Crystal structures of four new iridium complexes, each containing a highly flexible carbodiphosphorane PCP pincer ligand

Compound [Ir(C8H12)(C51H45P4)](Cl)(2) or [Ir(cod)(CH(dppm)2-kappa P-3,C,P)](Cl)(2) (1a), was obtained from [IrCl(cod)] 2 and the carbodiphosphorane (CDP) salt [CH(dppm)(2)]Cl [where cod = cycloocta-1,5-diene and dppm = bis(diphenylphosphino)methane]. Treatment of 1a with thallium(I) trifluoromethanesulfonate [Tl(OTf)] and subsequent crystallization gave complex [Ir(C8H12)(C51H45P4)](OTf)(2)center dot CH3CO2C2H5 center dot CH2Cl2 or [Ir(cod)(CH(dppm)(2)-kappa P-3,C,P)](OTf)(2)center dot CH3CO2C2H5 center dot CH2Cl2 (1b) [systematic name: (cycloocta-1,5-diene)(1,1,3,3,5,5,7,7-octaphenyl-1,7-diphospha-3,5-diphosphoniaheptan-4-yl)iridium(I)bis(trifluoromethanesulfonate)-ethyl acetate-dichloromethane (1/1/1)]. This five-coordinate iridium(I) complex cation adopts a trigonal-bipyramidal geometry with the CDP carbon and one cod double bond in axial sites. Compound 1b represents the first example of a non-meridional coordination of the PCP pincer ligand [CH(dppm)(2)](+) with a P-Ir-P angle of 98.08 (2)degrees. Compound 2, [Ir(Cl)(2)(H)(C51H44P4)]center dot(CH3)(2)CO or [Ir(Cl)(2)(H)(C(dppm)(2)-kappa P-3,C,P)]center dot(CH3)(2)CO [systematic name: dichloridohydrido(1,1,3,3,5,5,7,7-octaphenyl-1,5 lambda(5),7-triphospha-3-phosphoniahept-4-en-4-yl)iridium(III) acetone monosolvate], crystallizes as an acetone monosolvate. It is a six-coordinate Ir-III coordination compound. Here, the PCP pincer ligand is coordinated in a meridional manner; one chlorido ligand is positioned trans to the carbon donor, the remaining two coordination sites being occupied by the second chlorido and a hydrido ligand trans to each other. Complex 3, [Ir(Cl)(2)(H)(C51H45P4)]Cl center dot 5H(2)O or [Ir(Cl) 2(H)(CH(dppm)(2)-kappa P-3,C,P)]Cl center dot 5H(2)O [systematic name: dichloridohydrido(1,1,3,3,5,5,7,7-octaphenyl-1,7-diphospha3,5-diphosphoniaheptan-4-yl)iridium(III) chloride pentahydrate], represents the conjugate CH acid of 2. The ligand [CH(dppm)(2)](+) is coordinated in a meridional manner. In the cationic six-coordinate Ir-III complex 4, [Ir(Cl)(H)(CO)(C51H44P4)]Cl center dot 2CH(3)OH center dot H2O or [Ir(Cl)(H)(CO)(C(dppm)(2)-kappa P-3,C,P)]Cl center dot 2CH(3)OH center dot H2O [systematic name: carbonylchloridohydrido(1,1,3,3,5,5,7,7-octaphenyl-1,5 lambda(5),7-triphospha-3-phosphoniahept-4-en-4-yl) iridium(III) chloride-methanol-water (1/2/1)], the chlorido ligand is found in the plane defined by the Ir center and the meridional PCP ligand; the H and CO ligands are positioned axially to this plane and trans to each other.