RPTR STATES LOST STANDARD SEPARATION BTWN ACFT X AND ACFT Y AS HE ATTEMPTED TO KEEP THEM APART.

Narrative

ZNY (EMIH) REQUESTED THAT I (ZDC; POT-H; R04) TAKE ACFT X (SWBOUND ON J75) AT FL370 WRONG ALT FOR DIRECTION; WHICH I APPROVED. I REQUESTED THE SAME FROM SHD-H R72 AND WAS TOLD UNABLE; THEY NEEDED HIM AT RIGHT ALT FOR DIRECTION. AT TIME OF HDOF; THERE WAS A FL350 IN CLOSE TO ACFT X; ALSO ZNY DID NOT XFER COM UNTIL REPEATED REQUESTS WERE MADE AND ACFT X WAS 40-50 MI IN MY SECTOR. WHEN ACFT X CAME ON MY FREQ; I ASKED IF HE COULD ACCEPT FL390; HE REPLIED NEGATIVE. SO I CLRED HIM TO MAKE 360 DEG TURN TO R AND I WOULD HAVE LOWER SHORTLY ONCE CLR OF LOWER TFC. I DSNDED ACFT X TO FL350; ACFT Y WAS AT THIS TIME 60-70 MI NE AT FL350. I ASKED ACFT X TO MAKE TIGHT TURN AND DSND TO FL330. ACFT X WAS VERY SLOW IN HIS DSCNT AND SLOWER IN HIS TURN. ACFT Y WAS GIVEN R TURN TO 270 DEGS; LATER 20 SECONDS TO 300 DEGS; LATER TO 330 DEGS -- STILL AT FL350. CALLED TFC. ACFT Y RPTED TFC IN SIGHT. ACFT X STILL SLOW IN TURN AND VERY SLOW IN DSCNT. LOSS OF SEPARATION OCCURRED SHORTLY THEREAFTER. ACFT X STILL NOT LEVEL AT FL330. HAD TO CLB ANOTHER ACFT TO FL360 TO INSURE 2000 FT SEPARATION. TCASII ALERT OCCURRED FOR ACFT X WITH ACFT Y.