This progression lends itself to a variety of interpretations, all similar, but varying in technical detail. This progression, even more so than others, is highly dependent on context -- chord voicings, melody, and what happens before and after.
ii7 - i (F#7b5 - E minor)
ii moving to i as a cadence does not itself have a specific name.
However, it is related to a plagal cadence, iv - i. Although not a plagal cadence it provides a similar sound. And iv - i is built in: the iv chord =
A C E, and the ii7 chord is the same but with the addition of
F#. We could consider the chord as
Am6 rather than
A somewhat different interpretation comes into play if the E minor chord is voiced with
B as the lowest pitch. In that case, it might be considered a "cadential 6-4 chord", heading toward the V chord at the end of the progression.
vidim - Vsus4
vi moving to V also doesn't have a special name. The usual interpretation is that vi is functioning as a predominant moving to the dominant.
However, the "vi dim" chord "doesn't exist." That is, a diminished chord built on the sixth scale degree,
C, would be spelled
C Eb Gb, with the latter three tones being alien to
Instead, I think one of two things is happening:
Cdim is actually
D#dim7 with the fifth omitted. That makes the chord
E minor. The reason, then, it sounds like a cadence moving to
Vsus4 is that
Vsus4 is actually
Vsus4 = BEF#, and
EF#B: i.e., it is, in fact, a cadence ending on the (ambiguous)
- Also possible is that both the "C diminished" chord and the "B sus4" chords are a single chord:
B7b9sus4(omit7). Written in root position, this chord doesn't appear to make sense:
BD#EF#C. But with better voicing -- for example,
EBD#F#C -- it becomes a
V chord with the
E anticipating the (unresolved) resolution to
Emin. This is very Mozartean, placing the tonic below a dominant chord (before proceeding to the tonic chord). (Note: in Mozart's case, the "dominant over tonic" chord is likely a suspension from an actual dominant, where the bass resolves first followed by a delayed resolution of the rest of the chord.)
The progression is solidly in E minor and uses pitches only from the E harmonic minor scale. However, it's an ambiguous E minor due to the absence of a strong cadence confirming the key.