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Heterobimetallic alkoxides of Cu(II) of the types [Cu{η4-Ti2(OEt)9}Cl] (1) and [Cu{η3-Ti2(OR)9}2] [R = Pri(2), R = Et(3)] have been prepared for the first time by the reactions of CuCl2 · xROH with KTi2(OR)9 in 1:1 and 1:2 molar ratios, respectively, in benzene medium. The chloro(nonaalkoxo dititanato)copper(II) complexes undergo chloride replacement reactions by a variety of monodentate alkoxo (−OPri, −OEt) and chelating [Al(OPri)4−, Al(OEt)4−, Nb(OPri)6−, Zr2(OPri)9−, Sn2(OPri)9−, and Sn2(OEt)9−] ligands to form interesting hetero(bi-and tri-)metallic complexes. Alcoholysis (with methyl alcohol and tert-butyl alcohol) and hydrolytic [with Ba(OH)2 · 8H2O powder] reactions of a few typical compounds have also been investigated. All of these have been characterized by elemental analyses, molecular weight determinations, spectral (i.r. and visible) and magnetic studies. On attempted volatilization under reduced pressure these complexes liberated titanium alkoxides as a volatile component leaving nonvolatile residues.

Interesting varieties of heterobimetallic mixed-ligand complexes [Zr{M(OPri) n }2 (L)] (where M = Al, n = 4, L = OC6H4CH = NCH2CH2O (1); M = Nb, n = 6, L = OC6H4CH = NCH2CH2O (2); M = Al, n = 4, L = OC10H6CH = NCH2CH2O (3); M = Nb, n = 6, L = OC10H6CH = NCH2CH2O (4)), [Zr{Al(OPri)4}2Cl(OAr)] (where Ar = C6H3Me2-2,5 (5); Ar = C6H2Me-4-Bu2-2,6 (6), [Zr{Al(OPri)4}2(OAr)2] (where Ar = C6H3Me2-2,5 (7); Ar = C6H2Me-4-Bu2-2,6 (8), [Zr{Al(OPri)4}3(OAr)] (where Ar = C6H3Me2-2,5 (9); Ar = C6H3Me2-2,6 (10), [ZrAl(OPri)7-n (ON=CMe2) n ] (where n = 4 (11); n = 7 (12), [ZrAl2(OPri)10-n (ON=CMe2) n ] (where n = 4 (13); n = 6 (14); n = 10 (15) and [Zr{Al(OPri)4}2{ON=CMe(R)} n Cl2–n] [where n = 1, R = Me (16); n = 2, R = Me (17); n = 1, R = Et (18); n = 2, R = Et (19)] have been prepared either by the salt elimination method or by alkoxide-ligand exchange. All of these heterobimetallic complexes have been characterized by elemental analyses, molecular weight measurements, and spectroscopic (I.r., 1H-, and 27Al- n.m.r.) studies.

Reactions of Cp2ZrCl2 with homometallic complexes of aluminium containing one residual hydroxy group Al(OGO)(OGOH) and Al(L)(OGOH) [where G=G1=CMe2CMe2(1a); G=G2=CMe2CH2CHMe (1b); G= G3=CMe2CH2CH2CMe2(1c) and L=L1=OC6H4CH=NCH2CH2O, G=G1(2a); L=L1, G=G2(2b); L=L1, G=G3(2c); L=L2=OC10H6CH=NCH2CH2O, G=G1(2d); L=L2, G=G2(2e); L=L2, G=G3(2f)] in THF using Et3N as HCl acceptor affords novel heterobimetallic compounds of the types Al(OGO)2Zr(Cl)Cp2 and Al(L)(OGO)Zr(Cl)Cp2, respectively. All of these derivatives have been characterised by elemental analyses, molecular weight measurements, and spectroscopic [IR, NMR (1H and 27Al)] studies.

An entirely new class of heterobimetallic homoleptic glycolate complexes of the type Nb(OGO)3{Ta(OGO)2} [where G=CMe2CH2CH2CMe2 (G1) (3); CMe2CH2 CHMe(G2) (4); CHMeCHMe (G3) (5); CH2CMe2CH2 (G4) (6); CMe2CMe2(G5) (7); CH2CHMeCH2 (G6) (8); CH2CEt2CH2 (G7) (9); CH2CMe(Prn)CH2 (G8) (10)] have been prepared by the reactions of Nb(OGO)2(OGOH) [G=G1(1a); G2(1b); G3(1c); G4(1d); G5(1e); G6(1f); G7(1g); G8(1h)] with Ta(OGO)2 (OPri) (G=G1(2a); G2(2b); G3(2c); G4(2d); G5(2e) G6(2f); G7(2g); G8(2h). In addition to the novel derivatives (2)–(10), our earlier investigations on heterobimetallic glycolate-alkoxide derivatives have been extended to derivatives of the type Nb(OGO)\(_{3} \{\hbox{M}(\hbox{OPr}^i)_{n-1}\}\) [where M=A1 n=3, G=G3(11);G4(12); G6(13) G7(14); Gs(15); G9=CH2CH2CH2(16) and M=Ti (n=4, G=G4) (17), Zr(n=4,G=G4) (18)], which are conveniently prepared by the reactions of metalloligands Nb(OGO)2(OGOH) [G=G3(1c); G4(1d); G6(1f); G7(1g); G8(1h); G9(1i)] with different metal alkoxides. All of these new complexes have been characterized by elemental analyses, molecular weight determinations, and spectroscopic (I.r. and 1H, 27Al-n.m.r.) studies. Structural features of the new derivatives have been elucidated on the basis of molecular weight and spectroscopic data.

Soluble heterobimetallic-N-(hydroxyethyl) salicylaldiminate-alkoxide derivatives of the types [VO(L)2{M(OPr i ) n −1}] [M=Al (2) (n = 3); Ti (3), Zr (4) (n = 4); Nb (5), Ta (6) (n = 5)], [where L represents the dianionic N-(hydroxyethyl) salicylaldiminate group bonded to vanadium in a tridentate fashion involving both the oxygen atoms and azomethine nitrogen], have been prepared by the reactions of insoluble [VO(L)(LH)] (1) with different metal alkoxides in a 1:1 molar ratio in benzene. A monomeric heterobinuclear complex of the type [VO(η3-L)(μ-OPr i )2Al(η3-L)] (7) has been prepared by the equimolar reaction of [VO(η3-L)(μ-OPr i )]2 with [Al(η3-L) (μ-OPr i )]2 in benzene. All these complexes have been characterised by elemental analyses, molecular weight measurements, and by spectroscopic (l.r., 1H-, 27Al- and 51V-n.m.r.) studies. The monomeric nature of (1) and (2) has been supported by their FAB-mass spectral studies.

Homo- and heteroleptic aryloxides of the type MX4−x(OAr)x [M = TiIV, ZrIV; X = OPri, Cl; x = 1,2,3,4; OAr = OC6H4Pri-4(OAr1), OC6H3Me-2-Pri-5(OAr2), OC6H3Me-5-Pri-2(OAr3), OC6H2Me3-2,4,6(OAr4), OC6H3But2-2,4(OAr5), OC6H3But2-2,6(OAr6)] have been prepared either by alkoxo–aryloxo or chloro-aryloxo exchange reactions in benzene or tetrahydrofuran. All these new derivatives have been characterized by elemental analyses, spectroscopic (i.r., 1H-, 13C-n.m.r.) studies and molecular weight measurements. The FAB mass spectral studies of four representative derivatives Support a dimeric nature for [Ti(OC6H3Me-5-Pri-2)4], [TiCl2(OC6H3Me-5-Pri-2)2], and [Zr(OC6H3Bu t 2-2,4)4(thf)], whereas the derivative [ZrCl(OC6H3Bu t 2-2,4)3(thf)] is monomeric.

Reactions of Zr{Al(OPri)4}2Cl2 or Zr{Nb(OPri)6}2Cl2 with KNb(OPri)6/KAl(OPri)4 and diethanolamines RN(CH2CH2OH)2 [R=H(LHH2), Me(LMeH2), and Ph(LPhH2)] in the presence of two equivalents of Et3N yield interesting hetero(bi- and tri-) nuclear derivatives (1)–(8) All of these new derivatives have been characterized by elemental analyses, molecular weight measurements, and spectroscopic studies.

Homo- and heteroleptic N-arylsalicylaldiminate derivatives of TiIV and ZrIV of the type, MX4−x(OC6H4CH=NAr)x (X = OPri, x = 2,3; X = Cl, x = 1,2,3,4; Ar = C6H3Me2-2,6, C6H3Et2-2,6) have been prepared by reactions in the desired molar ratios of: (i) Ti(OPri)4/Zr(OPri)4·PriOH with N-arylsalicylaldimines in benzene, and (ii) MCl4 (M = Ti, Zr) with Me3SiOC6H4CH=NAr or HOC6H4CH=NAr in the presence of Et3N as a base or the potassium salt of N-arylsalicylaldimines in benzene. The three homoleptic derivatives of CrIII, Cr(OC6H4CH=NAr)3 (Ar = C6H2Me3-2,4,6, C6H3Et2-2,6, C6H3Pri2-2,6) have also been prepared by salt-elimination. All of these new derivatives have been characterized by elemental analyses, spectroscopic [i.r., 1H and 13C-n.m.r. (Ti and Zr complexes), and electronic (for Cr complexes)] studies, as well as molecular weight measurements.

CrCl3 · 3THF reacts with two equivalents of potassium alkoxometallates K{M(OPr i ) x } [M = Al(A), Ga(B), x = 4; M = Nb(C), x = 6] to give heterobimetallic chloride isopropoxides [Cr{M(OPr i ) x }2Cl(THF)] [M = Al(A − 1), Ga(B − 1), and Nb(C − 1)], in which the replacement of the chloride with an appropriate alkoxometallate (tetraisopropoxoaluminate, tetraisopropoxogallate, or hexaisopropoxoniobate) results in the formation of novel heterotrimetallic derivatives. The ‘single pot’ synthesis of an heterotetrametallic isopropoxide [Cr{Nb(OPr i )6}{Al(OPr i )4}{Ga(OPr i )4}] (7) has been carried out by the sequential addition of (A), (B), and (C) to a benzene suspension of CrCl3 · 3THF. Alcoholysis of [Cr{Al(OPr i )4}2{Nb(OPr i )6}] (1) and [Cr{Al(OPr i )4}2{Ga(OPr i )4}] (5) with t-BuOH has also been studied and the derivatives characterized by elemental analyses, molecular weight determinations, spectroscopic [Electronic, i.r., 27Al-n.m.r.] and magnetic susceptibility studies.

[Nb(OiPr)5] reacts with 2,5-dimethylhexane-2,5-diol (LH2), 2,3-dimethylbutane-2,3-diol (L1H2) and triethanolamine (teaH3) in different stoichiometric ratios to yield complexes of the types: [Nb(OiPr)3(L)] (1), [Nb(OiPr)(L)2] (2), [Nb(L)2(LH)] (3), [Nb(L1)2(L1H)] (4) and [Nb(tea)(teaH)] (5). Equimolar reactions of (3), (4) and (5) with Al(OiPr)3, Ti(OiPr)4 and [Ta(OiPr)5] yield novel heterobimetallic isopropoxide-glycolate (6)–(9) and -triethanolaminate (10)–(12) derivatives. Reactions in appropriate molar ratios of (1), (2) and (10) with alkoxyethanols [ROC2H4OH; R = Me, Et] and acetylacetone [acacH] give derivatives [(MeOC2H4O)3Nb(L)] (13), [(acac)Nb(L)2] (14), [Nb(tea)2{Al(OC2H4OMe)2}] (15), [Nb(tea)2{Al(OC2H4OEt)2}] (16) and [Nb(tea)2{Al(acac)2}] (17). The complexes (6), (8) and (10) on reaction with an excess of t-BuOH give the tert-butoxo analogues (18), (19) and (20), respectively. These new derivatives have been characterized by elemental analyses, spectroscopic studies and molecular weight measurements.

Four novel classes of hydrocarbon-soluble isopropoxometallates of chromium(III): [Cr{η2-Zr(OPri)5}3], [Cr- {η2-M2(OPri)9}3] [M = ZrIV, SnIV], [Cr{η2-M(OPri)xCl}3] (M = Al, x = 3; M = Nb, x = 5), and [Cr{η4-Zr2-(OPri)8Cl}Cl2]/[Cr{η3-Zr2(OPri)8Cl}{η2-Zr2(OPri)8Cl}Cl] [ηn represents the number of connectivity sites (n = 2, 3, 4) involved in binding CrIII] have been prepared for the first time and characterized by the elemental analyses, spectroscopic (i.r., electronic) and magnetic susceptibility studies as well as molecular weight measurements. The [Cr{η2-Ga(OPri)4}3] derivative has also been prepared and its magnetic and electronic properties compared with the above four novel types of CrIII complexes.

Ti(OPr i )4 or Zr(OPr i )4 · Pr i OH react with hydrocarbon-insoluble complexes M{(OCH2CH2)NH(CH2CH2OH)}2 (M = Mg, Ca, Sr, Ba) in a 2:1 molar ratio to yield hydrocarbon-soluble heterobimetallic diethanolaminate isopropoxide complexes [M{(OCH2CH2)2NH}2{M′(OPr i )3}2] (M = Mg, Ca, Sr, Ba; M′ = Ti, Zr), which have been characterized by elemental analyses, molecular weight measurements and spectroscopic [i.r., n.m.r. (1H and 13C)] studies.

Novel bimetallic alkoxides of copper(II) of the type Cu[M(OPr-i)6]2 (M = Nb or Ta) have been synthesised by the interaction of CuCl2 (1 mol) with K[M(OPr-i)6] (2 mol). These bimetallic isopropoxides undergo facile alcohol interchange with primary alcohols such as MeOH, EtOH,n-PrOH andn-BuOH. However, witht-BuOH, the reaction cannot be driven to completion even under prolonged continuous azeotropic fractionation of the liberatedi-PrOH and the final product corresponded in analysis to Cu[Ta(OPr-i)2(OBu-t)4]2.I.r., electronic and electron spin resonance spectral and magnetic susceptibility measurements indicate a distorted octahedralD4h geometry for copper(II) in these bimetallic alkoxides.