Completion of the series of M2(hpp)4Cl2 compounds from W to Pt: the W, Os, and Pt compounds.
The series of M2(hpp)4Cl2 complexes (hpp is the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) from M = W to M = Pt has been completed by the preparation and characterization of those with M = W, Os, and Pt. W(hpp)4Cl2 (1) has a W-W distance of 2.250(2) A, is diamagnetic, and can be assigned a W-W triple bond based on a sigma 2 pi 4 electron configuration. Os2(hpp)4Cl2 (2) has an Os-Os distance of 2.379(2) A and displays a temperature-independent paramagnetism. It can be assigned a sigma 2 pi 4 delta 2 delta*2 configuration. Pt2(hpp)4Cl2 has a Pt-Pt distance of 2.440(1) A and is diamagnetic. A bond order of 1, based on a configuration in which only the sigma* orbital is empty, is consistent with these data.
Clérac
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Department of Chemistry, College of Natural Science, Michigan State University, East Lansing, Michigan 48824, USA.
Cotton
F A
FA
Daniels
L M
LM
Donahue
J P
JP
Murillo
C A
CA
Timmons
D J
DJ