Shahram Mihan

Metal complexes of biologically important ligands, LXXXVII α-amino carboxylate complexes of palladium(II), iridium(III) and ruthenium(II) from chloro-bridged ortho-metallated metal compounds and [(OC)3Ru(Cl)(μ-Cl)]2

Abstract The chloro-bridged ortho-metallated compounds [(L)Pd(μ-Cl)] 2 (HL = 2-benzylpyridine, 2-phenylpyridine, azobenzene) and [(L) 2 Ir(μ-Cl)] 2 (LH = 2-phenylpyridine) react with α-amino carboxylase to give the N,O-chelate complexes (L)Pd-t-NH 2 C(H)(R)CO 2 and (L) 2 Ir-NH 2 C(H)(R)CO 2 . The chloro-bridged carbonyl complex [(OC) 3 Ru(Cl)(μ-Cl)] 2 and prolinate afford the N,O-chelate (Cl)(OC) 3 Ru(prolinate). From the osmium complex [(OC) 3 Os(Cl)(μ-Cl)] 2 and N , N -dimethylglycine methylester the ionic compound [HN(Me 2 )CH 2 CO 2 Et] + (Os(CO) 3 Cl 3 ) − ( 25 ) was obtained. The structures of [2-(2-pyridylmethyl)phenyl-C 1 ,N]Pd(prolinate)], [(2-pyridylphenyl-C 1 ,N) 2 Ir(prolinate)] a and of 25 were determined by X-ray diffraction.

Coordination chemistry of the activation of [(triazacyclohexane)CrCl3] with [PhNMe2H][B(C6F5)4] and AlR3

Complexes of N-substituted 1,3,5-triazacyclohexanes with CrCl3 form 1:1 adducts with [PhNMe2H][B(C6F5)(4)] with increased solubility in toluene. Addition of (AlBu3)-Bu-i leads to free PhNMe2 and a complex with [B(C6F5)(4)](-) weakly coordinated to chromium via a meta-fluorine atom. This complex can polymerise and/or trimerise olefins similar to methyl aluminoxane activated complexes. Decomposition of the active complex involves transfer of the triazacyclohexane to aluminium leading to [(triazacyclohexane) (AlBu2)-Bu-i][B(C6F5)(4)] and [(arene)(2)Cr][B(C6F5)(4)]. These chromium(I) complexes have been characterised by X-ray crystallography and prove that chromium is reduced to the oxidation state +I during the catalysis

Coordination Chemistry of Pentacarbonylrheniumacetylide Complexes with Copper, Silver, and Gold(I): (OC)5ReC≡CRe(CO)5 as Ligand

Dithioethyne (OC)5ReC≡CRe(CO)5functions as an alkyne ligand in CuI, AgI, and AuI complexes to give bis(alkyne) complexes and dimetallatetrahedranes. The latter are bridged in 1 (R = Re(CO)5) and 2 (R = SiMe3) by difluorophosphate.

Triazacyclohexane complexes of chromium as highly active homogeneous model systems for the Phillips catalyst

MAO activated 1,3,5-triazacyclohexane complexes of chromium(III) are highly active ethene polymerisation catalysts that resemble the Phillips catalyst in many important properties and may represent the first good homogeneous model system.

Kohlenwasserstoffverbrückte komplexe. XXXIII. Synthese zweikerniger kohlenwasserstoffverbrückter komplexe durch oxidation von fischer-carbenanionen und ferrocenenolaten and deren reaktionen☆

Abstract Oxidative coupling of [(OC) 5 CrC(OCH 3 )CH 2 ] − Li + and [FcCOCH 2 ] − K + with AgBF 4 gives the dinuclear neutral complexes (OC)5CrC(OMe)CH 2 CH 2 C(OMe)Cr(CO)5 ( 1 ) and FcCOCH 2 CH 2 COFc ( 2 ) (Fc = ferrocenyl) in good yield. 1 was characterized by X-ray diffraction. Double deprotonation of 1 and 2 with Bu n Li or KH, respectively, affords dianionic species 3 and 4 which are oxidized to the deeply colored conjugated complexes (OC) 5 CrC(OCH 3 )CHCHC(OCH 3 )Cr(CO) 5 ( 5 ) and FcCOCHCHCOFc ( 6 ). Addition of the dianion [(OC) 5 CrC(OCH 3 )CHCHC(OCH 3 )Cr(CO) 5 ] 2− (Li + ) 2 to the cationic electrophiles [Fe(CO) 3 (η 5 -C 6 H 7 )] + [BF 4 ] − and [Re(CO) 5 (η 2 -C 2 H 4 )] + [BF 4 ] − forms tetranuclear complexes ( 7, 8 ) as diastereoisomers. [FcCOCHCHCOFC] 2− (K + ) 2 reacts with [Re(CO) 5 (η 2 -C 2 H 4 )] + [BF 4 ] − to give the trinuclear complex FcCOCH 2 CH[CH 2 CH 2 Re(CO) 5 ]COFc ( 9 ).

Kohlenwasserstoffverbrückte Metallkomplexe, XXXIX Zur Chemie von Pentacarbonylrheniumacetyliden

Abstract Hydrocarbon-bridged Metal Complexes, XXXIX. Chemistry of Pentacarbonyl-rhenium-acetylides. As a by-product in the preparation of (OC) 5 Re-C≡C-Re(CO) 5 ( 1 ) from [(OC) 5 Re( μ - η 1 : η 2 -C≡CH)Re(O) 5 ]BF 4 and K[HBEt 3 ] the new fluxional hydride-bridged cluster (OC) 5 Re-C≡C-Re(CO) 4 [HRe(CO) 4 ] ( 2 ) is obtained. (OC) 5 Mn-C≡C-Mn(CO) 5 ( 4 ) is available from [(OC) 5 Mn( η 1 : η 2 -C≡CH)Mn(CO) 5 ]BF 4 ( 3 ) and K[HBEt 3 ]. Reaction of 1 with Me 3 O + BF 4 − gives the σ , π -bridged complex [(OC) 5 Re( μ - η 1 : η 2 -C≡CMe)Re(CO) 5 ]BF 4 ( 5 ). The alkynyl complex (OC) 5 Re-C≡C-SiMe 3 ( 6 ) can be prepared by reaction of Na[Re(CO) 5 ] with 1-tosyl-2-trimethylsilyl-ethyne. The reaction of tosylethyne with Na[Re(CO) 5 ] affords (OC) 5 Re-C≡CH ( 7 ) and (OC) 5 Re-C(H)=C(H)(tosyl) ( 9 ). Complex 7 is also formed by cleavage of the Me 3 Si group from 6 . (OC) 5 ReOSO 2 CF 3 reacts with Li(en)C≡CH to give the chelate carbamoyl complex ( 8 ). Elimination of CO from (OC) 5 Re-C≡C-Re(CO) 5 gives the tetrameric σ , π -acetylide-bridged cluster [(OC) 5 Re-C≡C-Re(CO) 4 ] 2 ( 11 ). Similarly, [Me 3 Si-C≡C-Re(CO) 4 ] 2 ( 12 ) is formed from Me 3 Si-Re(CO) 5 . The structures of 2 , 9 , 11 and 12 were determined by X-ray diffraction. As by-products from the thermolysis of 1 and 7 , [Re(CO) 3 OH] 4 · 4H 2 O and [(OC) 3 ReOH] 4 · 4(OC) 5 ReCOCH 3 were obtained.

1,3,5-Triazacyclohexane Complexes of Chromium as Homogeneous Model Systems for the Phillips Catalyst

1,3,5-triazacyclohexane complexes 2 prepared from trizazacyclohexanes 1 and CrCl3 can be activated by MAO or AIR3/PhNMe2H(BPhF 4) to give solutions that can polymerise and/or trimerise ethylene depending on the N-substituents R with unprecedented high activities. α-olefins are selectively trimerised or co-polymerised with ethylene. We have varied these substituents R in symmetrical and asymmetrical R2R’-triazacyclohexanes including some with different functional groups for a better understanding of this dependence. A detailed study of the activities and the polymer structures shows that these systems are very good models for the Phillips catalyst. The homogeneous reactions can be studied by several spectroscopic methods especially for the α-olefin trimerisation. The results show that the triazacyclohexane stays co-ordinated during the catalysis and that mono-nuclear metallacyclic complexes are likely involved.

Metallkomplexe mit biologisch wichtigen Liganden, CXXVII ☆: Halbsandwich-Komplexe von Ruthenium, Rhodium und Iridium sowie phosphanhaltige Palladium- und Platin(II)-Komplexe mit Schiff-Basen aus α-Aminosäureanionen und Aldehyden

Abstract Reactions of the anions (L) of Schiff bases from S -α-amino acids and cinnamic aldehyde or 4-methoxy or 2,4-dimethoxy benzaldehyde with chloro-bridged compounds (R 3 P)(Cl)M(μ-Cl) 2 M(Cl)(PR 3 ) (M=Pd, Pt), ( p -cymene)(Cl)Ru(μ-Cl) 2 Ru(Cl)( p -cymene) and (Cp*)(Cl)M(μ-Cl) 2 M(Cl)(Cp*) (M=Rh, IR) give the ( N , O ) chelate complexes cis / trans -(R 3 P)(Cl)M(L), ( p -cymene)(Cl)RuL and (Cp*)(Cl)M(L) (M=Rh, Ir). The complexes (Cp*)(Cl)M[O 2 CCH(CHMe 2 )NCHCHCHPh] (M=Rh, Ir) with a chiral metal atom are formed with a high diastereoisomeric excess (9/1). The structures of ( p -cymene)(Cl)Ir[O 2 CCH(CHMe 2 )NCHCHCHPh) ( 7 ), cis ( P , N )-( n Bu 3 )(Cl)Pt[O 2 CCH(Me)NCHC 6 H 4 OMe] ( 19 ), (Cp*)(Cl)Rh[O 2 CCH(Me)NCHC 6 H 4 OMe] ( 22 ) and of ( p -cymene)(Cl)Ru[O 2 CCH(Me)NCHC 6 H 3 (OMe) 2 ] ( 26 ) were determined by X-ray diffraction.

Metallkomplexe mit biologisch wichtigen Liganden LXXVI. Halbsandwichkomplexe von Cobalt(III), Iridium(III) und Ruthenium(II) mit Amiden von 2-Hydroxyiminocarbonsäuren☆

Abstract The reactions of Cp ★ Co(CO)I 2 , [( p -cymene)RuCl 2 ] 2 or [Cp ★ IrCl 2 ] 2 with the amide of 2-hydroxyiminopropionic acid and with N-(2-hydroxyiminopropionyl)amino acids gave the following chiral (N,O)- or (N,N)-chelate complexes: ( 3 ) ( 6 ) ( 9 ) (R = H, CH 2 Ph). The oxime of pyruvoyl methionine forms a (N,N,S)-trischelate complex 10 . Complex 5a can be deprotonated in the presence of donors to yield the compounds (7, L = PEt 3 , PPh 3 , py). The structures of 4, 6b (R = CH,), 8a (R = H) and 8b (R = CH 2 Ph) have been determined by X-ray diffraction. Also the dipeptide complexes which are analogues of 8 have been prepared. The observed diastereospecific formation of 8b and 11b (R = CH 2 Ph) can be explained by a hydrogen bond between the oxygen atoms of the carboxyl and the amide group.

New 3-Imidazoline Derivatives and their Palladium(II) Complexes

The protection of the hydroxy group of 1-hydroxy-2.2.4.5.5-pentamethyl-3-imidazoline by a t-butyldimethylsilyl group gives the silane 1 which allows via the 4-lithium salt the preparation of 4-substituted derivatives, i. e. a dithiocarboxylic acid (2), a disulfide (3), a phosphane (4) and a thioether (5). Oxidation of 4-lithiated 1 yields under C–C coupling an ethylene bridged bis(3-imidazoline) (6). From these compounds Pd(II) and Pt(II) complexes M(4)2Cl2 (M = Pd, Pt and Pd(5)Cl2 were prepared and the structure of the dithiocarboxylate chelate complex Pd(2-H+)2 (7) was determined by X-ray diffraction. Cleavage of the silyl group from 7 gives complex 8 which can be oxidized to the corresponding diradical (9). Complex 9 was characterized by its EPR spectrum. Measurements of the magnetic susceptibility of 9 reveal strong antiferromagnetic coupling between the two spins at low temperatures. Neue 3-Imidazolin-Derivate und ihre Palladium(II)-Komplexe In 1-Hydroxy-2,2,4,5,5-pentamethyl-3-imidazolin last sich die Hydroxygruppe durch t-Butyldimethylsilyl schutzen und aus diesem Silan 1 sind uber das 4-Lithium-Salz verschiedene 4-substituierte Imidazolin-Derivate zuganglich: eine Dithiocarbonsaure (2), ein Disulfid (3), ein Phosphan (4) und ein Thioether (5). Die Oxidation des lithierten 1 ergibt unter C–C-Kupplung ein Ethylen-verbrucktes Bis(3-imidazol). Mit den Liganden wurden die Pd(II)- und Pt(II)-Komplexe M(4)2Cl2 (M = Pd, Pt) und Pd(5)Cl2 erhalten. Die Struktur des Dithiocarboxylat-Komplexes Pd(2-H+)2 (7) wurde rontgenographisch bestimmt. Der durch Abspaltung der Silylgruppe aus 7 erhaltene Komplex 8 kann zum Dinitroxid-diradikal 9 oxidiert werden. Komplex 9 wurde durch sein EPR-Spektrum charakterisiert. Magnetische Messungen zeigen fur 9 bei tiefen Temperaturen starke antiferromagnetische Wechselwirkungen.