Nandu Bala Sharma

Homometallic glycolates containing hydroxyl functionality for anchoring another metal: synthesis and characterization of heterometallic alkoxide–glycolates of Ti and Zr incorporating Al and Nb

Abstract Reaction of Ti(OPri)4 with 2-methyl-2,4-pentanediol [HOGOH, where G = CMe2CH2CH(Me)] in 1 : 3 M ratio under reflux afforded the monomeric [Ti(OGO)(OGOH)2] (1), which on further reactions with [Al(OPri)3] or [Nb(OPri)5] in 1 : 1 and 1 : 2 M ratios afforded heterometallic derivatives, [Ti(OGO)3{M(OPri)n−2}] and [Ti(OGO)3{M(OPri)n−1}2] [where M = Al (n = 3), Nb (n = 5)], respectively. Similar reactions of Zr(OPri)4∙PriOH with a number of glycols [HOGOH, where G = CH(Me)CH(Me), CMe2CMe2, CMe2CH2CH(Me)] yielded dimeric [Zr2(OGO)2(OGOH)4]. [Zr2(OGO)6{M(OPri)n−2}2] and [Zr2(OGO)4(OGOH)2M(OPri)n−2] [M = Al (n = 3), Ti (n = 4), Nb (n = 5)] were prepared by 1 : 2 and 1 : 1 reactions, respectively, of [Zr2(OGO)2(OGOH)4] with Al(OPri)3, Ti(OPri)4, or Nb(OPri)5. Surprisingly, a 1 : 2 reaction of [VO(OPri)3] with 2,2-diethyl-1,3-propanediol in benzene followed a different reaction and produced a neutral tetranuclear derivative [V4(O)4(μ-OCH2CEt2CH2O)2(OCH2CEt2CH2O)4] (18). All of these derivatives were characterized by elemental analysis, molecular weight measurements, FT-IR, and 1H NMR (and wherever possible, by 27Al or 51V NMR) spectroscopic studies. The derivatives [Zr2(OCMe2CH2CH(Me)O)2(OCMe2CH2CH(Me)OH)4] (9 and 18) were additionally characterized by single-crystal X-ray structure analysis.

Synthesis and Spectroscopic Characterization of New Homo- and Heterobimetallic Diorganotin(IV) Derivatives

The interaction in a 1:1 molar ratio of Bu2Sn(OPr i)2 with Schiff bases HOC6H4CH═NC6H3Me2-2,6 (HL1) and HOC10H6CH═NC6H3Me2-2,6(HL2) yields homometallic derivatives Bu2Sn(η2-L1)(OPr i) 1 and Bu2Sn(η2-L2) (OPr i) 2, where deprotonated ligands L[1] and L[2] are bonded in a bidentate (η2) fashion through O and N atoms. Complexes 1 and 2 react in an equimolar ratio with Al(OCHMeCH2CMe2O)(OCHMeCH2CMe2OH) A or Al{(OCH2CH2)2(C6H5)N(OCH2 −CH2(C6H5)NCH2CH2OH)} B to afford heterobimetallic derivatives 3–6 incorporating five-coordinate tin and four-coordinate aluminium in 3 and 5 and five-coordinate both tin and aluminium in 4 and 6. Furthermore, the reaction of 2 with Ph3SiOH affords a heteronuclear derivative 7 having tin and silicon, respectively, in a five- and four-coordinate environment. All of these derivatives have been characterized by elemental analysis, spectroscopic (IR, NMR; 1H, 27Al, 29Si, and 119Sn) studies, and molecular weight determinations. The creation of new synthetic routes for heterometallic alkoxide coordination systems is an important goal, and investigations focused on this objective will ultimately increase our understanding of many aspects associated with the formation and stability of heterometallic coordination systems in general.

The First Butyltin(IV) Homo- and Heterobimetallic Diethanolaminates

Equimolar reactions of BuSn(OPri)3 with diethanolamines, RN(CH2CH2 OH) 2 (abbreviated as RdeaH2, where R = H or Me), afford dimeric isopropoxo-bridged six-coordinate butyltin(IV) complexes [{Bu(η3-Rdea)Sn(μ-OPri)}2] (R = H ( 1 ), Me ( 2 )). Interactions between BuSn(OPri)3 and diethanolamines (RdeaH2) in a 1:2 molar ratio yield monomeric derivatives of the type [BuSn(Rdea)(RdeaH)] (R = H ( 3 ), R = Me ( 4 )). These homometallic complexes on 1:1 reactions with an appropriate metal alkoxide form monomeric heterobimetallic complexes of the type [BuSn (Rdea)2 {M(OR′)n}] (R = H, M = Al, R′ = Pri, n = 2 ( 5 ); R = H, M = Ti, R = Pri, n = 3 ( 6 ); R = H, M = Zr, R′ = Pri, n = 3 ( 7 ); R = Me, M = Al, R′ = Pri, n = 2 ( 8 ); R = Me, M = Ti, R′ = Pri, n = 3 ( 9 ); R = Me, M = Ge, R′ = Et, n = 3 ( 10 )). The driving force behind this work was (i) to explore the utility of homometal complexes ( 1 ) –( 4 ) in assembling a metal alkoxide fragment via a condensation reaction and (ii) to gain insights into the structures of new compounds by NMR spectral data. All of these derivatives have been characterized by elemental analysis, spectroscopic (IR, NMR; 1H, 27Al, and 119Sn) studies, and molecular weight measurements. 119Sn NMR spectral studies indicate that both the homometallic ( 3 ) and ( 4 ) and heterobimetallic ( 5 ) – ( 9 ) complexes exist in a solution in an equilibrium of six- and five-coordinated tin(IV) species.

The synthesis and spectroscopic characterization of heterobimetallic Bu2Sn(IV) complexes derived from some chelating ligands

The interaction of Bu2Sn(OPri)2 with a trifunctional tetradentate Schiff base (LH3) (where H3L = HOC6H4CH═NCH3C(CH2OH)2) yields the precursor complex Bu2Sn(LH) 1, which, on equimolar reactions with different metal alkoxides [Al(OPri)3, Bu3Sn(OPri), Ge(OEt)4]; Al(Medea)(OPri) (where Medea = CH3N- (CH2CH2O)2); and Me3SiCl in the presence of Et3N], affords, respectively, the complexes Bu2Sn(L)Al(OPri)2 2, Bu2Sn(L)Al(Medea) 3, Bu2Sn(L)Bu3Sn 4, Bu2Sn(L)Ge(OEt)3 5, and Bu2Sn(L)SiMe3 6. The reactions of 2 with 2,5-dimethyl-2,5-hexanediol in a 1:1 ratio and with acetylacetone (acacH) in a 1:2 molar ratio afforded derivatives Bu2Sn(L)Al(OC(CH3)2CH2CH2C(CH3)2 O) 7 and Bu2Sn(L)Al(acac)2 8, respectively. All of the derivatives 1– 8 have been characterized by elemental analyses, molecular weight measurements, and spectroscopic [IR and NMR (1H, 119Sn, 29Si, and 27Al)] studies. Deceased.