Heteronuclear arrays

The building block [Au(CN)2] has been revealed as a versatile unit in the formation of heteronuclear arrays which, in some cases, display unusual and interesting luminescent properties, such as vapochromic behavior. In many of these complexes the cyanide group uses the carbon and nitrogen ends as Lewis bases able to coordinate two different metal cations (i.e., Au-CN-M) [82-86]. These ideas may be illustrated by the reaction of K[Au(CN)2] with MX2 salts (M = Cu, Ni, Co, Mn ... 

Ward, M.D. (2007) Transition-metal sensitized near-infrared luminescence from lanthanides in d-f heteronuclear arrays. Coordination Chemistry Reviews, 251, 1663-1677. 

The dimensional patterns or/and properties change upon formation of these heteronuclear derivatives. For example, the structure of the copper derivative consists of a 3D array with chains of Cu(II)-pyrazine units connected by [Au(CN)2] bridges a second identical network connected through aurophilic interactions interpenetrates. 

Chen, F.-F., Bian, Z.-Q., Lou, B., et al. (2008) Sensitised near-infrared emission from lanthanides using an iridium complex as a ligand in heteronuclear Ir2Ln arrays. Dalton Transactions, 5577. 

Polynuclear inorganic complexes exist in a bewildering array of structural types, such as ionic solids, molecular polymers, extended assemblies of oxoanions, chains and rings, bridged metal complexes, and homonuclear and heteronuclear clusters. This section primarily treats the nomenclature of bridged metal complexes and homonuclear and heteronuclear clusters. Coordination polymers are treated extensively elsewhere.6... 

A large array of heteronuclear H-X dipolar recoupling pulse sequences, developed mainly for X= C and N," combine information on H-chemical shift and H-X dipole-dipole coupling. 

In liquid solutions, nuclear spins are correlated through J-couplings, whereas in solids dipolar interactions come into play as well. The first report on the application of covariance to soHd-state NMR was published by Hu et al. in which an indirect covariance homonuclear correlation (HOMCOR) spectrum was obtained from a 2D-FT heteronuclear correlation (HETCOR) spectrum. The indirect covariance scheme, which will be discussed in Section 5.1, contrasts with the original direct covariance spectroscopy, where the covariance processing is performed over an array of one-dimensional spectra. 

They are most often combined with traditional two-dimensional experiments such as NOESY and TOC-SY to yield a three-dimensional experiment. For example, in the case of an HSQC-NOESY spectrum of a protein, two of the axes represent the heteronuclei such as and the protons which are directly attached to the nitrogen nuclei, while the third axis contains chemical shifts of protons which share an NOE effect with the amide proton. This offers a significant increase in resolution compared to a traditional two-dimensional NOESY. A large array of these types of three-dimensional, heteronuclear-edit-ed experiments have been designed to extract structural information in various situations. 

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