Synthesis and Reactivity of Group 6 Metal Carbonyl Complexes with Bis(pyrazol‐1‐yl)methanes Modified by the Vinyltin Groups

Abstract

Diphenyl(vinyl)stannylbis(3,5-dimethylpyrazol-1-yl)methane and diphenyl(vinyl)stannylbis(3,4,5-trimethylpyrazol-1-yl)methane have been synthesized by the reaction of bis(3,5-dimethylpyrazol-1-yl)methyl or bis(3,4,5trimethylpyrazol-1-yl)methyllithium with diphenyl(vinyl)tin iodide. Treatment of these bis(pyrazol-1-yl)methanes modified by the vinyltin groups with M(CO) 5 THF (M＝Mo and W) in refluxing THF resulted in new heterobimetallic complexes R 3 SnCHPz 2 M(CO) 3 (R 3 Sn represents trivinyltin or diphenyl(vinyl)tin, and Pz represents substituted pyrazol-1-yl), in which a vinyl group bonds to the molybdenum or tungsten atom in η 2 -fashion to lead to bis(pyrazol-1-yl)methanes acting as a tridentate κ 3 -(π,N,N) ligand. Reaction of (CH 2 ＝ CH) 3 SnCH(3,5-Me 2 Pz) 2 W(CO) 3 and Ph 2 (CH 2 ＝CH)SnCH(3,5-Me 2 Pz) 2 W(CO) 3 with I 2 has been investigated. The former gave a complex CH 2 (3,5-Me 2 Pz) 2 W(CO) 4 , while the latter yielded a four-membered heterometallocyclic complex CH(3,5-Me 2 Pz) 2 W(CO) 3 I with the loss of the organotin group. Treatment of this four-membered heterometallocyclic complex with PhSNa led to the iodide anion replaced by the thiophenolate anion to give a complex CH(3,5-Me 2 Pz) 2 W(CO) 3 SPh.

The modification of ArSCH2(3,5-Me2Pz) (Ar = phenyl or 2-pyridyl, Pz = pyrazol-1-yl) by organotin group and related reactions

“…The sulfur and pyrazolyl nitrogen atoms do not coordinate to the tin atom, possibly owing to the weak Lewis acidity of the tin atom in tetraalkyltin. Reaction of 5 with Mo(CO) 6 or W(CO) 5 THF in refluxing THF yielded Ph 3 SnCH(SPh)(3,5-Me 2 Pz) M(CO) 4 (M ¼ Mo (6) and W (7), respectively), with certain amount of complex 2 in the case of tungsten. No oxidative addition product of the SneC sp3 or SneC sp2 bond to the molybdenum(0) or tungsten (0) atom was obtained.…”

“…Related reaction of 1-phenylthiomethyl-3,5-dimethylpyrazole 1-Phenylthiomethyl-3,5-dimethylpyrazole [PhSCH 2 (3,5-Me 2 Pz), Pz ¼ pyrazol-1-yl] has been synthesized for about two decades [9], but its coordination chemistry has drawn little attention. To gain more convictive knowledge on its coordination ability to transition metals and comprehensive foundations for further research, we started our investigations with the reaction of this ligand with M (CO) 6 (M ¼ Mo or W) (Scheme 1). Reaction of PhSCH 2 (3,5-Me 2 Pz) with Mo(CO) 6 produced PhSCH 2 (3,5-Me 2 Pz)Mo(CO) 4 (1), similar reaction with W(CO) 6 yielded analogous complex PhSCH 2 (3,5-Me 2 Pz)W(CO) 4 (2) and concomitant desulfurized complex (3,5-Me 2 PzH)W(CO) 5 .…”

“…To gain more convictive knowledge on its coordination ability to transition metals and comprehensive foundations for further research, we started our investigations with the reaction of this ligand with M (CO) 6 (M ¼ Mo or W) (Scheme 1). Reaction of PhSCH 2 (3,5-Me 2 Pz) with Mo(CO) 6 produced PhSCH 2 (3,5-Me 2 Pz)Mo(CO) 4 (1), similar reaction with W(CO) 6 yielded analogous complex PhSCH 2 (3,5-Me 2 Pz)W(CO) 4 (2) and concomitant desulfurized complex (3,5-Me 2 PzH)W(CO) 5 . Succedent reaction of complexes PhSCH 2 -(3,5-Me 2 Pz)M(CO) 4 with SnCl 4 gave heterobimetallic complexes PhSCH 2 (3,5-Me 2 Pz)M(CO) 3 (Cl)(SnCl 3 ) (M ¼ Mo (3) and W (4), respectively) in good yields.…”

Reactivity of Cyclopentadienes Modified by Bis(3,5‐dimethylpyrazol‐1‐yl)methyl Group to W(CO)5THF

“…The reactions of bis(3,5-dimethylpyrazol-1-yl)-methyllithium with 6-phenylfulvene 8 and 6,6-diphenylfulvene 9 yielded the mixture of 1-[2,2-bis (3,5- 10 Complexes 3 and 4 form two isomers in solution owing to the interconversion of one hydrogen atom of the cyclopentadienyl ring. Two sets of 1 H NMR and 13 C NMR signals are observed for complexes 3 and 4, respectively, which is consistent with the presence of two tautomers, similar to those in ligands 1 and 2.…”

“…Our previous investigation showed that treatment of bis(pyrazol-1-yl)-methanes functionalized by the organic groups on the bridgehead carbon atom with W(CO) 5 THF resulted in unusual reactivity. [10][11][12] As an extension of our investigations on functionalized bis(pyrazol-1-yl)methanes, herein we report the reactivity of the hybrid heteroscorpionate/cyclopentadienyl ligands with W(CO) 5 THF, which affords κ 2 -(N,N) bidentate or κ 3 -(π,N,N) tridentate derivatives, significantly different from those reported for other monosubstituted cyclopentadienes.…”