The first example of a two-coordinated Au(I) atom bonded to an Fe(II) atom and an N-heterocyclic carbene (NHC) ligand.
01 Jun 2015-Acta Crystallographica Section C-crystal Structure Communications (International Union of Crystallography (IUCr))-Vol. 71, Iss: 6, pp 448-451
TL;DR: This is the first example of a two-coordinated Au atom bonded to an Fe and a C atom of an N-heterocyclic carbene.
Abstract: The aurophilicity exhibited by Au(I) complexes depends strongly on the nature of the supporting ligands present and the length of the Au-element (Au-E) bond may be used as a measure of the donor-acceptor properties of the coordinated ligands. A binuclear iron-gold complex, [1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene-2κC(2)]dicarbonyl-1κ(2)C-(1η(5)-cyclopentadienyl)gold(I)iron(II)(Au-Fe) benzene trisolvate, [AuFe(C5H5)(C27H36N2)(CO)2]·3C6H6, was prepared by reaction of K[CpFe(CO)2] (Cp is cyclopentadienyl) with (NHC)AuCl [NHC = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene]. In addition to the binuclear complex, the asymmetric unit contains three benzene solvent molecules. This is the first example of a two-coordinated Au atom bonded to an Fe and a C atom of an N-heterocyclic carbene.
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TL;DR: In this article, the second and third examples of structurally characterised (1,1′-diphosphaferrocene) gold complexes have been presented, and the results indicate that surface binding of 1 involves the Fe atom together with both P atoms, whereas in other cases, surface binding can be realised with just one phospholyl ring.
Abstract: 1,1′-Diphosphaferrocene (1) and its 3,3′,4,4′-tetramethyl (2), 3,3′,4,4′-tetraphenyl (3), octamethyl (4), octaethyl (5) and octaphenyl derivative (6) have been investigated in terms of the suitability of 1,1′-diphosphaferrocenes as adsorbate species for fabricating self-assembled monolayers (SAMs) on gold. Compounds 3 and 6 have been structurally characterised by X-ray diffraction. Complexes [Au(4)2][GaCl4] and [Au2(µ-5)2][FeCl4]2 have also been prepared and are only the second and third examples to date of structurally characterised (1,1′-diphosphaferrocene)gold complexes. [Au(4)2][GaCl4] exhibits intramolecular Au···Fe contacts compatible with Fe→Au bonding interactions, which have not been described before in ferrocene chemistry. [Au2(µ-5)2][FeCl4]2 exhibits an intramolecular Au···Au contact indicative of aurophilic bonding, leading to a structural motif unprecedented for 1,1′-diphosphaferrocenes. Ultrathin films obtained by chemisorption of the 1,1′-diphosphaferrocenes from solution onto gold substrates have been investigated by X-ray photoelectron spectroscopy and near-edge X-ray absorption fine-structure (NEXAFS) spectroscopy. The results indicate that the surface binding of 1 involves the Fe atom together with both P atoms, whereas in the other cases, surface binding can be realised with just one phospholyl ring. There is no indication of any oxidative decomposition of the adsorbates on the surface. According to NEXAFS spectroscopic results 6 gives rise to SAMs of high orientational order.
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TL;DR: This paper could serve as a general literature citation when one or more of the open-source SH ELX programs (and the Bruker AXS version SHELXTL) are employed in the course of a crystal-structure determination.
Abstract: 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.
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TL;DR: Mercury as discussed by the authors is a crystal structure visualization program that allows to display multiple structures simultaneously and overlay them, which can be used for comparison between crystal structures and to overlay them in a table or spreadsheets.
Abstract: Since its original release, the popular crystal structure visualization program Mercury has undergone continuous further development. Comparisons between crystal structures are facilitated by the ability to display multiple structures simultaneously and to overlay them. Improvements have been made to many aspects of the visual display, including the addition of depth cueing, and highly customizable lighting and background effects. Textual and numeric data associated with structures can be shown in tables or spreadsheets, the latter opening up new ways of interacting with the visual display. Atomic displacement ellipsoids, calculated powder diffraction patterns and predicted morphologies can now be shown. Some limited molecular-editing capabilities have been added. The object-oriented nature of the C++ libraries underlying Mercury makes it easy to re-use the code in other applications, and this has facilitated three-dimensional visualization in several other programs produced by the Cambridge Crystallographic Data Centre.
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TL;DR: publCIF is an application designed for creating, editing and validating crystallographic information files (CIFs) that are used in journal publication and provides a web interface to the checkCIF service of the International Union of Crystallography (IUCr), which provides a full crystallographic analysis of the structural data.
Abstract: publCIF is an application designed for creating, editing and validating crystallographic information files (CIFs) that are used in journal publication. It validates syntax and dictionary-defined data attributes through internal routines, and also provides a web interface to the checkCIF service of the International Union of Crystallography (IUCr), which provides a full crystallographic analysis of the structural data. The graphical interface allows users to edit the CIF either in its `raw' ASCII form (using a text editor with context-sensitive data validation and input facilities) or as a formatted representation of a structure report (using a word-processing environment), as well as via a number of convenience tools (e.g. spreadsheet representations of looped data). Beyond file and data validation, publCIF provides access to resources to facilitate preparation of a structure report (e.g. databases of author details, experimental data, standard references etc., either distributed with the program or collected during its use), along with tools for reference parsing, spell checking, structure visualization and image management. publCIF was commissioned by the IUCr, both as free software for authors and as a tool for in-house journal production; the tool for authors is described here. Binary distributions for Linux, MacOS and Windows operating systems are available.
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