Syntheses and crystal structures of [Ir{C(CHCOEt)(dppm)-κ ,,','}ClH]Cl·2.75CHCl and its derivatives, [Ir{C(CHCOEt)(dppm)-κ ,,','}(CHCOEt)Cl]Cl·CHOH·0.5HO, [Ir{C(CHCOEt)(dppm)-κ ,,','}Cl]Cl·CHOH·2HO and [Ir{C(CHCOEt)(dppm)-κ ,,','}(CHCOEt)(CO)]Cl·2CHCl·1.5HO.

The common feature of the four iridium(III) salt complexes, (bis-{[(di-phenyl-phosphan-yl)meth-yl]di-phenyl-phosphanyl-idene}(eth-oxy-oxoethanyl-idene)methane-κ ,,',')chlorido-hydridoiridium(III) chloride methyl-ene chloride 2.75-solvate (), (bis-{[(di-phenyl-phosphan-yl)meth-yl]di-phenyl-phosphanyl-idene}(eth-oxy-oxoethanyl-idene)methane-κ ,,',')chlorido-(eth-oxy-oxoethanido)iridium(III) chloride-methanol-water (1/1/0.5) (), (bis-{[(di-phenyl-phosphan-yl)meth-yl]di-phenyl-phosphanyl-idene}(eth-oxy-oxoethanyl-idene)methane-κ ,,',')di-chlorido-iridium(III) chloride-methanol-water (1/1/2) () and (bis-{[(di-phenyl-phosphan-yl)meth-yl]di-phenyl-phosphanyl-idene}(eth-oxy-oxoethanyl-idene)methane-κ ,,',')carbon-yl(eth-oxy-oxoethanide)iridium(III) dichloride-meth-yl-ene chloride-water (1/2/1.5) or in terms of their formulae [Ir(CHOP)ClH]Cl·2.75CHCl (), [Ir(CHO)(CHOP)Cl]Cl·CHOH·0.5HO (), [Ir(CHOP)Cl]Cl·CHOH·2HO () and [Ir(CHO)(CHOP)(CO)]Cl·2CHCl·1.5HO () is a central Ir atom coordin-ated in a distorted octa-hedral fashion by a PCCP ligand system and two additional residues, such as chlorides, a hydride, a carbonyl or an alkyl unit. Thereby, the PCP pincer ligand system and the residue to the carbodi-phospho-rane (CDP) C atom surround the iridium(III) transition metal in the equatorial plane under the formation of two five-membered dissimilar chelate rings [C-C-P (, , and ) for the first ring: 120.2 (3), 121.9 (5), 111.2 (3) and 121.7 (2) °; for the second ring: 112.1 (3), 113.5 (5), 120.5 (3) and 108.3 (2)°]. A cyclo-propane-like heterocycle is positioned approximately orthogonal (84.21-88.85°) to the equatorial plane, including an alkyl-idene bridge connecting the Ir atom and the coordinating CDP atom of the PCP subunit. In general, the neutral PCCP ligand system coordinates the metal in a tetra-dentate way via three Lewis acid/base bonds and by an alkyl-idene unit presenting strengthened inter-actions. In all the crystal structures, (disordered) solvent mol-ecules are present in the voids of the packed mol-ecules that inter-act with the positively charged complex and its chloride counter-ion(s) through weak hydrogen bonding.