The reaction between 1,3-bis(diphenylphosphinite)-benzene and Os3(CO)10(MeCN)2 affords complex Os3(CO)10[1,3-(PhPO)2C6H4]. A thermolysis of this cluster in refluxing toluene results in the activation of O–PPh2 and C–H bonds and the formation of unsaturated triosmium cluster Os3(μ-H)(μ-PPh2)(CO)7[(C6H3(O)(OPPh2)] that possesses a remarkable structure with the pseudo-pincer ligand containing a bridging μ-η1-aryl group.

Pincer complexes are widely used in catalysis and activation of small molecules. We present here the synthesis and spectroscopic study of rhodium dihydrogen and dinitrogen complexes with metallocene-based P,C,P pincer ligands. Relative electron donor ability of ferrocene-, ruthenocene- and benzene-derived pincer ligands, as well as HH distance were elucidated based on JHD coupling constants and T1 relaxation time for dihydrogen complexes.

The first (trifluoromethyl)tetramethylruthenocene-based ruthenium pincer complex RuCl(CO)[{2,5-(Bu 2 t PCH2)2C5H2}Ru(C5Me4CF3)] was synthesized by cyclometallation of the bisphosphine ligand {1,3-(Bu 2 t PCH2)2C5H2}Ru(C5Me4CF3) with RuCl2(DMSO)4 in 2-methoxyethanol in the presence of NEt3. The new complex was fully characterized by 1H, 19F, 31P{1H}, 13C{1H} NMR and IR spectroscopy.

The reaction of the divalent ruthenium complexes [CpFRuCl]n and [CpFRu(MeCN)3]PF6 with substituted pentafulvenes 1,2-(Me2NCH)(CO2Et)C5H3 and 1,3-(Me2NCH)(CO2Et)- C5H3 followed by hydrolysis affords new homoannular disubstituted ruthenocenes {1,2- (CO2Et)(CHO)C5H3}RuCpF and {1,3-(CO2Et)(CHO)C5H3}RuCpF (CpF = C5Me4CF3), re- spectively.

The reduction of the (1,3-diformylindenyl)cyclopentadienylruthenium derivatives {η5-1,3-(CHO)2C9H5}RuCp (Cp = C5H5), {η5-1,3-(CHO)2C9H5}RuCp* (Cp* = C5Me5), and {η5-1,3-(CHO)2C9H5}RuCpF (CpF = C5Me4CF3) with NaBH4 or LiAlH4 under mild conditions affords the [1,3-bis(hydroxymethyl)indenyl]cyclopentadienylruthenium complexes {η5-1,3-(CH2OH)2C9H5}RuCp, {η5-1,3-(CH2OH)2C9H5}RuCp*, and {η5-1,3-(CH2OH)2C9H5}-RuCpF, respectively, in good yields.

New conjugated copolyfluorenes containing covalently bound quinolinolate complexes of iridium in the backbone are synthesized under conditions of the Yamamoto reaction. The structures and properties of the polymers are characterized via NMR spectroscopy, GPC, TMA, and TGA. All copolymers show solubility in common organic solvents and feature good thermal and thermo-oxidative properties. The absorption, luminescence, and electrochemical properties of the polymers are investigated. In thin films, the polymers emit blue light with wavelengths in the range 450–470 nm. The electroluminescence spectra of the copolymers show broad intense bands in the visible region with maxima at 500–525 nm corresponding to various emission colors with the chromaticity coordinates (0.361, 0.437) and (0.247, 0.411). The synthesized iridium-containing copolyfluorenes may be used as electron-hole transport materials in light-emitting diodes.

Dehydrogenation of alcohols by three iridium pincer complexes, IrH(Cl)[2,6-((Bu2PO)-Bu-t)(2)C6H3] (1), {IrH-(acetone)[2,6-((Bu2PO)-Bu-t)(2)C6H3]}{BF4} (2), and IrH(Cl)[{2,5-((Bu2PCH2)-Bu-t)(2)C5H2}Ru(C5H5)] (3), is reported, in both the presence and the absence of a sacrificial hydrogen acceptor. Dehydrogenation of secondary alcohols proceeds in a catalytic mode with turnover numbers up to 3420 (85% conversion) for acceptorless dehydrogenation of 1-phenylethanol. Primary alcohols are readily decarbonylated even at room temperature to give catalytically inactive 16e Ir-GO adducts. The mechanism of this transformation was studied in detail, especially for EtOH; new intermediates were isolated and characterized.

The reaction of [CpRu(CH 3 CN) 3 ][PF 6 ], [Cp*RuCl] n , and [Cp F RuCl] n with 1,3-diformylindene results in the predominant formation of zwitter-ionic arene-cyclopentadienyl complexes {η 6 -1,3-(CHO) 2 C 9 H 5 }RuCp (Cp = C 5 H 5 ), {η 6 -1,3-(CHO) 2 C 9 H 5 }RuCp* (Cp* = C 5 Me 5 ), and {η 6 -1,3-(CHO) 2 C 9 H 5 }RuCp F (Cp F = C 5 Me 4 CF 3 ), respectively. The ruthenocenes {η 5 -1,3-(CHO) 2 C 9 H 5 }RuCp, {η 5 -1,3-(CHO) 2 C 9 H 5 }RuCp*, and {η 5 -1,3-(CHO) 2 C 9 H 5 }RuCpF were synthesized by the reaction of 1,3-diformylindenyl potassium with [CpRu(CH 3 CN) 3 ][PF 6 ], [Cp*RuCl] n , and [Cp F RuCl] n .

Rhodium and iridium complexes of a new ferrocene-derived bis(N-heterocyclic carbene) ligand, [M(cod){1,2-(MeNCHCHNCCH(2))(2)C(5)H(3)}Fe(C(5)H(5))]BF(4) (M = Rh, 8a; M = Ir, 8b; cod = 1,5-cyclooctadiene), were synthesized from the corresponding bis(imidazolium) salt 6. The molecular structure of 8a was determined by single-crystal X-ray diffraction. Complexes 8a and 8b smoothly react with CO with displacement of the chelating cod ligand to give the corresponding dicarbonyl derivatives 9a and 9b.

Palladium fluorophenyl complexes with different pincer ligands Pd(Ar)[2,6-(tBu(2)PCH(2))(2)C(6)H(3)] (13), Pd(Ar)[2,6-(tBu(2)PO)(2)C(6)H(3)] (14), Pd(Ar)[{2,5-(tBu(2)PCH(2))(2)C(5)H(2)}Fe(C(5)H(5))] (15), and Pd(Ar)[{2,5-(tBu(2)PCH(2))(2)C(5)H(2)}Ru(C(5)H(5))] (16) were synthesized by the reaction of LiAr (Ar = C(6)H(4)F-4) with the respective trifluoroacetate palladium pincer complexes 9-12. The molecular structures of 14 and 16 were determined by an X-ray crystallographic method. Complexes 13-16 and {Pd(Ar)[{2,5-(tBu(2)PCH(2))(2)C(5)H(2)}Fe(C(5)H(5))]}PF(6) (17) were studied by multinuclear NMR spectroscopy and cyclic voltammetry. On the basis of (19)F NMR chemical shifts and (1)J((13)C-(19)F) coupling constants, as well as Pd(II)/Pd(IV) oxidation potentials, electronic characteristics of the corresponding pincer ligands were elucidated.

Thermal reaction of Au(PPh3)(CСCСFc) (Fc=ferrocenyl) with Re2(CO)8(NCMe)2 gives complexes Re2(AuPPh3)(μ-C4Fc)(CO)8 (4) and Re4(AuPPh3)(μ4-C2)(μ3-C2Fc)(NCMe)(CO)13 (5). Compounds 4 and 5 are characterized by 1H and 31P{1H} NMR, cyclic voltammetry and single crystal X-ray diffraction.

The alkylation of imidazole and 5-benzyloxycarbonyl-3,4-diethylpyrrole with 1,3-bis-(hydroxymethyl)ferrocene (1) afforded bis-imidazole (4) and bis-pyrrole (7) derivatives of ferrocene, respectively. The reaction of diol 1 with trifluoroacetic acid gave the dicarbocationic complex [{1,3-(CH2)(2)C5H3}Fe(C5H5)](2+) (2) characterized by H-1 NMR spectroscopy.

The first ruthenocene- and pentamethylruthenocene-based ruthenium pincer complexes, RuCl(CO)[{2,5-(But 2PCH2)2C5H2}Ru(C5H5)] and RuCl(CO)[{2,5-(But 2PCH2)2C5H2}Ru-(C5Me5)], were synthesized by cyclometallation of {1,3-(But 2PCH2)2C5H2}Ru(C5H5) and {1,3-(But 2PCH2)2C5H2}Ru(C5Me5), respectively, with RuCl2(DMSO)4 in 2-methoxyethanol and characterized by 1H and 31P{1H} NMR spectroscopy, and X-ray diffraction.

Iridium pincer complexes [C 6 H 3 -2,6-(OPBu t 2 ) 2 ]Ir(H)Cl ( 10 ) and [4-EtOOCC 6 H 2 -2,6-(OPBu t 2 ) 2 ]Ir(H)Cl ( 11 ) react with protic acids undergoing metallation of one of the tert -butyl groups to form double cyclometallated products [4-R-C 6 H 2 -2-(OPBu t 2 )-6-(OP(Bu t )CMe 2 CH 2 )]IrCl ( 12 , R = H; 13 , R = COOEt), which are stable in air. Complex 12 reacts with CO and Bu t NC giving the corresponding 18-electron complexes [C 6 H 3 -2-(OP-Bu t 2 )-6-(OP(Bu t )CMe 2 CH 2 )]Ir(L)Cl ( 14 , L = CO; 15 , L = CNBu t ). The structure of compound 14 was established by X-ray diffraction analysis.

Resorcinol-based ruthenium bis(phosphinite) complexes were synthesized. Complexes RuCl(CO)[2,6-(Bu t 2 PO) 2 C 6 H 3 ] ( 9 ) and RuH(CO)[2,6-(Bu t 2 PO) 2 C 6 H 3 ] ( 10 ) were obtained by cyclometallation of 1,3-(Bu t 2 PO) 2 C 6 H 3 with RuCl 2 (DMSO) 4 in 2-methoxyethanol in the presence of Hünig’s base. The interconversion of complexes 9 and 10 was studied. The addition of carbon monoxide to complexes 9 and 10 yielded 18e adducts, RuCl(CO) 2 [2,6-(Bu t 2 PO) 2 C 6 H 3 ] ( 11 ) and RuH(CO) 2 [2,6-(Bu t 2 PO) 2 C 6 H 3 ] ( 12 ), respectively. In the case of complex 9 , this reaction is reversible. Reaction of complex 10 with trifluoroacetic acid resulted in complex Ru(CF 3 COO)(CO)[2,6-(Bu t 2 PO) 2 C 6 H 3 ] ( 13 ), which reacted with carbon monoxide to give complex Ru(CF 3 COO)(CO) 2 [2,6-(Bu t 2 PO) 2 C 6 H 3 ] ( 14 ). Based on the IR spectral data, the TFA ligand in complexes 13 and 14 is bound in a bi- and monodentate fashion, respectively. The structure of compound 9 was determined by X-ray diffraction analysis.

The alkylation of imidazole and 5-benzyloxycarbonyl-3,4-diethylpyrrole with 1,3-bis-(hydroxymethyl)ferrocene ( 1 ) afforded bis-imidazole ( 4 ) and bis-pyrrole ( 7 ) derivatives of ferrocene, respectively. The reaction of diol 1 with trifluoroacetic acid gave the dicarbocationic complex [{1,3-(CH 2 ) 2 C 5 H 3 }Fe(C 5 H 5 )] 2+ ( 2 ) characterized by 1 H NMR spectroscopy.

Cationic ruthenium hydrido-carbonyls {RuH(CO)[(BuP)-Bu-t,CH,P-M]}BAr4F (M = Fe, 3; M = Ru, 4) (Ar-F = 3,5-(CF3)(2)C6H3) obtained in the reaction of H-2 with RuCl(CO)[P-tBu,C,P-M] (M = Fe, 1; M = Ru, 2) in the presence of NaBArF4 add CO smoothly, giving the corresponding dicarbonyl complexes {RuH(CO)(2)[P-tBu,CH,PM]}BAr4F (M = Fe, 11; M = Ru, 12). According to X-ray analysis of 11 and 12, addition of extra CO to complexes 3 and 4 leads to strengthening of the C(1)-H(1)center dot center dot center dot Ru(1) agostic interaction. Simultaneously, CO addition to 3 and 4 triggers a sequence (up to three steps) of unprecedented intramolecular rearrangements including migration of H atoms. First metallocenylidene complexes {Ru(CO)(2)[P-tBu,C,P-M]}BAr4F (M = Fe, 15; M = Ru, 16) were obtained in the course of these rearrangements accompanied by H-2 evolution.

Rhodium hydrido chloride pincer complex RhH(Cl)[2,6-(Bupt b2PO)b2Cb6Hb3] was synthesized and used for the preparation of new complexes with labile two-electron ligands Rh(L)[2,6-(Bupt b2PO)b2Cb6Hb3] (L = MeCN or S(CHb2)b4) and complexes with small molecules, such as CO, Ob2, Hb2, and Nb2.