Substituent Effect on Organotin Tp* Compounds as the Tp* Reagent for the Preparation of Mono Tp* Complexes of Group 4—6 Metals (Tp* = Tris(3,5-dimethylpyrazol-1-yl)hydroborate)

Abstract

Organotin compounds [Tp*SnCl3-nBun] (2: n = 1; 3: n = 2) having a Tp* ligand (Tp* = tris(3,5-dimethylpyrazol-1-yl)hydroborate) are useful reagents for introducing a Tp* ligand on Group 4 and 5 metals and chromium. The test reactions of these organotin compounds along with [Tp*SnCl3] (1) with ZrCl4, affording a known complex [Tp*ZrCl3] (4), were examined. The reaction rates were in the order 3 > 2 1. This tendency was understood by the average Sn-N(Tp* ligand) bond distance being longer in the order 3 > 2 > 1 as revealed by the crystallographic studies and the orbital interactions between the Tp* ligand and the SnCl3-nBun fragments estimated by the ab initio calculations for 1—3. On the basis of the above findings, we applied the compound 3 to prepare Tp* complexes of Group 4—6 metals. Reactions of TiCl4 with an equimolar amount of 3 afforded [Tp*TiCl3] (7) in good yields after a simple rinse to remove the resulting tin compound, SnBu2Cl2. [Tp*HfCl3] (8) was prepared in moderate yield by reaction of [HfCl4(THF)2] with 3 under severe conditions. Similarly, the reactions of 3 with a stoichiometric amount of [NbCl4(THF)2] or [NbCl5(OEt)2] and TaCl5 in toluene gave [Tp*NbCl3] (9) and [Tp*TaCl3][TaCl6] (10), respectively. We also applied our synthetic method to prepare Tp* complexes of vanadium, [Tp*VCl2(THF)] (11), [Tp*VCl2(DNAP)] (12) (DMAP = 4-dimethylaminopyridine), and [Tp*VCl2(=NC6H3Me2-2,6)] (13) and those of chromium, [Tp*CrCl2(L)] (14: L = THF; 15: L = H2O; 16: L = DMAP). Some of these Tp* complexes, 4, 8, 12, 13, 15, and 16 were crystallographically characterized to have discrete octahedral geometry containing the facial coordination of the Tp* ligand.

Tin(IV) and organotin(IV) derivatives of bis(pyrazolyl)acetate: Synthesis, spectroscopic characterization and behaviour in solution.

“…Numerous fac-SnI 3 systems have been defined, a number oligonuclear with bridging associations which essentially constitute a tripod ligand; a number of tris(pyrazolyl)-N 3 complexes of the form {N 3 }SnX 3 have been defined for X = Cl [21,[33][34][35][36], only one example for X = Br [22], and seemingly no other iodides. Of relevance also is the complex of a highly hindered N,N 0 -disubstituted bis-imino-acetylacetonate N 2 SnI 3 , which, with a planar N,N 0 -donor six-membered chelate, is five-coordinate [37].…”

Syntheses, structures, and magnetic characterization of dicyanometalate(ii) building blocks: [NEt4][(Tp*)MII(CN)2] [MII= Cr, Co, Ni; Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate]

“…2 Herein we describe the syntheses, structures, and magnetic characterization of three structurally similar divalent five coordinate dicyanometalates. Treatment of [(Tp*)Cr III Cl 2 (THF)] 4 (Tp* = hydridotris(3,5-dimethylpyrazol-1-yl)borate) with Na/Hg amalgam in tetrahydrofuran, followed by tetraethylammonium cyanide ([NEt 4 ]CN) 5 For compounds 1-3 the anions are essentially isostructural and crystallize in the monoclinic P2 1 /c space group. { The metal centers adopt distorted square pyramidal, C s -symmetric [cis-M II (CN) 2 -(Tp*)] 2 coordination geometries, where the two cis-pyrazoles (Tp* ligand) and two cyanide ligands comprise the basal {C 2 N 2 } plane (Fig.…”

“…The M-C16-N7 bond angles range from 176.9(3) to 178.0(3)u, while the C16-M-C17 bond angles become more acute progressing from 89.6(2)u for 1, 88.7(2)u for 2, to 86. 4(2)u for 3. Consistent with ionic radii trends, the N1-M-N3 angles concomitantly increase from 84.4(2), to 87.1(2), and 88.3(2)u, for 1-3, respectively.…”

Synthesis and Crystal Structure of Diorganotin(IV) Derivatives Containing the bis(3,5-dimethylpyrazol-1-yl) Acetate Ligand

“…Some organotin(IV) complexes containing poly(pyrazol-1-yl)borate ligands have also shown interesting structural characteristics and reactivities. [5][6][7] As the isoelectronic and isosteric ligands of poly(pyrazol-1yl)borates, poly(pyrazol-1-yl)alkanes (e.g. 2) have also been found to act as good donors to organotin(IV) acceptors.…”