (Sheldrick & Gould, 1995;Burla et al, 2000) and a procedure called RELAX, which relaxes the symmetry constraints on the structure (Burla et al, 2002), has become a standard part of the structure solution process in the program SIR2011 (Burla, Caliandro et al, 2012).…”

Crystallographic study of PET radiotracers in clinical evaluation for early diagnosis of Alzheimers

“…Data collection: COLLECT (Nonius, 2002); cell determination and refinement: DIRAX (Duisenberg,1992;Duisenberg et al, 2000); data reduction: EVAL (Nonius, 2002;Duisenberg et al, 2003);program(s) used to solve structure: SIR2011 (Burla et al, 2012); program(s) used to refine structure: SHELXL2013 (Sheldrick, 2008b); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012) and EXPO2013 (Altomare et al, 2013); software used to prepare material for publication: WinGX (Farrugia, 2012) and publCIF (Westrip, 2010).…”

Structure of cis-dichlorobis(1,10-phenanthroline)manganese(II) and cis-dichlorobis(2,2´-bipyridine)manganese(II)

“…The semi-empirical absorption corrections were applied the using multi-scan method. The structures were solved by direct methods using SIR-2011 (Burla et al, 2012) and refined by the full-matrix least-squares procedure with SHELXL-2014 (Sheldrick, 2008) or CRYSTALS (Betteridge et al, 2003). Geometrical analyses were performed with SHELXL-2014 or CRYSTALS.…”