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The reaction of Ir4(CO)12 with potassium hydroxide in methanol and/or with sodium in tetrahydrofuran leads to the carbonyliridate anions [HIr4(CO)11]−, [Ir6(CO)22]2−, [Ir8(CO)20]2−, [Ir6(CO)15]2− and [Ir(CO)4]− obtained as salts with bulky cations. From these, the tetranuclear carbonyl hydride H2Ir4(CO)11 and the hexanuclear carbonyl compound Ir6(CO)16 are also obtained.

The reaction of IrH3(PPh3)3 with p-anisyldiazonium tetrafluoroborate gives an insertion product which very easily undergoes orthometalation, yielding [IrH(PPh3)3NHNC6H3OMe]+BF4− (V), the structure of which is tentatively assigned. By reaction with halides X−, the metalated fluoborate gives the neutral IrHX(PPh3)2NHNC6H3OMe, which with halogens X2 affords IrX2(PPh3)2NHNC6H3OMe, the structure of which has previously been determined.

The preparation of Ir2(CO)6(PPh3)2 by a new route is described, as are the reaction of this compound with hydrogen, mercury, tin(II) chloride, hydrogen halides and halogens, leading to new monophosphine carbonyl iridium compounds. The [Ir(CO)3PPh3]- anion has been isolated as the tris(phenanthroline)nickel salt.

The compounds obtained by reaction of 2-alkenols with tricarbonylbis(triphenylphosphine)iridium cation in basic medium, are alkenyloxycarbonyl derivatives, in which the alkenyloxycarbonyl moiety is chelated through a σ and a η bond.

The reaction of IrH3(PPh3)2 with p-substituted aryldiazonium salts gives the compounds [IrH2(NHNC6H4R)(PPh3)2]+BF4- at low temperature (-10°C) and the o-metalated complexes [I rH(NHN C6H3R)(PPh3)2]+BF4- (R  F, OCH3) at 40–50°C. The reactions of the o-metalated complexes with CO, PPh3, NaI and HCl have been studied.

The title compound [Ir(CO)2{[graphic omitted](CO)2(PPh3)}] has been obtained by reaction of [{Ir(CO)3(PPh3)}2] with EtO2CCCCO2Et in boiling benzene. The compound crystallizes as orthorhombic prisms in space group P212121 with a= 20.655(9), b= 18.496(8), c= 10.027(5)A, and Z= 4. The structure has been refined to R= 0.027 from 5 299 independent reflections. One metal atom is bonded to two carbonyl groups and to a metallacyclopentadienyl moiety via a η5 interaction; the other is bonded to two CO, one PPh3, and to a buta-1,3-diene-1,4-diyl radical. The molecular parameters are compared with those of known cyclopentadienyl and metallacyclopentadienyl complexes of transition metals.

In a search for better methods of preparaing carbonyl compounds of the transition metals the reaction of powdered iridium with carbon monoxide and chlorine under various conditions has been studied. The outcome of the reaction depends on the CO/Cl 2 ratio and on the temperature. The iridium(II) complex Ir(CO) 2 Cl (I) has been isolated, and its reactions with CO, AsPh 4 Cl, PPh 3 and Cl − ions examined. The anion (IrCOCl 4 ) − has been isolated as its caesium and bis-triphenyl-phosphine)iminium salts, and the complex Ir 2 (CO) 4 Cl 6 has been identified by mass spectrometry.

The reaction of [Ir(CO) 3 PPh 3 ] 2 with diphenylacetylene in boiling benzene gives the complex {[Ir(CO) 2 PPh 3 ] 2 (CPh) 2 } · C 6 H 6 , whose structure has been determined by X-ray diffraction. The compound is monoclinic, space group C 2/ c , with a 19.714(3), b 14.257(2), c 18.953(5) A, β 109.85(2)°. The {[Ir(CO) 2 PPh 3 ] 2 (CPh) 2 } structure is similar to that of binuclear carbonylcobalt-acetylene complexes such as Co 2 (CO) 6 (μ-C 6 H 5 C 2 C 6 H 5 ), and consists of two Ir(CO) 2 PPh 3 moieties bridged by diphenylacetylene with the CC bond approximately normal to the IrIr bond, which has a length of 2.689(1) A.

The stereochemistry of substitution reactions of complexes of the type [Ru(η 5 -C 5 H 4 R*)(CO)(PPh 3 )L] n+ (R* = menthyl or R = neomenth n = 1, L = NCCH 3 or NCCD 3 has been studied by X-ray crystallography. Circular Dichroism and 1 H, 13 C and 31 P NMR spectroscopy. All the reactions investigated have been unequivocably proved to occur with ⩾ 94% retention of configuration at the ruthenium atom. Thus ( S )-Ru(η 5 -C 5 H 4 R*)(CO)(PPh 3 )Cl reacts with NaI to give ( R )-Ru(η 5 -C 5 H 4 R*)(CO)(PPh 3 )I (R* = menthyl or neomenthyl) and reaction of Ru(η 5 -C 5 H 4 R*)CO(PPh 3 )X (R*=menthyl, ( S ) Ru , X = Cl; R* = neomenthyl, (R) Ru , X = I) with AgY in acetonitrile yields the corresponding complex ( R )-[Ru(η 5 - C 5 H 4 R*)(CO)(PPh 3 )(NCCH 3 )]Y (Y = PF 6 or BF 4 ). An X-ray structure determination of [Ru(η 5 -C 5 H 4 R*)(CO)(PPh 3 )NCCH 3 ]PF 6 (R* = neomenthyl) has confirmed that the absolute configuration of the ruthenium centre is R . The crystals are orthorhombic, space group P 2 1 2 1 2 1 (No. 19) with a 10.400(2), b 15.850(4), c 24.740(5) A and Z = 4. The structure was solved via the heavy-atom method and refined to R = 0.036 using 4183 diffractometer data with I ⩾ 1.56( I ). CD 3 CN undergoes exchange with the coordinated acetonitrile in ( R )-[Ru(C 5 H 4 R*)(CO)(PPh 3 )(NCCH 3 )]BF 4 (R* = neomenthyl) with retention of configuration at ruthenium and reaction of ( R )-[Ru(η 5 -C 5 H 4 R*)(CO)(PPh 3 )NCCD 3 ]BF 4 with NaI regenerates ( R )-[Ru(η 5 -C 5 H 4 R*)(CO)(PPh 3 )I] (R* = neomenthyl).

The reaction of [Ir(CO) 3 PPh 3 ] 2 with phenylacetylene in boiling CH 2 Cl 2 yields the dinuclear iridium complex {[Ir(CO) 2 PPh 3 ] 2 -μ-HC 2 Ph}. The molecule has an approximate C s symmetry and contains a quasi -tetrahedral moiety Ir 2 C 2 involving two alkyne carbon atons; the CC distance in the μ-bonded acetylenic ligand 1.412(17) A is the longest ever observed in dimetal-μ-alkyne complexes.

The preparation and the spectra of Ir2 (CO)4 (PPh3)2 (SO2)2 and of the title compound are reported; in the molecular structure of the latter, determined by X-ray crystallographic analysis, there is a relatively long IrIr bond which is accounted for in terms of the acidic nature of SO2

Die Umsetzung des Iridiumtrihydrids (II) mit Stickstoffmonoxid in siedendem Tetrahydrofuran und in Gegenwart von.N-Methyl-N-nitroso-p-toluolsulfonamid (I) ergibt in hoher Ausbeute den Komplex (III).

New class of carbonyliridium derivatives is, described, that is the halogenocarbonyliridiates of the types: K[Ir(CO)2Cl2,5]; K[Ir(CO)Br3]; K[Ir(CO)Br4].

The compound [{Ir(CO)3(PPh3)}2](1) reacts with P(OPh)3 to give [{Ir(CO)2[P(OPh)3]2}2] from which [{Ir(CO)3[P(OPh)3]}2] may be obtained. Compound (1) also gives [Ir2(CO)5(PPh3)3] with PPh3, [Ir2(CO)5{PPh2(C6H4Me-p)}2(PPh3)] with PPh2(C6H4Me-p), and [{Ir(CO)2(PPh3)(SO2)}2], having two bridging sulphur dioxide molecules, with SO2. Reaction of the last compound with hydrogen gives [{Ir(CO)2H(PPh3)}2SO2] and reaction with iodine gives [{Ir(CO)2(PPh3)I2}2SO2], having two bridging and two terminal iodine atoms and one bridging sulphur dioxide molecule, but no metal–metal bond. The compounds [{Ir(CO)2[P(OPh)3]2}2] and [{Ir(CO)3[P(OPh)3]}2] and sulphur dioxide gives [{Ir(CO)[P(OPh)3]2(SO2)}2] and [{Ir(CO)2[P(OPh)3](SO2)}2] respectively in each of which a metal–metal bond is postulated.

(Alkoxycarbonyl)iridium compounds of type [Irl2(CO2R)(CO)L2] have been prepared by the reaction of K[Ir(CO)2l4] with nitrogen bases L and alcohols ROH. The reaction takes place through nucleophilic attack of the alcohols on the intermediate cations [lrl2(CO)2L2]+, some of which have been isolated. Other (alkoxycarbonyl)iridium compounds containing triphenylphosphine (Y), [Irl2(CO2R)(CO)Y2] and [Irl(CO2R)(CO)2Y]2 were obtained by the reaction of [Irl(CO)2(Y2)] and [lr(CO)3Y]2 respectively with iodine and alcohols.

Tetranitrosylbis(triphenylphosphine)di-iridium, prepared in high yields by a new method, is characterized by a direct iridium–iridium bond and a strongly distorted tetrahedral co-ordination around each metal atom.