[MN(SALPHEN)(ETOH)(2)](BPH(4)) ENH(2)=N,N'-BIS(SALICYLIDENE)-1,2-DIAMINOBENZENE], A FURTHER EXAMPLE OF A PHOTOSYNTHETIC MODEL-COMPOUND FORMING DIMERS LINKED BY HYDROGEN AND PI-BONDS

The title molecule, omethylidyne)diphenolato]-N,N',O,O'}manganese(III) tetraphenylborate, [Mn(C20H14N2O2)(C2H6O)(2)](C24H20B), comprises a p lanar tetradentate Schiff base tightly bound to Mn-III via Mn-N bonds of 1.97 (1) and 1.99 (2) Angstrom, and two Mn-O bonds of 1.85 (1) Angs trom, with capping ethanol groups at the longer Mn-O distances of 2.27 (1) and 2.28 (1) Angstrom completing a distorted octahedral arrangeme nt. Pairs of molecules are linked across inversion centres by hydrogen bonds from the ethanol to the phenoxy O atoms [O...O 2.90 (2) Angstro m], which are augmented by pi-bonds between overlapping phenyl rings, resulting in an Mn Mn separation of 4.995 (6) cf. 5.21 (1) Angstrom fo r the salpn analogue [salpn = N,N'-bis(salicylidene)-1,3-diaminopropan e] [Ashmawy, Beagley, McAuliffe, Parish & Pritchard (1990). J. Chem. S oc. Chem. Commun. pp. 936-937].