Effects of anions on the solid state structures of linear gold(I) complexes of the type (o-xylyl isocyanide)gold(I) (monoanion)

Ecken, Holger; Olmstead, Marilyn M.; Noll, Bruce C.; Attar, Saeed; Schlyer, Bruce D.; Balch, Alan L.

doi:10.1039/a805086d

Cited by 41 publications

(30 citation statements)

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“…For example, the complexes [(o-xylylNC)AuX] (X ¼ Cl, Br, I, CN) [15] show quite similar molecular structures, consisting of nearly linear dispositions around gold and in the Au-C-N portions. For example, the complexes [(o-xylylNC)AuX] (X ¼ Cl, Br, I, CN) [15] show quite similar molecular structures, consisting of nearly linear dispositions around gold and in the Au-C-N portions.…”

Section: Network From Mononuclear Unitsmentioning

confidence: 99%

Luminescence of Supramolecular Gold‐Containing Materials

López‐de‐Luzuriaga

2008

Modern Supramolecular Gold Chemistry

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In addition to the characteristics that make gold a unique element, such as the lowest electrochemical potential of all metals, its high electronegativity, or the fact that it may have a mononegative oxidation state, perhaps the most intriguing characteristic is the tendency of many gold complexes to aggregate into oligomers or supramolecular assemblies through metal-metal interactions. This fact, far from being a chemical curiosity, has become an object of study because of the associated properties. One of the most studied properties and that which involves many groups all over the world is the luminescence displayed by many gold-containing complexes. In fact, after the discovery of the luminescence of the three-coordinate complex [AuCl(PPh 3 ) 2 ] by Dori and coworkers in 1970 [1], the number of groups that have studied this topic has increased rapidly in recent years, together with the number of synthesized luminescent gold molecules. At the same time, the large number of studies performed in this area has provided knowledge of the conditions that gold complexes require to display luminescence. For instance, luminescence can originate from ligands, assigned to certain geometries around the gold atom or from the presence of metal-metal interactions in the complexes. More specifically, it can be produced by transitions between orbitals of the metal center exclusively, in orbitals of the ligands, usually among p orbitals, or in transitions involving both metal and ligands, where these can act as donors or acceptors of electronic density (charge transfer transitions). In gold (I), with a d 10 closed shell configuration, the ground state is 1 S 0 , while the excited states are 3 D 2 , 3 D 1 , 3 D 0 and 1 D 0 (see Figure 6.1) [2].Of all these, the only permitted electronic transition is 1 D 0 1 S 0 , while the rest are forbidden according to the spin rule, leading to phosphorescent emissions. However, these are precisely the ones responsible for the emissions found in many luminescent gold complexes, appearing in a range between 500 and 700 nm (665 nm in the gaseous ion). j347Another very important factor that should be considered is the expected large spin-orbit effect promoted by a heavy atom such as gold. This effect produces a relaxation of the spin rule and makes orbital forbiddenness instead of the spin rule the key factor for determining whether a gold complex will show luminescence. For instance, phosphorescence is generally not observed for linear molecules (where the ligands are not involved in the transitions), since the mixing of s, p z and d z 2 of gold form a HOMO of S þ symmetry, while the LUMO orbital is formed mainly from p x and p y leading to a P symmetry, consequently, there is no orbital forbiddenness in the transition and phosphorescence is not observed [3]. Another possible coordination environment at gold is the tetrahedral one. In that case, the HOMO and the LUMO are 1 T 2 in symmetry and the transition is allowed according to Laportes rule; therefore, phosphorescence is not observed in thes...

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Section: Network From Mononuclear Unitsmentioning

confidence: 99%

Luminescence of Supramolecular Gold‐Containing Materials

López‐de‐Luzuriaga

2008

Modern Supramolecular Gold Chemistry

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“…, o-xylyl (gold-gold contacts connect side by side chains for R ¼ n Bu) and nets for R ¼ i Pr, Me [71,72]. Luminescent emissions have been described for many of these derivatives.…”

Section: Formation Of Infinite Chains and Supramolecular Arraysmentioning

confidence: 99%

Gold–Gold Interactions

Crespo

2008

Modern Supramolecular Gold Chemistry

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This chapter focuses mainly on closed shell gold(I) atoms which are found to feel attraction among themselves. This attraction is able to modify expected geometries or support one-, two-or three-dimensional arrays and also leads to interesting properties. Closed shell metal cations are expected to repel each other. Nevertheless, an important number of examples containing [d 8 -d 10 -s 2 ] interactions are known. Particularly strong evidence has been accumulated on the attraction between two or more d 10 shells. In the case of gold(I) such attraction between two or more monovalent gold(I) ions in compounds has been observed structurally for a long time. In these situations the gold centers approach each other to a distance of between 2.7 and 3.3 Å. This range includes the distance between gold atoms in gold metal and approaches, or even overlaps with the range of distances found in the few real Au-Au single bonds. Schmidbaur coined the name aurophilic attraction in 1990 and defined it as the unprecedented affinity between gold atoms even with closed-shell electronic configurations and equivalent electrical charges [1]. Since that moment, aurophilicity has become one of the hot topics in gold chemistry, at first with the aim of understanding such interaction, more recently because of the observation that it may play an important role in interesting properties, thus understanding and modulating aurophilic interactions could help to govern these properties, which include the optical behavior. Although different origins are possible for the luminescent emissions of coordination complexes, such as intraligand transitions (ILT), ligand to metal or metal to ligand charge transfer transitions (LMCT, MLCT) and metal centered (MCT) transitions, in many luminescent gold complexes the emissions have been related to the presence of aurophilic interactions.Information about aurophilicity and chemical situations in which it is observed may be found in different works that may be classified as those which analyse closed shell interactions in general [2], those focused on aurophilicity [1,3], and others which analyze the role of these interactions in coordination [4] and organometallic gold Modern Supramolecular Gold Chemistry: Gold-Metal Interactions and Applications. Edited by Antonio Laguna

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“…38 The IR absorptions (ν CtN ) for the isocyano-β-diketonate complexes Al(acphNC) 3 (14), Fe(acphNC) 3 (15), Cu(acphNC) 2 (16), and Zn(acphNC) 2 (17) appear at 2121, 2126, 2147, and 2124 cm -1 , respectively. The values for 14, 15, and 17 are very close to those for free aryl isocyanide ligands [39][40][41][42] and for the free ligand HacphNC (2122 cm -1 ; see below). The higher frequency for the Cu complex (16) may again indicate coordination of the isocyanide groups to adjacent Cu atoms, but it could be obtained only in impure form.…”

Section: Resultsmentioning

confidence: 51%

Inorganic-Organic Molecules and Solids with Nanometer-Sized Pores

Maverick¹

2011

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Effects of anions on the solid state structures of linear gold(I) complexes of the type (o-xylyl isocyanide)gold(I) (monoanion)

Cited by 41 publications

References 30 publications

Luminescence of Supramolecular Gold‐Containing Materials

Luminescence of Supramolecular Gold‐Containing Materials

Gold–Gold Interactions

Inorganic-Organic Molecules and Solids with Nanometer-Sized Pores

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