Molecular and Crystal Structures of Cp*M(S₂N₂) (M = Co, Rh, Ir) and Related Compounds

Abstract

Cp*Rh(S2N2) was prepared as a microcrystalline solid by using [S4N3]Cl in liquid ammonia or [nBu2Sn(S2N2)]2. It was characterised by NMR, IR and Raman spectroscopy andmass spectrometry. Low‐temperature crystal structures of Cp*Co(S2N2) and Cp*Ir(S2N2) were determined. The experimental characterisation of the Cp*M(S2N2) complexes was complemented by calculated geometries and bond orders at the DFT/B1B95 level of theory. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

Five-Membered Arsenic−Sulfur−Nitrogen Heterocycles, RAs(S2N2) (R = Me, Et,iPr,tBu, Ph, Mes)

“…Their mean value together with that of the N(1)−S(1)−N(2) angle (116.7° and 115.1(3)°, respectively) is close to the optimum 120° expected for a trigonal planar coordination, which supports the formal Lewis formula of 5 . The S(2)−As(1)−N(1) right angle corresponds well with the trend of inverse proportionality between van der Waals’ radius of an atom and a bond angle value at this atom in five-membered sulfur−nitrogen rings. ,,,, …”

“…The ligand exchange between [ n Bu 2 Sn(S 2 N 2 )] 2 and alkyl- or aryldihalogenoarsines offers a simple synthetic route to dithiadiazarsoles 1 − 6 . [ n Bu 2 Sn(S 2 N 2 )] 2 is a versatile reagent, , which, unlike Me 3 SiNSNSiMe 3 , is a stoichiometric source of the [S 2 N 2 ] 2− ligand (eq ). A facile cleavage of an Sn−N bond is well documented, , and the reaction between Me 3 SnNSNSnMe 3 and MeSiCl 3 , which results in Si−N bond formation, indicates an easier cleavage of an Sn−N bond. An additional driving force is the propensity of tin to form bonds with halogens.…”

“…Eight-membered AsSN rings are known to act as ligands coordinated to a metal center via the lone pair of electrons on arsenic. − The reactions of 5 with Pt(COD)Cl 2 , Mo(CO) 4 (pip) 2 , and Cp 2 Ti(CO) 2 resulted in formation of tarry materials or powders, which could not be worked up toward crystallization. 5 reacted with Cp*Co(CO) 2 to yield a small amount of Cp*Co(S 2 N 2 ) (proved by 1 H and 13 C NMR and MS; see Supporting Information for details) . Oxidation and reduction of 5 was investigated by means of cyclic voltammetry, which showed irreversible oxidation ( E pa = 1.08 V) and reduction ( E pc = −1.71 V) at both slower and faster scan rates (Supporting Information, Figure S3 and Table S9).…”

Hydrogen-Bonding Motifs in MS2N2H Metallacycles: A Crystallographic and Computational Study of [CpCoS2N2H][BF4]

“…37,41 By contrast, a Cp*IrCl 2 adduct of 6 was found to coordinate at N1. 38 Van Droogenbroeck et al predicted on the basis of DFT calculations that if 1 were protonated under thermodynamic control, the site of protonation should be N2, that is, the cation 7 which is predicted to be more stable than the alternative 8 by about 44 kJ•mol −1 . 40 This theoretical predication has never been substantiated.…”

“…Later, the synthesis of the Cp* analogue 2 was reported, followed by the iridium Cp* complex 6 in 2002 . The missing members of the series, the two rhodium complexes 3 and 4 as well as 5 and the first determination of a crystal structure for 2 were added in 2009 . Only 1 and 2 have been studied in detail, including an electrochemical study by cyclic and ac voltammetry, the chemical reduction of 1 with cobaltocene, , a UV-PES study of their oxidation potentials, and several computational investigations. ,− A consensus has developed from these investigations that the CoN 2 S 2 cobaltacycle in this complex shows extensive delocalization and satisfies criteria of metalloaromaticity .…”