One-dimensional chains in sodium tetraphenylphosphonium bis(2-mercapto-4-methylphenolato-O,S)oxovanadate(IV)

Abstract

The title compound, Na(C 24 H 20 P)[V(C 7 H 6 OS) 2 O], contains oxovanadium(IV) in a square-pyramidal coordination geometry with a basal plane consisting of a cis-S 2 O 2 donor group. The [VO(mmp) 2 ] 2À (mmpH 2 = 2-mercapto-4-methylphenol) units are linked into in®nite chains by the sodium ions. CommentThe controlled linking of discrete molecular building blocks into supramolecular aggregates can be achieved through utilizing a number of different kinds of inter-subunit interactions. For oxovanadium(IV) compounds, solid-state and solution structures have been stabilized by speci®c interactions including (i) V OÐV O linkages (Zheng et al., 1995;Aiello et al., 1997;Sa  ez-Puche et al., 1998), (ii) hydrogen bonds (Wen et al., 1998), (iii) bridging ligands (Salta et al., 1996) and (iv) alkali or alkaline earth ions functioning in a bridging mode (Garcia-Jaca et al., 1993). We have reported (Klich et al., 1996) the vanadyl(IV) complex Na(Ph 4 P)[VO(mp) 2 ]ÁEt 2 O containing the mixed O,S-donor ligand mp 2À [mpH 2 = 2mercaptophenol, C 6 H 4 (OH)(SH)]. In this solid, a pair of [VO(mp) 2 ] 2À anions are linked together through a pair of sodium ions into a centrosymmetric dimer. Each sodium ion is bonded to two ligand O atoms from one [VO(mp) 2 ] 2À unit and to one ligand O atom plus the vanadyl O atom from the other. In the course of these studies, we also prepared the related compound Na(Ph 4 P)[VO(mmp) 2 ] (mmpH 2 = 2-mercapto-4methylphenol), (I), which crystallized in a structure with anionic [NaVO(mmp) 2 À ] I chains. We report herein upon this structure.The square-pyramidal anion, [VO(mmp) 2 ] 2À , contains an apical O atom with a V O bond length of 1.619 (2) A Ê , and an O 2 S 2 basal plane with the two ®ve-membered VÐOÐCÐCÐ S chelate rings in a cis con®guration (Fig. 1). This cis con®guration has been seen in the other four oxovanadium(IV) complexes with an O 2 S 2 donor set which have been structurally characterized (Higes-Rolando et al., 1994;Tsagkalidis et al., 1994;Preuss et al., 1990; Klich et al., 1996;Wen et al., 1998). The V(O 2 S 2 ) core thus displays pseudo-C s symmetry with the ' plane passing through the VÐO3 bond and bisecting the O1ÐO2 and S1ÐS2 vectors. The V atom is displaced 0.598 (1) A Ê from the O 2 S 2 least-squares plane, giving a slightlȳ atter pyramid than in [VO(mp) 2 ] 2À , where the corresponding displacement is 0.638 A Ê . The VÐS and VÐO basal plane bond lengths average to 2.375 and 1.963 A Ê , respectively, and are very similar to those in [VO(mp) 2 ] 2À (2.365 and 1.959 A Ê , respectively) and the other three VO(OS) 2 complexes. The two ®ve-membered chelate rings are folded about the OÐS vector, with the aromatic rings bending toward the apical O atom and making angles of 24.54 (9) and 12.60 (8) with the O1ÐVÐS1 and O2ÐVÐS2 planes, respectively. While this bending is also observed in the related complexes [VO(mp) 2 ] 2À (Klich et al., 1996) and VO(Hmpp) 2 (Wen et al., 1998), it is more pronounced in the title compound. Figure 1The structure of the [VO(mmp) 2 ] 2À dianion. Displ...

Vanadium Complexes with Mixed O,S Anionic Ligands Derived from Maltol: Synthesis, Characterization, and Biological Studies

“…The absence of a ν V  O stretch in the IR spectra of the vanadium(III) complexes confirmed the lack of oxidation [of V(III) to VO 2+ ]. For these thio-vanadyl complexes, the ν V  O stretch was observed between 962 and 974 cm -1 , which is consistent with other similar vanadyl complexes containing an O 2 S 2 coordination sphere (∼951−965 cm -1 ). , Compared to the oxygen analogues, these complexes had lower ν V  O stretching frequencies, as expected because of the replacement of oxygen with the less-electronegative and heavier sulfur atom.…”

“…The vanadium atom is slightly displaced from the basal plane [V(1) = 0.656(3) Å, V(2) = 0.664(2) Å]. The VO bond distance is the same in both isomers (cis, trans 1.61 Å), and the value for the cis isomer of VO(tma) 2 matches the VO distances that were reported for other cis -VO(O 2 S 2 ) structures {e.g., VO is 1.691(2) Å for [VO(mmp) 2 ] 2- , where mmpH 2 = 2-mercapto-4-methylphenol} . Compared to the structure of its oxygen analogue, VO(ma) 2 , the VO bond length in VO(tma) 2 is longer [1.597(7) Å) in VO(ma) 2 ], as suggested by the IR data (vide supra).…”

“…To our knowledge, this is the first example of a trans isomer of a square-pyramidal vanadyl complex with an O 2 S 2 coordination sphere. All of the other similar complexes have been found to form only the cis geometry in the solid state 4 ORTEP diagrams of cis - and trans -VO(tma) 2 (50% thermal ellipsoids). …”