Table 1. Selected Infrared Vibrational Frequencies for [Mn(CNdippPh^OMe2)₆]PF₆ (Red Marked Frequencies in Figure 2) in Comparison with DFT Calculated Frequencies (PBEh-3c/def2-mSVP(C,H,N,O)/def2-mTZVP(Mn))^a Scaled by a Factor of 0.95^148,b.

complex	mode	IRexpc (cm–1)	IRDFT (cm–1)
[Mn(CNdippPhOMe2)6]PF6	υ(C≡N) T1u	2070	2176 (2973), 2181 (2863), 2184 (1231)d and 2184 (2134)d
	υ(C≡N) Eg		2184 (1231),d 2184 (2134)d and 2188 (218)
	υ(C≡N) A1g		2261 (1.07)
	PF6–	834
	υ(Mn–C) T1u	789	789.72 (118), 789.77 (121) and 790.38 (118)
	υ(Mn–C) Eg		792.46 (0.29) and 792.70 (1.66)
	υ(Mn–C) A1g		793.12 (0.71)
	δ(C–Mn–C) and δ(Mn–C≡N) T1u	586	599.57 (99), 601.19 (169), 608.21 (41), 610.13 (168), 613.87 (91) and 618.43 (131)
[Mn(Ltri)2]PF653 e	υ(C≡N) T1u	2081
	Mn–C	584
[Mn(Lbi)3]PF653 f	υ(C≡N) T1u	2064
	Mn–C	568
[Mn(CNPh)6]PF646	υ(C≡N) T1u	2088 (vs)
	PF6–	840 (m)
[Mn(CNPh)6]I/Br/Cl46	υ(C≡N) T1u	2088 (vs)
[Mn(CNPh)6]Cl52	υ(C≡N) T1u	2080g
[Mn(CNPh)6]BF4171	υ(C≡N) T1u	2084
[Mn(CNPh)6]I177	υ(C≡N) T1uh	2085 (vs) and 1993 (sh)
	υ(N(isocyanide)-C(pheny)) T1uh	1210
	δ(Mn–C≡N) T1uh	600 (vs)
	υ(Mn–C) T1uh	297 and 319 (multiplet)i
	δ(C–Mn–C) T1uh	113 (w)

^aThe intensities of the vibrational frequencies obtained from DFT calculations (PBEh-3c/def2-mSVP(C,H,N,O)/def2-mTZVP(Mn)) are indicated in parentheses. (Abbreviations: bend., bending; str., stretching; ip, in-plane).

^bIR data from previously reported comparable compounds are included for comparison.

^cof the solid state.

^dOne T_1u and E_g modes are mixed together at 2184 cm^–1 leading to two IR observable modes.

^eL^tri = 5,5′-(2-isocyano-5-methyl-1,3-phenylene)bis(2-(3,5-di-tert-butyl-2-isocyanophenyl)thiophene).

^fL^bi = 2,5-bis(3,5-di-tert-butyl-2-isocyanophenyl)thiophene.

^gThe peak shows a shoulder at lower wavenumbers.⁵²

^hApproximated local symmetry O_h.¹⁷⁷

ⁱDue to a breakdown of the T_1u degeneracy.¹⁷⁷