Cyclopentadienylindium(I), C5H5In, is an organoindium compound containing indium in the +1 oxidation state. Commonly abbreviated to CpIn, it is a cyclopentadienyl complex with a half-sandwich structure.
It was the first (1957[1]) low-valent organoindium compound reported.
Solid CpIn is polymeric consisting of zigzag chains of alternating indium atoms and C5H5 units. Two indium atoms interact with the opposite faces of each C5H5− ring, nearly perpendicularly to the ring plane, and two rings interact with each indium atom, forming an angle of about 128°.[5] In the CpIn monomer present in the vapour phase the indium atom sits on the central axis of the aromatic cyclopentadienyl anion, C5H5−.
Bonding studies have shown that the aromatic ring electrons of the cyclopentadienyl anion interact with the indium 5s and 5p atomic orbitals, and that the lone pair on the indium atom is a dominant feature.[6]
^Peppe C.; Tuck D.G.; Victoriano L. (1981). "A simple synthesis of cyclopentadienylindium(I)". J. Chem. Soc., Dalton Trans. 69 (12): 2592. doi:10.1039/DT9810002592.
^Contreras J. G.; Tuck D. G. (1973). "Coordination compounds of indium. XXIII. Adducts of cyclopentadienylindium(I) with boron trihalides or trimethylboron". Inorganic Chemistry. 12 (11): 2596–2599. doi:10.1021/ic50129a021.
^Habeeb J.J.; Tuck D.G. (1976). "Co-ordination compounds of indium. Part XXXI. Further studies of anionic complexes of indium(I)". J. Chem. Soc., Dalton Trans. (10): 866–869. doi:10.1039/DT9760000866.
^Beachley O. T.; Pazik J. C.; Glassman T. E.; Churchill M. R.; Fettinger J.C.; Blom R. (1988). "Synthesis, characterization and structural studies of In(C5H4Me) by x-ray diffraction and electron diffraction techniques and a reinvestigation of the crystalline state of In(C5H5) by x-ray diffraction studies". Organometallics. 7 (5): 1051–1059. doi:10.1021/om00095a007.
^Lin C.S.; Tuck D.G. (1982). "The electronic structure of cyclopentadienylindium". Can. J. Chem. 60 (6): 699–702. doi:10.1139/v82-103.
