Table 2. Infrared and UV–Vis Absorption Data for [Re(3,3′-DHBPY)(CO)₃Cl] and [Re(3,3′-DHBPY)(CO)₃(PrCN)]⁺ and Their Reduction Products.

complex	solvent	ν(CO) (cm–1)	λmax (nm)
[Re(BPY)(CO)3Cl]	THFa	2019, 1917, 1895
[Re(3,3′-DHBPY)(CO)3Cl]	THF	2018, 1914, 1893	351
	PrCN	2020, 1915, 1897	353
[Re(4,4′-di-tBu-BPY)(CO)3Cl]	DMFb	2018, 1913, 1890
[Re(3,3′-DHBPY-H+)(CO)3Cl]−	THF	2011, 1902, 1886	425
	PrCN	2012, 1903, 1885	426
	THFc	2011, 1902, 1885
	DMFd	2011, 1902, 1882	425
[Re(BPY)(CO)3Cl]•–	THF	1996, 1883, 1868a
		1996, 1882, 1867f	361, 486 sh, 511f
Re(3,3′-DHBPY)(CO)3Cl]•–	THF	1994, 1878, 1866
[Re(4,4′-di-tBu-BPY)(CO)3Cl]•–	DMFb	1992, 1878, 1860
[Re(3,3′-DHBPY-2H+)(CO)3Cl]2–	THFe	2002, 1883, 1873
	PrCNg	2002, 1885, 1867
[Re(3,3′-DHBPY-2H+)(CO)3]3–	THF	1921, 1818 br	354, 553, 654
[Re(3,3′-DHBPY)(CO)3(OTf)]	THF	2032, 1928, 1910
[Re(3,3′-DHBPY)(CO)3(PrCN)]+	PrCN	2039, 1933 br
[Re(BPY)(CO)3(PrCN)]+	PrCNa	2041, 1937 br
[Re(3,3′-DHBPY)(CO)3(PrCN)]	PrCN	2004, 1890 br
[Re(BPY)(CO)3(PrCN)]	PrCNa	2010, 1895 br
[Re(3,3′-DHBPY-H+)(CO)3(PrCN)]	PrCN	2031, 1928 br
[Re(3,3′-DHBPY-2H+)(CO)3(PrCN)]−	PrCNg	2023, unresolved
[Re(3,3′-DHBPY-2H+)(CO)3(PrCN)]2–	PrCN	1986, 1874 br
[Re(3,3′-DHBPY-2H+)(CO)3(PrCN)]3–	PrCN	1967, 1849, 1835
[Re(4,4′-DHBPY)(CO)3Cl]b	DMF	2019, 1911, 1893
[Re(4,4′-DHBPY-H+)(CO)3Cl]−b	DMF	2012, 1900, 1881
[Re(4,4′-DHBPY-2H+)(CO)3Cl]2–b	DMF	2002, 1886, 1865

^aReproduced from ref (24).

^bReported by Fujita and co-workers.⁴⁶

^cFormed by single deprotonation of the parent complex with NaHMDS.

^dFormed by instantaneous deprotonation of the parent complex in DMF.

^eObserved only as a transient in THF in a potential-step experiment.

^fT = 253 K. Reproduced from ref (59).

^gT = 223 K.