Hydrogen and covalent bonding in H2BHX and H2BXH (XÂ =Â CN and NC) dimers and cooperative effect in H2BHXHX and H2BXHXH trimers

► Hydrogen bond between H2B and HX (X = CN and NC) in dimers. ► Covalent bonding between H2B and HX (X = CN and NC) in dimers. ► Cooperativity in H2BHCNHCN and H2BHNCHNC trimers. ► Cooperativity in H2BCHNCH and H2BCNHCNH trimers.