E-1-Ferrocenyl-4,4-dimethylpent-2-ene-1-one has been synthesised from the Friedel-Crafts acylation of ferrocene with E-3-tert-butylacryloylchloride and converted to 1-ferrocenyl-3-chloro-4,4-dimethylpentan-1-one using ethereal hydrogen chloride. This new chloro ketone has been converted into three new ferrocene alcohols: 1-ferrocenyl-3,4-dimethyl-4-hydroxypentan-1-one, 1-ferrocenyl-3-chloro-4,4-dimethylpentan-1-ol, and 2,2,6,6-tetramethyl-3-ferrocenyl-5-chloroheptan-3-ol. A new dinuclear ferrocene derivative, E, E-2,2,9,9-tetramethyl-5,6-diferrocenyl-deca-3,7-diene, was isolated after treatment of 1-ferrocenyl-3-chloro-4,4-dimethylpentan-1-ol with acidic alumina; its structure was confirmed by X-ray crystallography, whilst electrochemistry revealed metal metal interactions of similar magnitude to those seen for other 1,2-bis(ferrocenyl)ethane derivatives. Crystal structures have also been determined for 2,2,6,6-tetramethyl-3-ferrocenyl-5-chloroheptan-3-ol, rac-1-hydroxy[3]ferrocenophane, rac-1S,3S-1,3-diphenyl-1-hydroxy[3]ferrocenophane, and of rac-1,1'-diphenyl-1,1'-(1,1'- ruthenocenediyl)dimethanol and show an intramolecular (ClH)-H-...-O hydrogen bond, a tetramer based on (OH)-H-...-O hydrogen bonds, no hydrogen bonding, and a dimer with inter- and intramolecular (OH)-H-...-O hydrogen bonds, respectively. (C) 2003 Elsevier B.V. All rights reserved.

[(tren)Co(N3)2]Br (I) and [(tren)Co(N3)2]I (III) was prepared and its crystal structure determined at 293 and at 120 K. At room temperature (293 K), (I) crystallizes as a conglomerate in space group P212121 and remains so at 120 K, (data sets Ia and Ib, respectively). The iodide crystallizes as a racemate, space group P21/n (z=4), data set (IIIa); but, cooling to 120 K results in a phase change whereby the crystal is enantiomorphic (IIIb)+(IIIc), space group P21(z=4). There is no damage to the crystal upon undergoing the phase transition (IIIa)→(IIIb)+(IIIc). In fact, the same crystals were used to collect the data sets which were cycled as follows: 293→120→293 K. The two molecules in the asymmetric unit of (IIIb and IIIc) are homochiral demanding that the phase transition observed causes the inversion of the axial chirality of one of the five-membered rings of the iodide. This result is reproducible and was observed for all crystals cooled to 120 K. Differential scanning calorimetry confirms the existence of phase changes in the crystalline material as a result of cooling.

The new compounds [K(18-crown-6)][SCNB(C6F5)3] (1), [K(18-crown-6)][(C6F5)3B(μ-NC)B(C6F5)3] (2), [K(18-crown-6)][NCB(C6F5)3] (3), [Me3Si(μ-NC)B(C6F5)3] (4) and [Hg{(μ-CN)B(C6F5)3}2] (5) have been synthesised. Reaction between [IrCl(PPh3)2(CO)] and one equivalent of 4 gives [Ir{(μ-NC)B(C6F5)3}(PPh3)2CO] (6). Similarly, the reaction between [Fe(η-C5H5)(CO)2Cl] and 4 gives [Fe{(μ-NC)B(C6F5)3}(η-C5H5)(CO)2] (7a). The NMR-scale reaction between [Fe(η-C5H5)(CO)2CN] and B(C6F5)3 gives the isomer [Fe{(μ-CN)B(C6F5)3}(η-C5H5)(CO)2] (7b). In the compounds 3, 4, 6 and 7a the anion [NCB(C6F5)3]− is coordinated to the metal through the nitrogen. Complexes 1, 2 and 7b incorporate a (μ-CN)B unit. The compounds containing the isomeric bridging (μ-CN)B or (μ-NC)B systems have been investigated by 11B{1H} NMR spectroscopy and by DFT calculations. The 11B{1H} NMR spectra enable distinction between the isomers. The single-crystal X-ray structures of 1, 3 and 7a have been determined.

The reactions of P,O type ligands with the half-sandwich complexes [(eta-C5R5)MCl4] (R-5=H-5, Me-5, (PrH4)-Pr-i; M=Nb, Ta, W) have been investigated. Monodentate P-adducts were obtained with the beta amidophosphine Ph2PCH2C(O)NPh2, whereas in the case of the keto ligand Ph2PCH2C(O)Ph a spontaneous HCl elimination occurred to give direct access to the corresponding phosphinoenolate complexes. The crystal structures of [(eta-C5H5)NbCl3 {PPh2CH-C(-O)Ph}], [(eta-C5H5)TaCl3 {PPh2CH-C(-O)Ph}] and [(eta-C5Me5)TaCl3{PPh2CH-C(O)Ph}] have been determined. Interestingly, the acetamido derived phosphine Ph2PNHC(O)Me afforded O-adducts, which is an unusual bonding mode for a P,O ligand.

The reactions of the ligands Ph2PCH2C(O)R (R = Ph, NPh2) with the eta(6)-arene molybdenum complexes [Mo(eta(3)-C3H5)(mu-Cl)(eta(6)-C6H5R)](2) (R = H, Me) have been investigated. A series of complexes in which the keto- or amidophosphine acts as a monodentate P ligand or as a neutral or anionic P,O chelating ligand have been synthesised and characterised. The crystal structures of the compounds [Mo(eta(3)-C3H5)Cl(eta(6)-C6H5Me){Ph2PCH2C(O)Ph}], [Mo(eta(3)-C3H5){Ph2PCH2C(O)NPh2-kappa(2) P,O}(eta(6)-C6H5Me)][PF6] and [Mo{Ph2PCH...C(...O) Ph-kappa(2)P,O}(2)(eta(6)-C6H5R)] (R = H, Me) have been determined. Interesting differences in the reactivity of the ketophosphine ligand versus the amidophosphine ligand were discovered and an unprecedented hydrogen-deuterium exchange of methylene and olefinic protons has been observed for the coordinated neutral or anionic ketophosphine ligands.

A series of porphyrins 5–9 has been prepared, in which an aryl substituent is linked to the porphyrin via azo, imine, alkene and alkyne bridges. The strength of aryl–porphyrin electronic coupling in these systems was evaluated from the red shift and intensification of the Q band absorption and emission spectra, and from the incremental red shift on changing from the phenyl to a 4-nitrophenyl substituent. The azo link provides the strongest electronic communication between the porphyrin and the benzene ring. The crystal structures of azo compounds 5a and 5c show that the porphyrin and benzene rings are almost coplanar, whereas imine 7a and alkene 8a are significantly twisted in the solid state. Imine and alkyne linked porphyrin dimers 18 and 23 were also synthesized; the alkyne-linked dimer is much more conjugated than its imine-linked analogue.

The oxalic amidine compounds C6H5N=C((NHBu)-Bu-t)-C((NHBu)-Bu-t)=NC6H5 1 and C6H5N=C{N(Bu-t)(SiMe3)}-C{N(Bu-t)(SiMe3)}=NC6H5 2 are described. The compound [(C6H5N)C((NHBu)-Bu-t)-C((NHBu)-Bu-t)(NHC6H5)][Br] 3* has been isolated from the reaction between 1 and [NiBr2(DME)]. Treatment of 1 with M(NMe2)(4) (M = Zr or Ti), [Ta(NEt2)(2)Cl-3(py)] or [Zr{N(SiMe3)(2)}(3)Cl] gives the bimetallic complexes [M(NMe2)(3)(C6H5N)C((NBu)-Bu-t)-](2) (M = Zr (4) or M = Ti (5)) and the mono-amidinato complexes [Ta(NEt2)Cl-3{(C6H5N)C((NBu)-Bu-t)C((HNBu)-Bu-t)(NC6H5)}] 6* and [Zr{N(SiMe3)(2)}(2)Cl{(C6H5N)C((NBu)-Bu-t)C((HNBu)-Bu-t)(NC6H5)}] 7* respectively: * indicates the crystal structure has been determined. The activity toward ethylene polymerisation has been investigated for compounds 4, 5 and 7.

A new iminophosphine ligand, [Ph2PCH2C(Ph)=N(2,6-Me2C6H3)] (HL), and the complexes [PdX2(HL)], where X = Cl (1) and Br (2), [PdMeX(HL)], X = Cl (3) and Br (4), and [PdMe2(HL)] (5) have been prepared and characterised. Reaction of 2 with MeLi or KH leads to deprotonation of the neutral ligand to give [Pd-2(mu -Br)(2)(L-)(2)], (6), where L- is [Ph2PCH=C(Ph)N(2,6-Me2C6H3)](-). Similarly, reaction of 3 with KH and triphenylphosphine affords the neutral complex [PdMe(PPh3)(L-)] (7). Insertion of CO into the Pd-Me bond has been investigated, as well as the catalytic properties of [PdClMe(HL)] towards CO/ethylene copolymerisation. The crystal structures of HL, 1-3 and 5-7 have been determined.

Neutral and cationic titanium imido complexes (R = t-Bu or SiMe3) with a triazacyclononane ligand bearing a monopendant arm have been synthesized. The structures of [Ti(NSiMe3)(L1)Cl] and [Ti(NBut)(L2)Cl]Cl are reported where HL1 = 1-(2-hydroxy-3,5-di-tert-butylbenzyl)-4,7-diisopropyl-1,4,7-triazacyclononane and L2 = 1-(2-pyridylmethyl)-4,7-diisopropyl-1,4,7-triazacyclononane.

The syntheses of the 4-coordinate Tp'MCl complexes (where M = Fe (1), Mn (2); and Tp' = hydrotris(3-isopropyl-4-bromopyrazolyl)borate) are described. The single-crystal X-ray structures show that the metal centers have distorted tetrahedral coordination. Analogous reaction of CrCl2(MeCN)(2) with TlTp' gave Cr(kappa (3)-Tp')(kappa (2)-Tp') (3) as the initial product. The 5-coordinate structure was assigned by single-crystal X-ray crystallography, and it was found that the kappa (3) ligand had isomerized to hydro(3-isopropyl-4-bromopyrazolyl)(2)(5-isopropyl-4-bromopyrazolyl)- borate). 3 is labile in solution: in pentane it slowly converts to the 6-coordinate isomer Cr(kappa (3)-Tp')(2) (4), whose structure was determined by X-ray crystallography.:In 4 both ligands are isomerized. Both 3 and 4 display Jahn-Teller distorted structures expected for high-spin d(4) configurations. Variable temperature magnetic susceptibility measurements confirm that 1, 2, and 3 all have high-spin electronic configurations in the range 5-300 K. In benzene solution 3 decomposes; one product [Cr(kappa (3)-Tp')(2)](+)[Tp'](-) (5), was identified by X-ray crystallography. 5 contains a pseudooctahedral Cr(III) cation with both ligands in the isomerized form and an uncoordinated Tp' ligand as counterion. Mechanistic studies reveal that this reaction is light rather than heat induced. IR spectroscopy is utilized to confirm the ligand hapticity in all complexes from the value of nu (B-H), and comparison is made with similar compounds.

Organometallic monomeric and dimeric, neutral and cationic, kappa (2)- and kappa (4)-coordinated mono-pendant arm triazacyclononane complexes of aluminium and indium have been prepared, along with three new mono-pendant arm triazacyclononane ligand precursors HL4, HL5 and HL6 (HL4 = 1-(2-hydroxy-2-methylethyl)-4,7-diisopropyl-1,4,7-triazacyclononane; HL5 = 1-(2-hydroxy-2-methylethyl)-4,7-dimethyl-1,4,7-triazacyclononane; HL6 = 1-(2-hydroxy-2,2-diphenylethyl)-4,7-diisopropyl-1,4,7-triazacyclononane). Reaction of HL4 or HL5 with AlMe3 or AlMe3. py gives the mu -alkoxide bridged dimeric complexes [Al-2(kappa (2)-L-4)(2)Me-4] and [Al-2(kappa (2)-L-5)(2)Me-4]. Reaction of HL4 with two equivalents of AlMe3 gives the monomeric compound [Al(kappa (2)-L-4. AlMe3)Me-2] which can also be prepared by treating [Al-2(kappa (2)-L-4)(2)Me-4] with two equivalents of AlMe3. Reaction of HL2 with AlMe3. py gives [Al(kappa (2)-L-2)Me-2], whereas AlMe3 reacts with one or two equivalents of HL1 to give exclusively [Al(kappa (2)-L-1)(2)Me] which contains two kappa (2)-L-1 ligands (HL1 = 1-(2-hydroxy-3,5-dimethylbenzyl)-4,7-diisopropyl-1,4,7-triazacyclononane; L-2 = 1-(3,5-di-tert-butyl-2-hydroxybenzyl)-4,7-diisopropyl-1,4,7-triazacyclononane). Reaction of AlMe3 with HL6 gives low yields of the monomeric derivative [Al(kappa (2)-L-6)Me-2]. The kappa (2)-coordination mode of the triazacyclononane ligands in all these compounds is unique in the chemisty of these ligands. The crystal structures of four of them are discussed. Methyl group abstraction from [Al(kappa (2)-L-4. AlMe3)Me-2] or [Al(kappa (2)-L-2)Me-2] using B(C6F5)(3) gives the kappa (4)-coordinated cationic derivatives [Al(kappa (4)-L-2)Me][MeB(C6F5)(3)] and [Al(kappa (4)-L-4. AlMe3)Me][MeB(C6F5)(3)], and the latter undergoes reaction with pyridine or MeCN to form [Al(kappa (4)-L-4)Me][MeB(C6F5)(3)]. The cationic centres in the last three compounds are unreactive to unsaturated substrates and aprotic Lewis bases. Reaction of In(CH2Ph)(3) with HL1 or HL2 affords the four-coordinate complexes [In(kappa (2)-L-1)(CH2Ph)(2)] and [In(kappa (2)-L-2)(CH2Ph)(2)] in which the L-1,L-2 ligand is kappa (2) bound to In. With the sterically less demanding HL3 [1-(3,5-di-tert-butyl-2-hydroxybenzyl)-4,7-dimethyl-1,4,7-triazacyclononane], however, the six-coordinate complex [In(kappa (4)-L-3)(CH2Ph)(2)] is formed. The compound [In(kappa (2)-L-2)(CH2Ph)(2)] reacts with B(C6F5)(3) to form [In(kappa (4)-L-2)(CH2Ph)][(PhCH2)B(C6F5)(3)].

The dimethylphosphino substituted cyclopentadienyl precursor compounds [M(C5Me4CH2PMe2)], where M=Li+ (1), Na+ (2), or K+ (3), and [Li(C5H4CR′2PMe2)], where R′2=Me2 (4), or (CH2)5 (5), [HC5Me4CH2PMe2H]X, where X−=Cl− (6) or PF6− (7) and [HC5Me4CH2PMe2] (8), are described. They have been used to prepare new metallocene compounds, of which representative examples are [Fe(η-C5R4CR′2PMe2)2], where R=Me, R′=H (9); R=H and R′2=Me2 (10), or (CH2)5 (11), [Fe(η-C5H4CMe2PMe3)2]I2 (12), [Fe{η-C5Me4CH2P(O)Me2}2] (13), [Zr(η-C5R4CR′2PMe2)2Cl2], where R=H, R′=Me (14), or R=Me, R′=H (15), [Hf(η-C5H4CMe2PMe2)2]Cl2] (16), [Zr(η-C5H4CMe2PMe2)2Me2] (17), {[Zr(η-C5Me4CH2PMe2)2]Cl}{(C6F5)3BClB(C6F5)3} (18), [Zr{(η-C5Me4CH2PMe2)2Cl2}PtI2] (19), [Mn(η-C5Me4CH2PMe2)2] (20), [Mn{(η-C5Me4CH2PMe2B(C6F5)3}2] (21), [Pb(η-C5H4CMe2PMe2)2] (23), [Sn(η-C5H4CMe2PMe2)2] (24), [Pb{η-C5H4CMe2PMe2B(C6F5)3}2] (25), [Pb(η-C5H4CMe2PMe2)2PtI2] (26), [Rh(η-C5Me4CH2PMe2)(C2H4)] 29, [M(η,κP-C5Me4CH2PMe2)I2], where M=Rh (30), or Ir, (31).

A family of new Group 3, Group 13 and early transition metal complexes of the previously described monoanionic, pendant arm macrocyclic ligands L-a, L-b and L-c are described where HLa = (3,5-dimethyl-2-hydroxybenzyl)-4,7-diisopropyl-1,4,7-triazacyclononane 1a, HLb = (3,5-di-tert-butyl-2-hydroxybenzyl)-4,7-diisopropyl-1,4,7-triazacyclononane 1b, and HLc = (3,5-di-tert-butyl-2-hydroxybenzyl)-4,7-dimethyl-1,4,7-triazacyclononane 1c. The ligand precusors 1a-c are quantitatively converted to the corresponding new potassium salts KLa, KLb and KLc 2a-c by reaction with potassium hydride in tetrahydrofuran (THF). An improved synthesis of HLc 1c is also reported. Reaction of KLa-c with Group 13 metal salts MCl3 (M = Al, Ga or In) gives monomeric derivatives [M(kappa (4)-La-c)Cl-2] 3-5 in good yields. The crystal structure of [In(kappa (4)-L-b)Cl-2] 5b has been determined and confirms the six-coordinate, cis-dichloride structures proposed for these complexes. Reaction of KLa-c with TlCl3 gives the asymmetric, binuclear analogues [Tl(kappa (4)-La-c)Cl-2](2) 6a-c. Reaction of [Al(kappa (4)-L-c)Cl-2] 3c with AlCl3 gives the unstable, five-coordinate cation [Al(kappa (4)-L-c)Cl](+) as its AlCl4- salt 8c. Reaction of KLa-c with MCl3 (M = Sc or Y) or [MCl3(THF)(3)] (M = Ti, V, Cr) in THF gives generally good yields of the Group 3 cis-dichloride derivatives [M(kappa (4)-L1a-c)Cl-2] (M = Sc 8a-c or Y 9b,c) and the early transition metal analogues [M(kappa (4)-L-b,L-c)Cl-2] (M = Ti 10b,c, V 11b,c or Cr 12b,c). Reaction of HL1a-c with TlOEt yields the monomeric, four-coordinate thallium(I) derivatives [Tl(kappa (4)-L1a-c)] 13a-c as confirmed by the X-ray crystal structures of 13b and 13c.

The 1,4-dialkyl-1,4,7-triazacyclononanes HR2[9]aneN(3) (R=Me or Pr-i) were smoothly deprotonated with n-butyllithium to give corresponding lithiated amides {Li[R-2[9]aneN(3)]}(x) 1, 2 which are in turn useful precursors to new transition metal complexes. Reaction of 1 or 2 with the mono(imido) or bis(imido) complexes [M(NBut)Cl-3(py)(2)] (M=Nb or Ta) or [Mo-2(NC6H3R'-2,6)(2)Cl-2(dme)] gave [M(NBut)(R-2[9]aneN(3))Cl-2] (M=Nb, R=Me 3 or Pr-i 4; M=Ta, R=Me 5 or Pr-i 6) or [Mo(NC6H3R'(2)-2,6)(2)(R-2[9]aneN(3))Cl] (R=Me, R'=Pr-i 8; R=Pr-i, R'=H 9, Me 10 or Pr-i 11). The compounds 3-6 are relatives of the d(0) metallocene dichlorides [M(eta -C5R5)(2)Cl-2] (M=Group 4 metal). The titanium imido analogue [Ti(NBut)(HPr2i[9]aneN(3))Cl-2] 7 has been prepared for purposes of comparison and exists as a mixture of isomers in solution. The crystal structure of the bis(imido) compound 11 has been determined and shows that the co-ordination of the amido N-donor of Pr-2(i)[9]aneN(3) is not greatly distorted from planarity. Examination of the molecular structure suggests that in this compound the Pr-2(i)[9]aneN(3) ligand acts effectively as a 5-electron donor with the molybdenum d(pi)-acceptor orbitals dominated by the strongly pi -donating arylimido ligands. Extrapolation to the mono(imido) complexes [M(NBut)(R-2[9]aneN(3))Cl-2] 3-6, in which the amido N-donor of Pr-2(i)[9]aneN(3) lies trans to one of the Cl ligands and cis to NBut, suggests that the amido N-donor should be able at least partly to pi -donate to the metal centres. Hence in 3-6 the Pr-2(i)[9]aneN(3) ligand can in principle act as up to a 7-electron donor.

Nickelocene in benzene reacts with the Bronsted acid H2O-B( C6F5)(3) to give the salt [(eta-C5H5) Ni(eta-C6H6) Ni(eta-C5H5)][ B-3(mu-O)(3)(C6F5)(5)] which is the first example of a triple-decker nickel sandwich with a bridging eta-benzene ligand; the borate anion is also unprecedented; treatment of Ni(eta-C5H5)(2) with Brookhart's acid [H(OEt2)(2)][B(3,5(CF3) 2C6H3)(4)] in benzene gives the paramagnetic bis(eta-benzene) nickel derivative {[Ni(eta-C6H6)(2)][B(3,5(CF3) 2C6H3)(4)]2 . Ni(eta-C5H5)(2)} in which nickelocene is present as a molecule of crystallisation.

Reaction of AlMe3 or [AlMe3·py] with the pendant arm OH-funtionalised 1,4,7-triazacyclononane proligands, HL1 or HL2, affords the four- and five-coordinate derivatives [Al(L1)Me2] 1 or [Al2(L2)2Me4] 2 in which the pendant alkoxide O-donor and only one macrocycle N-donor is bound to Al; methyl anion abstraction from 1 yields cationic, pentacoordinate [Al(L1)Me]+ in which L1 has a tetradentate coordination mode [L1 = 1-(2-hydroxy-3,5-di-tert-butylbenzyl)-4,7-diisopropyl-1,4,7-triaz cyclononane; L2 = 1-(2-hy- droxy-2-methylethyl)-4,7-diisopropyl-1,4,7-triazacyclononane].

The nitrosyl complex in trans-[RuCl(pdma)(bpy)(NO)][PF6]2 (pdma=1,2-phenylenebis(dimethylarsine), bpy=2,2′-bipyridine) reacts at room temperature with stoichiometric NaN3, followed by an excess of a neutral ligand L1 in 2-butanone under reflux, to afford high yields of the mono-substituted derivatives trans-[RuCl(pdma)(bpy)L1]PF6 (L1=pyridine (py) 1, triphenylphosphine (PPh3) 2, N-methylimidazole (mim) 3, acetonitrile (MeCN) 4, dimethylsulfoxide (dmso) 5 or pyrazine (pyz) 6). The related compound trans-[RuCl(pdma)(phen)(NO)][PF6]2 (phen=1,10-phenanthroline) reacts similarly to yield trans-[RuCl(pdma)(phen)L1]PF6 (L1=py 8, PPh3 9, mim 10 or pyz 11). The pyrazine complexes in 6 and 11 react with MeI at room temperature in acetone to afford trans-[RuCl(pdma)(L–L)(mpyz+)][PF6]2 (mpyz+=N-methylpyrazinium, L–L=bpy 7 or phen 12, respectively). 3 reacts with an excess of a neutral ligand L2 in the presence of stoichiometric AgCF3CO2 in water/acetone under reflux to afford high yields of the di-substituted derivatives trans-[Ru(pdma)(bpy)mim(L2)][PF6]2 (L2=mim 13, py 14 or MeCN 15) and 2 reacts similarly with AgCF3CO2 in water/MeCN to give trans-[RuCl(pdma)(bpy)PPh3(MeCN)][PF6]2 (16). The complexes in 1–16 exhibit intense dπ(RuII)→π*(L–L) and dπ(RuII)→π*(L1/L2) (L1/L2=py, pyz or mpyz+) metal-to-ligand charge-transfer absorption bands in the near-UV–visible region and are mildly photosensitive in solution. Solar irradiation leads to isomerization; for example 3 is converted into cis-[RuCl(pdma)(bpy)mim]PF6 (17) over a period of ca. 100 h exposure to diffuse sunlight in acetone. Single crystal X-ray structures have been determined for 1, 2·DMF, 3, 12·3MeCN, 14·DMF and 17.