Thiocyanato complexes structure

New problems on structure of cisplatin from number of known isomers, resonance structures of acetylacetonate and glycinate, structures of glycinato complexes, complexes of the ambidentate thiocyanato complexes, structure of a trien complex, and names of the Figure 3.18 complexes... 

An interesting study with BATO compounds concerns the linkage isomerization of coordinated [NCS] in [Tc(NCS)(cdoh)2(cdo)(BMe)] (440). Both a red, N-bond isothiocyanato complex [Tc(NCS)(cdoh)2(cdo)(BMe)] and the brown, S-bond thiocyanato complex [Tc(SCN)(dmg)3(BR)] (441) were isolated from the direct synthesis from [Tc04] . The N-bound (440) was found to be thermodynamically more stable than the S-bound isomer (441) and the conversion was monitored elegantly by spectroscopic methods. The X-ray crystal structure of (440) was determined. The NCS and SCN -substituted analogues exhibited r c N stretch at 2,114-2,124 cm and at 2,055-2,079 cm , respectively. " (Scheme 59). 

Figure 18 The structure of [W2CWOEt)J191 37.4.5 Thiocyanato Complexes...

Most of the bis adducts NiX2L2 (L = substituted imidazoles and pyrazoles) have pseudo-tetrahedral coordination, but some of the chloride and thiocyanato complexes can be six-coordinate in a polymeric structure. 

Mixed halide-thiocyanate compounds Hg(SCN)X (X = Cl, Br, I) are formed from equimolar amounts of the pure components. They contain six-coordinated mercury(H) achieved by bridging X and SCN groups.234 The formation constants of the mixed thiocyanato complexes have been detected spectroscopically.233 Raman spectra of mixed halothiocyanatomercurate(U) complexes have been reported by Cooney and Hall.236 The structure of ammonium... 

The reductive decomposition of thiocyanato complexes should be applicable to the electrodeposition of other metal sulfides. We have tried this with Pd2, Co2+, Ni2+, Zn2+ and In3+.I8 While thin films of PdS, CoS and NiS could be successfully electrodeposited, other metal sulfides such as ZnS and In2S3 could not be obtained. This is an interesting series of results when we think of the softness (hardness) of these metals as acid. TC coordinates with its sof basic S atom to soft acidic Cd2+ and Pd2+, while hard acidic In3+ only permits coordination with hard basic N atom to form an isothiocyanato-complex. Other metals are at the borderline accepting coordination of both S and N. Because reduction of TC is catalyzed by a central metal,75,76) such ligand reduction may result in the formation of metal sulfides only for thiocyanato-complexes. The difference in bahavior among Co2+, Ni2+ and Zn2+ could be reasoned as the consequence of efficient catalysis of the electron transfer reaction by the transition metals. Such trends fit nicely with the previous findings by electrochemical analyses. 7) It is therefore understood that the chemical structure of the active species is decisive to the film formation. Thus, designing such molecular precursors which are chemically stable but can be electrochemically decomposed to metal sulfides should broaden the possibilities of electrochemical thin film synthesis. 

Fig. 6. Structure of the bis(thiocyanato) complex ppyAu(SCN)2 142, showing the presence of N-bonded (trans to C) and S-bonded (trans to N) thiocyanate ligands.

Reports in the early literature of a black and a yellow isomer of Fepy4(NCS)a have been disproved by the X-ray analysis of both forms. The black compound is crystallographically equivalent to the yellow form which is a trans-JV-thiocyanato complex with Fe —N, N—C, and C—S distances of 2.088, 1.140, and 1.604 A, respectively (696). A transpentagonal bipyramidal structure is found in [FeL(NCS)2]C104, where... 

Titanocene dichorides with substituted Gp ligands react with ammonium thiocyanate to afford S- or N-bonded thiocyanato complexes depending on the reaction conditions and the nature of the ring substituted (Scheme 624). The crystal structure of (G5H4But)2Ti(NCS)2 has been determined.1043... 

The compound is a dark red-purple dichroic cystalline material. In time, the crystals develop a thin coating of sulfur. The rhodium(III) complex, which appears to be structurally similar to the platinum(IV) compound, shows much greater reactivity in that sulfur is readily lost on dissolving in water, dimethyl-formamide, or pyridine. From water, a product may be precipitated which appears to contain the [RhSi0] anion. Reaction with cyanide ultimately produces the thiocyanato complex. 

It is Clear that only a combination of these five criteria would provide reliable structural diagnosis. Table III-40 lists the vibrational frequencies of typical isothiocyanato and thiocyanato complexes. The s CMN) and /(MS) vibrations of some of these and other complexes were assigned by using metal isotopes and N-substituted ligands. The [Cd(SCN)3l ion is S-bonded in DMSO but N-bonded in water. ... 

Thallium, tetrakis(acetylacetone)-stereochemistry, 94 Thallium, triaquatrinitrato-structure, 97 Thermochromism, 470 Thiocyanato complexes linkage isomerism, 184 Thiocyanic acid metal extraction from, 540 Thioethers complexes chirality, 199 formation... 

The anionic thiocyanato complexes prepared from In(NCS)3 and different organic cations may be either [In(NCS)5] or [In(NCS)6] , apparently depending on the properties of the cation. A subsequent X-ray structural investigation of (Ph+As)3[In(NCS)6] confirmed the N-bonding mode of the ligand, and the presence of an octahedral InNe kernel. ... 

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